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1. (WO2019030731) SELECTION OF BEAMS TO BE INCLUDED IN THE MEASUREMENT REPORT
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SELECTION OF BEAMS TO BE INCLUDED

IN THE MEASUREMENT REPORT

TECHNICAL FIELD

Wireless communication and in particular, apparatuses and methods for selection of beams to be included in a wireless communication system measurement report.

BACKGROUND

Measurement Model in New Radio (NR)

According to 3rd Generation Partnership Project (3 GPP) Technical

Specification (TS) 38.300, in radio resource control (RRC)_CONNECTED, the wireless device (WD) measures multiple beams (at least one) of a cell and the measurements results (power values) are averaged to derive the cell quality. In doing so, the WD is configured to consider a subset of the detected beams: the N best beams above an absolute threshold. Filtering takes place at two different levels: at the physical layer to derive beam quality and then at RRC level to derive cell quality from multiple beams. Cell quality from beam measurements is derived in the same way for the serving cell(s) and for the non-serving cell(s). Measurement reports may contain the measurement results of the X best beams if the WD is configured to do so by the gNodeB (gNB).

A possible difference between serving and non-serving cells could be the value of "N," i.e., N best beams.

The corresponding high-level measurement model of FIG. 1 is described below.

Referring to FIG. 1, K beams correspond to the measurements on the new radio (NR) synchronization signal (SS) NR-SS block, or Channel State Information-Reference Signal (CSI-RS) resources configured for Layer 3 (L3) mobility by gNB and detected by WD at Layer 1 (LI). The following are summaries of the elements shown in FIG. 1.

• A: measurements (beam specific samples) internal to the physical layer.

• Layer 1 filtering: internal layer 1 filtering of the inputs measured at point A. Exact filtering is implementation dependent. How the measurements are actually

executed in the physical layer by an implementation (inputs A and Layer 1 filtering) in not constrained by the standard.

• Al: measurements (i.e., beam specific measurements) reported by layer 1 to layer 3 after layer 1 filtering.

· Beam Consolidation/Selection: beam specific measurements are consolidated to derive cell quality if N > 1, else when N = 1 the best beam measurement is selected to derive cell quality. The behavior of the beam consolidation/selection is

standardized and the configuration of this module is provided by radio resource control (RRC) signaling. Reporting period at B equals one measurement period at Al. · B: a measurement (i.e. cell quality) derived from beam-specific measurements reported to layer 3 after beam consolidation/selection.

• Layer 3 filtering for cell quality: filtering performed on the measurements provided at point B. The behavior of the Layer 3 filters is standardized and the configuration of the layer 3 filters is provided by RRC signaling. Filtering reporting period at C equals one measurement period at B.

• C: a measurement after processing in the layer 3 filter. The reporting rate is identical to the reporting rate at point B. This measurement is used as input for one or more evaluation of reporting criteria.

• Evaluation of reporting criteria: checks whether actual measurement reporting is necessary at point D. The evaluation can be based on more than one flow of measurements at reference point C, e.g., to compare between different measurements. This is illustrated by input C and CI. The WD may evaluate the reporting criteria at least every time a new measurement result is reported at point C, CI. The reporting criteria are standardized and the configuration is provided by RRC signaling (WD measurements).

• D: measurement report information (message) sent on the radio interface.

• L3 Beam filtering: filtering performed on the measurements (i.e. beam specific measurements) provided at point Al. The behavior of the beam filters is standardized and the configuration of the beam filters is provided by RRC signaling. Filtering reporting period at E equals one measurement period at Al.

• E: a measurement (i.e. beam-specific measurement) after processing in the beam filter. The reporting rate is identical to the reporting rate at point Al. This measurement is used as input for selecting the X measurements to be reported.

• Beam Selection for beam reporting: selects the X measurements from the measurements provided at point E. The behavior of the beam selection is standardized and the configuration of this module is provided by RRC signaling.

• F: beam measurement information included in measurement report (sent) on the radio interface.

Layer 1 filtering introduces a certain level of measurement averaging. How and when the WD exactly performs the required measurements is implementation specific to the point that the output at B may fulfill the performance requirements set in, for example, 3 GPP TS 38.133. Layer 3 filtering for cell quality and related parameters may be specified in 3GPP TS 38.331 and may not introduce any delay in the sample availability between B and C. Measurement at point C, CI is the input used in the event evaluation. L3 Beam filtering and related parameters may be used as specified, for example, in 3GPP TS 38.331 and may not introduce any delay in the sample availability between E and F.

SUMMARY

Some embodiments advantageously provide a method and system for selection of beams to be included in a measurement report that may enable the network to efficiently choose a handover candidate amongst the reported cells and provide beam level information to a chosen target cell for resource allocation.

