METHODS AND DEVICES RELATING TO DOWNLINK ASSIGNMENTS

• US 20090196204A1
• Filed: 02/05/2009
• Published: 08/06/2009
• Est. Priority Date: 02/06/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Astely, David, Parkvall, Stefan, Baldemair, Robert
• Granted Patent: US 8,072,911 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04L 1/1635 Cumulative acknowledgement, i.e. the acknowledgement message applying to all previous messages
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04L 1/1896 ARQ related signaling

Abstract

The invention relates to a method in a first communication device of receiving control information over a radio channel from a second communication device. The first communication device receives a subframe over the radio channel, and determines whether the subframe is a downlink subframe with downlink assignment intended for the first communication device by reading data in the subframe. That being the case, the first communication device decodes data within the subframe, and determines whether any data packet being sent from the second communication device before the subframe has been missed by analysing an indicator associated to the subframe in the data. The indicator provides knowledge about previous downlink subframes with downlink assignment intended for the first communication device.

Claims

1. A method in a first communication device for receiving control information and data over a radio channel from a second communication device the method comprising the steps of:

receiving part of a subframe over the radio channel,

detecting whether the subframe is a subframe with a downlink assignment intended for the first communication device and if so,

determining whether at least one downlink assignment for data being sent from the second communication device before the subframe has been missed by analysing an indicator associated to the subframe;

the indicator providing knowledge about previous downlink subframes with downlink assignments intended for the first communication device.

2. The according to claim 1, comprising

the receiving step further comprises receiving a plurality of subframes and the detecting step comprises detecting a plurality of subframes with downlink assignments intended for the first communication device;

generating ACK/NAK feedback of reception in response to the received plurality of detected subframes, wherein the ACK/NAK feedback is bundled into a single bundled ACK/NAK feedback message, and

transmitting the single bundled ACK/NAK feedback message in an uplink resource associated with a last received detected subframe with downlink assignment intended for the first communication device of an uplink subframe associated to the plurality of downlink subframes.

3. The method according to claim 2, is performed in case no downlink assignment is determined to have been missed, and in case at least if one downlink assignment is determined to have been missed, no feedback is transmitted.

4. The method according to claim 2, wherein the single bundled ACK/NAK feedback message comprises a negative acknowledgement, (NAK,) when decoding of data in one received subframe with a detected downlink assignment fails or a downlink assignment has been determined to have been missed.

5. The method according to claim 24, wherein the single, bundled ACK/NAK feedback message comprises a positive acknowledgement (ACK), when the decoding of data in all received subframes with detected downlink assignments is successful and it is determined that the first communication device has not missed any downlink assignments.

6. The method according to claim 1, wherein the indicator indicates which number of the plurality of subframes with a downlink assignment intended for the first communication device the subframe is, including an ordinal number and an accumulative number.

7. The method according to claim 1, wherein the indicator indicates a number of previous subframes with downlink assignment intended for the first communication device and comprises one bit indicating a numeral reference, such as consecutive numbers.

8. The method according to claim 1 wherein the indicator is arranged as a part of the downlink assignment on the control channel.

9. The method according to claim 1, the indicator indicating a number of previous subframes with downlink assignment intended for the first communication device and the indicator comprising a polynomial used to generate a Cyclic Redundancy Check (CRC) for the assigned subframe on a Physical Downlink Channel (PDCH), including Physical Downlink Shared Channel, (PDSCH) and Physical Downlink Control Channel, (PDCCH) and the first communication device retrieving this polynomial during the decoding of the data or control information.

10. The method according to claim 1 the indicator indicating a number of previous subframes with assignment intended for the first communication device and comprises a cyclic redundancy check value generated from a scramble/mask of a Cyclic Redundancy Check (CRC) generated with a polynomial for the assigned subframe on a Physical Downlink Channel (PDCH) including Physical Downlink Shared Channel (PDSCH) and Physical Downlink Control Channel (PDCCH, wherein the scramble/mask depends on the number of previous subframes with downlink assignment intended for the first communication device and the first communication device retrieving the indicator from decoding the data or control information.

11. The method according to claim 1, wherein the determining of whether a downlink assignment has been missed comprises to compare the indicator with an expected value of the indicator.

