Apparatus and method for random access signaling in a wireless communication system

• US 8,923,218 B2
• Filed: 11/01/2010
• Issued: 12/30/2014
• Est. Priority Date: 11/02/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Luo, Tao, Chen, Wanshi, Montojo, Juan, Gaal, Peter, Zhang, Xiaoxia
• Primary Examiner(s): ROBERTS, BRIAN S
• Application Number:
  US12/917,359
• Publication Number:
  US 20110268049A1
• Time in Patent Office: 1,520 Days
• Field of Search: None
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

An apparatus and method for providing random access signaling in a multiple input multiple output (MIMO) wireless communication system are provided. The apparatus and method determine a random access transmission scheme for the MIMO communication system based at least in part on a number of transmit antennas in the system. The random access signals are transmitted in a random access channel using the random access transmission scheme. Power control for the random access channel is performed based at least in part on the random access transmission scheme.

Claims

1. A method for wireless communication, comprising:

determining a random access transmission scheme at a user equipment (UE) for a multiple input multiple output (MIMO) communication based at least in part on a number of transmit antennas at the UE to be utilized for the MIMO communication, an identified format utilized by a random access channel, and a precoding vector that is selected based on the number of transmit antennas; and

transmitting random access signals from the UE using the random access transmission scheme determined at the UE.

2. The method of claim 1, wherein the transmitting further comprises transmitting the random access signals over a contention-based random access channel.

3. The method of claim 2, wherein the random access transmission scheme employs beamforming.

4. The method of claim 3, wherein the determining further comprises selecting the precoding vector from a set of precoding vectors and using the precoding vector to generate the random access signals.

5. The method of claim 4, wherein the determining further comprises selecting at least one of the precoding vectors for communication over the random access channel on a per-burst basis if the random access channel utilizes the format associated with a repeated preamble.

6. The method of claim 5, wherein the format comprises at least one of a physical random access channel (PRACH) format 2 or PRACH format 3.

7. The method of claim 2, wherein the MIMO communication includes random access re-transmission.

8. The method of claim 2, wherein the determining is based at least in part on the format of the random access channel.

9. The method of claim 1, wherein the random access transmission scheme comprises a transmit diversity scheme.

10. The method of claim 9, wherein the transmit diversity scheme comprises time switched transmit diversity (TSTD).

11. The method of claim 1, wherein the determining comprises receiving an indication of the random access transmission scheme.

12. The method of claim 11, wherein the random access transmission scheme comprises a non-contention-based transmission scheme.

13. The method of claim 11, wherein the determining comprises receiving a random access response (RAR) grant message containing the indication.

14. The method of claim 11, wherein the determining comprises receiving a control channel conveying the indication.

15. The method of claim 14, wherein the indication is conveyed using one or more zero-padding bits.

16. The method of claim 1, further comprising performing transmit power control for a physical random access channel based at least in part on the random access transmission scheme.

17. An apparatus for wireless communication, comprising:

means for determining a random access transmission at a user equipment (UE) for a multiple input multiple output (MIMO) communication based at least in part upon a number of transmit antennas at the UE to be utilized for the MIMO communication, an identified format utilized by a random access channel, and a precoding vector that is selected based on the number of transmit antennas; and

means for transmitting random access signals from the UE using the random access transmission scheme determined at the UE.

18. The apparatus of claim 17, wherein the means for transmitting further comprises means for transmitting the random access signals over a contention-based random access channel.

19. The apparatus of claim 17, wherein the means for transmitting comprises at least one of means for beamforming or means for transmit diversity.

20. The apparatus of claim 19, wherein the means for beamforming further comprises means for selecting the precoding vector from a set of precoding vectors and means for using the precoding vector to generate the random access signals.

21. The apparatus of claim 20, wherein the means for beamforming further comprises means for selecting at least one of the precoding vectors for communication over a random access channel on a per-burst basis if the random access channel utilizes the format associated with a repeated preamble.

22. The apparatus of claim 19, wherein the means for transmit diversity comprises means for implementing a time switched transmit diversity (TSTD) scheme.

23. The apparatus of claim 17, further comprising means for performing transmit power control for a physical random access channel based at least in part on the random access transmission scheme.

24. An apparatus for wireless communication, comprising:

a processor configured to;

determine a random access transmission scheme at a user equipment (UE) for a multiple input multiple output (MIMO) communication based at least in part on a number of transmit antennas at the UE to be utilized for the MIMO communication, an identified format utilized by a random access channel, and a precoding vector that is selected based on the number of transmit antennas; and

transmit random access signals from the UE using the random access transmission scheme determined at the UE.

25. The apparatus of claim 24, wherein the processor is further configured to perform transmit power control for a physical random access channel based at least in part on the random access transmission scheme.

26. A computer program product that facilitates a multiple input multiple output (MIMO) communication in a wireless communication system, comprising:

a non-transitory computer-readable storage medium comprising;

instructions for causing at least one computer to determine a random access transmission scheme at a user equipment (UE) for the MIMO communication based at least in part on a number of transmit antennas at the UE to be utilized for the MIMO communication, an identified format utilized by a random access channel, and a precoding vector that is selected based on the number of transmit antennas; and

instructions for causing the at least one computer to transmit random access signals from the UE using the random access transmission scheme determined at the UE.

27. The computer program product of claim 26, wherein the random access transmission scheme employs beamforming.

28. The computer program product of claim 26, wherein the random access transmission scheme comprises a transmit diversity scheme.

29. The computer program product of claim 26, wherein the computer-readable storage medium further comprises instructions for causing the at least one computer to perform transmit power control for a physical random access channel based at least in part on the random access transmission scheme.