Uplink pilot and signaling transmission in wireless communication systems

• US 20050215251A1
• Filed: 05/25/2005
• Published: 09/29/2005
• Est. Priority Date: 10/29/2002
• Status: Active Grant

• Current Assignee: Rajiv Vijayan, Ranganathan Krishnan, Tamer Kadous
• Original Assignee: Rajiv Vijayan, Ranganathan Krishnan, Tamer Kadous
• Inventors: Vijayan, Rajiv, Krishnan, Ranganathan, Kadous, Tamer
• Granted Patent: US 7,042,857 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0232 by interpolation between sounding signals
• CPC Class Codes: H04L 25/0248 Eigen-space methods
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0041 Frequency-non-contiguous
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network

Abstract

Techniques to more efficiently transmit pilot and signaling on the uplink in an OFDM system. With subband multiplexing, M usable subbands in the system are partitioned into Q disjoint groups of subbands. Each subband group may be assigned to a different terminal for uplink pilot transmission. Multiple terminals may transmit simultaneously on their assigned subbands. The transmit power for the pilot may be scaled higher to attain the same total pilot energy even though S instead of M subbands are used for pilot transmission by each terminal. Pilot transmissions from the terminals are received, and a channel estimate is derived for each terminal based on the pilot received on the assigned subbands. The channel estimate comprises a response for additional subbands not included in the assigned group. Subband multiplexing may also be used for uplink signaling transmission.

Claims

1. A method for assigning pilot signals for transmission, comprising:

assigning a first group of subbands to pilot signals of a first terminal, wherein each subband of the first group is non-contiguous with any other subband of the first group; and

assigning a second group of subbands to pilot signals a second terminal, wherein each subband of the second group is non-contiguous with any other subband of the second group.

2. The method of claim 1, wherein each of the first group and the second group includes a same number of subbands.

3. The method of claim 1, wherein each of the first group and the second group each includes a different number of subbands.

4. The method of claim 1, wherein at least one subband in the first group is adjacent to at least one subband in the second group.

5. The method of claim 1, wherein each subband of the first group is spaced N subbands from a nearest subband of the first group.

6. The method of claim 5, wherein each subband of the second group is spaced M subbands from a nearest subband of the second group.

7. The method of claim 6, wherein N and M are equal.

8. The method of claim 6, wherein N and M are not equal.

9. The method of claim 1, wherein each subband of the first group is uniformly distributed across a plurality of usable subbands.

10. The method of claim 1, wherein each subband of the first group is non-uniformly distributed across a plurality of usable subbands.

11. The method of claim 1, wherein the pilot signals are for forward link transmission.

12. An apparatus comprising:

a memory; and

a processor configured to assign a first group of subbands to pilot signals of a first terminal and assign a second group of subbands to pilot signals a second terminal, wherein each subband of the first group is non-contiguous with any other frequency band of the first group.

13. The apparatus of claim 12, wherein each of the first group and the second group includes a same number of subbands.

14. The apparatus of claim 12, wherein each of the first group and the second group each includes a different number of subbands.

15. The apparatus of claim 12, wherein at least one subband in the first group is adjacent to at least one subband in the second group.

16. The apparatus of claim 12, wherein each subband of the first group is spaced N subbands from a nearest subband of the first group.

17. The apparatus of claim 16, wherein each subband of the second group is spaced M subbands from a nearest subband of the second group.

18. The apparatus of claim 17, wherein N and M are equal.

19. The apparatus of claim 17, wherein N and M are not equal.

20. The apparatus of claim 13, wherein each subband of the first group is uniformly distributed across a plurality of usable subbands.

21. An apparatus comprising:

means for assigning a first group of non-contiguous subbands to pilot signals of a first terminal; and

means for assigning a second group of non-contiguous subbands to pilot signals of a second terminal.

22. The apparatus of claim 21, wherein each of the first group and the second group includes a same number of subbands.

23. The apparatus of claim 21, wherein each of the first group and the second group each includes a different number of subbands.

24. The apparatus of claim 21, wherein each subband of the first group is spaced N subbands from a nearest subband of the first group.

25. The apparatus of claim 24, wherein each subband of the second group is spaced M subbands from a nearest subband of the second group.

26. The apparatus of claim 25, wherein N and M are equal.

27. The apparatus of claim 25, wherein N and M are not equal.

28. The apparatus of claim 21, wherein each subband of the first group is uniformly distributed across a plurality of usable subbands.

29. The apparatus of claim 21, wherein each subband of the first group is non-uniformly distributed across a plurality of usable subbands.

30. The apparatus of claim 21, wherein the pilot signals are for forward link transmission.