Mitigating ACK/NACK errors in MIMO/SIC/HARQ

• US 7,940,663 B2
• Filed: 07/15/2005
• Issued: 05/10/2011
• Est. Priority Date: 07/20/2004
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kadous, Tamer
• Primary Examiner(s): Ferris; Derrick W
• Assistant Examiner(s): HOPKINS, MATTHEW A
• Application Number:
  US11/182,694
• Publication Number:
  US 20060018259A1
• Time in Patent Office: 2,125 Days
• Field of Search: 370/216, 370/230, 370/231, 370/236, 370/236.1, 370/236.2, 370/328, 370/329, 370/338, 455/69, 455/522, 714/748, 714/749, 714/750, 714/751, 714/758, 714/799
• US Class Current: 370/235
• 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 2001/125 Arrangements for preventing errors in the return channel

Abstract

Systems and methodologies are described that facilitate mitigating effects of mismatch errors related to incorrectly decoded acknowledgments indicative of successfully decoded data packets in a wireless network environment. Misinterpretation of a cumulative acknowledgment related to a number of successfully decoded data packets can be identified, and data packet transmission mismatch errors caused thereby can be evaluated to determine an optimal manner in which to decode and acknowledge remaining data packets to alleviate mismatch and restore synchronization between a transmitter of the data packets and a receiver thereof.

Claims

1. A method of mitigating effects of acknowledgement interpretation errors during communication in a wireless network, comprising:

identifying an error related to interpretation of an acknowledgement indicative of a successfully decoded data packet;

determining error type, wherein the error is a downward mismatch error in which a transmitter incorrectly interprets the acknowledgment as indicating that a smaller number of data packets were successfully decoded by a receiver than actually were successfully decoded, and wherein the transmitter redundantly transmits one or more data packets in a subsequent transmission based at least in part on the incorrect interpretation of the acknowledgement;

generating, by the receiver, a replica of a last successfully decoded data packet prior to decoding data packets in the subsequent transmission, and comparing the replica to a data packet in the subsequent transmission to determine whether a predetermined threshold correlation value is exceeded; and

remedially restoring a state of synchronization between the receiver that provided the acknowledgement and the transmitter that misinterpreted the acknowledgement, based at least in part on the type of error identified.

2. The method of claim 1, further comprising employing a hybrid automatic request (HARQ) protocol for transmission of one or more data packets between the transmitter and the receiver.

3. The method of claim 2, further comprising employing cumulative acknowledgement protocol for acknowledging successful decode by the receiver of at least one data packet to the transmitter of the at least one data packet.

4. The method of claim 1, wherein the error is an upward mismatch error in which the transmitter incorrectly interprets the acknowledgment as indicating that a greater number of data packets were successfully decoded by the receiver than actually were successfully decoded.

5. The method of claim 4, wherein the transmitter omits one or more data packets from a subsequent transmission based at least in part on the incorrect interpretation of the acknowledgement.

6. The method of claim 5, further comprising estimating an energy level associated with the omitted data packet and comparing the estimated energy level to a predetermined threshold value to verify that the omitted data packet is not present in the subsequent transmission.

7. The method of claim 6, further comprising initiating a decode of a next expected data packet in the subsequent transmission.

8. The method of claim 7, further comprising providing an acknowledgement of a successfully decoded data packet, received in the subsequent transmission, to the transmitter.

9. The method of claim 8, wherein the transmitter and the receiver are synchronized when the transmitter correctly interprets the acknowledgement of the successfully decoded data packet received in the subsequent transmission.

10. The method of claim 1, further comprising recognizing the data packet as a redundant data packet when the correlation between the data packet and the replica exceeds the predetermined threshold correlation value.

11. The method of claim 10, further comprising initiating decoding of a next expected data packet in the subsequent transmission.

12. The method of claim 11, further comprising providing an acknowledgement of a successfully decoded data packet that was received in the subsequent transmission, to the transmitter.

13. The method of claim 11, further comprising providing an acknowledgement of the last successfully decoded data packet if no data packet received in the subsequent transmission is successfully decoded.

14. The method of claim 1, executed by a mobile device.

15. The method of claim 14, wherein the mobile device is at least one of a cellular phone, a smart phone, a laptop, a handheld communication device, a handheld computing device, a satellite radio, a global positioning system, or a personal digital assistant.

