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1. WO2020222692 - METHODS AND APPARATUS RELATING TO HANDOVER IN A WIRELESS COMMUNICATION NETWORK

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[ EN ]

METHODS AND APPARATUS RELATING TO HANDOVER IN A WIRELESS

COMMUNICATION NETWORK

Technical field

Embodiments of the disclosure relate to wireless communications, and particularly relate to methods and apparatus relating to handover in a wireless communication network.

Background

Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

Wireless communication systems in 3GPP

Consider the simplified wireless communication system illustrated in Figure 1, in which a User Equipment

(UE) 102 communicates with one or multiple access nodes 103-104 using radio connections 107-108. The access nodes 103-104 are connected to a network node 106. The access nodes 103-104 are part of the radio access network 100.

For wireless communication systems pursuant to the 3rd Generation Partnership Project (3GPP) Evolved Packet System (EPS) standard specifications, also referred to as Long Term Evolution (LTE) or 4G, such as those specified in 3GPP TS 36.300, v 15.5.0 and related specifications, the access nodes 103-104 correspond typically to an Evolved NodeB (eNB) and the network node 106 corresponds typically to a Mobility Management Entity (MME) and/or a Serving Gateway (SGW). The eNB is part of the radio access network 100, which in this case is the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), while the MME and SGW are both part of the Evolved Packet Core (EPC) network.

For wireless communication systems pursuant to 3GPP 5G System (5GS) standard specifications, also referred to as New Radio (NR) or 5G, such as those specified in 3GPP TS 38.300, v 15.5.0 and related specifications, the access nodes 103-104 correspond typically to a 5G NodeB (gNB) and the network node 106 corresponds typically to either an Access and Mobility Management Function (AMF) and/or a User Plane Function

(UPF). The gNB is part of the radio access network 100, which in this case is the Next Generation Radio Access Network (NG-RAN), while the AMF and UPF are both part of the 5G Core Network (5GC). The gNB is sometimes referred to as an NG-RAN node.

To support fast mobility between NR and LTE and avoid change of core network, LTE eNBs can also be connected to the 5GC via the NG-U/NG-C interface(s) and support the Xn interface. An eNB connected to 5GC is called a next generation eNB (ng-eNB) and is considered part of the NG-RAN. LTE eNBs connected to 5GC will not be discussed further in this document; however, it should be noted that the solutions/features described for LTE and NR in this document also apply to LTE eNBs connected to 5GC. In this document, when the term LTE is used without further specification, it refers to LTE-Evolved Packet Core (EPC).

Mobility in RRC_CONNECTED in LTE and NR

Mobility in RRC_CONNECTED state is also known as handover. The purpose of handover is to move the UE 102, due to e.g. mobility, from a source access node 103, using a source radio connection 107, to a target access node 104, using a target radio connection 108. The source radio connection 107 is associated with a source cell controlled by the source access node 103. The target radio connection 108 is associated with a target cell controlled by the target access node 104. So in other words, during a handover, the UE 102 moves from the source cell to a target cell. Sometimes the source access node or the source cell is referred to as the“source”, and the target access node or the target cell is sometimes referred to as the“target”.

In some cases, the source access node 103 and target access node 104 are different nodes, such as different eNBs or gNBs. These cases are also referred to as inter-node handover, inter-eNB handover or inter-gNB handover. In other cases, the source access node 103 and target access node 104 are the same node, such as the same eNB and gNB. These cases are also referred to as intra-node handover, intra-eNB handover or intra-gNB handover and cover the case when source and target cells are controlled by the same access node. In yet further cases, handover is performed within the same cell (and thus also within the same access node controlling that cell) - these cases are also referred to as intra-cell handover.

It should therefore be understood that the terms“source access node” and“target access node” refer to a role served by a given access node during a handover of a specific UE. For example, a given access node may serve as source access node during handover of one UE, while it also serves as the target access node during handover of a different UE. And, in case of an intra-node or intra-cell handover of a given UE, the same access node serves both as the source access node and target access node for that UE.

An RRC_CONNECTED UE in E-UTRAN or NG-RAN can be configured by the network to perform measurements of serving and neighbor cells. Based on the measurement reports sent by the UE, the network may decide to perform a handover of the UE to a neighbor cell. The network then sends a Flandover Command message to the UE (in LTE an RRConnectionReconfiguration message with a field called mobilityControllnfo and in NR an RRCReconfigu ration message with a reconfigurationWithSync Md).

These reconfigurations are typically prepared by the target access node upon a request from the source access node (over X2 or S1 interface in case of EUTRA-EPC or Xn or NG interface in case of NG-RAN-5GC) and take into account the existing RRC configuration and UE capabilities as provided in the request from the source access node and its own capabilities and resource situation in the intended target cell and target access node. The reconfiguration parameters provided by the target access node contain, for example, information needed by the UE to access the target access node, e.g., random access configuration, a new Cell Radio Network Temporary Identifier (C-RNTI) or other identifier assigned by the target access node and security parameters enabling the UE to calculate new security keys associated with the target access node so the UE can send a Handover Complete message on Signalling Radio Bearer SRB1 (encrypted and integrity protected) based on new security keys upon accessing the target access node.

Figures 2a and 2b summarize the signaling flow between UE, source access node 103 (also known as source gNB, source eNB or source cell) and target access node 104 (also known as target gNB, target eNB or target cell) during a handover procedure, using 5G/NR as an example. The signaling also shows the AMF and UPF(s).

Initially, user data is exchanged between UE and source gNB, and between source gNB and UPF. Steps

200-205 of Figures 2a are a handover preparation stage. In step 200 of Figure 2a, Mobility Control Information is provided by AMF to source gNB. In step 201 , measurement control and reports are exchanged between UE and source gNB. In step 202, the source gNB makes a handover (HO) decision. In step 203, source gNB sends a handover request to a target gNB. In step 204, target gNB performs admission control. In step 205, target gNB sends a Handover (HO) request acknowledge to source gNB. Steps 206-208 are a handover execution stage. In step 206, Uu handover trigger information is exchanged between source gNB and UE. The UE detaches from the old cell and synchronises to the new cell. In step 207, source gNB sends SN status transfer to target gNB, and delivers buffered and in transit user data to target gNB. The source gNB may also forward user data to target gNB. The target gNB buffers user data from source gNB. In step 208, the UE synchronises to the new cell (target gNB) and completes the RRC HO procedure. User data may then be exchanged between UE and target gNB. User data may be forwarded from target gNB to UPF. Steps 209-212 are a handover completion stage. In step 209, target gNB sends a path switch request to AMF. In step 210, AMF and UPF(s) exchange path switch related 5G CN internal signalling and actual downlink (DL) path switch is performed in UPF(s). User data may then be exchanged between target gNB and UPF. In step 211 , AMF returns a path switch request acknowledgment to the target gNB. In step 212, target gNB sends a UE context release to source gNB.

Although the signaling flow in Figures 2a and 2b shows a handover scenario in 5G/NR, there are some common principles for a UE performing handover (or in more general terms, mobility in RRC_CONNECTED) in LTE and NR:

- Mobility in RRC_CONNECTED is network-controlled as the network has the best information regarding the current situation such as load conditions, resources in different nodes, available frequencies, etc.

The network can also take into account the impact from other UEs served by the network, e.g. from a resource allocation perspective.

The network prepares a target cell controlled by the target access node before the UE accesses that access node. Source access node provides the UE with the Radio Resource Control (RRC) configuration to be used in the target cell, including SRB1 configuration to be used by the UE when sending the HO Complete message in the target cell.

The UE is provided by the target access node with a C-RNTI. The UE identifies itself by conveying the C-RNTI in MSG3. Hence, there is no context fetching between target access node and source access node, unless a failure occurs.

To speed up the handover, the network provides the UE with information as to how to access the target access node e.g. Random Access Channel (RACH) configuration, so the UE does not have to acquire system information (SI) prior to the handover.

The UE may be provided with contention-free random access (CFRA) resources, i.e. in that case the target access node identifies the UE from the preamble in MSG1. The principle is that the handover procedure can always be optimized with network pre-allocated resources

Security is prepared before the UE accesses the target cell controlled by the target access node i.e. keys are refreshed before sending the encrypted and integrity protected HO Complete message (in LTE the RRC Connection Reconfiguration Complete message) so that the UE can be verified by the target access node.

Both full and delta reconfiguration are supported so that the HO command can be minimized.

Make-Before-Break Rel- 14

Handover interruption time is typically defined as the time from when the UE stops transmission/reception with the source access node 103 (eNB/gNB) until the target access node 104 (eNB/gNB) resumes transmission/reception with the UE.

In LTE pre-Rel-14, according to 3GPP TR 36.881, v 14.0.0, the handover interruption time is at least 45 ms. In LTE and NR, different solutions to decrease the handover interruption time have since been discussed. Improvements are driven for example by new service requirements on low latency (e.g. aerial, industrial automation, industrial control) for which low interruption time shall be guaranteed.

As an example of one such improvement, Make-Before-Break (MBB) was introduced in LTE Rel-14 in purpose to shorten handover interruption time as close to 0ms as possible. See Figures 3a to 3c.

The signaling begins in step 300, in which the source eNB and target eNB are configured with handover restriction lists, enabling them to restrict user UEs from participating in specified handovers. In step 301 the source eNB configures the UE to perform certain radio measurements, and thereafter packet data is transferred between the UE and the source eNB, and between the source eNB and the serving gateway. The source eNB provides the

UE with an allocation of radio resources, which are used by the UE in step 302 to transmit measurement reports. In step 303, the source eNB makes a decision, based on the measurement reports, to handover the UE to the target eNB. In step 304, the source eNB transmits a handover request message to the target eNB. The target eNB receives the handover request message and, in step 305, performs admission control to determine whether or not to admit the UE. In step 306, the target eNB transmits an acknowledgement of the handover request message to the source eNB. In step 307, after allocating downlink radio resources to the UE, the source eNB transmits an RRC Connection Reconfiguration message to the UE, comprising mobility control information and a makeBeforeBreak information element (IE). Thereafter, the UE calculates a pre-allocated grant of uplink radio resources, if provided via the RRC signaling, while packet data is still transmitted between the UE and the source eNB. The UE detaches from the old cell (i.e., the source eNB) and starts to synchronize to the new cell (i.e., the target eNB). User data transmitted to or received from the old cell stops at this point. In step 308, the source eNB transmits a sequence number (SN) in the SN Status Transfer message to the target eNB, and the source eNB starts to deliver buffered and in-transit packets for the UE to the target eNB. New data arriving from the UPF is also forwarded from the source eNB to the target eNB. The target eNB buffers the packets received from the source eNB. In step 309, the UE synchronizes to the target eNB. In step 310, the UE receives an allocation of uplink radio resources and a timing advance; or, alternatively in step 310a receives an allocation of periodic uplink radio resources. In step 31 1 , the UE transmits an RRC Connection Reconfiguration Complete message to the target eNB, and at that point user data can be transmitted via the new cell; thus, packet data is transmitted between the UE and the target eNB, and from the target eNB to the serving gateway. In step 312, the target eNB transmits a path switch request to the MME, and in step 313 the MME transmits a Modify Bearer Request message to the serving gateway. In step 314, the serving gateway switches the downlink path for user data from the source eNB to the target eNB, and transmits an end marker to the source eNB. Packet data thereafter is transmitted between the target eNB and the serving gateway. The source eNB forwards the end marker to the target eNB. In step 315, the serving gateway transmits a Modify Bearer Response message to the MME, and in step 316 the MME transmits an acknowledgement of the path switch request message to the target eNB. In step 317, the target eNB transmits a UE context release message to the source eNB, and in step 318 the source eNB releases resources for the UE.

