METHODS AND APPARATUS FOR SUPPORTING MULTIPLE USERS IN A SYSTEM WITH MULTIPLE POLARIZED ANTENNAS

• US 20090227260A1
• Filed: 03/06/2008
• Published: 09/10/2009
• Est. Priority Date: 03/06/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tavildar, Saurabh, Laroia, Rajiv, Wu, Xinzhou, Cezanne, Juergen, Anreddy, Vikram Reddy
• Granted Patent: US 8,331,946 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0469 taking special antenna structures, e.g. cross polarized antennas into account
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04J 99/00 Subject matter not provided for in other groups of this subclass

Abstract

Methods and apparatus which support the use of differently polarized antennas to schedule two or more users employing multiple antennas with different polarization, on the same communications segment, e.g. a time/frequency slab, in either the uplink or downlink are described. Various embodiments include an access node which classifies and schedules wireless terminals to segments as a function of suitability for single polarization direction communications. Some embodiments are directed to methods and apparatus for operating a communications device supporting the use of multiple antennas having different polarization, to implement a polarization based multiple access scheme. Unlike Spatial Division multiple access schemes, the users sharing a communications segment in the polarization based scheme need not be geographically well separated. Another advantage of using the proposed method is that the communications system does not necessarily have to use a complex minimum mean square error receiver or implement successive iteration cancellation techniques, thereby reducing cost and system complexity.

Claims

1. A method of operating an access node, the method comprising:

storing information indicating assignment of a first set of wireless terminals to a first polarized antenna mode of operation;

storing information indicating assignment of a second set of wireless terminals to a second polarized antenna mode of operation which is different from the first polarized antenna mode of operation; and

signaling to a wireless terminal, the mode of polarized antenna operation to be used.

2. The method of claim 1, further comprising:

assigning said wireless terminal to operate in one of said first and second polarized antenna modes of operation based on a signal received from said wireless terminal, the signal being one of;

i) a pilot signal received from the wireless terminal and ii) a channel quality information signal received from the wireless terminal.

3. The method of claim 2, wherein said first and second modes of polarized antenna operation are vertical and horizontal modes of antenna operation.

4. The method of claim 2, wherein said signaling to the wireless terminal further includes rate information.

5. The method of claim 2, wherein said mode of polarized antenna operation to be used which is signaled to said wireless terminal is an uplink mode of polarized antenna operation to be used for transmitting signals to said access node.

6. The method of claim 5, wherein said wireless terminal operates in a downlink mode of polarized antenna operation which is different from the uplink mode of antenna operation being signaled, said signaling being performed using an antenna corresponding to the downlink mode of polarized antenna operation in which said wireless terminal is operating.

7. The method of claim 1, further comprising:

assigning a first communications segment to be used by two wireless terminals at the same time, said assigning including selecting a first wireless terminal from the first set of wireless terminals and a second wireless terminal from the second set of wireless terminals.

8. The method of claim 1, further comprising:

storing information indicating assignment of a third set of wireless terminals, said third set of wireless terminals operating in a tilted mode of antenna polarization operation; and

assigning a second communications segment to be used by a single wireless terminal, said assigning including selecting a third wireless terminal from the third set of wireless terminals.

9. The method of claim 8, further comprising:

assigning a first communications segment to be used by two wireless terminals at the same time, said assigning including selecting a first wireless terminal from the first set of wireless terminals and a second wireless terminal from the second set of wireless terminals.

10. The method of claim 9,

wherein the first and second communications segments correspond to the same time;

and

wherein said first and second communications segments are uplink traffic channel segments.

11. The method of claim 9, further comprising

recovering information from the first communications segment without combining signals from first and second antennas having said first and second polarizations respectively.

12. An access node, the access node comprising:

memory including information indicating assignment of a first set of wireless terminals to a first polarized antenna mode of operation and assignment of a second set of wireless terminals to a second polarized antenna mode of operation which is different from the first polarized antenna mode of operation; and

a transmitter module for signaling to a wireless terminal, the mode of polarized antenna operation to be used.

13. The access node of claim 12, further comprising:

an assignment module for assigning wireless terminals to operate in one of said first and second polarized antenna modes of operation, said assigning for an individual one of said wireless terminals being based on a signal received from said individual one of the wireless terminals, the signal being one of;

i) a pilot signal and ii) a channel quality information signal.

