Method and system for switching antenna and channel assignments in broadband wireless networks

• US 20090274059A1
• Filed: 07/07/2009
• Published: 11/05/2009
• Est. Priority Date: 12/07/2004
• Status: Active Grant

• Current Assignee: Adaptix, Inc. (Acacia Research Corporation)
• Original Assignee: Adaptix, Inc. (Acacia Research Corporation)
• Inventors: Liu, Hui, Xing, Guanbin, Shen, Manyuan
• Granted Patent: US 8,797,970 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• 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 72/542 using measured or perceived quality

Abstract

A method and apparatus for antenna switching, grouping, and channel assignments in wireless communication systems. The invention allows multiuser diversity to be exploited with simple antenna operations, therefore increasing the capacity and performance of wireless communications systems. Channel characteristics indicative of signal reception quality for downlink or bi-directional traffic for each channel/antenna resource combination are measured or estimated at a subscriber. Corresponding channel characteristic information is returned to the base station. Channel characteristics information may also be measured or estimated for uplink or bi-directional signals received at each of multiple receive antenna resources. The base station employs channel allocation logic to assign uplink, downlink and/or bi-directional channels for multiple subscribers based on channel characteristics measured and/or estimated for the uplink, downlink and/or bi-directional channels.

Claims

1. A method for assigning channels to support communication between one or more subscribers and a base station in a broadband wireless network, comprising:

for each of multiple antenna resources configured for communication on multiple channels, at the said base station, obtaining one or more channel characteristics for each channel hosted by each antenna resource, the channel characteristics indicative of reception quality for a corresponding channel; and

assigning, at the base station, one or more channels to the one or more subscribers based on the one or more channel characteristics that are obtained;

wherein said obtaining one or more channel characteristics is accomplished, at least in part, by ranging operations performed by the one or more subscribers.

2. The method of claim 1, wherein the one or more channels assigned comprise one or more downlink channels for use with transmissions sent from the base station to the one or more subscribers.

3. The method of claim 1, wherein the one or more channel assigned comprise one or more uplink channels for use with transmissions sent from the one or more subscribers to the base station.

4. The method of claim 1, wherein the one or more channel assigned comprise one or more bi-directional link channels employed for both uplink and downlink transmissions between the base station and the one or more subscribers.

5. The method of claim 1, wherein the channel characteristics are measured by performing operations comprising:

broadcasting a respective beacon signal from each of the antenna resources at the base station, each beacon signal including transmissions over multiple channels;

measuring channel characteristics indicative of signal quality for each of the multiple channels at a subscriber; and

sending data corresponding to the channel characteristics that are measured from the subscriber to the base station.

6. The method of claim 5, wherein the respective beacon signals that are broadcast from each of the antenna resources comprise orthogonal frequency division multiple access (OFDMA) signals including OFDMA pilot symbols.

7. The method of claim 6, further comprising the subscriber using information from pilot symbol periods and data periods to measure channel and interference information.

8. The method of claim 6, wherein the pilot symbols occupy an entire OFDM frequency bandwidth.

10. The method of claim 1, wherein the multiple antenna resources comprises multiple individual antennas.

11. The method of claim 1, wherein at least one antenna resource comprises a set of antennas that are operated collectively to perform at least one of transmit and receive radio frequency transmissions.

12. The method of claim 1, wherein the wireless broadband network supports OFDMA (orthogonal frequency division multiple access) transmissions, and the channels comprise combinations of OFDMA subchannels and antenna resources.

13. The method of claim 12, further comprising switching antennas by adjusting the inputs to fast Fourier transform (FFT) blocks in an OFDMA transmitter module at the base-band.

14. The method of claim 12, wherein each subscriber is assigned to a single OFDMA channel, transmission for the single channel provided by a single antenna resource.

15. The method of claim 1, wherein the channel assignment operations are employed to assign respective channels for downlink and uplink transmissions.

16. The method of claim 1, wherein the channel characteristic measurements comprise at least one of Signal-to-interference plus noise ratio (SINR), carrier-to-interference plus noise ratio (CINR) and relative-signal strength indicator (RSSI) measurements.

17. The method of claim 1, wherein the channel characteristic measurements comprise bit error rate (BER) measurements.

18. The method of claim 1, wherein the channel characteristic measurements comprise measurement of Quality of Service (QoS) parameters.

19. The method of claim 1, wherein the channels comprise one of channels or subchannels corresponding to at least one of a FDMA (frequency division multiple access), TDMA (time division multiple access), CDMA (code division multiple access), OFDMA (orthogonal frequency division multiple access), and SDMA (space division multiple access) channel schemes.

20. The method of claim 1, further comprising:

periodically updating channel characteristics information for one or more subscribers; and

reassigning channels for at least one subscriber in view of changed channel characteristics.

9. (canceled)

21-32. -32. (canceled)

33. A method for assigning channels in a broadband wireless network, comprising:

obtaining one or more channel characteristics for each of multiple channels hosted by one or more antenna resources configured for communication, wherein said on or more antenna resources are located at a base station and wherein the channel characteristics are indicative of reception quality of the one or more subscribers;

determining, at said base station, an available channel with the highest gain among the antenna resources, wherein said determination is based at least on the one or more channel characteristics and available channels of the one or more antenna resources; and

assigning, at said base station, one or more channels to one or more subscribers, said assignment is based at least on said determination.