The MBB handover procedure as introduced in LTE Rel-14 refers to a handover mechanism where the UE connects to the target cell before disconnecting from the source cell, unlike the standard handover procedure where the UE resets MAC and re-establishes Packet Data Convergence Protocol (PDCP) upon receiving the HO Command message (RRCConnectionReconfiguration message with mobilityControllnfo) in the source cell. In the MBB solution, the connection to the source cell is maintained after the reception of RRCConnectionReconfiguration message (with the makeBeforeBreak information element (IE) present in the mobilityControllnfo) until the UE executes initial uplink transmission in the target cell, i.e. Medium Access Control (MAC) and Packet Data Convergence Protocol (PDCP) reset is delayed in the UE until the UE performs random-access in the target cell. It is up to UE implementation when to stop the uplink transmission/downlink reception with the source cell to initiate re-tuning for connection to the target cell.

At the point when the source eNB has stopped transmission/reception to/from the UE, the source eNB sends the SN STATUS TRANSFER message (step 308) to the target eNB to convey the uplink PDCP sequence number (SN) receiver status and the downlink PDCP SN transmitter status of the radio bearers for which PDCP status preservation applies.

MBB as specified in LTE Rel-14 (3GPP TS 36.300, v 14.9.1 and TS 36.331 , v 14.10.0) has some known limitations. Even if MBB and other improvements such as RACH-less handover are combined it is still not possible to reach ~0ms handover interruption time. MBB in Rel-14 is designed for UEs with a single Tx/Rx chain which means that MBB in practice only supports intra-frequency handover. In an intra-frequency handover scenario, a single Rx UE is capable of receiving DL data from both target and source cell. However, a single Tx UE will not be able to transmit to both cells simultaneously. Thus, in MBB Rel-14, the UE will release the connection to the source cell at the first UL transmission. This occurs when the UE transmits the RACH preamble; or transmits the HO Complete message (if RACH-less HO is configured).

Consequently, the UE releases the connection with the source cell before the connection with the target cell is ready for packet transmission/reception.

Enhanced Make-Before-Break

Two new work items for mobility enhancements in LTE and NR have started in 3GPP in release 16. The main objectives of the work items are to improve the robustness at handover and to further decrease the interruption time at handover.

Improvements to the LTE Rel-14 make-before-break handover have been proposed in the past. Some of these improvements would benefit from UEs with dual Tx/Rx radio chain (such a UE has dual radio transmitters and receivers and associated dual user plane protocol stacks). One example of such a proposed improvement for LTE Rel-16 is shown in Figures 4a and 4b.

The key steps to support 0ms HO interruption time by means of Enhanced MBB procedure are as follows:

Step 401 : After exchanging UL and DL packet data, the UE transmits measurement reports to the source eNB.

Step 402: Based on the measurement reports, the source eNB decides to handover the UE to a target eNB, and transmits a handover request message to the target eNB.

Step 403, the target eNB acknowledges the handover request message to the source eNB.

Step 404: Source eNB sends Handover Command (i.e. RRCConnectionReconfiguration message with mobilityControllnfo) to the UE, containing an indicator (e.g. enhanced MBB indicator) to perform 0ms HO interruption.

Step 405: Source eNB starts forwarding DL PDCP packets to the target eNB and continues to send and receive PDCP packets to/from the UE (step 407). DL PDCP packets forwarded from source eNB are buffered in the target eNB.

Step 406: UE starts synchronizing with the target cell, while keeping its connection with the source cell.

Step 407: Packet data is still sent and received via the source cell.

Step 408: UE performs random-access in the target cell and target eNB schedules uplink resources. Step 409: UE sends RRCConnectionReconfigurationComplete message in the target cell. The target eNB can now start sending PDCP packets to the UE, while at the same time the source eNB may continue to send PDCP packets to the UE. From this point in time the UE only sends UL data via the target cell. In order to assist the target eNB with PDCP duplication check, the UE may convey a PDCP status report in the RRCConnectionReconfigurationComplete message. Based on the information in the PDCP Status Report, the target eNB will only send PDCP packets to the UE that were not received by the UE in the source cell.

Step 410: The UE distinguishes PDCP packets received from source and target cells.

Step 411 : Source eNB sends an SN Status Transfer message to the target eNB when the transmission/reception to/from the UE has ended, indicating the uplink PDCP Sequence Number (SN) and Hyper Frame Number (HFN) receiver status and the downlink PDCP SN and HFN transmitter status for COUNT preservation.

Step 412: UE detaches from the source cell when the connection procedure to the target cell is completed.

Step 413: Target eNB informs source eNB to release UE Context.

3GPP discussions on enhanced make-before-break for LTE and NR are currently ongoing.

Summary

There currently exist certain challenge(s). For enhanced make-before-break handover, one problem is at which point the UE 102 should release the source radio connection 107 to the source access node 103. Several alternative proposals are being discussed, such as the UE keeping the source radio connection 107 until an RRC message is received from the target access node 104, which is used to trigger the release of this source radio connection 107. Another proposal is that the UE should release the source radio connection 107 when it starts receiving or transmitting data packets to/from the target access node 104.

During enhanced make-before-break handover, the UE 102 has the possibility to transmit uplink data and to receive downlink data to/from the source access node 103 even after the target radio connection 108 to the target access node 104 has been established. In other words, the UE continues to send UL PDCP Protocol Data Units (PDUs) to the source access node 103 (and receive DL PDCP PDUs from the source access node 103) after receiving the Handover Command, and until it has completed the handover to the target access node 104.

In the source access node 103, there are two alternative solutions for handling the UL PDCP PDUs after the Handover Command has been sent to the UE:

• The source access node 103 continues to send UL PDCP Service Data Units (SDUs) to the Serving Gateway (SGW) on the old S1-U path (as before sending the Handover Command to the UE) until the “end marker” packet is received from the SGW (as a result of the DL path switch request triggered by the target access node 104), or

· the source access node 103 starts forwarding UL PDCP SDUs to the target access node 104 for further transmission to the SGW on the new S1-U path.

For the enhanced make-before-break solution depicted in Figures 4a and 4b, the source access node 103 sends an SN Status Transfer message to the target access node 104 to convey DL PDCP SN transmitter status and UL PDCP SN receiver status (as well as HFN DL and UL status for COUNT preservation in the target access node 104) of radio access bearers for which PDCP status preservation applies when the UE has released the source radio connection 107 and thus has sent the last uplink packet to the source access node 103.

One problem with the enhanced make-before-break solution depicted in Figures 4a and 4b, when the source access node continues to send UL PDCP SDUs to the SGW on the old S1-U path, is how the source access node 103 becomes aware that the UE 102 has released the source connection and/or has sent the last uplink packet to the source access node 103 and thus when to send the SN Status T ransfer message to the target access node 104.

One possible solution is that the source access node 103 sends a first SN Status Transfer message to the target access node 104, and if additional UL packets are received from the UE 102, sends additional SN Status Transfer message(s). The problem with this solution is that many SN status transfer messages may need to be sent, potentially as many as one per UL packet. It is also difficult for the target access node to determine if a received SN status transfer message is the last one or if more are coming. If the target access node mistakes a received SN status transfer message to be the last one, it may result in the target access node forwarding a received uplink packet to the SGW which has already been received and forwarded by the source access node. This would result in the uplink endpoint receiving the same uplink packet twice which could have adverse/unexpected effects.

Another possible solution is that the SN STATUS TRANSFER message may be sent in dependence on autonomous detection by the source access node 103 that the UE is no longer connected to it, e.g. by missing MAC HARQ or RLC ARQ feedback when sending a DL PDCP PDU to the UE 102. The problem with this solution is that the sending of the SN STATUS TRANSFER message may be delayed due to the repeated transmissions of DL PDCP PDUs (i.e. before the source access node 103 understands that the UE 102 in fact has released the connection), or due to more frequent uplink data than downlink data. If the source access node 103 has no DL data to send to the UE 102, then the source access node 103 will not discover that the UE 102 has released the source radio connection 107. Delaying the transmission of the SN STATUS TRANSFER message may cause an interruption in the UL data flow since the target access node 104 cannot process the UL PDCP data received from the UE 102 in the target cell before the UL PDCP SN receiver status and the HFN UL status are received from the source access node 103. Another disadvantage is that transmission resources in the source access node 103 will be tied up in vain.

Another possible solution is to send the SN STATUS TRANSFER message at reception of the“end marker” packet in the source access node 103 (an“end marker” packet may be received from the SGW as a result of the DL path switch request triggered by the target access node 104— see step 314 in Figure 3b). Flowever, it is expected that the "end marker” packet will be received by the source access node 103 very late in the Flandover Completion phase which will delay the sending of the SN STATUS TRANSFER message.

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. In one aspect, the target access node 104 sends a new message over X2/Xn (e.g. a“Flandover Request Complete” message) to the source access node 103 to indicate that the UE has completed the handover, i.e. the UE 102 has successfully connected to the target access node 104 and no further UL PDCP PDUs will be sent to the source access node 103. When the source access node 103 receives the“Flandover Request Complete” message over X2/Xn, it is explicitly informed that the UE 102 will not send any more UL PDCP PDUs to the source access node 103, thus the source access node 103 can send the SN Status Transfer message to the target access node 104 conveying the UL PDCP SN receiver status and the HFN UL status.

