Method and Apparatus in a Telecommunication System

• US 20120120855A1
• Filed: 01/20/2012
• Published: 05/17/2012
• Est. Priority Date: 04/11/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Torsner, Johan, Astely, David, Parkvall, Stefan, Tynderfeldt, Tobias
• Granted Patent: US 8,472,358 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04L 1/1621 Group acknowledgement, i.e. the acknowledgement message defining a range of identifiers, e.g. of sequence numbers
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements

Abstract

Method and apparatus in a communication unit employing a wireless TDD or half duplex FDD transmission arrangement when communicating with a data sending party, for scheduling feedback reports for data blocks in received receive (RX) sub-frames, in transmit (TX) sub-frames available for transmission. An obtaining unit in the communication unit receives allocation parameters for the connection where the number of required feedback reports is greater than the number of allowed feedback reports. A scheduling unit in the communication unit then schedules feedback reports in available TX sub-frames according to a predetermined spreading rule also known by the data sending party, dictating that the feedback reports are spread out or distributed evenly over the available TX sub-frames. In this way, the number of feedback reports in a TX sub-frame can be reduced.

Claims

1. A method in a communication unit acting as a data receiving party and employing a TDD or half duplex FDD arrangement when communicating with a data sending party, of transmitting feedback reports for data blocks received in receive (RX) sub-frames to indicate whether errors have occurred in the data blocks, said method comprising the following steps:

obtaining allocation parameters for a connection indicating that a number of required feedback reports is greater than a number of allowed feedback reports during a given sub-frame sequence, and

scheduling feedback reports in available transmit (TX) sub-frames according to a predetermined spreading rule also known by the data sending party, dictating that the feedback reports are spread out or distributed evenly over the available TX sub-frames.

2. The method according to claim 1 wherein the number of allocated RX sub-frames exceeds the number of allocated TX sub-frames, according to the obtained allocation parameters.

3. The method according to claim 1 wherein said predetermined spreading rule further dictates that the number of RX sub-frames reported in any TX sub-frame is minimized, and that the maximum delay between any RX sub-frame and its associated TX sub-frame is minimized.

4. The method according to claim 1 wherein said spreading rule dictates that a feedback report is transmitted as soon as possible under the restriction that feedback reports for no more than X RX sub-frames are sent per TX sub-frame in a transmit direction, where X=CEILING (k_RX/k_TX), k_RX=the number of allocated RX sub-frames, and k_TX=the number of allocated TX sub-frames, CEILING being a mathematical operation that rounds up to the next integer.

5. The method according to claim 1 wherein the allocated RX sub-frames and TX sub-frames in said TDD or half duplex FDD arrangement are arranged in a given repeated sequence of sub-frames in a radio frame.

6. The method according to claim 1 wherein the communication unit acting as said data receiving party is a terminal, said RX sub-frames are downlink sub-frames and said TX sub-frames are uplink sub-frames.

7. The method according to claim 1 wherein the communication unit acting as said data receiving party is a base station, said RX sub-frames are uplink sub-frames and said TX sub-frames are downlink sub-frames.

8. The method according to claim 1 wherein a compressed feedback report is scheduled that refers to a set of data blocks in plural received RX sub-frames, if the number of feedback reports scheduled according to said predetermined spreading rule is greater than the number of bits or messages available for reporting.

9. The method according to claim 8 wherein the compressed feedback report indicates correct reception (ACK) if all the data blocks in the set have been received correctly, and incorrect reception (NACK) if at least one data block in the set has been received with errors.

10. The method according to claim 8 wherein the compressed feedback report contains a plurality of bits or messages each referring to a specific set of received data blocks.

11. The method according to claim 1 wherein a mapping operation is performed to associate each received data block or RX sub-frame with said feedback report(s).

12. The method according to claim 11 wherein a plurality of bits or messages in a feedback report refer to a single received data block, if the number of bits or messages available for reporting is greater than the number of received data blocks to report.

13. The method according to claim 1 wherein the RX sub-frames are divided into groups or sets, so that each TX sub-frame corresponds to a specific group or set of RX sub-frames.

14. The method according to claim 1 wherein a Hybrid ARQ (HARD) protocol is used whereby each feedback report includes an ACK message or a NACK message.

15. An apparatus in a communication unit acting as a data receiving party and employing a TDD or half duplex FDD arrangement when communicating with a data sending party, for transmitting feedback reports for data blocks received in receive (RX) sub-frames to indicate whether errors have occurred in the data blocks, said apparatus comprising:

an obtaining unit adapted to obtain allocation parameters for a connection indicating that a number of required feedback reports is greater than a number of allowed feedback reports during a given sub-frame sequence, and

a scheduling unit adapted to schedule feedback reports in available transmit (TX) sub-frames according to a predetermined spreading rule also known by the data sending party, dictating that the feedback reports are spread out or distributed evenly over the available TX sub-frames.

16. The apparatus according to claim 15 wherein the number of allocated RX sub-frames exceeds the number of allocated TX sub-frames, according to the obtained allocation parameters.

17. The apparatus according to claim 15 wherein said predetermined spreading rule further dictates that the number of RX sub-frames reported in any TX sub-frame is minimized, and that the maximum delay between any RX sub-frame and its associated TX sub-frame is minimized.

18. The apparatus according to claim 15 wherein said spreading rule dictates that a feedback report is transmitted as soon as possible under the restriction that feedback reports for no more than X RX sub-frames are sent per TX sub-frame in a transmit direction, where X=CEILING (k_RX/k_TX), k_RX=the number of allocated RX subframes, and k_TX=the number of allocated TX sub-frames, CEILING being a mathematical operation that rounds up to the next integer.

19. The apparatus according to claim 15 wherein the allocated RX sub-frames and TX sub-frames in said TDD or half duplex FDD arrangement are arranged in a given repeated sequence of sub-frames in a radio frame.

20. The apparatus according to claim 15 wherein the communication unit acting as said data receiving party is a terminal, said RX sub-frames are downlink sub-frames and said TX sub-frames are uplink sub-frames.

21. The apparatus according to claim 15 wherein the communication unit acting as said data receiving party is a base station, said RX sub-frames are uplink sub-frames and said TX sub-frames are downlink sub-frames.

22. The apparatus according to claim 15 wherein the scheduling unit is further adapted to schedule a compressed feedback report that refers to a set of data blocks in plural received RX sub-frames, if the number of feedback reports scheduled according to said predetermined spreading rule is greater than the number of bits or messages available for reporting.

23. The apparatus according to claim 22 wherein the compressed feedback report indicates correct reception (ACK) if all the data blocks in the set have been received correctly, and incorrect reception (NACK) if at least one data block in the set has been received with errors.

24. The apparatus according to claim 22 wherein the compressed feedback report contains a plurality of bits or messages each referring to a specific set of received data blocks.

25. The apparatus according to claim 15 further comprising a mapping unit adapted to perform a mapping operation to associate each received data block or RX sub-frame with said feedback report{s).

26. The apparatus according to claim 25 wherein a plurality of bits or messages in a feedback report refer to a single received data block, if the number of bits or messages available for reporting is greater than the number of received data blocks to report.

27. The apparatus according to claim 15 wherein the RX sub-frames are divided into groups or sets, so that each TX sub-frame corresponds to a specific group or set of RX sub-frames.

28. The apparatus according to claim 15 wherein the communication unit is adapted to use a Hybrid ARQ (HARD) protocol whereby each feedback report includes an ACK message or a NACK message.