Pre-allocated random access identifiers

• US 8,229,437 B2
• Filed: 07/11/2011
• Issued: 07/24/2012
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Inventors: Bourlas, Yair, Newham, Adam E., Wang, Lei, Gummadi, Srikanth
• Primary Examiner(s): Afshar, Kamran
• Assistant Examiner(s): Obayanju, Omoniyi
• Application Number:
  US13/180,135
• Publication Number:
  US 20110268081A1
• Time in Patent Office: 379 Days
• Field of Search: 370/331, 370/330, 455/436
• US Class Current: 455/436
• CPC Class Codes: H04B 7/2668 Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation, for code acquisition H04B1/7075, for code tracking H04B1/7085
• CPC Class Codes: H04J 11/0073 Acquisition of primary synchronisation channel, e.g. detection of cell-ID within cell-ID group
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/085 collision avoidance
• CPC Class Codes: H04W 74/0875 with assigned priorities based access
• CPC Class Codes: H04W 74/0891 for synchronized access
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Systems and methods of pre-allocating identifiers to wireless devices for use in requesting resources over a random access channel are described. A wireless communication system includes a random access channel over which wireless devices can anonymously send requests for resources. The base stations receiving and processing the anonymous requests reduces the probability of random access channel collisions and conserves the resources needed to support the anonymous requests by pre-allocating one or more codes to select wireless devices. The wireless devices having the pre-allocated codes can transmit a particular code over the random access channel as a request for resources that uniquely identifies the requester.

Claims

1. A method for handover of an existing communication link of a mobile station to a target base station, the method comprising:

allocating, by the target base station, a random access identifier that uniquely identifies the mobile station in a coverage area of the target base station in association with the handover of the existing communication link;

receiving, by the target base station, the allocated random access identifier from the mobile station over a random access channel;

generating, by the target base station, based on the receiving the allocated random access identifier, a feedback message comprising a timing adjustment; and

transmitting, by the target base station, the feedback message to the mobile station for synchronizing the mobile station with the target base station.

2. The method of claim 1, wherein the random access identifier is released after synchronization.

3. The method of claim 1, wherein the random access channel is limited to time and frequency resources within an uplink communication channel.

4. The method of claim 1, further comprising:

receiving, by the target base station, a registration message from a mobile station.

5. The method of claim 1, wherein the feedback message further comprises a power adjustment.

6. The method of claim 1, wherein the feedback message further comprises a frequency offset.

7. The method of claim 1, wherein the random access identifier is a code division multiple access (CDMA) code.

8. A target base station comprising:

a processor configured to allocate a random access identifier uniquely identifying a mobile station in a coverage area of the target base station in association with a handover of an existing communication link;

a receiver configured to receive the allocated random access identifier from the mobile station over a random access channel;

the processor further configured to generate, based on the reception of the random access identifier by the receiver, a feedback message comprising a timing adjustment; and

a transmitter configured to transmit the feedback message to the mobile station for synchronizing the mobile station with the target base station.

9. The target base station of claim 8, wherein the random access identifier is released after synchronization.

10. The target base station of claim 8, wherein the random access channel is limited to time and frequency resources within an uplink communication channel.

11. The target base station of claim 8, wherein the receiver is further configured to receive a registration message from a mobile station.

12. The base station of claim 8, wherein the feedback message further comprises a power adjustment.

13. The base station of claim 8, wherein the feedback message further comprises a frequency offset.

14. The base station of claim 8, wherein the random access identifier is a code division multiple access (CDMA) code.

15. A method for handover of an existing communication link of a mobile station from a serving base station to a target base station, the method comprising:

receiving, by the serving base station, an allocation of a random access identifier from the target base station that uniquely identifies the mobile station in a coverage area of the target base station in association with the handover, wherein the allocated random access identifier, when received by the target base station from the mobile station over a random access channel, is usable by the target base station to generate a feedback message comprising a timing adjustment to synchronize the mobile station with the target base station; and

transmitting, by the serving base station, the allocation of the random access identifier to the mobile station over the existing communication link of the mobile station, wherein the allocated random access identifier is usable by the mobile station for synchronizing the mobile station with the target base station in association with the handover.

16. The method of claim 15, wherein the random access identifier is a code division multiple access (CDMA) code.

17. The method of claim 15, wherein the received random access identifier is usable by the target base station for handing over the existing communication link of the mobile station.

18. A serving base station comprising:

a module configured to receive an allocation of a random access identifier from a target base station that uniquely identifies a mobile station in a coverage area of the target base station, wherein the allocated random access identifier, when received by the target base station from the mobile station over a random access channel, is usable by the target base station to generate a feedback message comprising a timing adjustment to synchronize the mobile station with the target base station in association with a handover of an existing communication link between the mobile station and the serving base station to the target base station; and

a transmitter configured to transmit the allocation of the random access identifier to the mobile station over the existing communication link of the mobile station, wherein the allocated random access identifier is usable by the mobile station for synchronizing the mobile station with the target base station in association with the handover.

19. The base station of claim 18, wherein the random access identifier is a code division multiple access (CDMA) code.

20. The base station of claim 18, wherein the received random access identifier is usable by the target base station for handing over the existing communication link of the mobile station.