According to one aspect, a method for a wireless device for selection of beams to be included in a measurement report is provided. The method comprises selecting at least one cell for a measurement report; for each of the selected at least one cell, including at least a strongest beam in the measurement report; and transmitting the measurement report to a network node.

According to this aspect, in some embodiments, the method further comprises including a number of beams in the measurement report until the number of beams exceeds a threshold number. In some embodiments, the transmission of the

measurement report to the network node is in response to the number of beams in the measurement report exceeding the threshold number. In some embodiments, the method further comprises including at least one beam in the measurement report above a beam strength threshold. In some embodiments, the beam strength threshold is an absolute threshold. In some embodiments, the strongest beam for each of the at least one cell is a best beam for each of the at least one cell. In some embodiments, the transmitted measurement report includes at least the strongest beam for each of the selected at least one cell. In some embodiments, the method further comprises, for each of the at least one cell, including a next strongest beam in the measurement report. In some embodiments, the method further comprises, after including at least the strongest beam for each of the selected at least one cell in the measurement report, selecting at least one remaining beam to be included in the measurement report. In some embodiments, selecting the at least one remaining beam to be included in the measurement report further comprises selecting at least one strongest beam among beams of the at least one cell that are not yet included in the measurement report. In some embodiments, the method further comprises including the selected at least one remaining beam in the measurement report. In some embodiments, the transmitted measurement report includes the strongest beam for each of the selected at least one cell and the selected at least one remaining beam. In some embodiments, the method further comprises sorting selected cells to be included in the measurement report in a descending order of cell level quality; and selecting at least one beam of a strongest cell from the sorted selected cells to include in the measurement report. In some embodiments, the method further comprises, if a number of beams included in the transmitted measurement report does not exceed a threshold number of beams, transmitting beam level information associated with at least one non-triggered cell. In some embodiments, the method further comprises, receiving, from a network node, an indication of a beam selection strategy for including beams in the measurement report; and including the beams in the measurement report based on the indicated beam selection strategy.

According to another aspect, a wireless device for selection of beams to be included in a measurement report is provided. The wireless device comprising processing circuitry configured to cause the wireless device to select at least one cell for a measurement report; for each of the selected at least one cell, include at least a strongest beam in the measurement report; and transmit the measurement report to a network node.

According to this aspect, in some embodiments, the processing circuitry is further configured to cause the wireless device to include a number of beams in the measurement report until the number of beams exceeds a threshold number. In some embodiments, the transmission of the measurement report to the network node is in response to the number of beams in the measurement report exceeding the threshold number. In some embodiments, the processing circuitry is further configured to cause the wireless device to include at least one beam in the measurement report above a beam strength threshold. In some embodiments, the beam strength threshold is an absolute threshold. In some embodiments, the strongest beam for each of the at least one cell is a best beam for each of the at least one cell. In some embodiments, the transmitted measurement report includes at least the strongest beam for each of the selected at least one cell. In some embodiments, the processing circuitry is further configured to cause the wireless device to, for each of the at least one cell, include a next strongest beam in the measurement report. In some embodiments, the processing circuitry is further configured to cause the wireless device to, after including at least the strongest beam for each of the selected at least one cell in the measurement report, select at least one remaining beam to be included in the measurement report. In some embodiments, the processing circuitry is further configured to cause the wireless device to select the at least one remaining beam to be included in the measurement report by being further configured to cause the wireless device to select at least one strongest beam among beams of the at least one cell that are not yet included in the measurement report. In some embodiments, the processing circuitry is further configured to cause the wireless device to include the selected at least one remaining beam in the measurement report. In some embodiments, the transmitted measurement report includes the strongest beam for each of the selected at least one cell and the selected at least one remaining beam. In some embodiments, the processing circuitry is further configured to cause the wireless device to: sort selected cells to be included in the measurement report in a descending order of cell level quality; and select at least one beam of a strongest cell from the sorted selected cells to include in the measurement report. In some embodiments, wherein the processing circuitry is further configured to cause the wireless device to, if a number of beams included in the transmitted measurement report does not exceed a threshold number of beams, transmit beam level information associated with at least one non-triggered cell. In some embodiments, the processing circuitry is further configured to cause the wireless device to: receive, from a network node, an indication of a beam selection strategy for including beams in the measurement report; and include the beams in the

measurement report based on the indicated beam selection strategy.

According to yet another aspect, a method for a wireless device for selection of beams to be included in a measurement report is provided. The method comprises including at least one beam in a measurement report based at least in part on whether the at least one beam exceeds a beam strength threshold; and transmitting the measurement report to a network node.

According to this aspect, in some embodiments, the beam strength threshold is an absolute threshold. In some embodiments, the method further comprises selecting at least one cell for the measurement report; and for each of the selected at least one cell, including at least another beam to be included in the measurement report. In some embodiments, including the at least another beam in the measurement report further comprises, for each of the selected at least one cell, including at least a strongest beam in the measurement report.