16. An apparatus that facilitates mitigation of throughput deterioration due to mismatch errors in a wireless network, comprising:

a transmitter that transmits one or more data packets utilizing a hybrid automatic request (HARQ) protocol; and

a receiver that receives the one or more data packets utilizing a HARQ protocol, provides a cumulative acknowledgement to the transmitter related to a number of successfully decoded data packets, and remedially compensates for mismatch errors related to misinterpretation of an acknowledgement at the transmitter, wherein the receiver further comprises

a decoder that decodes the one or more data packets and an acknowledgement component that generates the acknowledgment,

an error detection component that detects a mismatch error caused by a misinterpreted acknowledgement, and comprises a downward mismatch error detection component that identifies a downward mismatch error related to an acknowledgement that is incorrectly interpreted as indicating a lesser number of successfully decoded packets than were actually successfully decoded and generates a codeword for at least one successfully decoded data packet duplicated in a subsequent data packet transmission due to the downward mismatch error, wherein the receiver compares the codeword to a duplicate data packet to evaluate whether a predetermined threshold correlation value is exceeded.

17. The apparatus of claim 16, the error detection component comprises an upward mismatch error detection component that identifies an upward mismatch error related to an acknowledgement that is incorrectly interpreted as indicating a greater number of successfully decoded packets than were actually successfully decoded.

18. The apparatus of claim 17, the receiver further comprises an energy estimation component that estimates an energy level for at least one data packet omitted from a subsequent data packet transmission due to the upward mismatch error.

19. The apparatus of claim 18, the receiver compares the estimated energy level to a predetermined threshold value to ensure that the data is not present in the subsequent data packet transmission.

20. The apparatus of claim 19, the decoder decodes a next expected data packet and acknowledges the decode if successful.

21. The apparatus of claim 16, the decoder disregards the duplicate data packet and initiates a decode of a next expected data packet when the predetermined threshold correlation value is exceeded.

22. The apparatus of claim 21, the acknowledgement component provides an acknowledgement of a successful decode of the next expected data packet if the decode thereof is successful.

23. The apparatus of claim 21, the acknowledgement component provides an acknowledgement of a successful decode of the duplicate data packet if the decode of the next expected data packet is unsuccessful.

24. An apparatus that facilitates detecting and compensating for mismatch errors in a wireless network, comprising:

means for receiving a first transmission of at least one data packet;

means for decoding the at least one data packet;

means for providing an acknowledgement of successful decode of the at least one data packet;

means for determining whether the acknowledgement is correctly interpreted based at least in part on a second transmission of one or more data packets;

means for identifying an error related to interpretation of an acknowledgement indicative of a successfully decoded data packet, wherein the error is a downward mismatch error in which the acknowledgment is incorrectly interpreted as indicating that a smaller number of data packets were successfully decoded by the means for receiving than actually were successfully decoded, and wherein at least a portion of the second transmission of one or more data packets are redundantly transmitted based at least in part on the incorrect interpretation of the acknowledgement;

means for generating a replica of a last successfully decoded data packet prior to decoding data packets in the second transmission, and comparing the replica to a data packet in the second transmission to determine whether a predetermined threshold correlation value is exceeded; and

means for remedially restoring a state of synchronization between the means for receiving and a means for transmitting one or more data packets, which misinterpreted the acknowledgement, based at least in part on the identified error.

25. The apparatus of claim 24, further comprising means for determining whether one or more expected data packets are omitted from the second transmission.

26. The apparatus of claim 25, further comprising means for proceeding decoding the one or more data packets in the second transmission upon evaluation of an omitted data packet.

27. The apparatus of claim 26, further comprising means for providing an acknowledgement of successful decode of at least one data packet in the second transmission to synchronize the means for receiving to the means for transmitting the one or more data packets.

28. The apparatus of claim 24, further comprising means for determining whether one or more successfully decoded data packets are duplicated from the second transmission.

29. The apparatus of claim 28, further comprising means for decoding the one or more data packets in the second transmission upon evaluation of a duplicate data packet.

30. The apparatus of claim 29, further comprising means for providing an acknowledgement of successful decode of at least one data packet in the second transmission to facilitate restoring the state of synchronization between the means for receiving to the means for transmitting the one or more data packets.

31. The apparatus of claim 29, further comprising means for providing an acknowledgement of a successful decode of the duplicate data packet if none of the one or more data packets in the second transmission is successfully decoded.

