System and Method for Relay Node Flow Control in a Wireless Communications System

• US 20100302946A1
• Filed: 05/20/2010
• Published: 12/02/2010
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Xia, Pengfei, Xiao, Weimin, Yang, Yunsong, Lu, Jianmin
• Granted Patent: US 8,576,714 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04W 28/0231 based on communication conditions dynamic wireless traffic scheduling definition based on channel quality criteria H04W72/54
• CPC Class Codes: H04W 28/0278 using buffer status reports dynamic wireless traffic scheduling definition H04W72/12
• CPC Class Codes: H04W 28/0284 detecting congestion or overload during communication monitoring arrangements H04L43/00
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

A system and method for relay node flow control and/or congestion control in a wireless communications system are provided. A method for relay operation includes determining a buffer status of a buffer for data to be transmitted on a communications channel allocated from network resources controlled by a communications controller, computing buffer status information based on the buffer status, and transmitting the buffer status information to the communications controller.

Claims

1. A method for operating a relay in a communication system, the method comprising:

determining a buffer status of a buffer for data to be transmitted on a communications channel allocated from network resources controlled by a communications controller;

determining a consumption rate or a filling rate for the buffer;

determining buffer status information based on the buffer status and either the consumption rate or the filling rate for the buffer; and

transmitting the buffer status information to the communications controller.

2. The method of claim 1, wherein determining a buffer status comprises measuring an amount of data buffered in the buffer, measuring an amount of an unoccupied portion of the buffer, or a combination thereof.

3. The method of claim 1, wherein the buffer status information comprises a consumption time of the buffer, wherein the consumption time of the buffer is an amount of data buffered in the buffer divided by the consumption rate for the buffer.

4. The method of claim 3, wherein the consumption rate is determined based on a channel quality information reported by a communications device associated with the buffer for a communication channel between the relay and the communication device.

5. The method of claim 3, wherein the consumption rate is determined based on a history of data throughput for a communications channel from the communications controller to a communications device associated with the buffer.

6. The method of claim 1, wherein the buffer status information comprises a filling time of the buffer, wherein the filling time of the buffer is an amount of an unoccupied portion of the buffer divided by the filling rate for the buffer.

7. The method of claim 6, wherein the filling rate is determined based on a channel quality information measured for a communication channel between the relay and a communications device associated with the buffer.

8. The method of claim 6, wherein the filling rate is determined based on a history of data throughput for a communications channel from a communications device associated with the buffer to the buffer.

9. The method of claim 1, wherein there are a plurality of buffers, wherein each buffer in the plurality of buffers stores data to be transmitted on a different communications channel allocated from network resources controlled by the communications controller, and wherein determining buffer status comprises aggregating a buffer status for at least two buffers.

10. The method of claim 9, wherein the at least two buffers are associated with a single communications device, a single traffic class, a single transmission direction, or a combination thereof.

11. The method of claim 1, wherein transmitting the buffer status information comprises piggy backing the buffer status information onto a message being sent to the communications controller.

12. The method of claim 1, wherein transmitting the buffer status information comprises:

concatenating more than one buffer status information onto a message; and

transmitting the concatenated buffer status information message to the communications controller.

13. The method of claim 12, wherein the more than one buffer status information comprises at least one buffer status information for a first communications device and at least one buffer status information for a second communications device, at least one buffer status information for a first traffic class and at least one buffer status information for a second traffic class, at least one buffer status information for a first communications direction and at least one buffer status information for a second communications direction, or a combination thereof.

14. The method of claim 1, further comprising receiving a buffer status report related to a buffer for data to be transmitted on an access communications channel between the relay and a communications device, wherein the access communications channel is allocated from network resources controlled by the relay, and wherein determining the buffer status information is further based on the received buffer status report.

15. A method for controller operation, the method comprising:

receiving, from a relay device, buffer status information for a buffer at the relay device, wherein the buffer status information comprises a buffer status of at least one uplink buffer and at least one downlink buffer at the relay device; and

adjusting a network resources allocation for a communications channel associated with the buffer based on the buffer status information, wherein the communications channel is allocated from network resources controlled by the controller.

16. The method of claim 15, wherein adjusting a network resource allocation comprises:

increasing the network resources allocation for an uplink portion of the communications channel in response to determining that the uplink buffer is full; and

altering a network resource usage for a downlink portion of the communications channel in response to determining that the downlink buffer is full.

17. The method of claim 16, wherein adjusting a network resource allocation further comprises decreasing the wireless resource allocation for the uplink portion of the communications channel in response to determining that the uplink buffer is empty.

18. The method of claim 16, wherein there are multiple downlink buffers, and wherein altering a network resource usage comprises suspending transmissions over the downlink portion of communications channels with full downlink buffers.

19. The method of claim 18, wherein suspending transmissions comprises decreasing a priority of the transmissions over the downlink portions of communications channels with full downlink buffers.

20. The method of claim 18, wherein altering a network resource usage further comprises increasing downlink transmissions over the downlink portion of communications channels with downlink buffers that are not full.

21. The method of claim 15, wherein receiving, from a relay device, buffer status information comprises receiving the buffer status information piggy backed on a received message.

22. The method of claim 15, wherein receiving, from a relay device, buffer status information comprises receiving a buffer status report message.

23. The method of claim 22, wherein there are multiple buffers, and wherein receiving a buffer status report message comprises receiving concatenated buffer status information for the multiple buffers on the received buffer status report message.

24. The method of claim 15, wherein receiving, from a relay device, buffer status information comprises receiving a service request indication message.

25. The method of claim 15, wherein the buffer status information reports a multi-bit value indicating a degree of buffer fullness of the buffer, and wherein adjusting a network resource allocation comprises adjusting the network resource allocation based on the degree of buffer fullness.

26. A relay comprising:

a receiver to be coupled to a receive antenna, the receiver configured to receive signals detected by the receive antenna;

a transmitter to be coupled to a transmit antenna, the transmitter configured to transmit signals with the transmit antenna;

uplink buffers coupled to the receiver and to the transmitter, the uplink buffers configured to store data for uplink communications channels allocated from network resources controlled by a communications controller;

downlink buffers coupled to the receiver and to the transmitter, the downlink buffers configured to store data for downlink communications channels allocated from the network resources controlled by the communications controller; and

a controller coupled to the uplink buffers, to the downlink buffers, to the transmitter, and to the receiver, the controller configured to determine a buffer status for the uplink buffers and the downlink buffers, to compute buffer status information from the buffer status, and to transmit the buffer information to the communications controller.

27. The relay of claim 26, wherein the controller comprises:

a buffer status unit configured to determine buffer status for the uplink buffers and the downlink buffers;

a buffer time compute unit coupled to the buffer status unit, the buffer time compute unit configured to compute a buffer fill/empty time for a buffer based on the buffer status and a consumption rate for the buffer; and

a threshold compare unit coupled to the buffer status unit, the threshold compare unit configured to compute a state of the buffer based on the buffer status.

28. The relay of claim 27, wherein the controller further comprises an information aggregate unit coupled to the buffer status unit, the information aggregate unit configured to aggregate buffer status information for at least two buffers, wherein the aggregation is based on traffic class, channel direction, buffer status, or a combination thereof.