Multi-carrier communications with adaptive cluster configuration and switching

• US 20020147017A1
• Filed: 04/17/2001
• Published: 10/10/2002
• Est. Priority Date: 12/15/2000
• Status: Active Grant

• Current Assignee: Adaptix, Inc. (Acacia Research Corporation)
• Original Assignee: SDR Holdings, LLC
• Inventors: Zhang, Wenzhong, Li, Xiaodong, Liu, Hui, Li, Kemin
• Granted Patent: US 7,146,172 B2
• Time in Patent Office: Days
• US Class Current: 455/447
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0005 applied to payload information
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0011 applied to payload information
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0079 Formats for control data H04L1/16 takes precedence; training sequences H04L25/00 and H04L27/00
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0035 : Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0037 : Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0042 : intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0046 : Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/0048 : Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/005 : of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/006 : Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 : Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0073 : Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04L 5/0082 : at predetermined intervals
• CPC Class Codes: H04L 5/0094 : Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 5/023 : Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 24/08 : Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 72/04 : Wireless resource allocation
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/20 : Control channels or signalling for resource management
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/541 : using the level of interference
• CPC Class Codes: H04W 72/542 : using measured or perceived quality
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02

Abstract

A method and apparatus for allocating subcarriers in an orthogonal frequency division multiple access (OFDMA) system is described. In one embodiment, the method comprises allocating at least one diversity cluster of subcarriers to a first subscriber and allocating at least one coherence cluster to a second subscriber.

Claims

1. A method for use in allocating subcarriers in an OFDMA system comprising

allocating at least one diversity cluster of subcarriers to a first subscriber;

and

allocating at least one coherence cluster to a second subscriber.

2. The method defined in claim 1 wherein the first subscriber comprises a mobile subscriber and the second subscriber comprises a fixed subscriber.

3. The method defined in claim 1 wherein the first subscriber comprises a fixed subscriber located at a cell edge.

4. The method defined in claim 1 further comprising transmitting information using one diversity cluster while performing frequency hopping.

5. The method defined in claim 1 wherein using one diversity cluster includes channel coding across subcarriers of the one diversity cluster.

6. The method defined in claim 1 further comprising transmitting codewords in which each codeword contains bits transmitted from multiple subcarriers and with difference bits between codewords being distributed among multiple subcarriers.

7. The method defined in claim 1 wherein subcarriers of one coherence cluster are within the coherent bandwidth of a channel between a base station and a subscriber.

8. The method defined in claim 1 further comprising updating allocation of clusters to the subscriber.

9. The method defined in claim 1 further comprising reconfiguring cluster classification when population of mobile and fixed subscribers in a cell changes.

10. The method defined in claim 1 wherein the at least one diversity cluster is configured to reduce the effect of inter-cell interference.

11. A method for use in allocating subcarriers in an OFDMA system comprising

determining whether a subscriber is mobile or fixed;

allocating at least one diversity cluster of subcarriers to the subscriber if the subscriber is determined to be mobile; and

allocating at least one coherence cluster of subcarriers to the subscriber if the subscriber is determined to be fixed.

12. The method defined in claim 11 wherein determining whether a subscriber is mobile or fixed comprises detecting a rate of change of pilot signals and indicating a subscriber is mobile when the rate of change is greater than a predetermined amount.

13. The method defined in claim 11 wherein determining whether a subscriber is mobile or fixed comprises measuring channel variation periodically.

14. The method defined in claim 11 wherein determining whether a subscriber is mobile or fixed comprises measuring channel variation periodically for each cluster.

15. The method defined in claim 11 wherein determining whether a subscriber is mobile or fixed comprises measuring SINR values periodically for each cluster.

16. The method defined in claim 11 wherein determining whether a subscriber is mobile or fixed comprises measuring a power difference between pilot symbols for each cluster and averaging the difference over a window of time slots.

17. The method defined in claim 16 wherein the window of time slots comprises a moving window of time slots.

18. The method defined in claim 17 wherein the window of time slots comprises four time slots.

19. The method defined in claim 11 further comprising transmitting information using one diversity cluster while performing frequency hopping.