12. The method according to claim 1 wherein the step of determining whether one downlink assignment has been missed is done;

for a last subframe or after each subframe in a bundling window of a plurality of subframes with downlink assignments intended to the first communication.

13. The method according to claim 1 wherein the radio channel comprises a time divisional duplex scheme.

14. The method according to claim 1, wherein the first communication device stops decoding and/or receiving more subframes within a bundling window if it is detected that is has missed a subframe with a downlink assignment intended for the first communication device.

23. The method according to claim 1, wherein the indicator indicates a number of previous subframes with downlink assignment intended for the first communication device by comprising one bit indicating a numeral reference, including consecutive numbers.

15. A method in a second communication device for transmitting control information and data over a radio channel to a first communication device in a subframe with a downlink assignment intended for the first communication device, the method comprising the steps of:

adding an indicator to the subframe providing knowledge about previous subframes with a downlink assignment intended for the first communication device in the control information, and

transmitting the control information and data with the subframe to the first communication device.

16. The method according to claim 15, wherein the second communication device assigns a plurality of downlink subframes to the first communication device forming a bundling window and feedback of the reception of the plurality of downlink subframes is arranged to be bundled into a single ACK/NAK feedback message at the first communication device the method further comprising the step of

determining whether the control information or data has been received by checking an uplink resource of an uplink subframe assigned to the plurality of assigned downlink subframes for the single ACK/NAK feedback message feedback of reception, wherein the first uplink resource is related to a last assigned downlink subframe of the plurality of assigned downlink subframes.

17. The method according to claim 16, wherein an uplink resource of the last assigned downlink subframe comprises no feedback of reception, checking a second uplink resource related to an assigned downlink subframe before the last assigned downlink subframe for the single ACK/NAK feedback message.

18. The method according to claim 16, wherein if no single ACK/NAK feedback message is detected on the uplink resource, it is determined that one downlink assignment has been missed.

19. The method according to claim 16, wherein ACK in the single ACK/NAK feedback message indicates properly received control information and NAK indicates a failed decoded subframe and/or a missed downlink assignment.

20. The method according to claim 16, wherein it is determined that one downlink assignment has been missed if no single ACK/NAK feedback message is detected on the uplink resource.

21. The method according to claim 20 further comprising determining to resend assigned a downlink subframe based on a result of the checking of the uplink subframe resource.

22. The method according to claim 16, wherein the indicator indicates which number of the plurality of subframes with a downlink assignment intended for the first communication device the subframe comprises, including ordinal and accumulative number, within the bundling window.

24. The method according to claim 15, wherein the indicator is arranged as a part of the downlink assignment on the control channel

25. The method according to claim 15, wherein the indicator indicates a number of previous subframes with assignment intended for the first communication device by using a polynomial to generate a Cyclic Redundancy Check (CRC) for the assigned subframe on a Physical Downlink Channel (PDCH) including Physical Downlink Shared Channel (PDSCH) and Physical Downlink Control Channel (PDCCH).

26. The method according to claim 15, wherein the indicator of previous subframes with assignment intended for the first communication device comprises a cyclic redundancy check value generated from a scramble/mask of a Cyclic Redundancy Check (CRC) generated with a polynomial for the assigned subframe on a Physical Downlink Channel (PDCH), including Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH), wherein the scramble/mask depends on the number of previously scheduled assigned subframes.

27. The method according to claim 15 wherein the radio channel comprises a time divisional duplex scheme.

28. A first communication device for receiving control information and data over a radio channel from a second communication device comprising a receiving arrangement adapted to receive a subframe of a radio frame, and a control unit arranged to determine whether the subframe is a subframe with downlink assignment intended for the first communication device the control unit being further arranged to determine whether any downlink assignment for data, that has been scheduled in and sent from the second communication device previous the subframe, has been missed by analysing an indicator associated to the subframe;

the indicator is arranged to provide knowledge of previous subframe with downlink assignments intended for the first communication device.

29. A second communication device for transmitting control information and data with a subframe comprising a downlink assignment intended for a first communication device of a radio frame over a radio channel to the first communication device, the second communication device comprising:

a control unit arranged to add an indicator to the subframe arranged to provide knowledge of previous subframes with a downlink assignment intended for the first communication device in the control information to the first communication device, and

a transmitting arrangement for transmitting the control information and data with the subframe to the first communication device.