System and related methods for beamforming in a multi-point communications environment

• US 20030064753A1
• Filed: 09/28/2001
• Published: 04/03/2003
• Est. Priority Date: 09/28/2001
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Zhan, Jun, Liu, Jason, Kasapi, Athanasios A.
• Application Number:
  US09/967,568
• Publication Number:
  US 20030064753A1
• Time in Patent Office: Days
• US Class Current: 455/561
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A system and related methods for beamforming in a multi-point communication environment is presented. According to one aspect of the invention, a method comprising identifying one or more spatial signature attributes associated with each of a plurality of targets in a wireless communication system, and assigning one or more of the plurality of targets into a cluster based, at least in part, on the identified one or more spatial signature attributes, wherein the target(s) populating a cluster will each share wireless communication channel(s).

Claims

1. A method comprising:

identifying one or more spatial signature attributes associated with each of a plurality of targets in a wireless communication system; and

assigning one or more of the plurality of targets to a cluster based, at least in part, on the identified one or more spatial signature attributes, wherein the target(s) populating a cluster will each share wireless communication channel(s).

2. A method according to claim 1, wherein identifying one or more spatial signature attributes comprises:

calculating a composite spatial signature distance differential between each target and all remaining unclustered target(s).

3. A method according to claim 2, wherein the composite spatial signature distance differential comprises a sum of distance differentials between a normalized spatial signature of the target and each remaining unclustered target.

4. A method according to claim 3, wherein the normalized spatial signature distance differential between target (i) and target (j) is calculated according to d_i,j=|a_i−

(aⁱ′

*a_j)a_j|.

5. A method according to claim 4, wherein the composite spatial signature distance differential for target (i) is calculated according to d_i=Σ

(d_i,j) over all targets j.

6. A method according to claim 2, further comprising:

identifying a target with a lowest relative composite spatial signature distance differential as an anchor for a cluster; and

identifying up to (N−

1) additional targets with a next-lowest relative composite spatial signature distance differential, wherein the relative composite spatial signature distance differential does not exceed a threshold, and adding such targets to the cluster.

7. A method according to claim 6, wherein N is a maximum number of targets permitted within a cluster.

8. A method according to claim 7, wherein the maximum number of targets permitted within a cluster is based, at least in part, on the multiple access type of the wireless communication system.

9. A method according to claim 1, further comprising:

developing a cluster spatial signature for at least a subset of cluster(s); and

generating a transmission beam to targets within one or more cluster(s) based, at least in part, on the cluster spatial signature.

10. A method according to claim 1, wherein identifying one or more spatial attributes comprises:

calculating a normalized spatial signature distance differential between at least a subset of targets in a wireless communication system.

11. A method according to claim 10, wherein the normalized spatial signature distance differential between two targets (i) and (j) is determined by calculating an inner product (d_i,j) between normalized spatial signatures (a_i) and (a_j) associated with such targets.

12. A method according to claim 11, wherein the inner product is calculated as:

(d_i,j)=|a_i−

(a_i′

*a_j)a_j|.

13. A method according to claim 11, wherein assigning comprises:

establishing a cluster target pool, wherein targets with a normalized spatial signature differential that does not exceed a threshold are added to the pool; and

eliminating target(s) from the cluster target pool whose normalized spatial signature distance differential to other targets exceeds a threshold.

14. A method according to claim 13, wherein the first threshold and the second threshold are set to common value.

15. A method according to claim 13, further comprising:

eliminating target(s) from the cluster target pool that exhibit a higher normalized spatial signature distance differential than other target(s) if the cluster target pool is too large.

16. A method according to claim 13, further comprising:

assigning additional channel(s) to handle at least a subset of targets within a cluster if the number of targets in the cluster exceed a bandwidth capability of a single channel to service such multiple targets.

17. A method according to claim 13, further comprising:

assigning a target to a cluster despite dissimilar spatial signature attribute(s); and

servicing the target with a disparate communication channel resource(s).

18. A method according to claim 1, wherein the physical channel into which the targets are assigned is a subset of a larger set of channel which may be assigned to other cluster(s) and/or target(s).

19. In a wireless communication system implementing general packet radio services (GPRS), a method comprising:

populating cluster(s) with one or more target(s) that share similar spatial signature attribute(s); and

calculating a cluster spatial signature for at least a subset of the populated clusters from which transmission weight(s) are generated and applied to transmission of a communication channel to spatially direct the communication channel to target(s) within the cluster.

20. A method according to claim 19, further comprising:

modifying one or more physical properties of a signal associated with the communication channel to form a transmission beam to the target(s) within the cluster based, at least in part, on the cluster spatial signature.

21. A method according to claim 19, further comprising:

transmitting the formed transmission beam to the cluster(s).

22. A method according to claim 19, wherein populating cluster(s) comprises:

identifying one or more spatial signature attributes associated with each of a plurality of targets in a wireless communication system; and

assigning one or more of the plurality of targets into a cluster based, at least in part, on the identified one or more spatial signature attributes, wherein the target(s) populating a cluster will each share a wireless communication link.