32. A computer-readable medium having stored thereon computer-executable instructions executed by at least one processor to perform acts of:

receiving a first transmission of at least one data packet;

decoding the at least one data packet;

providing an acknowledgement of successful decode of the at least one data packet;

determining whether the acknowledgement is correctly interpreted based at least in part on a second transmission of one or more data packets;

identifying an error related to interpretation of an acknowledgement indicative of a successfully decoded data packet, wherein the error is a downward mismatch error in which the acknowledgment is incorrectly interpreted as indicating that a smaller number of data packets were successfully decoded after reception than actually were successfully decoded, and wherein one or more data packets are redundantly transmitted in the second transmission based at least in part on the incorrect interpretation of the acknowledgement;

generating a replica of a last successfully decoded data packet prior to decoding the one or more data packets in the second transmission, and comparing the replica to a data packet in the second transmission to determine whether a predetermined threshold correlation value is exceeded; and

remedially restoring a state of synchronization between a receiver that provided the acknowledgement and a transmitter that misinterpreted the acknowledgement, based at least in part on the identified error, wherein the computer-readable medium is at least one of a magnetic storage device, an optical disk, a digital versatile disk, a smart card, or a memory device.

33. The computer-readable medium of claim 32, further comprising instructions for determining whether at least one of an expected data packet and a duplicate data packet is present in the second transmission.

34. The computer-readable medium of claim 33, further comprising instructions for:

bypassing a duplicate data packets, and

decoding a next expected data packet.

35. The computer-readable medium of claim 34, further comprising instructions for providing an acknowledgement of a successfully decoded data packet received during the second transmission.

36. The computer-readable medium of claim 34, further comprising instructions for providing an acknowledgement of the duplicate data packet if no data packets in the second transmission are decoded.

37. The computer-readable medium of claim 33, further comprising instructions for employing an energy estimation protocol to determine whether to proceed with decoding a next expected data packet.

38. The computer-readable medium of claim 37, further comprising instructions for providing an acknowledgement of a successfully decoded data packet in the second transmission.

39. A processor that executes instructions for mitigating acknowledgement errors in a wireless network, comprising:

means for receiving a first transmission of at least one data packet;

means for decoding the at least one data packet;

means for providing an acknowledgement of successful decode of the at least one data packet; and

means for determining whether the acknowledgement is correctly interpreted based at least in part on a second transmission of one or more data packets;

means for identifying an error related to interpretation of an acknowledgement indicative of a successfully decoded data packet, wherein the error is a downward mismatch error in which the acknowledgment is incorrectly interpreted as indicating that a smaller number of data packets were successfully decoded after reception than actually were successfully decoded, and wherein one or more data packets are redundantly transmitted in the second transmission based at least in part on the incorrect interpretation of the acknowledgement;

means for generating a replica of a last successfully decoded data packet prior to decoding the one or more data packets in the second transmission, and comparing the replica to a data packet in the second transmission to determine whether a predetermined threshold correlation value is exceeded; and

means for remedially restoring a state of synchronization between a receiver that provided the acknowledgement and a transmitter that misinterpreted the acknowledgement, based at least in part on the identified error.

40. A mobile device that facilitates communicating over a wireless network, comprising:

a receiving component that receives data packet transmission from a transmitter in the wireless network;

an error detection component that identifies an error comprising at least one of an upward mismatch error or a downward mismatch error related to interpretation of an acknowledgement indicative of a successfully decoded data packet, wherein the error is the downward mismatch error in which a transmitter incorrectly interprets the acknowledgment as indicating that a smaller number of data packets were successfully decoded by the receiving component than actually were successfully decoded, and wherein the transmitter redundantly transmits one or more data packets in the subsequent transmission based at least in part on the incorrect interpretation of the acknowledgement, the error detection component generates a replica of a last successfully decoded data packet prior to decoding the one or more data packets in the subsequent transmission, compares the replica to at least one data packet in the subsequent transmission to determine whether a predetermined threshold correlation value is exceeded, and remedially restores a state of synchronization between the receiving component and the transmitter that misinterpreted the acknowledgement, based at least in part on the identified error;

an energy estimation component that evaluates an energy level associated with the at least one data packet; and

an acknowledgement component that generates an acknowledgement of one or more successfully decoded data packets.

41. The mobile device of claim 40, wherein the device is at least one of a cellular phone, a smart phone, a laptop, a handheld communication device, a handheld computing device, a satellite radio, a global positioning system, or a personal digital assistant.