According to another aspect, a wireless device for selection of beams to be included in a measurement report is provided. The wireless device comprising processing circuitry configured to cause the wireless device to include at least one beam in a measurement report based at least in part on whether the at least one beam exceeds a beam strength threshold; and transmit the measurement report to a network node.

According to this aspect, in some embodiments, the beam strength threshold is an absolute threshold. In some embodiments, the processing circuitry is further configured to cause the wireless device to select at least one cell for the measurement report; and for each of the selected at least one cell, include at least another beam to be included in the measurement report. In some embodiments, the processing circuitry is further configured to cause the wireless device to include the at least another beam in the measurement report by being further configured to cause the wireless device to, for each of the selected at least one cell, include at least a strongest beam in the measurement report.

According to another aspect, a method for a network node for configuring a wireless device to include beams in a measurement report is provided. The method comprises transmitting a beam selection strategy to a wireless device; and receiving a measurement report including beam level measurements from the wireless device, the beam level measurements included in the measurement report based at least in part on the transmitted beam selection strategy.

According to this aspect, in some embodiments, the method further comprises transmitting an indication of a number of beams to be included in the measurement report to the wireless device. In some embodiments, the method further comprises selecting the transmitted beam selection strategy from a plurality of available beam selection strategies. In some embodiments, the method further comprises selecting a first beam selection strategy for a first number of cells to be reported by the wireless device; and selecting a second beam selection strategy for remaining cells to be reported by the wireless device, the first beam selection strategy being different from the second beam selection strategy.

According to another aspect, a network node for configuring a wireless device to include beams in a measurement report is provided. The network node comprises processing circuitry configured to cause the network node to transmit a beam selection strategy to a wireless device; and receive a measurement report including beam level measurements from the wireless device, the beam level measurements included in the measurement report based at least in part on the transmitted beam selection strategy.

According to this aspect, in some embodiments, the processing circuitry is further configured to cause the network node to transmit an indication of a number of beams to be included in the measurement report to the wireless device. In some embodiments, the processing circuitry is further configured to cause the network node to select the transmitted beam selection strategy from a plurality of beam selection strategies. In some embodiments, the processing circuitry is further configured to cause the network node to select a first beam selection strategy for a first number of cells to be reported by the wireless device; and select a second beam selection strategy for remaining cells to be reported by the wireless device, the first beam selection strategy being different from the second beam selection strategy.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a measurement model in New Radio;

FIG.2 is a block diagram of a wireless communication system constructed in accordance with principles set forth herein;

FIG. 3 is block diagram of a network node constructed in accordance with principles set forth herein;

FIG. 4 is a block diagram of an alternative embodiment of the network node;

FIG. 5 is a block diagram of a wireless device constructed in accordance with principles set forth herein;

FIG. 6 is a block diagram of an alternative embodiment of the wireless device; FIG. 7 is a flowchart of an exemplary process in a network node for configuring a wireless device to generate measurement reports; and

FIG. 8 is a flowchart of an exemplary process in a wireless device for generating measurement reports;

FIG. 9 is a flowchart of yet another exemplary process in a wireless device for generating measurement reports;

FIG. 10a is a signal flow graph when beam selection strategy is hardcoded at the wireless device;

FIG. 10b is a signal flow graph when beam selection strategy is configurable by the network;

FIG. 11 is a flowchart of a process for generating a measurement report according to a first embodiment;

FIG. 12 is a flowchart of a process for generating a measurement report according to a second embodiment;

FIG. 13 is a flowchart of a process for generating a measurement report according to a third embodiment;

FIG. 14 is a flowchart of a process for generating a measurement report according to a fourth embodiment;

FIG. 15 is a flowchart of a process for generating a measurement report according to a fifth embodiment; and

FIG. 16 is a flowchart of a process for generating a measurement report according to a sixth embodiment.

DETAILED DESCRIPTION

Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related for selection of beams to be included in the measurement report. Accordingly, the system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

As used herein, relational terms, such as "first" and "second," "top" and "bottom," and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill

in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In embodiments described herein, the joining term, "in communication with" and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

Measurement Report Contents in NR

It has been considered that measurement reports may be characterized by the following:

· Measurement reports include the measurement identity of the associated measurement configuration that triggered the reporting;

• Cell and beam measurement quantities to be included in measurement reports are configured by the network;

• The number of non-serving cells to be reported can be limited through configuration by the network;

• Cells belonging to a blacklist configured by the network are not used in event evaluation and reporting, and conversely when a whitelist is configured by the network, only the cells belonging to the whitelist are used in event evaluation and reporting; and

· Beam measurements to be included in measurement reports are configured by the network (beam identifier only, measurement result and beam identifier, or no beam reporting);

In Long Term Evolution (LTE), the measurement reports from the WD can contain cell level measurement quantities. However, in New Radio (NR) beam level information associated to cells may also be configured, as described in herein. It has been considered that the WD include the beam level measurements in the

measurement report.