20. The method defined in claim 11 wherein using one diversity cluster includes channel coding across subcarriers of the one diversity cluster.

21. The method defined in claim 11 further comprising transmitting codewords in which each codeword contains bits transmitted from multiple subcarriers and with difference bits between codewords being distributed among multiple subcarriers.

22. The method defined in claim 11 wherein subcarriers of one coherence cluster are within the coherent bandwidth of a channel between a base station and a subscriber.

23. The method defined in claim 11 further comprising updating allocation of clusters to the subscriber.

24. The method defined in claim 11 further comprising reconfiguring cluster classification when population of mobile and fixed subscribers in a cell changes.

25. The method defined in claim 11 wherein the at least one diversity cluster is configured to reduce an effect of inter-cell interference.

27. The apparatus defined in claim 26 wherein the variation detector is located at the base station.

28. The apparatus defined in claim 26 wherein the variation detector is located at the subscriber.

29. The apparatus defined in claim 26 wherein the variation detector measures channel variation periodically for each cluster.

30. The apparatus defined in claim 26 wherein the variation detector measures SINR values periodically for each cluster.

31. The apparatus defined in claim 26 wherein the variation detector measures a power difference between pilot symbols for each cluster and average the difference over a window of time slots.

32. The apparatus defined in claim 31 wherein the window of time slots comprises a moving window of time slots.

33. The apparatus defined in claim 32 wherein the window of time slots comprises four time slots.

35. The apparatus defined in claim 34 wherein the means for determining whether a subscriber is mobile or fixed comprises means for detecting a rate of change of pilot signals and indicating a subscriber is mobile when the rate of change is greater than a predetermined amount.

36. The apparatus defined in claim 34 wherein the means for determining whether a subscriber is mobile or fixed comprises means for measuring channel variation periodically for each cluster.

37. The apparatus defined in claim 34 wherein the means for determining whether a subscriber is mobile or fixed comprises means for measuring SINR values periodically for each cluster.

38. The apparatus defined in claim 34 wherein the means for determining whether a subscriber is mobile or fixed comprises means for measuring a power difference between pilot symbols for each cluster and averaging the difference over a window of time slots.

39. The apparatus defined in claim 38 wherein the window of time slots comprises a moving window of time slots.

40. The apparatus defined in claim 39 wherein the window of time slots comprises four time slots.

41. The apparatus defined in claim 34 further comprising means for transmitting information using one diversity cluster while performing frequency hopping.

42. The apparatus defined in claim 11 wherein using one diversity cluster includes channel coding across subcarriers of the one diversity cluster.

43. The apparatus defined in claim 11 further comprising means for transmitting codewords in which each codeword contains bits transmitted from multiple subcarriers and with difference bits between codewords being distributed among multiple subcarriers.

44. The apparatus defined in claim 34 wherein subcarriers of one coherence cluster are within the coherent bandwidth of a channel between a base station and a subscriber.

45. The apparatus defined in claim 11 further comprising means for updating allocation of clusters to the subscriber.

46. The apparatus defined in claim 34 further comprising means for reconfiguring cluster classification when population of mobile and fixed subscribers in a cell changes.

47. The apparatus defined in claim 34 wherein the at least one diversity cluster is configured to reduce an effect of inter-cell interference.

26. An apparatus comprising:

a subscriber;

a base station including a subcarrier allocator, the base station being communicatively coupled to the subscriber;

a variation detector to detect channel variation, wherein the subcarrier allocator allocates either one or more diversity clusters of subcarriers or one or more coherence clusters of subcarriers to the subscriber based on results of channel variation detection by the variation detector.

34. An apparatus for use in allocating subcarriers in an OFDMA system, the apparatus comprising

means for determining whether a subscriber is mobile or fixed;

means for allocating at least one diversity cluster of subcarriers to the subscriber if the subscriber is determined to be mobile; and

means for allocating at least one coherence cluster of subcarriers to the subscriber if the subscriber is determined to be fixed.