There are, proposed herein, various embodiments which address one or more of the issues disclosed herein.

One aspect of the disclosure provides a method performed by a target base station for handover of a wireless device from a source base station. The method comprises: causing transmission, to the source base station, of a first message comprising an indication that a connection between the wireless device and the target base station has been established.

Apparatus for performing this method is also provided. For example, one aspect provides a base station, comprising: processing circuitry configured to cause the base station, when configured as a target base station for handover of a wireless device from a source base station, to cause transmission, to the source base station, of a first message comprising an indication that a connection between the wireless device and the target base station has been established; and power supply circuitry configured to supply power to the base station.

A further aspect of the disclosure provides a method performed by a source base station for handover of a wireless device from the source base station to a target base station. The method comprises: receiving, from the target base station, a first message comprising an indication that a connection between the wireless device and the target base station has been established.

Apparatus for performing this method is also provided. For example, one aspect provides a base station, comprising: processing circuitry configured to cause the base station, when configured as a source base station for handover of a wireless device from the source base station to a target base station, to receive, from the target base station, a first message comprising an indication that a connection between the wireless device and the target base station has been established; and power supply circuitry configured to supply power to the base station.

Certain embodiments may provide one or more of the following technical advantage(s). Embodiments of the disclosure reduce the amount of signaling messages since only one SN Status Transfer message needs to be sent to the target node to convey the uplink PDCP SN receiver status and the HFN UL status of the radio bearers for which PDCP status preservation applies.

The solution also minimizes the likelihood of the same uplink packet being sent twice which could have adverse/unexpected effects at the receiving end point.

Some embodiments reduce the handover interruption time since the SN Status Transfer message is sent at the right point in time without unnecessary delay. The solution will also contribute to better utilization of transmission resources in the source access node.

Brief description of the drawings

Figure 1 shows a simplified wireless communication system.

Figures 2a and 2b show a signaling flow for handover in 5G or NR.

Figures 3a to 3c show a make-before-break procedure according to LTE Release 14.

Figures 4a and 4b shows a proposed signaling flow for enhanced MBB procedure to support 0 ms handover interruption time.

Figures 5a and 5b show a signaling flow according to embodiments of the disclosure.

Figure 6 shows a wireless network in accordance with some embodiments.

Figure 7 shows a user equipment in accordance with some embodiments.

Figure 8 shows a virtualization environment in accordance with some embodiments.

Figure 9 shows a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments.

Figure 10 shows a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments.

Figures 11 to 14 shows methods implemented in a communication system including a host computer, a base station and a user equipment in accordance with some embodiments.

Figure 15 is a flowchart of a method performed by a target access node according to embodiments of the disclosure.

Figure 16 shows a virtualization apparatus in accordance with some embodiments.

Figure 17 is a flowchart of a method performed by a source access node according to embodiments of the disclosure.

Figure 18 shows a virtualization apparatus in accordance with some embodiments.

Figure 19 is a flowchart of a method performed by a user equipment according to embodiments of the disclosure.

Figure 20 shows a virtualization apparatus in accordance with some embodiments.

Detailed description

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. Additional information may also be found in the document(s) provided in the Appendix.

Figures 5a and 5b show a sequence diagram of a handover according to one embodiment of the disclosure. For the purposes of illustration, LTE and the components of the network shown in Figure 1 are used as an example. The access nodes 103 and 104 therefore correspond to eNBs and the network node 106 corresponds to an SGW or an MME. It should be understood that a similar solution can be used for NR (whereby the access nodes 103 and 104 correspond to gNBs and the network node 106 corresponds to an AMF or a UPF). In some embodiments, the UE 102 may correspond to the wireless device 610 or the UE 700 described below with respect to Figures 6 and 7. The access nodes 103 and 104 may correspond to the network nodes 660 described below with respect to Figure 6.

Prior to handover, uplink and downlink packet data is transmitted between the UE 102 and the source access node 103, and also between the source access node 103 and the network node 106.

Steps 501-502: The source access node 103 decides to request handover with enhanced MBB, thus a FIANDOVER REQUEST message with an eMBB (enhanced make before break) indicator is sent to the target access node 104.

Steps 503-505: The target access node 104 performs admission control and generates the

RRCConnectionReconfiguration message (also known as Flandover Command) to be sent by the source access node 103 to the UE 102. The presence of an eMBB indicator in the RRC message serves as a request to the UE 102 to perform a handover with enhanced MBB. If some MBB Rel-16 specific interaction is needed between the source access node 103 and the target access node 104 (e.g. early sending of the SN STATUS TRANSFER message, see step 506 below), the source access node 103 may need to know whether the target access node 104 supports enhanced MBB for each individual handover request. For that purpose, an“eMBB support indicator” (or similar) may be included in the FIANDOVER REQUEST ACK message. Consequently, if the target access node 104 does not support enhanced MBB for this specific handover request, a fallback to a legacy handover (or legacy MBB as defined in Rel-14) is possible.

Steps 506-507 : The source access node 103 applies early start of DL data forwarding to the target access node 104 while it continues to send and receive PDCP PDUs to/from the UE 102. Flowever, the exact time at which the source access node 103 starts DL data forwarding may vary according to the implementation.

The SN Status Transfer message is sent to convey the SN of the first forwarded DL PDCP SDU as well as the HFN DL status for COUNT preservation in the target access node 104.

Forwarding of DL PDCP SDUs continues until the“end marker” packet is received from the SGW on the old path as a result of the DL path switch request triggered by the target access node 104.

The source access node 103 continues to send UL PDCP SDUs to the SGW on the old S1-U path until the“end marker” packet is received from the SGW.

Steps 508-509: UE 102 starts to synchronize with the target cell while it continues to receive and transmit packet data in the source cell. UE 102 performs random-access in the target cell and target access node 104 schedules uplink resources.

Steps 510-511 : In order to assist the target access node 104 with PDCP duplication check, the UE

102 sends a PDCP Status Report for each RLC-AM bearer configured to the UE 102. The PDCP Status Report may be sent either together with the RRCConnectionReconfigurationComplete (Handover Complete) message (multiplexed on MAC level if the provided UL grant is sufficiently large) or immediately after the RRC message. Based on the First Missing SDU (FMS) field (i.e., the first missing PDCP SN) in the PDCP Status Report, the target access node 104 may start sending DL PDCP PDUs to the UE from the first missing PDCP SN (i.e. from the last PDCP SN +1 received in the source cell) whereby sending of duplicated packets over the radio interface is avoided.

If a bitmap is present in the PDCP Status Report indicating one or more PDCP SDUs stored out-of-sequence in the UE, then the PDCP PDUs of the missing SNs may be delivered by the target access node 104.

Step 512: At the point when completing the random-access procedure or when receiving the RLC ACK for the RRCConnectionReconfigurationComplete message, the UE 102 stops sending UL PDCP PDUs in the source cell. The UE 102 may still receive DL PDCP PDUs from the source access node 103 but new and retransmitted UL PDCP PDUs are only sent in the target cell. The UE 102 may keep the source protocol stack active until the source access node 103 stops transmitting DL PDCP PDUs. In some embodiments, as a distinct “switching point” is defined when the UE 102 stops using the source protocol stack for UL/DL transmission/reception (e.g., upon completion of the random-access procedure or upon receiving an ACK message for the RRCConnectionReconfigurationComplete message in step 510), a network-controlled release by means of an explicit release/reconfiguration message sent from the target access node 104 to the UE 102 is not needed.

Steps 513-514: The target access node 104 sends a Handover Request Complete message over the X2 interface to the source access node 103 to indicate that the handover has completed, thus based on this information the source access node 103 can with certainty stop the transmission/reception to/from the UE 102. The Handover Request Complete message may be a new X2AP message.

The target access node 104 then sends a Path switch request message to the network node 106, in order to trigger the switch of the downlink data path from the network node 106 to the target access node 104 (instead of the source access node 103).

Steps 515-516: The source access node 103 stops transmission and reception to/from the UE 102 and sends an SN Status Transfer message to the target access node 104 conveying the UL PDCP SN receiver status and the HFN UL status. The uplink PDCP SN receiver status includes at least the PDCP SN of the first

missing UL SDU and may include a bit map of the receive status of the out of sequence UL SDUs that the UE needs to retransmit in the target cell, if there are any such SDUs. The target node makes use of this information to ensure PDCP status preservation towards the UE. The SN Status Transfer message also contains the HFN of the first missing UL SDU. This information, together with the PDCP SN of the first missing UL SDU, is used by the target access node 104 for deciphering the UL PDCP PDUs sent from the UE.

Step 517: Prior to switching of the downlink path, uplink data is sent from the target access node 104 to the network node 106. When the network node 106 has switched the downlink path, it transmits a Path Switch Request Ack message to the target access node 104. Now uplink and downlink data flow uses the new path.

Step 518: Finally, the target access node 104 sends a UE Context Release message to the source access node 103, which releases the UE context for this UE 102, and this completes the handover procedure in the network.

As shown in Figures 5a and 5b, the SN status transfer may be divided into an uplink and a downlink part. The downlink SN status transfer message contains the downlink PDCP SN status and HFN status and is sent from the source access node 103 to the target access node 104 immediately after the handover command is sent to the UE (see step 516), while the uplink SN status transfer message contains the uplink PDCP SN status and HFN status and can be sent from the source access node 103 to the target access node 104 when the source access node obtains a trigger which confirms the completion of the handover (e.g. a Handover Request Complete message from the target access node 104 or the UE 102). See step 513. By sending the downlink SN status transfer message and starting to forward DL packets when the handover command is sent, the target access node 104 can start transmitting the downlink data earlier which reduces the downlink latency.

Figures 5a and 5b thus show a signaling diagram for handover in which the target access node 104 transmits a Handover Request Complete message to the source access node 103 to indicate that the handover has completed. Based on this information, the source access node 103 is able to send an SN Status Transfer message to the target access node which relates to the sequence number of those data packets which were transmitted between the source access node 103 and the UE 102, but not received (or not acknowledged as being received).

In an alternative embodiment, the UE 102 itself may send a message to the source access node 103 comprising an indication that the UE has left the source cell and/or that the UE 102 has connected to the target cell. Such a message may be equivalent to or correspond to the Handover Request Complete message described in step 513 above, in that it acts as a trigger for the source access node 103 to send an SN Status Transfer message to the target access node as described in step 515 above. The message may be an RRC message, or some other type of message or signal, such as a MAC control element. The message may be sent to the source access node 103 just prior to or during step 512 described above.