In NR, as in LTE, it may be possible to include cell quality (e.g., RSRP and/or RSRQ) in the measurement report.

The WD can indicate the SS block identifier of x best beams, where x is configurable in measurement reports triggered by the events on the SS block.

The following have also been considered regarding measurement reporting:

SS block identifier may not be included in measurement reporting triggered by CSI-RS events;

SS block identifier can be included in measurement reporting triggered by event A1-A6 for measurement reporting triggered by NR-SS events;

For SS based events, the WD reports the beams in the order of quality; CSI-RS identifier can be included in measurement reporting triggered by event A1-A6 for measurement reporting triggered by CSI-RS events; and For CSI-RS based events, the WD report the beams in the order of quality. In summary, it has been considered that the WD can be configured to perform

L3 filtered beam measurement results and include these if measurement reports are triggered.

It has also been considered in NR to include up to 'X' beams in the measurement report. However, it is remains an open issue as to how the WD selects these 'X' beams.

The following have been considered:

Beam measurement (based on NR-SS and CSI-RS) can be included in the measurement report and can be configured by the network (i.e. network configures the WD to report beam identifier only, beam measurement result and identifier, or no beam reporting); and

For selection of x SS blocks to be included in the measurement report for each cell:

o x can be configured separately from N (N used in cell quality

derivation); and

o future studies may include how to select the up to x SS blocks to be included.

Some previous considerations point to including the beams based on the order of quality, as follows:

for SS based events, the WD reports the beams in the order of quality; and for CSI-RS based events, the WD reports the beams in the order of quality. However, how to select the beams to be included in the measurement report is an open issue. The reasons may include that the amount of information that is included in measurement reports should be limited (to reduce the overhead), which can be evidenced in LTE by a limitation of the maximum number of cells whose measurements can be reported per message. Thus, at least some embodiments of the disclosure are directed to techniques for how to select beam measurements to be included in a measurement report.

Returning to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 2 a block diagram of a wireless

communication system 10 constructed according to at least some of the principles set forth herein. The wireless communication network 10 includes a cloud 12 which may include the Internet and/or the public switched telephone network (PSTN). Cloud 12 may also serve as a backhaul network of the wireless communication network 10.

The wireless communication network 10 includes one or more network nodes such as network nodes 14A and 14B, which may communicate directly via an X2 interface in LTE embodiments, and are referred to collectively as network nodes 14. It is contemplated that other interface types can be used for communication between network nodes 14 for other communication protocols such as New Radio (NR). The network nodes 14 may serve wireless devices 16A and 16B, referred to collectively herein as wireless devices 16. Note that, although only two wireless devices 16 and two network nodes 14 are shown for convenience, the wireless communication network 10 may typically include many more wireless devices (WDs) 16 and network nodes 14. Further, in some embodiments, WDs 16 may communicate directly using what is sometimes referred to as a side link connection.

The term "wireless device" or mobile terminal used herein may refer to any type of wireless device communicating with a network node 14 and/or with another wireless device 16 in a cellular or mobile communication system 10. Examples of a wireless device 16 are user equipment (UE), target device, device to device (D2D) wireless device, machine type wireless device or wireless device capable of machine to machine (M2M) communication, PDA, tablet, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongle, etc.

The term "network node" used herein may refer to any kind of radio base station in a radio network which may further comprise any base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), evolved Node B (eNB or eNodeB), NR gNodeB, NR gNB, Node B, multi-standard radio (MSR) radio node such as MSR BS, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), nodes in distributed antenna system (DAS), etc.

In some embodiments, the phrases "beam level measurements," "beam strength measurements," "beam information," "beam in the measurement report," and the like may be used interchangeably herein and may be used to indicate a beam measurement, such as a measurement of a beam' s strength, that may be selected for and/or included in and/or indicated in and/or received in a measurement report from e.g., a wireless device 16 to a network node 14.

Although embodiments are described herein with reference to certain functions being performed by network node 14, it is understood that the functions can be performed in other network nodes and elements. It is also understood that the functions of the network node 14 can be distributed across network cloud 12 so that other nodes can perform one or more functions or even parts of functions described herein.

As shown in FIG. 2, the network node 14 includes a measurement report receiver 18 configured to receive a measurement report including beam level measurements from the wireless device 16. In some embodiments, the network node 14 is further configured to transmit a beam selection strategy to a wireless device 16 and the beam level measurements included in the received measurement report may be based at least in part on the transmitted beam selection strategy.

The wireless device 16 includes a beam selector 20 configured to: for each selected cell, include a strongest beam in the measurement report. In some embodiments, the wireless device 16 is further configured to select at least one cell for the measurement report and transmit the measurement report to a network node 14. In some embodiments, the beam selector 20 may be configured to, when a

number of beams in the measurement report exceeds a threshold number, transmit the measurement report to a network node 14.

