Method and an apparatus for a quick retransmission of signals in a communication system

• US 6,694,469 B1
• Filed: 04/14/2000
• Issued: 02/17/2004
• Est. Priority Date: 04/14/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Esteves, Eduardo A. S., Black, Peter J., Jalali, Ahmad, Attar, Rashid A., Sindhushayana, Nagabhushana T.
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): Britt, Cynthia
• Application Number:
  US09/549,017
• Time in Patent Office: 1,404 Days
• Field of Search: 714/748, 370/349, 370/342, 370/330, 370/436, 370/469, 370/474, 375/224, 375/228, 375/358
• US Class Current: 714/748
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/1877 for semi-reliable protocols, e.g. for less sensitive applications like streaming video buffer level management for video bitstream control arrangements H04N21/44004
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements

Abstract

A method and an apparatus for quick retransmission of signals in a communication system are disclosed. A transmitting terminal, e.g., a base station, transmits signals in a form of packets to a receiving terminal, e.g., a subscriber station. The receiving terminal determines if the packet was intended for the receiving terminal, and if so, the receiving terminal demodulates the packet. The receiving terminal then computes a quality metric of the packet, e.g., a cyclic redundancy check, and compares the computed quality metric with a quality metric contained in the packet. If the quality metrics match, the packet is declared correctly received, and is forwarded for further processing. If the quality metrics fail to match, the receiving terminal sends a request for retransmission of the packet. The transmitting terminal determines which packet needs to be retransmitted based on the request for retransmission. The transmitting terminal then schedules the packet for retransmission. If delivery of the packet in accordance with the aforementioned description fails, retransmission in accordance with conventional sequence-number-based schemes, e.g., radio link protocol, is attempted.

Claims

1. An apparatus configured to retransmit signals in a communication system, comprising:

a decoder configured to decode contents of a unit of received signal;

a first feedback signal generator configured to generate a first feedback signal; and

a first processor configured to determine a quality metric of said unit of signal, to instruct said feedback signal generator to generate a feedback signal in accordance with said quality metric, and to prevent decoding of said unit of signal if an indication received on a control channel indicates that said unit of signal is not to be decoded.

2. The apparatus of claim 1 wherein the unit of signal is a packet.

3. The apparatus of claim 1 wherein the quality metric is a cyclic redundancy check.

4. The apparatus of claim 1 wherein said decoder decodes contents of said unit of signal in accordance with information carried on a control channel.

5. The apparatus of claim 1 wherein said first feedback signal is a burst of energy.

6. The apparatus of claim 5 wherein said burst of energy is a bit.

7. The apparatus of claim 1 wherein said first feedback signal contains no energy.

8. The apparatus of claim 7 wherein said first feedback signal is a bit.

9. The apparatus of claim 1 wherein the first processor is further configured to transmit said first feedback signal at a determinable time instant.

10. The apparatus of claim 9 wherein said determinable time instant is fixedly delayed from an event time instant, said event time instant being selected from a group consisting of:

a time instant when said unit of signal is received;

a time instant when said determination if said unit of signal is to be demodulated is made;

a time instant when said unit of signal is demodulated; and

a time instant when said quality metric is computed.

11. An apparatus configured to retransmit signals in a communication system, comprising:

a decoder configured to decode contents of a unit of received signal;

a first feedback signal generator configured to generate a first feedback signal;

a first processor configured to determine a quality metric of said unit of signal; and

instruct said feedback signal generator to generate a feedback signal in accordance with said quality metric; and

a preamble detector configured to detect and decode a preamble of said unit of signal; and

wherein said first processor is further configured to prevent decoding of said unit of signal if said preamble indicates that said unit of signal is not to be decoded.

12. The apparatus of claim 11 wherein the unit of signal is a packet.

13. The apparatus of claim 11 wherein the quality metric is a cyclic redundancy check.

14. The apparatus of claim 11 wherein said decoder decodes contents of said unit of signal in accordance with information carried on a control channel.

15. The apparatus of claim 11 wherein said first feedback signal is a burst of energy.

16. The apparatus of claim 15 wherein said burst of energy is a bit.

17. The apparatus of claim 11 wherein said first feedback signal contains no energy.

18. The apparatus of claim 17 wherein said first feedback signal is a bit.

19. The apparatus of claim 11 wherein the first processor is further configured to transmit said first feedback signal at a determinable time instant.