It will also be noted that the source access node receives a message (whether from the target access node— Handover Request Complete— or from the UE 102) comprising an indication that a connection has been established between the UE 102 and the target access node 104. Those skilled in the art will appreciate that in some embodiments the UE 102 may wish to maintain connections to both the target access node 104 and the source access node 103 for a period of time. A“Handover Complete” message may be inappropriate in such cases as it may result in the connection to the source access node 103 being released following transmission of the SN Status Transfer message. In these embodiments, the message from the target access node 104 or the UE 102 may alternatively comprise an indication that the UE 102 is about to leave the source cell. The message again prompts the source access node 103 to prepare and transmit a SN Status Transfer message as detailed above. However, this would not necessarily be prepared upon the connection to the target access node being established, but rather upon the connection to the source access node being dropped (or about to be dropped).

Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in Figure 6. For simplicity, the wireless network of Figure 6 only depicts network 606, network nodes 660 and 660b, and WDs 610, 610b, and 610c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node 660 and wireless device (WD) 610 are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices’ access to and/or use of the services provided by, or via, the wireless network.

The wireless network may comprise and/or interface with any type of communication, telecommunication, data, cellular, and/or radio network or other similar type of system. In some embodiments, the wireless network may be configured to operate according to specific standards or other types of predefined rules or procedures. Thus, particular embodiments of the wireless network may implement communication standards, such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, or 5G standards; wireless local area network (WLAN) standards, such as the IEEE 802.11 standards; and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave and/or ZigBee standards.

Network 606 may comprise one or more backhaul networks, core networks, IP networks, public switched telephone networks (PSTNs), packet data networks, optical networks, wide-area networks (WANs), local area networks (LANs), wireless local area networks (WLANs), wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between devices.

Network node 660 and WD 610 comprise various components described in more detail below. These components work together in order to provide network node and/or wireless device functionality, such as providing wireless connections in a wireless network. In different embodiments, the wireless network may comprise any number of wired or wireless networks, network nodes, base stations, controllers, wireless devices, relay stations, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections.

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As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the wireless network to enable and/or provide wireless access to the wireless device and/or to perform other functions (e.g., administration) in the wireless network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)). Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and may then also be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS). Yet further examples of network nodes include multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), core network nodes (e.g., MSCs, MMEs), O&M nodes, OSS nodes, SON nodes, positioning nodes (e.g., E-SMLCs), and/or MDTs. As another example, a network node may be a virtual network node as described in more detail below. More generally, however, network nodes may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a wireless device with access to the wireless network or to provide some service to a wireless device that has accessed the wireless network.

In Figure 6, network node 660 includes processing circuitry 670, device readable medium 680, interface 690, auxiliary equipment 684, power source 686, power circuitry 687, and antenna 662. Although network node 660 illustrated in the example wireless network of Figure 6 may represent a device that includes the illustrated combination of hardware components, other embodiments may comprise network nodes with different combinations of components. It is to be understood that a network node comprises any suitable combination of hardware and/or software needed to perform the tasks, features, functions and methods disclosed herein. Moreover, while the components of network node 660 are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, a network node may comprise multiple different physical components that make up a single illustrated component (e.g., device readable medium 680 may comprise multiple separate hard drives as well as multiple RAM modules).

Similarly, network node 660 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 660 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeB’s. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 660 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate device readable medium 680 for the different RATs) and some components may be reused (e.g., the same antenna 662 may be shared by the RATs). Network node 660 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 660, such as, for example, GSM, WCDMA, LTE, NR, WiFi, or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 660.

Processing circuitry 670 is configured to perform any determining, calculating, or similar operations (e.g., certain obtaining operations) described herein as being provided by a network node. These operations performed by processing circuitry 670 may include processing information obtained by processing circuitry 670 by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination.

Processing circuitry 670 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 660 components, such as device readable medium 680, network node 660 functionality. For example, processing circuitry 670 may execute instructions stored in device readable medium 680 or in memory within processing circuitry 670. Such functionality may include providing any of the various wireless features, functions, or benefits discussed herein. In some embodiments, processing circuitry 670 may include a system on a chip (SOC).

In some embodiments, processing circuitry 670 may include one or more of radio frequency (RF) transceiver circuitry 672 and baseband processing circuitry 674. In some embodiments, radio frequency (RF) transceiver circuitry 672 and baseband processing circuitry 674 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 672 and baseband processing circuitry 674 may be on the same chip or set of chips, boards, or units

In certain embodiments, some or all of the functionality described herein as being provided by a network node, base station, eNB or other such network device may be performed by processing circuitry 670 executing instructions stored on device readable medium 680 or memory within processing circuitry 670. In alternative embodiments, some or all of the functionality may be provided by processing circuitry 670 without executing instructions stored on a separate or discrete device readable medium, such as in a hard-wired manner. In any of those embodiments, whether executing instructions stored on a device readable storage medium or not, processing circuitry 670 can be configured to perform the described functionality. The benefits provided by such functionality are not limited to processing circuitry 670 alone or to other components of network node 660, but are enjoyed by network node 660 as a whole, and/or by end users and the wireless network generally.

Device readable medium 680 may comprise any form of volatile or non-volatile computer readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic

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media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by processing circuitry 670. Device readable medium 680 may store any suitable instructions, data or information, including a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry 670 and, utilized by network node 660. Device readable medium 680 may be used to store any calculations made by processing circuitry 670 and/or any data received via interface 690. In some embodiments, processing circuitry 670 and device readable medium 680 may be considered to be integrated.

Interface 690 is used in the wired or wireless communication of signalling and/or data between network node 660, network 606, and/or WDs 610. As illustrated, interface 690 comprises port(s)/terminal(s) 694 to send and receive data, for example to and from network 606 over a wired connection. Interface 690 also includes radio front end circuitry 692 that may be coupled to, or in certain embodiments a part of, antenna 662. Radio front end circuitry 692 comprises filters 698 and amplifiers 696. Radio front end circuitry 692 may be connected to antenna 662 and processing circuitry 670. Radio front end circuitry may be configured to condition signals communicated between antenna 662 and processing circuitry 670. Radio front end circuitry 692 may receive digital data that is to be sent out to other network nodes or WDs via a wireless connection. Radio front end circuitry 692 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 698 and/or amplifiers 696. The radio signal may then be transmitted via antenna 662. Similarly, when receiving data, antenna 662 may collect radio signals which are then converted into digital data by radio front end circuitry 692. The digital data may be passed to processing circuitry 670. In other embodiments, the interface may comprise different components and/or different combinations of components.

In certain alternative embodiments, network node 660 may not include separate radio front end circuitry 692, instead, processing circuitry 670 may comprise radio front end circuitry and may be connected to antenna

662 without separate radio front end circuitry 692. Similarly, in some embodiments, all or some of RF transceiver circuitry 672 may be considered a part of interface 690. In still other embodiments, interface 690 may include one or more ports or terminals 694, radio front end circuitry 692, and RF transceiver circuitry 672, as part of a radio unit (not shown), and interface 690 may communicate with baseband processing circuitry 674, which is part of a digital unit (not shown).

Antenna 662 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. Antenna 662 may be coupled to radio front end circuitry 690 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In some embodiments, antenna 662 may comprise one or more omni-directional, sector or panel antennas operable to transmit/receive radio signals between, for example, 2 GFIz and 66 GFIz. An omni-directional antenna may be used to transmit/receive radio signals in any direction, a sector antenna may be used to transmit/receive radio signals from devices within a particular area, and a panel antenna may be a line of sight antenna used to transmit/receive radio signals in a

relatively straight line. In some instances, the use of more than one antenna may be referred to as MIMO. In certain embodiments, antenna 662 may be separate from network node 660 and may be connectable to network node 660 through an interface or port.

Antenna 662, interface 690, and/or processing circuitry 670 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by a network node. Any information, data and/or signals may be received from a wireless device, another network node and/or any other network equipment. Similarly, antenna 662, interface 690, and/or processing circuitry 670 may be configured to perform any transmitting operations described herein as being performed by a network node. Any information, data and/or signals may be transmitted to a wireless device, another network node and/or any other network equipment.

Power circuitry 687 may comprise, or be coupled to, power management circuitry and is configured to supply the components of network node 660 with power for performing the functionality described herein. Power circuitry 687 may receive power from power source 686. Power source 686 and/or power circuitry 687 may be configured to provide power to the various components of network node 660 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 686 may either be included in, or external to, power circuitry 687 and/or network node 660. For example, network node 660 may be connectable to an external power source (e.g., an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry 687. As a further example, power source 686 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry 687. The battery may provide backup power should the external power source fail. Other types of power sources, such as photovoltaic devices, may also be used.

Alternative embodiments of network node 660 may include additional components beyond those shown in Figure 6 that may be responsible for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, network node 660 may include user interface equipment to allow input of information into network node 660 and to allow output of information from network node 660. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 660.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE) a vehicle-mounted wireless terminal device, etc.. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (loT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

As illustrated, wireless device 610 includes antenna 611, interface 614, processing circuitry 620, device readable medium 630, user interface equipment 632, auxiliary equipment 634, power source 636 and power circuitry 637. WD 610 may include multiple sets of one or more of the illustrated components for different wireless technologies supported by WD 610, such as, for example, GSM, WCDMA, LTE, NR, WiFi, WiMAX, or Bluetooth wireless technologies, just to mention a few. These wireless technologies may be integrated into the same or different chips or set of chips as other components within WD 610.

Antenna 611 may include one or more antennas or antenna arrays, configured to send and/or receive wireless signals, and is connected to interface 614. In certain alternative embodiments, antenna 611 may be separate from WD 610 and be connectable to WD 610 through an interface or port. Antenna 611 , interface 614, and/or processing circuitry 620 may be configured to perform any receiving or transmitting operations described herein as being performed by a WD. Any information, data and/or signals may be received from a network node and/or another WD. In some embodiments, radio front end circuitry and/or antenna 611 may be considered an interface.