FIG. 3 is a block diagram of an embodiment of the network node 14 constructed in accordance with principles set forth herein. The network node 14 includes processing circuitry 22. In some embodiments, the processing circuitry 22 may include a memory 24 and processor 26, the memory 24 containing instructions which, when executed by the processor 26, configure processor 26 to perform the one or more functions described herein. In addition to a traditional processor and memory, processing circuitry 22 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry).

Processing circuitry 22 may include and/or be connected to and/or be configured for accessing (e.g., writing to and/or reading from) memory 24, which may include any kind of volatile and/or non- volatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only

Memory). Such memory 24 may be configured to store code executable by control circuitry and/or other data, e.g., data pertaining to communication, e.g., configuration and/or address data of nodes, etc. Processing circuitry 22 may be configured to control any of the methods described herein (such as, for example, the methods described with reference to FIG. 7) and/or to cause such methods to be performed, e.g., by processor 26. Corresponding instructions may be stored in the memory 24, which may be readable and/or readably connected to the processing circuitry 22. In other words, processing circuitry 22 may include a controller, which may comprise a microprocessor and/or microcontroller and/or FPGA (Field-Programmable Gate Array) device and/or ASIC (Application Specific Integrated Circuit) device. It may be considered that processing circuitry 22 includes or may be connected or connectable to memory, which may be configured to be accessible for reading and/or writing by the controller and/or processing circuitry 22.

The transceiver 28 also includes a measurement report receiver 18 configured to receive a measurement report including beam level measurements from the

wireless device 16. The memory 24 is configured to store beam selection strategies 30 to be transmitted to the wireless device 16 via the beam selection strategy transmitter 32 of a transceiver 28. In some embodiments, the beam level

measurements included in the measurement report are based at least in part on the transmitted beam selection strategy 30.

FIG. 4 is a block diagram of an alternative embodiment of the network node 14, which may be implemented at least in part by software modules containing software executable by a processor to perform the functions described herein. The memory module 34 is configured to store beam selection strategies 30 to be transmitted to the wireless device 16 via the beam selection strategy transmitter 32 of a transceiver module 36. The transceiver module 36 also includes the measurement report receiver 18 configured to receive a measurement report including beam level measurements from the wireless device.

FIG. 5 is a block diagram of an embodiment of a wireless device 16 constructed in accordance with principles set forth herein. The wireless device 16 includes processing circuitry 42. In some embodiments, the processing circuitry 42 may include a memory 44 and processor 46, the memory 44 containing instructions which, when executed by the processor 46, configure processor 46 to perform the one or more functions described herein. In addition to a traditional processor and memory, processing circuitry 42 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry).

Processing circuitry 42 may include and/or be connected to and/or be configured for accessing (e.g., writing to and/or reading from) memory 44, which may include any kind of volatile and/or non- volatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only

Memory). Such memory 44 may be configured to store code executable by control circuitry and/or other data, e.g., data pertaining to communication, e.g., configuration and/or address data of nodes, etc. Processing circuitry 42 may be configured to control any of the methods described herein (such as, for example, the methods

described with reference to FIGS. 8 and/or 9) and/or to cause such methods to be performed, e.g., by processor 46. Corresponding instructions may be stored in the memory 44, which may be readable and/or readably connected to the processing circuitry 42. In other words, processing circuitry 42 may include a controller, which may comprise a microprocessor and/or microcontroller and/or FPGA (Field-Programmable Gate Array) device and/or ASIC (Application Specific Integrated Circuit) device. It may be considered that processing circuitry 42 includes or may be connected or connectable to memory, which may be configured to be accessible for reading and/or writing by the controller and/or processing circuitry 42.

The wireless device 16 also includes a transceiver 48 configured to transmit the measurement report to the network node 14. The memory 44 is configured to store beam strength measurements 50 measured by the wireless device 16. The processor 46 implements a beam selector 20 and a cell selector 52. The cell selector 52 is configured to select cells to be included in a measurement report. The beam selector 20 is configured to: for each selected cell, include a strongest beam in the measurement report. In some embodiments, the beam selector 20 is further configured to, when a number of beams in the measurement report exceeds a threshold number, transmit, via a transceiver 48, the measurement report to the network node 14.

FIG. 6 is a block diagram of an alternative embodiment of the wireless device

16, that includes software modules that contain software executable by a processor to perform functions of the wireless device 16. The memory module 54 is configured to store beam strength measurements 50 measured by the wireless device 16. The cell selector module 56 is configured to select cells to be included in a measurement report. The beam selector module 58 is configured to: for each selected cell, include a strongest beam in the measurement report. In some embodiments, the beam selector module 58 is further configured to, when a number of beams in the measurement report exceeds a threshold number, transmit, via a transceiver module 60, the measurement report to the network node 14.