14. The access node of claim 13,

wherein said first and second modes of polarized antenna operation are vertical and horizontal modes of antenna operation, respectively;

wherein said access node further includes;

a first antenna polarized in said vertical direction; and

a second antenna polarized in said horizontal direction.

15. The access node of claim 13, further comprising:

a communications rate information generation module for generating communications rate information relating to communications between said wireless terminal and said base station; and

a signal generation module for generating a rate information signal to be transmitted to said wireless terminal in addition to the mode of polarized antenna operation to be used.

16. The access node of claim 13, wherein said mode of polarized antenna operation to be used which is signaled to said wireless terminal is an uplink mode of polarized antenna operation to be used for transmitting signals to said access node.

17. The access node of claim 16, wherein said wireless terminal operates in a downlink mode of polarized antenna operation which is different from the uplink mode of antenna operation being signaled, the access node further comprising:

a transmission control module for controlling transmission using one of a first antenna and a second antenna, the antenna being used for signaling the mode of polarized antenna operation to be used, corresponding to the downlink mode of polarized antenna operation in which said wireless terminal is operating.

18. The access node of claim 12, further comprising:

a scheduling module including a first segment assignment module for assigning a first communications segment to be used by two wireless terminals at the same time, said assigning including selecting a first wireless terminal from the first set of wireless terminals and a second wireless terminal from the second set of wireless terminals.

19. The access node of claim 12, further comprising:

additional stored information in said memory, said additional stored information indicating assignment of a third set of wireless terminals, said third set of wireless terminals operating in a titled mode of antenna polarization operation; and

a scheduling module including a second segment assignment module for assigning a second communications segment to be used by a single wireless terminal, said second assignment module assigning a third wireless terminal from the third set of wireless terminals.

20. The access node of claim 19, wherein said scheduling module further includes a first assignment module for assigning a first communications segment to be used by two wireless terminals at the same time, said first assignment module selecting a first wireless terminal from the first set of wireless terminals and a second wireless terminal from the second set of wireless terminals to which said first segment are assigned.

21. The access node of claim 20,

wherein the first and second communications segments correspond to the same time;

and

wherein said first and second communications segments are uplink traffic channel segments.

22. The access node of claim 20, further comprising:

a first information recovery module for recovering information from the first communications segment without use of signals from said second antenna; and

a second information recovery module for recovering information from the first communications segment without use of signals from the first antenna, said first and second antennas having said first and second polarizations respectively.

23. An access node, the access node comprising:

means for storing information indicating assignment of a first set of wireless terminals to a first polarized antenna mode of operation and assignment of a second set of wireless terminals to a second polarized antenna mode of operation which is different from the first polarized antenna mode of operation; and

means for transmitting a signal to a wireless terminal indicating the mode of polarized antenna operation to be used.

24. The access node of claim 23, further comprising:

means for assigning wireless terminals to operate in one of said first and second polarized antenna modes of operation, said assigning for an individual one of said wireless terminals being based on a signal received from said individual one of the wireless terminals, the signal being one of;

i) a pilot signal and ii) a channel quality information signal.

25. The access node of claim 24,

wherein said first and second modes of polarized antenna operation are vertical and horizontal modes of antenna operation, respectively;

and

wherein said access node further includes;

a first antenna polarized in said vertical direction; and

a second antenna polarized in said horizontal direction.

26. The access node of claim 24, further comprising:

communications rate information generation means for generating communications rate information relating to communications between said wireless terminal and said base station; and

signal generation means for generating a rate information signal to be transmitted to said wireless terminal in addition to the mode of polarized antenna operation to be used.

27. A computer readable medium embodying machine executable instructions for controlling a device to implement a method, the method comprising:

storing information indicating assignment of a first set of wireless terminals to a first polarized antenna mode of operation;

storing information indicating assignment of a second set of wireless terminals to a second polarized antenna mode of operation which is different from the first polarized antenna mode of operation; and

signaling to a wireless terminal, the mode of polarized antenna operation to be used.

28. The computer readable medium of claim 27, wherein the method further comprises:

assigning said wireless terminal to operate in one of said first and second polarized antenna modes of operation based on a signal received from said wireless terminal, the signal being one of;

i) a pilot signal received from the wireless terminal and ii) a channel quality information signal received from the wireless terminal.

29. The computer readable medium of claim 28, wherein said first and second modes of polarized antenna operation are vertical and horizontal modes of antenna operation.

