Random access for wireless multiple-access communication systems

• US 8,711,763 B2
• Filed: 01/19/2012
• Issued: 04/29/2014
• Est. Priority Date: 10/25/2002
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walton, Jay Rodney, Ketchum, John W., Wallace, Mark S., Howard, Steven J.
• Primary Examiner(s): Moore, Ian N
• Assistant Examiner(s): Le, Brian T
• Application Number:
  US13/353,924
• Publication Number:
  US 20120140664A1
• Time in Patent Office: 831 Days
• Field of Search: None
• US Class Current: 370/327
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0017 where the mode-switching is based on Quality of Service requirement
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0242 using matrix methods
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2601 : Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 : Signal structure
• CPC Class Codes: H04L 27/261 : Details of reference signals
• CPC Class Codes: H04L 27/2647 : Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04W 28/20 : Negotiating bandwidth
• CPC Class Codes: H04W 52/50 : at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/002 : Transmission of channel access control information
• CPC Class Codes: H04W 74/08 : Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 : Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0866 : using a dedicated channel for access
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

Techniques for facilitating random access in wireless multiple-access communication systems are described. A random access channel (RACH) is defined to comprise a “fast” RACH (F-RACH) and a “slow” RACH (S-RACH). The F-RACH and S-RACH can efficiently support user terminals in different operating states and employ different designs. The F-RACH can be used to quickly access the system, and the S-RACH is more robust and can support user terminals in various operating states and conditions. The F-RACH may be used by user terminals that have registered with the system and can compensate for their round trip delays (RTDs) by properly advancing their transmit timing. The S-RACH may be used by user terminals that may or may not have registered with the system, and may or may not be able to compensate for their RTDs. Other aspects, embodiments, and features are also claimed and described.

Claims

1. A user terminal configured for operation in a wireless multiple-access communication system, comprising:

a receiver to receive at least one broadcast message including information regarding configuration of at least two contention-based random access channels for a frame, said at least two contention-based random access channels include a first and second contention-based random access channels;

a controller for determining an operating state of the user terminal indicating a current status of the user terminal, wherein the controller is operative to select the first contention-based random access channel and the second contention-based random access channel based on the determined operating state of the user terminal; and

a transmitter configured to transmit a first message on the first contention-based random access channel when the user terminal is in a first operating state and to transmit a second message on the second contention-based random access channel when the user terminal is in a second operating state,

wherein the first contention-based random access channel is configured for use by registered terminals for system access and the second contention-based random access channel is configured for use by registered/unregistered terminals for system access.

2. The user terminal of claim 1, wherein the controller is operative to determine the operating state of the user terminal based upon whether or not the user terminal has registered with the wireless multiple-access communication system.

3. The user terminal of claim 1, wherein the controller is operative to determine the operating state of the user terminal based upon whether or not the user terminal can compensate for propagation delay to an access point receiving messages sent by the user terminal.

4. The user terminal of claim 1, wherein the controller is operative to determine the operating state of the user terminal based upon whether or not the user terminal achieves a required received signal-to-noise ratio (SNR).

5. The user terminal of claim 1, wherein the transmitter is operative to process the first or second message to include an identifier for the user terminal.

6. The user terminal of claim 1, wherein the controller is configured to process received information corresponding to parameters conveying configuration information for at least the first and second contention-based random access channels.

7. The user terminal of claim 1, wherein the transmitter is configured to process the first or second message for transmission on a set of subbands of a plurality of subbands of the first or second contention-based random access channel.

8. The user terminal of claim 1, wherein the transmitter is operative to process the first or second message ranging from one OFDM symbol to a plurality of OFDM symbols.

9. A method of accessing a wireless communication system, the method comprising:

receiving at least one broadcast message including information regarding configuration of at least two contention-based random access channels for a frame, said at least two contention-based random access channels include first and second contention-based random access channels;

determining, by a user terminal, whether the user terminal is registered or unregistered with a wireless communication system;

selecting the first contention-based random access channel when the user terminal is determined to be registered with the wireless communication system;

selecting the second contention-based random access channel when the user terminal is determined to be unregistered with the wireless communication system; and

transmitting a message on the selected first or second contention-based random access channel.

10. The method of claim 9, wherein the message is transmitted in a manner to account for propagation delay to an access point receiving the message.

11. The method of claim 9, further comprising receiving information corresponding to parameters conveying configuration information for the first contention-based random access channel.

12. The method of claim 9, further comprising receiving an assignment, from a base station, responsive to the message.

13. The method of claim 9, wherein the message comprises a range of OFDM symbols from one to a plurality.

14. A method for operation of a user terminal in a wireless multiple-access communication system, comprising:

receiving at least one broadcast message including information regarding configuration of at least two contention-based random access channels for a frame, said at least two contention-based random access channels include first and second contention-based random access channels;

determining, by the user terminal, an operating state of the user terminal indicating a current status of the user terminal based upon whether or not the user terminal has registered with the wireless multiple-access communication system;

selecting from a group comprising the first contention-based random access channel and the second contention-based random access channel based on the determined operating state of the user terminal; and

transmitting a message on the selected first or second contention-based random access channel.

15. The method of claim 14, wherein the operating state of the user terminal is determined based upon whether or not the user terminal can compensate for propagation delay to an access point receiving messages sent by the user terminal.

16. The method of claim 14, wherein the operating state of the user terminal is determined based upon whether or not the user terminal achieves a required received signal-to-noise ratio (SNR).

17. The method of claim 14, further comprising processing the message to include an identifier for the user terminal.

18. The method of claim 14, further comprising processing received information corresponding to parameters conveying configuration information for at least the first and second contention-based random access channels.

19. The method of claim 14, further comprising processing the message for transmission on a set of subbands of a plurality of subbands of the first or second contention-based random access channel.

20. The method of claim 14, further comprising processing the message ranging from one OFDM symbol to a plurality of OFDM symbols.

21. A user terminal for accessing a wireless communication system, comprising:

a receiver for receiving at least one broadcast message including information regarding configuration of at least two contention-based random access channels for a frame, said at least two contention-based random access channels include first and second contention-based random access channels;

a controller configured to determine whether the user terminal is registered or unregistered with the wireless communication system, wherein the controller is operative to select the first contention-based random access channel to access the wireless communication system when the user terminal is determined to be registered with the wireless communication system and the second contention-based random access channel to access the wireless communication system when the user terminal is determined to be unregistered with the wireless communication system; and

a transmitter for transmitting a message on the first or second selected contention-based random access channel.

22. The user terminal of claim 21, wherein the message is transmitted in a manner to account for propagation delay to an access point receiving the message.

23. The user terminal of claim 21, further comprising a receiver for receiving information corresponding to parameters conveying configuration information for the first contention-based random access channel.

24. The user terminal of claim 21, further comprising a receiver for receiving an assignment, from a base station, responsive to the message.

25. The user terminal of claim 21, wherein the message comprises a range of OFDM symbols from one to a plurality.