FIG. 7 is a flowchart of an exemplary process in a network node 14 for configuring a wireless device 16 to include beams in a measurement report. The process includes processing circuitry 22 causing the network node 14 to transmit, via the beam selection strategy transmitter 32, a beam selection strategy to the wireless device 16 (block S lOO). The process also includes the processing circuitry 22 causing the network node 14 to receive, via the measurement report receiver 18, a

measurement report including beam level measurements from the wireless device 16, the beam level measurement included in the measurement report based at least in part on the transmitted beam selection strategy (block S 102).

In some embodiments of this process, the method includes the processing circuitry 22 causing the network node 14 to transmit an indication of a number of beams to be included in the measurement report to the wireless device 16. In some embodiments, processing circuitry 22 is further configured to cause the network node 14 to select the transmitted beam selection strategy from a plurality of beam selection strategies. In some embodiments, the processing circuitry 22 is further configured to cause the network node 14 to select a first beam selection strategy for a first number of cells to be reported by the wireless device 16; and select a second beam selection strategy for remaining cells to be reported by the wireless device 16, the first beam selection strategy being different from the second beam selection strategy.

FIG. 8 is a flowchart of an exemplary process in a wireless device 16 for selection of beams to be included in the measurement report. The process includes processing circuitry 42 selecting, via the cell selector 52, cells to be included in a measurement report (block S 104). The process also includes processing circuitry 42, via the beam selector 20, to, for each selected cell, include a strongest beam in the measurement report (block S 106). The process further includes processing circuitry 42 causing the wireless device 16 to transmit, via transceiver 48, the measurement report to a network node 14 (block S 108). In some embodiments, processing circuitry 42 causes the wireless device 16 to, when a number of beams in the measurement report exceeds a threshold number, transmit, via transceiver 48, the measurement report to a network node 14.

In some embodiments of this process, the method includes the processing circuitry 42 causing the wireless device 16 to include a number of beams in the measurement report until the number of beams exceeds a threshold number. In some embodiments, the transmission of the measurement report to the network node is in response to the number of beams in the measurement report exceeding the threshold number. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to include at least one beam in the measurement report above a beam strength threshold. In some embodiments, the beam strength threshold is an absolute threshold. In some embodiments, the strongest beam for each of the at least one cell is a best beam for each of the at least one cell. In some embodiments, the transmitted measurement report includes at least the strongest beam for each of the selected at least one cell. In some embodiments, the processing circuitry 14 is further configured to cause the wireless device to, for each of the at least one cell, include a next strongest beam in the measurement report. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to, after including at least the strongest beam for each of the selected at least one cell in the measurement report, select at least one remaining beam to be included in the measurement report. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to select at least one strongest beam among beams of the at least one cell that are not yet included in the measurement report. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to include the selected at least one remaining beam in the measurement report. In some embodiments, the transmitted measurement report includes the strongest beam for each of the selected at least one cell and the selected at least one remaining beam. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to sort selected cells to be included in the measurement report in a descending order of cell level quality; and select at least one beam of a strongest cell from the sorted selected cells to include in the measurement report. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to, if a number of beams included in the transmitted measurement report does not exceed a threshold number of beams, transmit beam level information associated with at least one non-triggered cell. In some embodiments, the processing circuitry 42 is further configured to cause the wireless device 16 to receive, from a network node 14, an indication of a beam selection strategy for including beams in the measurement report; and include the beams in the measurement report based on the indicated beam selection strategy.

FIG. 9 is a flowchart of an yet another exemplary process in a wireless device 16. The exemplary process comprises including, by e.g., processing circuitry 42, at least one beam in a measurement report based at least in part on whether the at least one beam exceeds a beam strength threshold (block S 110). The process further includes processing circuitry 42 causing the wireless device 16 to transmit, via e.g., transceiver 48, the measurement report to a network node 14 (block S 112).

In some embodiments of this process, the beam strength threshold is an absolute threshold. In some embodiments, the processing circuitry 42 causes the wireless device 16 to select at least one cell for the measurement report; and for each of the selected at least one cell, include at least another beam to be included in the measurement report. In some embodiments, the processing circuitry 42 further causes the wireless device 16 to, for each of the selected at least one cell, include at least a strongest beam in the measurement report.

Having described some embodiments of the present disclosure, a more detailed description of some of the embodiments will now be described with reference to FIGS. 10-16.

Some embodiments advantageously provide a method and apparatus where the wireless device 16 can be configured by the network, e.g., network node 14, to populate measurement reports with up to 'X' beams where this maximum number of beams are distributed for the reported cells according to different criteria. These different criteria can either be defined as a fixed wireless device 16 behavior (FIG. 10a), with 'X' being a configured value (FIG. 10b) or configurable, where the network, e.g., network node 14, can select one of the criteria (or "strategies") which could be translated into configuration e.g., per measObject or reportConfig (FIG. 10b). Different embodiments related to 'strategies' that could be either hardcoded at the wireless device 16 or configured by the network, e.g., network node 14, are included in the detailed explanation section.

