Method and apparatus for mitigating interference in a wireless communication system

• US 20060212133A1
• Filed: 02/08/2006
• Published: 09/21/2006
• Est. Priority Date: 02/11/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Malladi, Durga Prasad, Damnjanovic, Jelena
• Granted Patent: US 8,144,658 B2
• Time in Patent Office: Days
• US Class Current: 700/1
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning

Abstract

Techniques to mitigate inter-cell interference using joint time and frequency division are described. A frequency band is divided into multiple non-overlapping frequency subbands. The transmission timeline is divided into T_in and T_out time intervals. Data is exchanged with users in at least one inner region of a cell on the entire frequency band in the T_in time intervals. Data is exchanged with users in multiple outer regions of the cell on the multiple frequency subbands in the T_out time intervals. The frequency band may be partitioned into three frequency subbands. Data may then be exchanged with users in first, second and third outer regions on first, second and third frequency subbands, respectively. The regions in which the users are located may be determined based on pilot and/or other measurements.

Claims

1. An apparatus comprising:

at least one processor configured to exchange data with users in at least one inner region of a cell in a first time interval on a frequency band, and to exchange data with users in multiple outer regions of the cell in a second time interval on multiple frequency subbands formed with the frequency band; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor exchanges data with users in each outer region on a different frequency subband that is non-overlapping with at least one frequency subband used for at least one adjacent outer region in at least one neighboring cell.

3. The apparatus of claim 1, wherein the multiple outer regions comprise first, second and third outer regions, wherein the multiple frequency subbands comprise first, second and third frequency subbands, and wherein the at least one processor exchanges data with users in the first, second and third outer regions on the first, second and third frequency subbands, respectively, in the second time interval.

4. The apparatus of claim 1, wherein the at least one processor exchanges data with at least one user in the at least one inner region in the second time interval at reduced transmit power.

5. The apparatus of claim 1, wherein the at least one processor determines regions in which users are located based on pilot measurements.

6. The apparatus of claim 1, wherein the at least one processor determines an active set for a user and determines a region in which the user is located based on the active set.

7. The apparatus of claim 1, wherein the frequency band comprises a plurality of frequency bins, and wherein each of the multiple frequency subbands comprises a different subset of the plurality of frequency bins.

8. The apparatus of claim 1, wherein the at least one processor exchanges data with the users using orthogonal frequency division multiplexing (OFDM).

9. The apparatus of claim 1, wherein the at least one processor exchanges data with the users using single-carrier frequency division multiple access (SC-FDMA).

10. A method comprising:

exchanging data with users in at least one inner region of a cell in a first time interval on a frequency band; and

exchanging data with users in multiple outer regions of the cell in a second time interval on multiple frequency subbands formed with the frequency band.

11. The method of claim 10, wherein the exchanging data with the users in the multiple outer regions comprises

exchanging data with users in first, second and third outer regions on first, second and third frequency subbands, respectively, in the second time interval.

12. The method of claim 10, further comprising:

processing the data for the users in the at least one inner region and the data for the users in the multiple outer regions with orthogonal frequency division multiplexing (OFDM).

13. The method of claim 10, further comprising:

determining regions in which users are located based on pilot measurements.

14. An apparatus comprising:

means for exchanging data with users in at least one inner region of a cell in a first time interval on a frequency band; and

means for exchanging data with users in multiple outer regions of the cell in a second time interval on multiple frequency subbands formed with the frequency band.

15. The apparatus of claim 14, wherein the means for exchanging data with the users in the multiple outer regions comprises

means for exchanging data with users in first, second and third outer regions on first, second and third frequency subbands, respectively, in the second time interval.

16. The apparatus of claim 14, further comprising:

means for processing the data for the users in the at least one inner region and the data for the users in multiple outer regions with orthogonal frequency division multiplexing (OFDM).

17. The apparatus of claim 14, further comprising:

means for determining regions in which users are located based on pilot measurements.

18. An apparatus comprising:

at least one processor configured to exchange data with users in a first region of a sector in a first time interval on a frequency band, and to exchange data with users in a second region of the sector in a second time interval on a frequency subband corresponding to a portion of the frequency band; and

a memory coupled to the at least one processor.