23. A method according to claim 22, wherein identifying one or more spatial signature attributes comprises:

calculating a composite spatial signature distance differential between each target and all remaining unclustered target(s).

24. A method according to claim 23, wherein the composite spatial signature distance differential comprises a sum of distance differentials between a normalized spatial signature of the target and each remaining unclustered target.

25. A method according to claim 22, further comprising:

identifying a target with a lowest relative composite spatial signature distance differential as an anchor for a cluster; and

identifying up to (N−

1) additional targets with a next-lowest relative composite spatial signature distance differential, wherein the relative composite spatial signature distance differential does not exceed a threshold, and adding such targets to the cluster.

26. A method according to claim 25, wherein N is a maximum number of targets permitted within a cluster and serviced by a single channel.

27. A method according to claim 26, wherein another channel is assigned to support communication to at least a subset of target(s) within a cluster if the number of target(s) within the cluster exceed a threshold (N).

28. A method according to claim 25, where N is equal to eight or less in a wireless communication system implementing GPRS.

29. A storage medium comprising content which, when executed by an accessing computing device, causes the device to implement a method according to claim 19.

33. A transceiver according to claim 23, wherein the clustering engine calculates a composite spatial signature distance differential between each target and all remaining unclustered target(s).

34. A transceiver according to claim 33, wherein the composite spatial signature distance differential comprises a sum of distance differentials between a normalized spatial signature of the target and each remaining unclustered target.

35. A transceiver according to claim 33, wherein the clustering engine identifies a target with a lowest relative composite spatial signature distance differential as an anchor for a cluster, and identifies up to (N−

1) additional targets for the cluster having a next-lowest relative composite spatial signature distance differential, wherein the relative composite spatial signature distance differential does not exceed a threshold.

36. A transceiver according to claim 35, wherein N is a maximum number of targets permitted within a cluster.

37. A transceiver according to claim 36, wherein additional channel(s) are assigned to support subset(s) of target(s) within a cluster if the number of targets within a cluster exceeds a threshold (N).

38. A transceiver according to claim 33, the communications agent further comprising:

a beamforming engine, responsive to the clustering engine, to modify one or more physical characteristics of a transmission signal associated with the communication channel to form a beam directed at target(s) within one or more cluster(s) based, at least in part, on the generated cluster spatial signature.

39. A transceiver according to claim 38, wherein the beamforming engine modifies one or more of an amplitude and/or phase characteristic(s) of a signal to form a beam directed to target(s) within one or more cluster(s).

40. A transceiver according to claim 19, the communication agent comprising:

a beamforming engine, to modify one or more physical characteristics of a transmission signal associated with the communication channel to form a beam directed at target(s) within one or more cluster(s) based, at least in part, on the generated cluster spatial signature.

41. A transceiver according to claim 19, further comprising:

a memory subsystem having stored therein content; and

control logic, coupled with the memory subsystem, to access and execute at least a subset of the stored content to implement the communications agent.

30. A transceiver comprising:

wireless communication resources; and

a communication agent, coupled with the wireless communication resources, to populate cluster(s) with one or more target(s) sharing similar spatial signature attributes, and to calculate a cluster spatial signature for at least a subset of the populated clusters from which transmission weight(s) are generated and applied to transmission of a communication channel to spatially direct the communication channel to target(s) within the cluster.

31. A transceiver according to claim 30, wherein the wireless communication resources include at least a transmitter subsystem, and the communication channel is a downlink communication channel.

32. A transceiver according to claim 30, the communication agent comprising:

a clustering engine, to identify one or more spatial signature attributes associated with each of a plurality of targets in a wireless communication system, and to assign one or more of the plurality of targets into a cluster based, at least in part, on the identified one or more spatial signature attributes, wherein the target(s) populating a cluster will each share a wireless communication channel with at least a subset of any other target(s) within the cluster.

42. A method comprising:

calculating a spatial signature of each of a plurality of targets in a wireless communication system;

comparing the spatial signature of at least one target with at least one other target; and

assigning physical channel resource(s) to said targets such that targets with substantially different spatial signatures are assigned different physical channel resources.

43. A method according to claim 42, wherein comparing the spatial signature of targets comprises:

calculating a normalized spatial signature differential (d_i,j) between a normalized spatial signature (a_i) associated with one target (i) and a normalized spatial signature (a_j) associated with another target (j).

44. A method according to claim 43, wherein the normalized spatial signature differential (d_i,j) is calculated according to d_i,j=|a_i−

(a_i′

* a_j)a_j}, where a_i′

is the complex conjugate of the normalized spatial signature (a_i) for target (i).

45. A method according to claim 43, wherein targets whose normalized spatial signature differential (d_i,j) does not exceed a threshold exhibit a substantially similar spatial signature, and are grouped in a cluster target pool.

46. A method according to claim 45, further comprising:

computing an average distance differential between each target in the cluster target pool and other target(s) within the pool; and

eliminating target(s) whose average distance differential with at least one other target in s the pool exceeds a threshold.

47. A method according to claim 46, further comprising:

assigning common communication channel resource(s) to at least a subset of target(s) remaining within the cluster target pool.