As illustrated, interface 614 comprises radio front end circuitry 612 and antenna 611. Radio front end circuitry 612 comprise one or more filters 618 and amplifiers 616. Radio front end circuitry 614 is connected to antenna 611 and processing circuitry 620, and is configured to condition signals communicated between antenna 611 and processing circuitry 620. Radio front end circuitry 612 may be coupled to or a part of antenna 611. In some embodiments, WD 610 may not include separate radio front end circuitry 612; rather, processing circuitry 620 may comprise radio front end circuitry and may be connected to antenna 611. Similarly, in some embodiments, some or all of RF transceiver circuitry 622 may be considered a part of interface 614. Radio front end circuitry 612 may receive digital data that is to be sent out to other network nodes or WDs via a wireless connection. Radio front end circuitry 612 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 618 and/or amplifiers 616. The radio signal may then be transmitted via antenna 611. Similarly, when receiving data, antenna 611 may collect radio signals which are then converted into digital data by radio front end circuitry 612. The digital data may be passed to processing circuitry 620. In other embodiments, the interface may comprise different components and/or different combinations of components.

Processing circuitry 620 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software, and/or encoded logic operable to provide, either alone or in conjunction with other WD 610 components, such as device readable medium 630, WD 610 functionality. Such functionality may include providing any of the various wireless features or benefits discussed herein. For example, processing circuitry 620 may execute instructions stored in device readable medium 630 or in memory within processing circuitry 620 to provide the functionality disclosed herein.

As illustrated, processing circuitry 620 includes one or more of RF transceiver circuitry 622, baseband processing circuitry 624, and application processing circuitry 626. In other embodiments, the processing circuitry may comprise different components and/or different combinations of components. In certain embodiments processing circuitry 620 of WD 610 may comprise a SOC. In some embodiments, RF transceiver circuitry 622, baseband processing circuitry 624, and application processing circuitry 626 may be on separate chips or sets of chips. In alternative embodiments, part or all of baseband processing circuitry 624 and application processing circuitry 626 may be combined into one chip or set of chips, and RF transceiver circuitry 622 may be on a separate chip or set of chips. In still alternative embodiments, part or all of RF transceiver circuitry 622 and baseband processing circuitry 624 may be on the same chip or set of chips, and application processing circuitry 626 may be on a separate chip or set of chips. In yet other alternative embodiments, part or all of RF transceiver circuitry 622, baseband processing circuitry 624, and application processing circuitry 626 may be combined in the same chip or set of chips. In some embodiments, RF transceiver circuitry 622 may be a part of interface 614. RF transceiver circuitry 622 may condition RF signals for processing circuitry 620.

In certain embodiments, some or all of the functionality described herein as being performed by a WD may be provided by processing circuitry 620 executing instructions stored on device readable medium 630, which in certain embodiments may be a computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by processing circuitry 620 without executing instructions stored on a separate or discrete device readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a device readable storage medium or not, processing circuitry 620 can be configured to perform the described functionality. The benefits provided by such functionality are not limited to processing circuitry 620 alone or to other components of WD 610, but are enjoyed by WD 610 as a whole, and/or by end users and the wireless network generally.

Processing circuitry 620 may be configured to perform any determining, calculating, or similar operations (e.g., certain obtaining operations) described herein as being performed by a WD. These operations, as performed by processing circuitry 620, may include processing information obtained by processing circuitry 620 by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored by WD 610, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination.

Device readable medium 630 may be operable to store a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry 620. Device readable medium 630 may include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device readable and/or computer executable memory devices that store information, data, and/or instructions that may be used by processing circuitry 620. In some embodiments, processing circuitry 620 and device readable medium 630 may be considered to be integrated.

User interface equipment 632 may provide components that allow for a human user to interact with WD

610. Such interaction may be of many forms, such as visual, audial, tactile, etc. User interface equipment 632 may be operable to produce output to the user and to allow the user to provide input to WD 610. The type of interaction may vary depending on the type of user interface equipment 632 installed in WD 610. For example, if WD 610 is a smart phone, the interaction may be via a touch screen; if WD 610 is a smart meter, the interaction may be through a screen that provides usage (e.g., the number of gallons used) or a speaker that provides an audible alert (e.g., if smoke is detected). User interface equipment 632 may include input interfaces, devices and circuits, and output interfaces, devices and circuits. User interface equipment 632 is configured to allow input of information into WD 610, and is connected to processing circuitry 620 to allow processing circuitry 620 to process the input information. User interface equipment 632 may include, for example, a microphone, a proximity or other sensor, keys/buttons, a touch display, one or more cameras, a USB port, or other input circuitry. User interface equipment 632 is also configured to allow output of information from WD 610, and to allow processing circuitry 620 to output information from WD 610. User interface equipment 632 may include, for example, a speaker, a display, vibrating circuitry, a USB port, a headphone interface, or other output circuitry. Using one or more input and output interfaces, devices, and circuits, of user interface equipment 632, WD 610 may communicate with end users and/or the wireless network, and allow them to benefit from the functionality described herein.

Auxiliary equipment 634 is operable to provide more specific functionality which may not be generally performed by WDs. This may comprise specialized sensors for doing measurements for various purposes, interfaces for additional types of communication such as wired communications etc. The inclusion and type of components of auxiliary equipment 634 may vary depending on the embodiment and/or scenario.

Power source 636 may, in some embodiments, be in the form of a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic devices or power cells, may also be used. WD 610 may further comprise power circuitry 637 for delivering power from power source 636 to the various parts of WD 610 which need power from power source 636 to carry out any functionality described or indicated herein. Power circuitry 637 may in certain embodiments comprise power management circuitry. Power circuitry 637 may additionally or alternatively be operable to receive power from an external power source; in which case WD 610 may be connectable to the external power source (such as an electricity outlet) via input circuitry or an interface such as an electrical power cable. Power circuitry 637 may also in certain embodiments be operable to deliver power from an external power source to power source 636. This may be, for example, for the charging of power source 636. Power circuitry 637 may perform any formatting, converting, or other modification to the power from power source 636 to make the power suitable for the respective components of WD 610 to which power is supplied.

Figure 7 illustrates one embodiment of a UE in accordance with various aspects described herein. As used herein, a user equipment or UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter). UE 700 may be any UE identified by the 3rd Generation Partnership Project (3GPP), including a NB-loT UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE. UE 700, as illustrated in Figure 7, is one example of a WD configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP), such as 3GPP’s GSM, UMTS, LTE, and/or 5G standards. As mentioned previously, the term WD and UE may be used interchangeable. Accordingly, although Figure 7 is a UE, the components discussed herein are equally applicable to a WD, and vice-versa.

In Figure 7, UE 700 includes processing circuitry 701 that is operatively coupled to input/output interface 705, radio frequency (RF) interface 709, network connection interface 711 , memory 715 including random access memory (RAM) 717, read-only memory (ROM) 719, and storage medium 721 or the like, communication subsystem 731 , power source 733, and/or any other component, or any combination thereof. Storage medium 721 includes operating system 723, application program 725, and data 727. In other embodiments, storage medium 721 may include other similar types of information. Certain UEs may utilize all of the components shown in Figure 7, or only a subset of the components. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

In Figure 7, processing circuitry 701 may be configured to process computer instructions and data. Processing circuitry 701 may be configured to implement any sequential state machine operative to execute machine instructions stored as machine-readable computer programs in the memory, such as one or more hardware-implemented state machines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logic together with appropriate firmware; one or more stored program, general-purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 701 may include two central processing units (CPUs). Data may be information in a form suitable for use by a computer.

In the depicted embodiment, input/output interface 705 may be configured to provide a communication interface to an input device, output device, or input and output device. UE 700 may be configured to use an output device via input/output interface 705. An output device may use the same type of interface port as an input device. For example, a USB port may be used to provide input to and output from UE 700. The output device may be a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. UE 700 may be configured to use an input device via input/output interface 705 to allow a user to capture information into UE 700. The input device may include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, another like sensor, or any combination thereof. For example, the input device may be an accelerometer, a magnetometer, a digital camera, a microphone, and an optical sensor.

In Figure 7, RF interface 709 may be configured to provide a communication interface to RF components such as a transmitter, a receiver, and an antenna. Network connection interface 711 may be configured to provide a communication interface to network 743a. Network 743a may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 743a may comprise a Wi-Fi network. Network connection interface 711 may be configured to include a receiver and a transmitter interface used to communicate with one or more other devices over a communication network according to one or more communication protocols, such as Ethernet, TCP/IP, SONET, ATM, or the like. Network connection interface 711 may implement receiver and transmitter functionality appropriate to the communication network links (e.g., optical, electrical, and the like). The transmitter and receiver functions may share circuit components, software or firmware, or alternatively may be implemented separately.

RAM 717 may be configured to interface via bus 702 to processing circuitry 701 to provide storage or caching of data or computer instructions during the execution of software programs such as the operating system, application programs, and device drivers. ROM 719 may be configured to provide computer instructions or data to processing circuitry 701. For example, ROM 719 may be configured to store invariant low-level system code or data for basic system functions such as basic input and output (I/O), startup, or reception of keystrokes from a keyboard that are stored in a non-volatile memory. Storage medium 721 may be configured to include memory such as RAM, ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, or flash drives. In one example, storage medium 721 may be configured to include operating system 723, application program 725 such as a web browser application, a widget or gadget

engine or another application, and data file 727. Storage medium 721 may store, for use by UE 700, any of a variety of various operating systems or combinations of operating systems.

Storage medium 721 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), floppy disk drive, flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a subscriber identity module or a removable user identity (SIM/RUIM) module, other memory, or any combination thereof. Storage medium 721 may allow UE 700 to access computer-executable instructions, application programs or the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied in storage medium 721 , which may comprise a device readable medium.

In Figure 7, processing circuitry 701 may be configured to communicate with network 743b using communication subsystem 731. Network 743a and network 743b may be the same network or networks or different network or networks. Communication subsystem 731 may be configured to include one or more transceivers used to communicate with network 743b. For example, communication subsystem 731 may be configured to include one or more transceivers used to communicate with one or more remote transceivers of another device capable of wireless communication such as another WD, UE, or base station of a radio access network (RAN) according to one or more communication protocols, such as IEEE 802.11, CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like. Each transceiver may include transmitter 733 and/or receiver 735 to implement transmitter or receiver functionality, respectively, appropriate to the RAN links (e.g., frequency allocations and the like). Further, transmitter 733 and receiver 735 of each transceiver may share circuit components, software or firmware, or alternatively may be implemented separately.

In the illustrated embodiment, the communication functions of communication subsystem 731 may include data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. For example, communication subsystem 731 may include cellular communication, Wi-Fi communication, Bluetooth communication, and GPS communication. Network 743b may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 743b may be a cellular network, a Wi-Fi network, and/or a near-field network. Power source 713 may be configured to provide alternating current (AC) or direct current (DC) power to components of UE 700.