19. The apparatus of claim 18, wherein the first and second regions are inner and outer regions, respectively, of the sector.

20. The apparatus of claim 18, wherein the at least one processor distributes total transmit power across frequency bins in the frequency band for the first time interval, and distributes total transmit power across frequency bins in the frequency subband for the second time interval.

21. An apparatus comprising:

means for exchanging data with users in a first region of a sector in a first time interval on a frequency band; and

means for exchanging data with users in a second region of the sector in a second time interval on a frequency subband corresponding to a portion of the frequency band.

22. The apparatus of claim 21, further comprising:

means for distributing total transmit power across frequency bins in the frequency band for the first time interval, and

means for distributing total transmit power across frequency bins in the frequency subband for the second time interval.

23. An apparatus comprising:

at least one processor configured to exchange data with a first set of users in a first time interval based on a first frequency reuse scheme, and to exchange data with a second set of users in a second time interval based on a second frequency reuse scheme; and

a memory coupled to the at least one processor.

24. The apparatus of claim 23, wherein the first frequency reuse scheme is associated with a frequency use factor of one, and wherein the second frequency reuse scheme is associated with a frequency use factor of less than one.

25. The apparatus of claim 23, wherein the at least one processor selects the first set of users from among users in an inner region of a sector or a cell, and sends data to the selected users in the inner region on a frequency band in the first time interval.

26. The apparatus of claim 23, wherein the at least one processor selects the second set of users from among users in multiple outer regions of a cell, and sends data to the selected users in the multiple outer regions on different frequency subbands in the second time interval.

27. The apparatus of claim 23, wherein the at least one processor selects the second set of users from among users in multiple outer regions of a cell, and sends data to the selected users in the multiple outer regions in different parts of the second time interval.

28. The apparatus of claim 23, wherein the at least one processor selects the second set of users from among users in an outer region of a sector, and sends data to the selected users in the outer region on a frequency subband in the second time interval.

29. An apparatus comprising:

means for exchanging data with a first set of users in a first time interval based on a first frequency reuse scheme; and

means for exchanging data with a second set of users in a second time interval based on a second frequency reuse scheme.

30. The apparatus of claim 29, wherein the means for exchanging data with the second set of users comprises

means for selecting the second set of users from among users in multiple outer regions of a cell, and

means for exchanging data with the selected users in the multiple outer regions on different frequency subbands in the second time interval.

31. The apparatus of claim 29, wherein the means for exchanging data with the second set of users comprises

means for selecting the second set of users from among users in an outer region of a sector, and

means for exchanging data with the selected users in the outer region on a frequency subband in the second time interval.

32. A terminal comprising:

at least one processor configured to exchange data with a base station on a frequency band in a first time interval if the terminal is located in an inner region of a sector or a cell, and to exchange data with the base station on a frequency subband in a second time interval if the terminal is located in an outer region of the sector or cell, the frequency subband being one of multiple frequency subbands formed with the frequency band; and

a memory coupled to the at least one processor.

33. The terminal of claim 32, wherein the at least one processor determines the region in which the terminal is located based on an active set for the terminal.

34. The terminal of claim 32, wherein the at least one processor obtains pilot measurements for base stations, and determines the region in which the terminal is located based on the pilot measurements.

35. A method comprising:

exchanging data with a base station on a frequency band in a first time interval if a terminal is located in an inner region of a sector or a cell; and

exchanging data with the base station on a frequency subband in a second time interval if the terminal is located in an outer region of the sector or cell, the frequency subband being one of multiple frequency subbands formed with the frequency band.

36. The method of claim 35, further comprising:

obtaining pilot measurements for base stations, and

determining the region in which the terminal is located based on the pilot measurements.

37. An apparatus comprising:

means for exchanging data with a base station on a frequency band in a first time interval if a terminal is located in an inner region of a sector or a cell; and

means for exchanging data with the base station on a frequency subband in a second time interval if the terminal is located in an outer region of the sector or cell, the frequency subband being one of multiple frequency subbands formed with the frequency band.

38. The apparatus of claim 37, further comprising:

means for obtaining pilot measurements for base stations, and

means for determining the region in which the terminal is located based on the pilot measurements.