Hybrid Contention-Based and Schedule-Based Access to a Communication Link

• US 20090103558A1
• Filed: 10/19/2007
• Published: 04/23/2009
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Guey, Jiann-Ching, Zangi, Kambiz C.
• Granted Patent: US 7,978,646 B2
• Time in Patent Office: Days
• US Class Current: 370/447
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 74/0841 with collision treatment

Abstract

One or more embodiments taught herein provide a hybrid access arrangement using a contention-based channel and a scheduled channel on a communication link. As a point of significant efficiency, given users transmit autonomously on the contention-based channel, without need for scheduling overhead. However, if a contention overload occurs on the contention-based channel, the involved users are identified from unique signature sequences included in their user transmissions. The identified users are temporarily managed as scheduled users on the scheduled channel, which supplements the contention-based channel and therefore may use limited communication link resources in comparison to the contention-based channel. Users not involved in the contention overload generally continue operating on the contention-based channel.

Claims

1. A method of managing multiple user access to a communication link comprising:

receiving user transmissions on a contention-based channel of the communication link that supports a maximum number of simultaneous user transmissions, wherein each user transmission includes a unique signature sequence;

detecting contention overloads where more than the maximum number of users simultaneously transmit on the contention-based channel;

identifying the users involved in a contention overload based on the unique signature sequences received from those users; and

scheduling retransmissions for one or more of the identified users on a scheduled channel of the communication link.

2. The method of claim 1, wherein scheduling retransmissions for one or more of the identified users on a scheduled channel of the communication link comprises determining retransmission schedule information for each of the one or more of the identified users, and sending the retransmission schedule information to the one or more of the identified users such that the one or more of the identified users operate at least temporarily as scheduled users on the scheduled channel.

3. The method of claim 1, further comprising dynamically allocating channel resources from the communication link for scheduled channel use responsive to detecting contention overloads.

4. The method of claim 1, further comprising statically allocating channel resources from the communication link for scheduled channel use.

5. The method of claim 1, further comprising defining the contention-based channel and the scheduled channel based on allocating channel resources from the communication link, said channel resources comprising at least one of frequency, time, and code channelization resources.

6. The method of claim 1, further comprising indicating whether scheduled retransmissions are to be full retransmissions or partial retransmissions that exploit incremental or redundant decoding.

7. The method of claim 1, wherein receiving user transmissions on a contention-based channel of the communication link comprises receiving user transmissions within synchronized transmission slots of the contention-based channel.

8. The method of claim 7, wherein detecting contention overloads comprises detecting contention overloads on a transmission slot basis, and wherein identifying the users involved in a contention overload comprises identifying users on a transmission slot basis.

9. The method of claim 8, wherein scheduling retransmissions comprises, for a given transmission slot in which a contention overload occurred, sending scheduling information to the users identified from the unique signature sequences that were received in the given transmission slot.

10. The method of claim 7, further comprising sending individualized acknowledgment information to the users that transmitted in a given transmission slot, if a contention overload did not occur in the given transmission slot, and otherwise sending individualized scheduling information to those users, at least to the extent that unique signature sequences were successfully received from the users that transmitted in the given transmission slot.

11. A base station for use in a wireless communication network and configured to manage multiple user access to a communication link supported by the base station, said base station comprising:

receiver circuits to receive user transmissions on a contention-based channel of the communication link that supports a maximum number of simultaneous user transmissions, wherein each user transmission includes a unique signature sequence; and

one or more processing circuits operatively associated with the receiver circuits and configured to detect contention overloads where more than the maximum number of users simultaneously transmit on the contention-based channel, identify the users involved in a contention overload based on the unique signature sequences received from those users, and schedule retransmissions for one or more of the identified users on a scheduled channel of the communication link.

12. The base station of claim 11, wherein the one or more processing circuits include a detection processor configured to detect contention overloads in cooperation with the receiver, an identification processor configured to identify the users involved in contention overloads from the unique signature sequences received during the contention overloads, and a scheduling processor configured to schedule retransmissions on the scheduled channel for the identified users.

13. The base station of claim 11, wherein the one or more processing circuits include a channel allocation processor configured to dynamically allocate channel resources from the communication link for scheduled channel use responsive to the detection of contention overloads.

14. The base station of claim 11, wherein the one or more processing circuits include a channel allocation processor that is configured to define the contention-based channel and the scheduled channel by allocating channel resources from the communication link, said channel resources comprising at least one of frequency, time, and code channelization resources.

15. The base station of claim 11, wherein the one or more processing circuits include a retransmission processor configured to control whether scheduled retransmissions are to be full retransmissions or partial retransmissions that exploit incremental or redundant decoding at the base station.

16. The base station of claim 11, wherein the base station is configured to receive the user transmissions on the contention-based channel within synchronized transmission slots.

17. The base station of claim 16, wherein the base station is configured to detect contention overloads on a transmission slot basis, and to identify the users involved in a contention overload on a transmission slot basis.

18. The base station of claim 17, wherein the base station is configured to schedule retransmissions in response to a contention overload occurring within a given transmission slot by sending scheduling information to the users identified from the unique signature sequences that were successfully received at the base station on the contention-based channel for that given transmission slot.

19. The base station of claim 16, wherein the base station is configured to send individualized acknowledgment information to the users that transmitted in a given transmission slot, if a contention overload did not occur in the given transmission slot, and otherwise send individualized scheduling information to those users for whom unique signature sequences were successfully received at the base station in the given transmission slot.

20. A method of managing multiple users sharing access to a communication link comprising:

defining a contention-based channel on the communication link;

defining a scheduled channel on the communication link;

receiving user transmissions on the contention-based channel from individual users transmitting autonomously on the contention-based channel, wherein each user transmission on the contention-based channel includes a unique signature sequence;

detecting a contention overload on the contention-based channel where too many users simultaneously transmit on the contention-based channel;

identifying the users involved in the contention overload based on successfully decoding the unique signature sequences received during the contention overload; and

sending retransmission schedule information to the identified users to control scheduled retransmissions by the identified users on the scheduled channel.