Einige Inhalte dieser Anwendung sind momentan nicht verfügbar.
Wenn diese Situation weiterhin besteht, kontaktieren Sie uns bitte unterFeedback&Kontakt
1. (WO2018067050) SPATIAL MULTIPLEXING TRANSMISSION
Anmerkung: Text basiert auf automatischer optischer Zeichenerkennung (OCR). Verwenden Sie bitte aus rechtlichen Gründen die PDF-Version.

CLAIMS

1. A method for spatial multiplexing transmission from spatially separated transmission points (iioa, nob, HOC) in a network (looa, loob, looc, lood, looe) where transmit antennas are distributed between antenna branches on at least two of the spatially separated transmission points, the method being performed by a network node (200), the method comprising:

determining (S102) channel conditions based on measurements of received signal strength per antenna branch for an uplink signal received from a wireless device (140a, 140b);

estimating (S104) channel rank for each of at least two sub-sets of the transmission points based on the channel conditions; and

initiating (S108) the spatial multiplexing transmission to the wireless device from the sub-set of transmission points having highest channel rank.

2. The method according to claim 1, wherein the channel conditions comprise amplitude and phase of the uplink signal.

3. The method according to any of the preceding claims wherein the channel rank is estimated based on at least one of eigenvalues, singular values, condition numbers, and ratios of singular values.

4. The method according to claim 2 or 3, wherein estimating the channel rank comprises:

determining (Si04a) singular values of a channel matrix defined by the channel conditions; and

estimating (Si04b) the channel rank from a ratio of the singular values, wherein a respective ratio is determined for each of the at least two sub-sets of transmission points.

5. The method according to any of the preceding claims, wherein the spatial multiplexing transmission is initiated such that different spatial multiplexing transmission layers are transmitted from different transmission points in the sub-set of transmission points having highest channel rank.

6. The method according to any of the preceding claims, wherein the uplink signal is an uplink sounding reference signal.

7. The method according to any of the preceding claims, wherein each of the transmission points comprises at least two of the antenna branches, the method further comprising:

estimating (S104C) a further channel rank for different sub-sets of the antenna branches at one or more of the transmission points, and

wherein the spatial multiplexing transmission is initiated to the wireless device from the sub-set of antenna branches having highest channel rank.

8. The method according to claim 7, wherein the further channel rank is based on the channel conditions.

9. The method according to claim 7 or 8, wherein, when the further channel rank is below a channel rank threshold value, the sub-set of transmission points for which the spatial multiplexing transmission is initiated from comprises at least two transmission points.

10. The method according to any of the preceding claims, further

comprising:

determining (S106) a difference between the measurements of received signal strength per antenna branch and measurements of received signal strength per antenna branch for a further uplink signal received from the wireless device, and

wherein the sub-set of transmission points for which the spatial multiplexing transmission is initiated from comprises at least two

transmission points only when said difference is smaller than a threshold value.

11. The method according to any of the preceding claims, wherein the transmission points are associated with a radio access node (130), and wherein the threshold value is based on at least one of number of wireless devices served by the radio access node, data buffer size of the transmission points, and channel utilization.

12. The method according to any of the preceding claims, wherein the transmission points are associated with a radio access node (130) having a load parameter with a value, and wherein those transmission points for which the load parameter value fulfils a threshold criterion are excluded from the determination of channel rank.

13. The method according to claim 12, wherein the load parameter is based on number of wireless devices served by the radio access node.

14. The method according to claim 13, wherein for each of the served wireless devices one of the transmission points is excluded from each of the sub-sets of transmission points.

15. The method according to claim 11, wherein the load parameter is based on amount of data to be transmitted by the radio access node.

16. The method according to claim 14, wherein how many of the

transmission points to be in each of the sub-sets of transmission points is dependent on the load.

17. The method according to any of the preceding claims, wherein the network (100a, 100b, 100c, lood, lood, looe) is a time division duplex, TDD, network.

18. A network node (200) for spatial multiplexing transmission from spatially separated transmission points (110a, nob, 110c) in a network (100a, 100b, 100c, lood, looe) where transmit antennas are distributed between antenna branches on at least two of the spatially separated transmission points, the network node (200) comprising processing circuitry (210), the processing circuitry being configured to cause the network node (200) to: determine channel conditions based on measurements of received signal strength per antenna branch for an uplink signal received from a wireless device (140a, 140b);

estimate channel rank for each of at least two sub-sets of the

transmission points based on the channel conditions; and

initiate the spatial multiplexing transmission to the wireless device from the sub-set of transmission points having highest channel rank.

19. A network node (200) for spatial multiplexing transmission from spatially separated transmission points (110a, nob, 110c) in a network (100a, 100b, 100c, lood, looe) where transmit antennas are distributed between antenna branches on at least two of the spatially separated transmission points, the network node (200) comprising:

processing circuitry (210); and

a storage medium (230) storing instructions that, when executed by the processing circuitry (210), causes the network node (200) to:

determine channel conditions based on measurements of received signal strength per antenna branch for an uplink signal received from a wireless device (140a, 140b);

estimate channel rank for each of at least two sub-sets of the transmission points based on the channel conditions; and

initiate the spatial multiplexing transmission to the wireless device from the sub-set of transmission points having highest channel rank.

20. A network node (200) for spatial multiplexing transmission from spatially separated transmission points (110a, 110b, 110c) in a network (100a, 100b, 100c, lood, looe) where transmit antennas are distributed between antenna branches on at least two of the spatially separated transmission points, the network node (200) comprising:

a determine module (210a) configured to determine channel conditions based on measurements of received signal strength per antenna branch for an uplink signal received from a wireless device (140a, 140b);

an estimate module (210b) configured to estimate channel rank for each of at least two sub-sets of the transmission points based on the channel conditions; and

an initiate module (2iog) configured to initiate the spatial multiplexing transmission to the wireless device from the sub-set of transmission points having highest channel rank.

21. A radio access node (130) comprising a network node (200) according to any of claims 18, 19, or 20.

22. A computer program (820) for spatial multiplexing transmission from spatially separated transmission points (110a, nob, 110c) in a network (100a, 100b, 100c, lood, looe) where transmit antennas are distributed between antenna branches on at least two of the spatially separated transmission points, the computer program comprising computer code which, when run on processing circuitry (210) of a network node (200), causes the network node (200) to:

determine (S102) channel conditions based on measurements of received signal strength per antenna branch for an uplink signal received from a wireless device (140a, 140b);

estimate (S104) channel rank for each of at least two sub-sets of the transmission points based on the channel conditions; and

initiate (S108) the spatial multiplexing transmission to the wireless device from the sub-set of transmission points having highest channel rank.

23. A computer program product (810) comprising a computer program (820) according to claim 22, and a computer readable storage medium (830) on which the computer program is stored.