30. An apparatus for use in a device, the apparatus comprising:

a processor configured to control said device to;

store information indicating assignment of a first set of wireless terminals to a first polarized antenna mode of operation;

store information indicating assignment of a second set of wireless terminals to a second polarized antenna mode of operation which is different from the first polarized antenna mode of operation; and

signal to a wireless terminal, the mode of polarized antenna operation to be used.

31. The apparatus of claim 30, wherein the processor is further configured to:

assign a first communications segment to be used by two wireless terminals at the same time, said assigning including selecting a first wireless terminal from the first set of wireless terminals and a second wireless terminal from the second set of wireless terminals.

32. The apparatus of claim 31, wherein said first and second modes of polarized antenna operation are vertical and horizontal modes of antenna operation.

33. A method of operating a wireless terminal, the method comprising:

receiving a signal from an access node indicating an assigned mode of polarized antenna operation to be used when communicating with said access node;

configuring the wireless terminal to said assigned mode of polarized operation; and

communicating with said access node while configured in said assigned mode of polarized operation.

34. The method of claim 33, further comprising:

storing information indicating the assigned mode of polarized antenna operation;

35. The method of claim 33, wherein communicating with said access node includes transmitting a signal to the access node.

36. The method of claim 33, further comprising:

prior to said receiving a signal from an access node indicating an assigned mode of polarized antenna operation transmitting at least one of;

i) a pilot signal; and

ii) channel quality information signal to said access node.

37. The method of claim 36, wherein said assigned mode of polarized antenna operation is one of:

i) a first mode which is a vertical polarization direction mode and ii) a second mode which is a horizontal polarization direction mode.

38. The method of claim 36, further comprising:

receiving rate information corresponding to said assigned mode of polarized antenna operation.

39. The method of claim 36, wherein said assigned mode of polarized antenna operation to be used which is signaled to said wireless terminal is an uplink mode of polarized antenna operation to be used for transmitting signals to said access node.

40. The method of claim 39, wherein said wireless terminal operates in a downlink mode of polarized antenna operation which is different from the uplink mode of antenna operation being signaled, said receiving being performed using an antenna corresponding to the downlink mode of polarized antenna operation in which said wireless terminal is operating.

41. The method of claim 33, further comprising:

receiving a first communications segment assignment, wherein said first communications segment is to be used by two wireless terminals at the same time. but with said two wireless terminals using different antenna polarizations, and wherein said first communications segment assignment indicates that said wireless terminal is one of said two wireless terminals.

42. The method of claim 41, wherein said assigned mode of polarized antenna operation is from a set of assigned modes of polarized antenna operation including a first mode which is a vertical polarization direction mode, a second mode which is a horizontal polarization direction mode, and a third mode which is a tilted mode of polarization operation and wherein said assigned mode of polarized operation is one of the vertical polarization mode and the horizontal polarization mode;

the method further comprising;

subsequent to said first communications segment, receiving a second mode assignment signal from said access node indicating that the assigned mode of polarized antenna operation to be used when communicating with said access node is said third mode;

configuring the wireless terminal to said assigned third mode of polarized operation; and

transmitting a signal to said access node while configured in said assigned third mode of polarized operation.

43. The method of claim 42, further comprising:

storing information indicating the third mode of polarized operation.

44. The method of claim 42, further comprising:

prior to transmitting a signal to said access node in said assigned third mode of polarized operation;

receiving a second communications segment assignment, said second communications segment being used by a single wireless terminal and indicating that said wireless terminal is assigned the second communications segment; and

wherein transmitting a signal to said access node while configured in said assigned third mode of polarized operation includes transmitting uplink signals in said second communications segment using both a vertical polarization antenna and a horizontal polarization antenna.

45. The method of claim 44, wherein said first and second communications segments are uplink traffic channel segments.

46. A wireless terminal, comprising:

a receiver for receiving a mode indicator signal from an access node indicating an assigned mode of polarized antenna operation to be used when communicating with said access node;

a first antenna being polarized in a first direction;

a second antenna being polarized in a second direction, said second direction being different from said first direction,

a first control module for configuring the wireless terminal to use said antennas in accordance with said assigned mode of polarized operation; and

a transmitter for transmitting a signal to said access node while configured in said assigned mode of polarized operation.

47. The wireless terminal of claim 46, further comprising:

memory for storing information indicating the assigned mode of polarized operation.

48. The wireless terminal of claim 46, wherein said first control module includes an antenna selection module for selecting which of the available first and second antennas are used at a given point in time.