Using at least some of the proposed methods to select the beams to be reported by the wireless device 16, the serving node, e.g., network node 14 (serving gNodeB in NR or serving eNodeB in LTE) obtains information related to each of the cells included in the measurement report, thus enabling the network, e.g., network node 14, to choose the handover candidate amongst the reported cells and provide beam level

information to the chosen target cell for contention free random access (CFRA) resource allocation.

In addition, more beam level information associated to multiple cells compared to basing a decision on few cells enables the network, e.g., network node 14, to take into account the fact that some cells may have a higher number of stable beams than others, which may be taken into account in the tradeoff between handover failure and handover ping-pongs.

FIG. 11 provides a flow chart of beam selection strategy for one of the embodiments of the invention. In this first embodiment, after the event triggering condition is satisfied, in step 201, and the cells are selected for the measurement report, in step 202, the wireless device 16 includes the strongest beam from each of the triggered cells, those cells that are included in the measurement report, in the measurement report, in step 203. The wireless device 16 determines whether the quota of 'X' beams is at least met, in step 204. If the number of beams included in the measurement report do not fill up the quota of 'X' beams to be reported, the wireless device 16 includes the second strongest beam and so on, as in step 205. If after including the second strongest beams the quota is still not filled up, the wireless device 16 can include the third strongest beams and so on, until the quota is at least met and the wireless device 16 can send the measurement report, in step 206.

Notice that different cells may have a different number of detectable beams.

Hence, by interpreting the results, the network, e.g., network node 14, can determine how many beams per cell were detectable or not, where detectable relates to the number of beams after L3 filtering (alternatively, only good beams could be reportable, i.e., the ones above an absolute threshold, or within a relative threshold from the best beam). Different steps in the flowchart could be best explained using an example. Thus, the following description may assume the cell and beam level measurements as provided in Table 1 below to be available at the wireless device 16 when the event triggering condition is satisfied. In this example, the network, e.g., network node 14, has configured the wireless device 16 with 'X' as four.

This arrangement may allow the network, e.g., network node 14, to understand the best beam of each reported cell, at least if X is set to a higher value than the number of detectable cells that are to be included in the measurement reports. In other words, the strategy provides some diversity for the network, e.g., network node 14, to know the best beam of neighbor candidates, likely the beams the wireless device 16 may connect to after a handover. And, in the case of a handover request (where that reported beam information can be included in a HandoverPreparationlnformation container) to be target, any selected target cell by the source is able, to a certain extent, to provide contention-free Random Access Channel (RACH) resources (as all candidates may have at least some best beam information).

FIG. 12 provides a flow chart of a second embodiment. In step 301, an event triggering condition may be satisfied to trigger a measurement report. In step 302, the wireless device 16 selects the cells to be included in the measurement report, which may correspond to Ύ number of cells to be included in the measurement report. In step 303, the wireless device 16 includes the strongest beams from the selected cells, e.g., cell-A and cell-B, in the measurement report. The wireless device 16 could include, those cells that have triggered the measurement report, those cells whose Time-to-Trigger is running but not yet expired, those cells who have more than few beams above a certain absolute/relative threshold, etc.

In step 303, for example, the wireless device 16 includes {Beam (1,A), Beam (1,B)} in the measurement report.

In step 304, the wireless device 16 determines whether the total number of beams in the measurement report at least meets the quota 'X' . In the example, the wireless device 16 may determine that it can add two more beams to the measurement report.

In step 305, the wireless device 16 determines whether the number of beams in the measurement report plus Y at least meets the quota 'X' . If no, the process proceeds to step 306, otherwise the process proceeds to step 307. In the example, the wireless device 16 includes {Beam (2,A), Beam (2,B)} in the measurement report.

In step 308, the wireless device 16 sends a measurement report which amongst other things includes {Beam (1,A), Beam (1,B), Beam (2,A), Beam (2,B)}.

In this example, the value 'X' was 4, which is a multiple of the number of cells included in the measurement report. If that is not the case, for example, if X==5, in a second embodiment of the invention as shown in FIG. 12, the wireless device 16 proceeds to step 307 and includes the fifth beam to be the one that is strongest

amongst the rest of the beams from the cells included in step 302. Based on this embodiment, for X==5, the wireless device 16 includes {Beam (1,A), Beam (1,B), Beam (2,A), Beam (2,B), Beam (3,B)} as part of the beam level information in the measurement report.