The features, benefits and/or functions described herein may be implemented in one of the components of UE 700 or partitioned across multiple components of UE 700. Further, the features, benefits, and/or functions described herein may be implemented in any combination of hardware, software or firmware. In one example,

communication subsystem 731 may be configured to include any of the components described herein. Further, processing circuitry 701 may be configured to communicate with any of such components over bus 702. In another example, any of such components may be represented by program instructions stored in memory that when executed by processing circuitry 701 perform the corresponding functions described herein. In another example, the functionality of any of such components may be partitioned between processing circuitry 701 and communication subsystem 731. In another example, the non-computationally intensive functions of any of such components may be implemented in software or firmware and the computationally intensive functions may be implemented in hardware.

Figure 8 is a schematic block diagram illustrating a virtualization environment 800 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to a node (e.g., a virtualized base station or a virtualized radio access node) or to a device (e.g., a UE, a wireless device or any other type of communication device) or components thereof and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components (e.g., via one or more applications, components, functions, virtual machines or containers executing on one or more physical processing nodes in one or more networks).

In some embodiments, some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines implemented in one or more virtual environments 800 hosted by one or more of hardware nodes 830. Further, in embodiments in which the virtual node is not a radio access node or does not require radio connectivity (e.g., a core network node), then the network node may be entirely virtualized.

The functions may be implemented by one or more applications 820 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) operative to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein. Applications 820 are run in virtualization environment 800 which provides hardware 830 comprising processing circuitry 860 and memory 890. Memory 890 contains instructions 895 executable by processing circuitry 860 whereby application 820 is operative to provide one or more of the features, benefits, and/or functions disclosed herein.

Virtualization environment 800, comprises general-purpose or special-purpose network hardware devices 830 comprising a set of one or more processors or processing circuitry 860, which may be commercial off-the-shelf (COTS) processors, dedicated Application Specific Integrated Circuits (ASICs), or any other type of processing circuitry including digital or analog hardware components or special purpose processors. Each hardware device may comprise memory 890-1 which may be non-persistent memory for temporarily storing instructions 895 or software executed by processing circuitry 860. Each hardware device may comprise one or more network interface controllers (NICs) 870, also known as network interface cards, which include physical network interface 880. Each hardware device may also include non-transitory, persistent, machine-readable

storage media 890-2 having stored therein software 895 and/or instructions executable by processing circuitry 860. Software 895 may include any type of software including software for instantiating one or more virtualization layers 850 (also referred to as hypervisors), software to execute virtual machines 840 as well as software allowing it to execute functions, features and/or benefits described in relation with some embodiments described herein.

Virtual machines 840, comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 850 or hypervisor. Different embodiments of the instance of virtual appliance 820 may be implemented on one or more of virtual machines 840, and the implementations may be made in different ways.

During operation, processing circuitry 860 executes software 895 to instantiate the hypervisor or virtualization layer 850, which may sometimes be referred to as a virtual machine monitor (VMM). Virtualization layer 850 may present a virtual operating platform that appears like networking hardware to virtual machine 840.

As shown in Figure 8, hardware 830 may be a standalone network node with generic or specific components. Hardware 830 may comprise antenna 8225 and may implement some functions via virtualization. Alternatively, hardware 830 may be part of a larger cluster of hardware (e.g. such as in a data center or customer premise equipment (CPE)) where many hardware nodes work together and are managed via management and orchestration (MANO) 8100, which, among others, oversees lifecycle management of applications 820.

Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

In the context of NFV, virtual machine 840 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of virtual machines 840, and that part of hardware 830 that executes that virtual machine, be it hardware dedicated to that virtual machine and/or hardware shared by that virtual machine with others of the virtual machines 840, forms a separate virtual network elements (VNE).

Still in the context of NFV, Virtual Network Function (VNF) is responsible for handling specific network functions that run in one or more virtual machines 840 on top of hardware networking infrastructure 830 and corresponds to application 820 in Figure 8.

In some embodiments, one or more radio units 8200 that each include one or more transmitters 8220 and one or more receivers 8210 may be coupled to one or more antennas 8225. Radio units 8200 may communicate directly with hardware nodes 830 via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station.

In some embodiments, some signalling can be effected with the use of control system 8230 which may alternatively be used for communication between the hardware nodes 830 and radio units 8200.

With reference to FIGURE 9, in accordance with an embodiment, a communication system includes telecommunication network 910, such as a 3GPP-type cellular network, which comprises access network 911 , such as a radio access network, and core network 914. Access network 911 comprises a plurality of base stations 912a, 912b, 912c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 913a, 913b, 913c. Each base station 912a, 912b, 912c is connectable to core network 914 over a wired or wireless connection 915. A first UE 991 located in coverage area 913c is configured to wirelessly connect to, or be paged by, the corresponding base station 912c. A second UE 992 in coverage area 913a is wirelessly connectable to the corresponding base station 912a. While a plurality of UEs 991 , 992 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 912.

Telecommunication network 910 is itself connected to host computer 930, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. Host computer 930 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. Connections 921 and 922 between telecommunication network 910 and host computer 930 may extend directly from core network 914 to host computer 930 or may go via an optional intermediate network 920. Intermediate network 920 may be one of, or a combination of more than one of, a public, private or hosted network; intermediate network 920, if any, may be a backbone network or the Internet; in particular, intermediate network 920 may comprise two or more subnetworks (not shown).

The communication system of Figure 9 as a whole enables connectivity between the connected UEs 991 ,

992 and host computer 930. The connectivity may be described as an over-the-top (OTT) connection 950. Host computer 930 and the connected UEs 991, 992 are configured to communicate data and/or signaling via OTT connection 950, using access network 911 , core network 914, any intermediate network 920 and possible further infrastructure (not shown) as intermediaries. OTT connection 950 may be transparent in the sense that the participating communication devices through which OTT connection 950 passes are unaware of routing of uplink and downlink communications. For example, base station 912 may not or need not be informed about the past routing of an incoming downlink communication with data originating from host computer 930 to be forwarded (e.g., handed over) to a connected UE 991. Similarly, base station 912 need not be aware of the future routing of an outgoing uplink communication originating from the UE 991 towards the host computer 930.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Figure 10. In communication system 1000, host computer 1010 comprises hardware 1015 including communication interface 1016 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of communication system 1000. Host computer 1010 further comprises processing circuitry 1018, which may have storage and/or processing capabilities. In particular, processing circuitry 1018 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Host computer 1010 further comprises software 1011 , which is stored in or accessible by host computer 1010 and executable by processing circuitry 1018. Software 1011 includes host application 1012. Host application 1012 may be operable to provide a service to a remote user, such as UE 1030 connecting via OTT connection 1050 terminating at UE 1030 and host computer 1010. In providing the service to the remote user, host application 1012 may provide user data which is transmitted using OTT connection 1050.

Communication system 1000 further includes base station 1020 provided in a telecommunication system and comprising hardware 1025 enabling it to communicate with host computer 1010 and with UE 1030. Hardware 1025 may include communication interface 1026 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of communication system 1000, as well as radio interface 1027 for setting up and maintaining at least wireless connection 1070 with UE 1030 located in a coverage area (not shown in Figure 10) served by base station 1020. Communication interface 1026 may be configured to facilitate connection 1060 to host computer 1010. Connection 1060 may be direct or it may pass through a core network (not shown in Figure 10) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, hardware 1025 of base station 1020 further includes processing circuitry 1028, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Base station 1020 further has software 1021 stored internally or accessible via an external connection.

Communication system 1000 further includes UE 1030 already referred to. Its hardware 1035 may include radio interface 1037 configured to set up and maintain wireless connection 1070 with a base station serving a coverage area in which UE 1030 is currently located. Hardware 1035 of UE 1030 further includes processing circuitry 1038, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. UE 1030 further comprises software 1031 , which is stored in or accessible by UE 1030 and executable by processing circuitry 1038. Software 1031 includes client application 1032. Client application 1032 may be operable to provide a service to a human or non-human user via UE 1030, with the support of host computer 1010. In host computer 1010, an executing host application 1012 may communicate with the executing client application 1032 via OTT connection 1050 terminating at UE 1030 and host computer 1010. In providing the service to the user, client application 1032 may receive request data from host application 1012 and provide user data in response to the request data. OTT connection 1050 may transfer both the request data and the user data. Client application 1032 may interact with the user to generate the user data that it provides.

It is noted that host computer 1010, base station 1020 and UE 1030 illustrated in Figure 10 may be similar or identical to host computer 930, one of base stations 912a, 912b, 912c and one of UEs 991 , 992 of Figure 9, respectively. This is to say, the inner workings of these entities may be as shown in Figure 10 and independently, the surrounding network topology may be that of Figure 9.

In Figure 10, OTT connection 1050 has been drawn abstractly to illustrate the communication between host computer 1010 and UE 1030 via base station 1020, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from UE 1030 or from the service provider operating host computer 1010, or both. While OTT connection 1050 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

Wireless connection 1070 between UE 1030 and base station 1020 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE 1030 using OTT connection 1050, in which wireless connection 1070 forms the last segment. More precisely, the teachings of these embodiments may improve the latency (particularly during handover) and thereby provide benefits such as reduced user waiting time and better responsiveness.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring OTT connection 1050 between host computer 1010 and UE 1030, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring OTT connection 1050 may be implemented in software 1011 and hardware 1015 of host computer 1010 or in software 1031 and hardware 1035 of UE 1030, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which OTT connection 1050 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 1011 , 1031 may compute or estimate the monitored quantities. The reconfiguring of OTT connection 1050 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect base station 1020, and it may be unknown or imperceptible to base station 1020. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating host computer 1010’s measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that software 1011 and 1031 causes messages to be transmitted, in particular empty or‘dummy’ messages, using OTT connection 1050 while it monitors propagation times, errors etc.

Figure 11 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 9 and 10. For simplicity of the present disclosure, only drawing references to Figure 11 will be included in this section. In step 1110, the host computer provides user data. In substep 1111 (which may be optional) of step 1110, the host computer provides the user data by executing a host application. In step 1120, the host computer initiates a transmission carrying the user data to the UE. In step 1130 (which may be optional), the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1140 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.

Figure 12 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may

be those described with reference to Figures 9 and 10. For simplicity of the present disclosure, only drawing references to Figure 12 will be included in this section. In step 1210 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In step 1220, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1230 (which may be optional), the UE receives the user data carried in the transmission.