20. The apparatus of claim 19 wherein said determinable time instant is fixedly delayed from an event time instant, said event time instant being selected from a group consisting of:

a time instant when said unit of signal is received;

a time instant when a determination as to whether said unit of signal is to be demodulated is made;

a time instant when said unit of signal is demodulated; and

a time instant when said quality metric is computed.

21. An apparatus configured to retransmit signals in a communication system, comprising:

a decoder configured to decode contents of a unit of received signal;

a first feedback signal generator configured to generate a first feedback signal;

a first processor configured to determine a quality metric of said unit of signal; and

instruct said feedback signal generator to generate a feedback signal in accordance with said quality metric;

a second feedback signal generator for generating a second feedback signal; and

a second processor configured to instruct said second feedback generator to generate a second feedback signal in accordance with a sequence number of said unit of signal when said retransmission of said signal in accordance with said quality metric is declared a failure.

22. The apparatus of claim 21 further comprising means for declaring said retransmission of said signal in accordance with said quality metric a failure when:

said unit of signal is not received within a predetermined number of retransmissions;

or

said unit of signal is not received within a predetermined period measured from a first transmission of said unit of signal;

or

said unit of signal is not received within a predetermined period measured from transmission of a request signal corresponding to said unit of signal.

23. The apparatus of claim 21 wherein the unit of signal is a packet.

24. The apparatus of claim 21 wherein the quality metric is a cyclic redundancy check.

25. The apparatus of claim 21 wherein said decoder decodes contents of said unit of signal in accordance with information carried on a control channel.

26. The apparatus of claim 21 wherein said first feedback signal is a burst of energy.

27. The apparatus of claim 26 wherein said burst of energy is a bit.

28. The apparatus of claim 21 wherein said first feedback signal contains no energy.

29. The apparatus of claim 28 wherein said first feedback signal is a bit.

30. The apparatus of claim 21 wherein the first processor is further configured to transmit said first feedback signal at a determinable time instant.

31. The apparatus of claim 30 wherein said determinable time instant is fixedly delayed from an event time instant, said event time instant being selected from a group consisting of:

a time instant when said unit of signal is received;

a time instant when a determination as to whether said unit of signal is to be demodulated is made;

a time instant when said unit of signal is demodulated; and

a time instant when said quality metric is computed.

32. An apparatus for retransmission of signals in a communication system, comprising:

a data queue for storing a plurality of units of signal to be transmitted;

a scheduler for scheduling a transmission of said units of signal to a destination receiving terminal;

a first detector for detecting a first feedback signal received from the destination receiving terminal; and

a first control processor configured to receive said first feedback signal, select a unit of signal which was transmitted at a time instant preceding a time instant of receiving said first feedback signal by a sum of a round trip delay and a determinable delay, and schedule said unit of signal for retransmission, wherein the determinable delay is a difference between a first time instant of transmitting said retransmission request and a second time instant, said second time instant being selected from a group consisting of;

a time instant when said unit of signal is received;

a time instant when a determination as to whether said unit of signal is to be demodulated is made;

a time instant when said unit of signal is demodulated; and

a time instant when a quality metric of said unit of signal is computed.

33. The apparatus of claim 32 wherein the determinable delay is contained in the first feedback signal.

34. The apparatus of claim 32 wherein the first processor is further configured to determine a time instant at which to retransmit said unit of signal, said time instant being variably delayed from receipt of said first feedback signal.

35. The apparatus of claim 32 wherein the first processor is further configured to determine a time instant at which to retransmit said unit of signal, said time instant being fixedly delayed from receipt of said first feedback signal.

36. The apparatus of claim 32 further comprising:

a second detector for detecting a second feedback signal received from the destination receiving terminal; and

a second control processor configured to receive said second feedback signal, select a unit of signal in accordance with said second feedback signal, and schedule said unit of signal for retransmission.

37. The apparatus of claim 36 wherein the second feedback signal contains sequence numbers of said unit of signal to be retransmitted.