A third embodiment is contemplated for the scenario when 'X' is not a multiple of number of cells included in the measurement report. This is illustrated in FIG. 13. In this embodiment, if the number of beams to be filled in is less than the number of beams already included in the measurement report (as mentioned in step 405), the wireless device 16 will select the beams of those cells, cells as chosen in 402, that have the higher cell level measurement values. Based on this embodiment, for X==5, the wireless device 16 should include {Beam (1,A), Beam (1,B), Beam (2,A), Beam (2,B), Beam (3,A)} in the example (using the data from Table 1 below), as part of the beam level information in the measurement report.


TABLE 1: Example cell and beam level RSRP measurements at the wireless device

In a fourth embodiment, the wireless device 16 is made to include at least one beam for each of the cells included in the measurement report. This embodiment is described in FIG. 14. In step 502, the wireless device 16 selects the cells Y to be included in the measurement report. The wireless device 16 then includes the strongest beam for each of the Y cells included in the measurement report, as indicated in step 503. If the quota X has not yet been met according to step 504, then considering that Ύ' cells are included in the measurement report in step 502, the wireless device 16 will fill up the rest of (X-Y) beams as the strongest beams amongst the remaining beams of the Y cells included in the measurement report, per step 505. Once the beam quota X is met, the measurement report is sent, in step 506. For the example given in Tablel, with X=4, the wireless device 16 will include Beam (1,A) and Beam (1,B), per step 503 and include Beam (2,A) and Beam (2,B), per step 505. Thus, the measurement report will be sent, per step 506, as including {Beam (1,A), Beam (1,B), Beam (2,A), Beam (2,B)} as part of the beam level information in the measurement report. If X==5, the wireless device 16 will include {Beam (1,A), Beam (1,B), Beam (2,A), Beam (2,B), Beam (3,B)} as part of the beam level information in the measurement report.

FIG. 15 describes a fifth embodiment. In the fifth embodiment, in step 601, an event triggering condition may be satisfied to trigger a measurement report. In step 602, the wireless device 16 selects the cells to be included in the measurement report, which may correspond to Ύ number of cells to be included. In step 603, the wireless device 16 may then include the strongest 'X' beams that the wireless device 16 receives. The strongest 'X' beams may be determined by selecting the strongest 'X' beams amongst the beams above a detected threshold, as indicated in FIG. 15. For each beam, there may be an indication of which cell the beam belongs to. They can also be encoded per cell. In an alternative embodiment, as provided in step 603' in FIG. 15, the wireless device 16 is configured to select the strongest 'X' beams amongst the beams of the cells that are already included in the measurement report from step 602.

FIG. 16 describes a sixth embodiment. In the sixth embodiment, the wireless device 16 will first include the strongest beams in the order for the strongest triggered cell. If the number of detected beams is higher than X, the wireless device 16 will include the strongest X beams. If the number of detected beams is lower than X, the wireless device 16 will include the strongest detected beams for the strongest

triggered cell and check the detected beams (whose L3 measurement are available) to include the beam information from the second best triggered cell. If still X is not filled in, the process may continue until the total number of beams included in the measurement report at least meets the quota 'X' beams. This arrangement allows the network, e.g., network node 14, to prioritize more information to be reported for the most likely candidates to be the target cell, i.e., the strongest / triggered cells, and, provides more flexibility for these cells to configure contention free random-access resources.

In a seventh embodiment, when triggered cell beams are reported and X is not met or exceeded, the wireless device 16 can include beam level information related to non-triggered cells in the same manner as any of the previous strategies described.

In an eighth embodiment, the network, e.g., the network node 14, can choose between any one of these strategies depending on what the network wants to prioritize. For example, if the network node 14 wants beam reporting to prioritize ping-pong avoidance, the network node 14 can configure the strategy where beam information for more cells is reported. If the network node 14 wants more flexibility in terms of contention free RACH resource allocation, it may prefer that the network node 14 prioritize more beam information for the strongest cells. There can be further parameters configured by the network node 14 such as, for example, the number of cells to be first used for one strategy to then go for another strategy. For example, network node 14 can configure the wireless device 16 to apply the best beam per cell strategy at least for the Y/n cells and, another strategy for the remaining cells to be reported, e.g. starting with best beam per cell, then second best, etc., where n may represent a total number of cells to be included in the measurement report and Y represents a number of cells on which a first strategy, e.g., best beam per cell, may be applied.

For the evaluation of the quality, any of the reporting quantities (e.g., Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), Signal to Interference-and-Noise Ratio (SINR)) could be used.

Also, in some embodiments where more than one RS (Reference Signal) is configured for Radio Resource Management (RRM) measurements, the network, such

as via the network node 14, may be able to choose the beam selection strategy and the value of 'X' specific to the RS type used.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, and/or computer program product. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a "circuit" or "module." Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other

programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that

communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

It will be appreciated by persons skilled in the art that the present embodiments are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings, without departing from the scope of the following claims.