49. The wireless terminal of claim 46, further comprising.

a transmission control module for controlling said wireless terminal to transmit, at least one of:

i) a pilot signal; and

ii) a channel quality information signal to said access terminal.

50. The wireless terminal of claim 49, wherein said assigned mode of polarized antenna operation is one of:

i) a first mode which is a vertical polarization direction mode, and ii) a second mode which is a horizontal polarization direction mode.

51. The wireless terminal of claim 49, wherein said assigned mode of polarized antenna operation is one of:

i) a first mode which is a vertical polarization direction mode, ii) a second mode which is a horizontal polarization direction mode; and

iii) a third mode which is a tilted mode.

52. The wireless of claim 49, further comprising:

a rate information recovery module for recovering rate information corresponding to said assigned mode of polarized antenna operation.

53. The wireless of claim 49, wherein said assigned mode of polarized antenna operation to be used is an uplink mode of polarized antenna operation to be used for transmitting signals to said access node.

54. The wireless terminal of claim 53,

wherein said first control module is an uplink control module, the wireless terminal further comprising:

a downlink polarization control module for controlling the wireless terminal to operate at different times in different downlink polarization modes of polarized antenna operation said receiving being performed using an antenna corresponding to the downlink mode of polarized antenna operation in which said wireless terminal is operating.

55. The wireless terminal of claim 46, further comprising:

an assignment information processing module for processing a first communications segment assignment, wherein said first communications segment is to be used by two wireless terminals at the same time but with said two wireless terminals using different antenna polarizations, and wherein said first communications segment assignment indicates that said wireless terminal is one of said two wireless terminals.

56. The wireless terminal of claim 55, further comprising:

a traffic data flow control module for controlling transmission of a portion of traffic data, said traffic data flow control module controlling transmission of the same data during a first period of time from said first and second antennas in parallel and controlling transmission of data during a second period of time from at most one of said first and second antenna, the mode of operation during said first and second periods of time being determined from the assigned mode of operation.

57. A wireless terminal, comprising:

receiver means for receiving a mode indicator signal from an access node indicating an assigned mode of polarized antenna operation to be used when communicating with said access node;

first antenna means being polarized in a first direction;

second antenna means being polarized in a second direction, said second direction being different from said first direction;

first control means for configuring the wireless terminal to use said first and second antenna means in accordance with said assigned mode of polarized operation; and

transmitter means for transmitting a signal to said access node while configured in said assigned mode of polarized operation.

58. The wireless terminal of claim 57, further comprising:

memory means for storing information indicating the assigned mode of polarized operation.

59. The wireless terminal of claim 57, wherein said first control means includes an antenna selection means for selecting which of the available first and second antenna means are used at a given point in time.

60. The wireless terminal of claim 57, further comprising:

transmission control means for controlling said wireless terminal to transmit, at least one of;

i) a pilot signal; and

ii) a channel quality information signal to said access terminal.

61. A computer readable medium embodying machine executable instructions for controlling a wireless terminal to implement a method:

receiving a signal from an access node indicating an assigned mode of polarized antenna operation to be used when communicating with said access node;

configuring the wireless terminal to said assigned mode of polarized operation; and

communicating with said access node while configured in said assigned mode of polarized operation.

62. The computer readable medium of claim 61, wherein the method further comprises:

storing information indicating the assigned mode of polarized antenna operation.

63. The computer readable medium of claim 61, wherein communicating with said access node includes transmitting a signal to the access node.

64. The computer readable medium of claim 61, wherein the method further comprises:

prior to said receiving a signal from an access node indicating an assigned mode of polarized antenna operation transmitting at least one of;

i) a pilot signal; and

ii) channel quality information signal to said access node.

65. An apparatus for use in a wireless terminal, the apparatus comprising:

a processor configured to control the wireless terminal to implement a method, the method comprising;

receiving a signal from an access node indicating an assigned mode of polarized antenna operation to be used when communicating with said access node;

configuring the wireless terminal to said assigned mode of polarized operation; and

communicating with said access node while configured in said assigned mode of polarized operation.

66. The apparatus of claim 65, wherein the method further comprises:

storing information indicating the assigned mode of polarized antenna operation.

67. The apparatus of claim 65, wherein communicating with said access node includes transmitting a signal to the access node.

68. The apparatus of claim 65, wherein the method further comprises:

prior to said receiving a signal from an access node indicating an assigned mode of polarized antenna operation transmitting at least one of;

i) a pilot signal; and

ii) channel quality information signal to said access node.