Figure 13 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 9 and 10. For simplicity of the present disclosure, only drawing references to Figure 13 will be included in this section. In step 1310 (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step 1320, the UE provides user data. In substep 1321 (which may be optional) of step 1320, the UE provides the user data by executing a client application. In substep 1311 (which may be optional) of step 1310, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in substep 1330 (which may be optional), transmission of the user data to the host computer. In step 1340 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

Figure 14 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 9 and 10. For simplicity of the present disclosure, only drawing references to Figure 14 will be included in this section. In step 1410 (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In step 1420 (which may be optional), the base station initiates transmission of the received user data to the host computer. In step 1430 (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station.

Figure 15 is a flowchart of a method in a target access node according to embodiments of the disclosure. The target access node may correspond to the node 104 described above with respect to Figures 5a and 5b, for example, and/or the network node 660 described with respect to Figure 6.

Step 1501 : The target access node 104 obtains an indication that the UE 102 has successfully completed the handover to the target access node 104. For example, such an indication may be reception of the RRCConnectionReconfigurationComplete message in the LTE case, or the RRCReconfigurationComplete message in the NR case. Or for example, such an indication is completion of the random access procedure by the UE 102 in the target cell.

Step 1502: The target access node 104 causes transmission of a Handover Request Complete message to the source access node 103 comprising an indication that the UE has completed the handover, or that a connection between the wireless device and the source access node 103 is about to be released or dropped. The message may thus be transmitted upon the wireless device establishing a connection with the target access node 104. Alternatively, the message may be transmitted upon the wireless device initiating a random-access procedure with the target access node or completing a random-access procedure with the target access node. The Handover Request Complete message may be transmitted to the source access node via a direct interface (such as the X2 or Xn interfaces). In these embodiments, the message may be a new type of X2AP (in LTE) or XNAP (in NR) message.

Step 1503: The target access node 104 receives one or more SN Status T ransfer messages from the source access node 103. The SN Status Transfer messages contain indications of the receive status and/or a sequence number transmitter status of data packets transmitted between the source access node 103 and the UE 102. For example, the data packets may be PDCP packets, transmitted in the UL and/or DL.

The indication of the receive status may comprise a sequence number of a data packet which has been transmitted (by one of the source access node and the UE) but not received (by the other of the source access node and the UE), or not acknowledged as being received. This data packet may be the earliest data packet in the sequence which has been so transmitted but not received. The indication may alternatively or additionally comprise an indication of any out-of-sequence data packets which have been transmitted but not received (e.g. a bitmap).

The SN Status Transfer messages may additionally comprise an indication of the hyper frame number

(or other appropriate frame number) associated with those data packets.

Step 1504: The target access node 104 make use of the information provided in the SN Status Transfer message to ensure PDCP status preservation towards the UE. The uplink PDCP SN receiver status includes at least the PDCP SN of the first missing UL SDU and may include a bitmap of the receive status of the out of sequence UL SDUs that the UE needs to retransmit in the target cell, if there are any such SDUs. The target node makes use of this information to ensure PDCP status preservation towards the UE. For example, the target access node may cause retransmission to the UE of data packets which were transmitted but not received. The SN Status Transfer message also contains the Hyper Frame Number (HFN) of the first missing UL SDU. This information, together with the PDCP SN of the first missing UL SDU, is used by the target access node 104 for deciphering of the UL PDCP PDUs sent from the UE.

Figure 16 illustrates a schematic block diagram of an apparatus 1600 in a wireless network (for example, the wireless network shown in Figure 6). The apparatus may be implemented in a network node (e.g., network node 660 shown in Figure 6). Apparatus 1600 is operable to carry out the example method described with reference to Figure 15 and possibly any other processes or methods disclosed herein. It is also to be understood that the method of Figure 15 is not necessarily carried out solely by apparatus 1600. At least some operations of the method can be performed by one or more other entities.

Virtual Apparatus 1600 may comprise processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In some implementations, the processing circuitry may be used to cause causing unit 1602, and any other suitable units of apparatus 1600 to perform corresponding functions according one or more embodiments of the present disclosure.

As illustrated in Figure 16, apparatus 1600 includes causing unit 1602, which is configured to cause transmission, to the source base station, of a first message comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped.

Figure 17 is a flowchart of a method in a source access node according to embodiments of the disclosure.

The source access node may correspond to the node 103 described above with respect to Figures 5a and 5b, for example, and/or the network node 660 described with respect to Figure 6.

Step 1701 : The source access node 103 obtains a trigger which confirms the completion of the handover. In one embodiment, this trigger is when the source access node 103 receives a Handover Request Complete message from the target access node 104 comprising an indication that the UE has completed the handover, or that a connection between the wireless device and the source access node 103 is about to be released or dropped. The message may thus be received upon the wireless device establishing a connection with the target access node 104. Alternatively, the message may be received upon the wireless device initiating a random-access procedure with the target access node or completing a random-access procedure with the target access node. The Handover Request Complete message may be received from the target access node via a direct interface (such as the X2 or Xn interfaces). In these embodiments, the message may be a new type of X2AP (in LTE) or XNAP (in NR) message.

In alternative embodiments (e.g., see Figure 19), a corresponding message may be received from the

UE 102.

Subsequent to or responsive to receipt of the trigger in step 1101 , the source access node 103 may refrain from transmitting data packets to the wireless device.

Step 1702: The source access node 103 can now assume that the UE 102 will not send any more UL PDCP PDUs to the source access node 103. The source access node 103 assembles one or more SN Status Transfer messages and transmits them to the target access node 104. The SN Status Transfer messages contain indications of the receive status and/or the sequence number transmitter status of data packets transmitted

between the source access node 103 and the UE 102. For example, the data packets may be PDCP packets, transmitted in the UL and/or DL.

The indication of the receive status may comprise a sequence number of a data packet which has been transmitted (by one of the source access node and the UE) but not received (by the other of the source access node and the UE), or not acknowledged as being received. This data packet may be the earliest data packet in the sequence which has been so transmitted but not received. The indication may alternatively or additionally comprise an indication of any out-of-sequence data packets which have been transmitted but not received (e.g. a bitmap).

The SN Status Transfer messages may additionally comprise an indication of the hyper frame number (or other appropriate frame number) associated with those data packets.

Figure 18 illustrates a schematic block diagram of an apparatus 1800 in a wireless network (for example, the wireless network shown in Figure 6). The apparatus may be implemented in a network node (e.g., network node 660 shown in Figure 6). Apparatus 1800 is operable to carry out the example method described with reference to Figure 17 and possibly any other processes or methods disclosed herein. It is also to be understood that the method of Figure 17 is not necessarily carried out solely by apparatus 1800. At least some operations of the method can be performed by one or more other entities.

Virtual Apparatus 1800 may comprise processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In some implementations, the processing circuitry may be used to cause receiving unit 1802, and any other suitable units of apparatus 1800 to perform corresponding functions according one or more embodiments of the present disclosure.

As illustrated in Figure 18, apparatus 1800 includes receiving unit 1802 which is configured to receive, from the target base station or the wireless device, a first message comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped.

As noted above, in some embodiments of the disclosure the wireless device (or UE) itself transmits a message to the source access node comprising an indication that a connection between the wireless device and the target access node has been established, or that the wireless device is about to leave the source cell. Figure 19 is a flowchart of a method in a wireless device according to such embodiments.

Step 1901 : During the handover from a source access node 103 to the target access node 104, the UE 102 detects that a criterion for leaving the source cell is fulfilled. For example, a criterion may be that the UE 102 has successfully transmitted an RRCReconfigurationComplete (also known as Handover Complete) to the target access node 104. Alternatively, the criterion may be that a random access procedure has been initiated with the target access node 104.

Step 1902: When this criterion is fulfilled, the UE 102 now transmits a message to the source access node comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped. This indication may be an RRC message, or some other type of message or signal, such as a MAC CE. The indication may be sent immediately before or during step 512 in Figure 5a. The wireless device may refrain from transmitting uplink data packets to the source access node subsequent to transmission of the message to the source access node in step 1202.

In the embodiment of Figure 19, when the source access node 103 receives this indication from the UE 102, the indication corresponds to the trigger which confirms the completion of the handover. The source access node 103 then sends the SN Status Transfer message to the target access node 104 as shown in step 516 of Figure 5b.

Figure 20 illustrates a schematic block diagram of an apparatus 2000 in a wireless network (for example, the wireless network shown in Figure 6). The apparatus may be implemented in a wireless device network node (e.g., UE 102 shown in Figures 5a and 5b, wireless device 610 shown in Figure 6, or UE 700 shown in Figure 7). Apparatus 2000 is operable to carry out the example method described with reference to Figure 19 and possibly any other processes or methods disclosed herein. It is also to be understood that the method of Figure 19 is not necessarily carried out solely by apparatus 2000. At least some operations of the method can be performed by one or more other entities.

Virtual Apparatus 2000 may comprise processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In some implementations, the processing circuitry may be used to cause transmitting unit 2002, and any other suitable units of apparatus 2000 to perform corresponding functions according one or more embodiments of the present disclosure.

As illustrated in Figure 20, apparatus 2000 includes transmitting unit 2002 which is configured to transmit, to the source base station, a first message comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped.

The term unit may have conventional meaning in the field of electronics, electrical devices and/or electronic devices and may include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those that are described herein.

For the avoidance of doubt, the following numbered statements set out embodiments of the disclosure:

Group A Embodiments

1. A method performed by a wireless device during handover of the wireless device from a source base station to a target base station, the method comprising:

- transmitting, to the source base station, a first message comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped.

2. The method of embodiment 1 , wherein the first message is transmitted upon the wireless device establishing a connection with the target base station.

3. The method of embodiment 1 , wherein the first message is transmitted upon the wireless device initiating a random-access procedure with the target base station.

4. The method of embodiment 1 , wherein the first message is transmitted upon the wireless device completing a random-access procedure with the target base station.

5. The method of any one of the preceding embodiments, further comprising, subsequent to transmission of the first message, refraining from transmitting uplink data packets to the source base station.

6. The method of any one of the preceding embodiments, wherein the first message comprises an RRC message.

7. The method of any one of embodiments 1 to 5, wherein the first message comprises a MAC control element.

8. The method of any of the previous embodiments, further comprising:

- providing user data; and

- forwarding the user data to a host computer via a transmission to the target base station.

Group B Embodiments

9. A method performed by a target base station for handover of a wireless device from a source base station, the method comprising:

- causing transmission, to the source base station, of a first message comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped.