34. The method of claim 33 wherein obtaining channel characteristics comprises:

measuring, at the one or more subscriber stations, the one or more channel characteristics; and

reporting the measurements to said base station.

35. The method of claim 33 wherein obtaining channel characteristics comprises:

measuring, at said base station, the one or more channel characteristics.

36. The method of claim 35 further comprising:

receiving, at said base station, test data for one or more uplink channels from the one or more subscribers.

37. The method of claim 33 wherein said determination step is performed for each of the one or more subscribers in assigning the one or more channels.

38. The method of claim 33 further comprising:

storing the obtained one or more channel characteristics;

wherein the one or more characteristics are updated on an ongoing basis; and

maintaining and updating the available channels of the one or more antenna resources on an ongoing basis to provide current channel allocation information.

39. The method of claim 33 wherein said determination comprises:

selecting a channel with the highest gain for each of the antenna resources;

determining whether said selected channels are available;

if a selected channel for an antenna resource is not available, selecting a channel with the next best gain for said antenna resource;

comparing the gains of the selected channels; and

selecting the channel with the highest gain for assignment to the one or more subscribers in response to said comparison.

40. A base station, comprising:

one or more antenna resources for communication over a wireless communication system;

a transmission module to generate signals to transmit data over at least one downlink or bi-directional channel via the one or more antenna resources to one or more multiple subscribers;

a reception module to extract data from signals received at the one or more antenna resources over said at least one uplink or bi-directional channel from said one or more subscribers;

channel allocation logic to determine an available channel associated with highest gain among the antenna resources and assigning at least one of uplink, downlink, and bi-directional channels to the one or more subscribers, said assignment is based at least on said determination;

wherein said determination is based at least on available channels of the one or more antenna resources and one or more channel characteristics indicative of reception quality for a corresponding channel obtained at said base station.

41. The base station of claim 40 wherein obtaining channel characteristics comprises:

measuring, at the one or more subscriber stations, the one or more channel characteristics; and

reporting the measurements to said base station. one or more channel characteristics are obtained at the one or more subscribers.

42. The base station of claim 40 wherein obtaining channel characteristics comprises:

measuring, at said base station, the one or more channel characteristics.

43. The base station of claim 42 wherein said base station receives test data for one or more uplink channels from the one or more subscribers.

44. The base station of claim 40 further comprising:

a channel profile register for storing the obtained one or more channel characteristics;

wherein the one or more characteristics are updated on an ongoing basis; and

a channel assignment register for maintaining and updating the available channels of the one or more antenna resources on an ongoing basis to provide current channel allocation information.

45. The base station of claim 40 wherein said assigning further comprises:

selecting a channel with the highest gain for each of the antenna resources;

determining whether said selected channels are available;

if a selected channel for an antenna resource is not available, selecting a channel with the next best gain for said antenna resource;

comparing the gains of the selected channels; and

selecting the channel with the highest gain for assignment to the one or more subscribers in response to said comparison.

46. A method for wireless communication, said method comprising:

measuring, at a subscriber station, one or more channel characteristics of at least one channel hosted by one or more antenna resources located at a base station;

wherein the channel characteristics are indicative of reception quality for a corresponding channel;

sending, from said subscriber station, to said base station data corresponding to the one or more channel characteristics; and

receiving, at said subscriber station, notification of assignment of one or more channels, wherein said assignment is based at least on the one or more channel characteristics and available channels of said one or more antenna resources.

47. The method of claim 46 wherein said measuring comprises:

receiving, at said subscriber station, one or more beacon signals from said base station; and

tuning, at said subscriber station, a receiving unit to cycle through the one or more channels associated with the one or more beacon signals while measuring the associated channel characteristics.

48. The method of claim 47 wherein said measuring further comprises:

estimating channel response and interference by using information from pilot symbol periods and data periods.

49. The method of claim 46, wherein the channel characteristic measurements comprise at least one of Signal-to-interference plus noise ratio (SINR), carrier-to-interference plus noise ratio (CINR), and relative-signal strength indicator (RSSI) measurements.

50. The method of claim 46, wherein said assignment comprises at least one of uplink, downlink, and bi-directional channels.

51. The method of claim 46, further comprising:

periodically updating channel characteristics received by said base station by periodically measuring, at said subscriber station, the channel characteristics of the at least one channel hosted by the antenna resources of said base station and sending, from said subscriber station, to said base station data corresponding to the periodically measured channel characteristics; and

receiving notification of reassignments of one or more channels, wherein said reassignment is based at least on the updated channel characteristics and available channels of said one or more antenna resources.

52. The method of claim 46 further comprising:

synchronizing said subscriber station with said base station;

transmitting, from said subscriber station, test data to each of said one or more antenna resources; and

measuring, at said base station, one or more channels of at least one channel hosted by said antenna resources.

53. The method of claim 46, wherein the one or more channels comprise one of channels or subchannels corresponding to at least one of a FDMA (frequency division multiple access), TDMA (time division multiple access), CDMA (code division multiple access), OFDMA (orthogonal frequency division multiple access), and SDMA (space division multiple access) channel schemes.