10. The method of embodiment 9, wherein the first message is transmitted upon the wireless device establishing a connection with the target base station.

11. The method of embodiment 9, wherein the first message is transmitted upon the wireless device initiating a random-access procedure with the target base station.

12. The method of embodiment 9, wherein the first message is transmitted upon the wireless device completing a random-access procedure with the target base station.

13. The method of any one of embodiments 9 to 12, wherein the first message is transmitted via a direct interface between the target base station and the source base station.

14. The method of any one of embodiments 9 to 13, wherein the indication that the connection between the wireless device and the target base station has been established is an indication that handover of the wireless device to the target base station is complete.

15. The method of any one of embodiments 9 to 14, further comprising:

- receiving one or more second messages from the source base station, the one or more second messages comprising an indication of a receive status of data packets transmitted between the source base station and the wireless device.

16. The method of embodiment 15, wherein the one or more second messages comprise an indication of a receive status of uplink data packets transmitted between the source base station and the wireless device.

17. The method of embodiment 15, wherein the one or more second messages comprise an indication of a receive status of downlink data packets transmitted between the source base station and the wireless device.

18. The method of any one of embodiments 15 to 17 wherein the one or more second messages comprise respective messages comprising indications of the receive statuses for downlink packets and uplink packets transmitted between the source base station and the wireless device.

19. The method of any one of embodiments 15 to 18, wherein the indication of the receive status of data packets comprises a sequence number of a data packet which has been transmitted but not received.

20. The method of embodiment 19, wherein the indication of the receive status of data packets comprises a sequence number of the earliest data packet which has been transmitted but not received.

21. The method of any one of embodiments 15 to 20, wherein the indication of the receive status of data packets comprises a bitmap identifying out-of-sequence data packets which have been transmitted but not received.

22. The method of any one of embodiments 15 to 21 , wherein the indication of the receive status of data packets comprises a hyper frame number of data packets which have been transmitted but not received.

23. The method of any one of embodiments 15 to 22, wherein the data packets are packet data convergence protocol service data units.

24. The method of any one of embodiments 15 to 23, further comprising:

- causing re-transmission, to the wireless device, of downlink data packets indicated in the one or more second messages.

25. The method of any one of embodiments 15 to 24, further comprising:

- requesting re-transmission, from the wireless device, of uplink data packets indicated in the one or more second messages.

26. The method of any one of embodiments 15 to 25, wherein the one or more second messages are received subsequent to the transmission of the first message.

27. The method of any one of embodiments 15 to 26, wherein the one or more second messages are received via a direct interface between the target base station and the source base station.

28. A method performed by a source base station for handover of a wireless device from the source base station to a target base station, the method comprising:

- receiving, from the target base station or the wireless device, a first message comprising an indication that a connection between the wireless device and the target base station has been established, or that a connection between the wireless device and the source base station is about to be released or dropped.

29. The method of embodiment 28, wherein the first message is received upon the wireless device establishing a connection with the target base station.

30. The method of embodiment 28, wherein the first message is received upon the wireless device initiating a random-access procedure with the target base station.

31. The method of embodiment 28, wherein the first message is received upon the wireless device

completing a random-access procedure with the target base station.

32. The method of any one of embodiments 28 to 31 , wherein the first message is received via a direct interface between the target base station and the source base station.

33. The method of any one of embodiments 28 to 32, wherein the indication that the connection between the wireless device and the target base station has been established is an indication that handover of the wireless device to the target base station is complete.

34. The method of any one of embodiments 28 to 33, further comprising:

- causing transmission, to the target base station, of one or more second messages, the one or more second messages comprising an indication of a receive status of data packets transmitted between the source base station and the wireless device.

35. The method of embodiment 34, wherein the one or more second messages comprise an indication of a receive status of uplink data packets transmitted between the source base station and the wireless device.

36. The method of embodiment 34, wherein the one or more second messages comprise an indication of a receive status of downlink data packets transmitted between the source base station and the wireless device.

37. The method of any one of embodiments 34 to 36 wherein the one or more second messages comprise respective messages comprising indications of the receive statuses for downlink packets and uplink packets transmitted between the source base station and the wireless device.

38. The method of any one of embodiments 34 to 37, wherein the indication of the receive status of data packets comprises a sequence number of a data packet which has been transmitted but not received.

39. The method of embodiment 38, wherein the indication of the receive status of data packets comprises a sequence number of the earliest data packet which has been transmitted but not received.

40. The method of any one of embodiments 34 to 39, wherein the indication of the receive status of data packets comprises a bitmap identifying out-of-sequence data packets which have been transmitted but not received.

41. The method of any one of embodiments 34 to 40, wherein the indication of the receive status of data packets comprises a hyper frame number of data packets which have been transmitted but not received.

42. The method of any one of embodiments 34 to 41 , wherein the data packets are packet data convergence protocol service data units.

43. The method of any one of embodiments 34 to 42, wherein the one or more second messages are transmitted subsequent to receipt of the first message.

44. The method of any one of embodiments 34 to 43, wherein the one or more second messages are

transmitted via a direct interface between the target base station and the source base station.

45. The method of any one of embodiments 28 to 44, further comprising, subsequent to receipt of the first message, refraining from transmitting data packets to the wireless device.

46. The method of any of embodiments 9 to 45, further comprising:

- obtaining user data; and

- forwarding the user data to a host computer or the wireless device.

Group C Embodiments

47. A wireless device, comprising:

- processing circuitry configured to perform any of the steps of any of the Group A embodiments; and

- power supply circuitry configured to supply power to the wireless device.

48. A base station, comprising:

- processing circuitry configured to perform any of the steps of any of the Group B embodiments;

- power supply circuitry configured to supply power to the base station.

49. A user equipment (UE), comprising:

- an antenna configured to send and receive wireless signals;

- radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry;

- the processing circuitry being configured to perform any of the steps of any of the Group A embodiments;

- an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry;

- an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and

- a battery connected to the processing circuitry and configured to supply power to the UE.

50. A communication system including a host computer comprising:

processing circuitry configured to provide user data; and

a communication interface configured to forward the user data to a cellular network for transmission to a user equipment (UE),

wherein the cellular network comprises a base station having a radio interface and processing circuitry, the base station’s processing circuitry configured to perform any of the steps of any of the Group B embodiments.

51. The communication system of the previous embodiment further including the base station.

52. The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station.

53. The communication system of the previous 3 embodiments, wherein:

- the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and

- the UE comprises processing circuitry configured to execute a client application associated with the host application.

54. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

- at the host computer, providing user data; and

- at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the base station performs any of the steps of any of the Group B embodiments.

55. The method of the previous embodiment, further comprising, at the base station, transmitting the user data.

56. The method of the previous 2 embodiments, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the UE, executing a client application associated with the host application.

57. A user equipment (UE) configured to communicate with a base station, the UE comprising a radio

interface and processing circuitry configured to performs the of the previous 3 embodiments.

58. A communication system including a host computer comprising:

- processing circuitry configured to provide user data; and

- a communication interface configured to forward user data to a cellular network for transmission to a user equipment (UE),

- wherein the UE comprises a radio interface and processing circuitry, the UE’s components configured to perform any of the steps of any of the Group A embodiments.

59. The communication system of the previous embodiment, wherein the cellular network further includes a base station configured to communicate with the UE.

60. The communication system of the previous 2 embodiments, wherein:

- the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and

- the UE’s processing circuitry is configured to execute a client application associated with the host application.

61. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

- at the host computer, providing user data; and

- at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the UE performs any of the steps of any of the Group A embodiments.

62. The method of the previous embodiment, further comprising at the UE, receiving the user data from the base station.

63. A communication system including a host computer comprising:

- communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station,

- wherein the UE comprises a radio interface and processing circuitry, the UE’s processing circuitry configured to perform any of the steps of any of the Group A embodiments.

64. The communication system of the previous embodiment, further including the UE.

65. The communication system of the previous 2 embodiments, further including the base station, wherein the base station comprises a radio interface configured to communicate with the UE and a communication interface configured to forward to the host computer the user data carried by a transmission from the UE to the base station.

66. The communication system of the previous 3 embodiments, wherein:

- the processing circuitry of the host computer is configured to execute a host application; and

- the UE’s processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data.

67. The communication system of the previous 4 embodiments, wherein:

- the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; and

- the UE’s processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.

68. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

- at the host computer, receiving user data transmitted to the base station from the UE, wherein the UE performs any of the steps of any of the Group A embodiments.

69. The method of the previous embodiment, further comprising, at the UE, providing the user data to the base station.

70. The method of the previous 2 embodiments, further comprising:

- at the UE, executing a client application, thereby providing the user data to be transmitted; and - at the host computer, executing a host application associated with the client application.

71. The method of the previous 3 embodiments, further comprising:

at the UE, executing a client application; and

- at the UE, receiving input data to the client application, the input data being provided at the host computer by executing a host application associated with the client application,

- wherein the user data to be transmitted is provided by the client application in response to the input data.

72. A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station, wherein the base station comprises a radio interface and processing circuitry, the base station’s processing circuitry configured to perform any of the steps of any of the Group B embodiments.

73. The communication system of the previous embodiment further including the base station.

74. The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station.

75. The communication system of the previous 3 embodiments, wherein:

- the processing circuitry of the host computer is configured to execute a host application;

- the UE is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer.

76. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

- at the host computer, receiving, from the base station, user data originating from a transmission which the base station has received from the UE, wherein the UE performs any of the steps of any of the Group A embodiments.

77. The method of the previous embodiment, further comprising at the base station, receiving the user data from the UE.

78. The method of the previous 2 embodiments, further comprising at the base station, initiating a transmission of the received user data to the host computer.

79. A method in a source access node to perform handover of a UE to a target access node comprising: a. Obtaining a trigger which confirms the completion of the handover

b. As response to obtaining said trigger, transmitting an SN Status T ransfer message to the target access node

80. The method in 79, when the trigger is one of

a. An indication from the UE of leaving the source cell

b. Reception of a Handover Request Complete message from the target access node

81. A method in a target access node to perform handover of a UE from a source access node comprising: a. Obtain an indication of that the UE has successfully connected to the target access node b. Transmit a Handover Request Complete message to the source access node to confirm the completion of the handover

82. A method in a UE to perform handover of a UE from a source access node to a target access node comprising:

a. When criterion for leaving the source cell is fulfilled, transmit an indication to the source access node