Handling of disrupted synchronous hybrid automatic repeat request (HARQ) cycle at system time rollover

• US 8,473,799 B2
• Filed: 08/20/2009
• Issued: 06/25/2013
• Est. Priority Date: 08/21/2008
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Zhang, Xiaoxia, Liu, Zhengwei, Xu, Hao, Meylan, Arnaud
• Primary Examiner(s): SCHELL, JOSEPH O
• Application Number:
  US12/544,455
• Publication Number:
  US 20100050039A1
• Time in Patent Office: 1,405 Days
• Field of Search: 714/18, 714/55, 714/748, 714/751, 370/315, 370/328
• US Class Current: 714/748
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04L 1/1822 involving configuration of automatic repeat request [ARQ] with parallel processes
• CPC Class Codes: H04L 1/1874 Buffer management

Abstract

Certain aspects of the present disclosure propose techniques for avoiding a disruption in synchronous hybrid automatic repeat request operation at system time rollover. The techniques define the behavior of a system before and after the system frame number (SFN) rollover point to ensure a known relationship between a hybrid automatic repeat request (HARQ) process identification number and system time.

Claims

1. A method for wireless communications, comprising:

identifying a system frame number (SFN) rollover time, indicating when a system frame number rolls over from a first value to a second value, wherein the second value is smaller than the first value;

stopping hybrid automatic repeat request (HARQ) operation at or near SFN rollover time for one or more HARQs; and

restarting an uplink HARQ operation from the SFN rollover time.

2. The method of claim 1, further comprising:

adjusting one or more SFN rollover times for one or more user equipments (UEs) in a system such that the rate of HARQ reset due to SFN rollover is constant in time.

3. The method of claim 1, further comprising:

determining a system rollover number M;

wherein the system rollover number is a difference between two consecutive SFN rollover times.

4. The method of claim 3, wherein the system rollover number M is a multiple of the least common multiple of one or more of the HARQ repetition periods of a plurality of uplink HARQ operations of a system, wherein the plurality of uplink HARQ operations of the system include HARQ operations performed in a frequency division multiplexing mode, and HARQ operations performed in a plurality of different uplink-downlink configurations of a time division multiplexing mode.

5. The method of claim 3, wherein the system rollover number M is the largest integer that satisfies a relation n=

6. The method of claim 1, wherein stopping hybrid automatic repeat request (HARQ) operation at SFN rollover time for one or more HARQs comprises:

sending an uplink grant message if roundtrip processing of a message can be finished before SFN rollover time, wherein the roundtrip processing of a message comprises transmitting the message and receiving a response to the message.

7. The method of claim 1, wherein stopping hybrid automatic repeat request (HARQ) operation at SFN rollover time for one or more HARQs comprises:

sending an uplink grant if a corresponding uplink transmission time ends before SFN rollover time.

8. The method of claim 7, further comprising:

combining HARQ processes that did not have time to send ACK/NACK before SFN rollover; and

sending the combined HARQ process using a process identification (ID) after SFN rollover time;

wherein the process ID is similar to a process ID before the SFN rollover time.

9. An apparatus for wireless communications, comprising:

at least one processor configured to;

identify a system frame number (SFN) rollover time, indicating when a system frame number rolls over from a first value to a second value, wherein the second value is smaller than the first value;

stop hybrid automatic repeat request (HARQ) operation at or near SFN rollover time for one or more HARQs; and

restart an uplink HARQ operation from the SFN rollover time and a memory coupled to the at least one processor.

10. The apparatus of claim 9, wherein the at least one processor is further configured to:

adjust one or more SFN rollover time for one or more user equipments (UEs) in a system such that the rate of HARQ reset due to SFN rollover is constant in time.

11. The apparatus of claim 9, wherein the at least one processor is further configured to:

determine a system rollover number M;

wherein the system rollover number is a difference between two consecutive SFN rollover times.

12. The apparatus of claim 11, wherein the system rollover number M is a multiple of the least common multiple of one or more of the HARQ repetition periods of a plurality of uplink HARQ operations of a system, wherein the plurality of uplink HARQ operations of the system include HARQ operations performed in a frequency division multiplexing mode, and HARQ operations performed in a plurality of different uplink-downlink configurations of a time division multiplexing mode.

13. The apparatus of claim 11, wherein the system rollover number M is the largest integer that satisfies a relation

14. The apparatus of claim 9, wherein the at least one processor configured to stop hybrid automatic repeat request (HARQ) operation at SFN rollover time for one or more HARQs is further configured to:

send an uplink grant message if roundtrip processing of a message can be finished before SFN rollover time, wherein the roundtrip processing of a message comprises transmitting the message and receiving a response to the message.

15. The apparatus of claim 9, wherein the at least one processor configured to stop hybrid automatic repeat request (HARQ) operation at SFN rollover time for one or more HARQs is further configured to:

send an uplink grant if a corresponding uplink transmission time ends before SFN rollover time.

16. The apparatus of claim 15, wherein the at least one processor is further configured to:

combine HARQ processes that did not have time to send ACK/NACK before SFN rollover; and

send the combined HARQ process using a process identification (ID) after SFN rollover time;

wherein the process ID is similar to a process ID before the SFN rollover time.

17. A hardware apparatus for wireless communications, comprising:

means for identifying a system frame number (SFN) rollover time, indicating when a system frame number rolls over from a first value to a second value, wherein the second value is smaller than the first value;

means for stopping hybrid automatic repeat request (HARQ) operation at or near SFN rollover time for one or more HARQs; and

means for restarting an uplink HARQ operation from the SFN rollover time.

18. The apparatus of claim 17, further comprising:

means for adjusting one or more SFN rollover times for one or more user equipments (UEs) in a system such that the rate of HARQ reset due to SFN rollover is constant in time.

19. The apparatus of claim 17, further comprising:

means for determining a system rollover number M;

wherein the system rollover number is a difference between two consecutive SFN rollover times.

20. The apparatus of claim 19, wherein the system rollover number M is a multiple of the least common multiple of one or more of the HARQ repetition periods of a plurality of uplink HARQ operations of a system, wherein the plurality of uplink HARQ operations of the system include HARQ operations performed in a frequency division multiplexing mode, and HARQ operations performed in a plurality of different uplink-downlink configurations of a time division multiplexing mode.

21. The apparatus of claim 19, wherein the system rollover number M is the largest integer that satisfies a relation

22. The apparatus of claim 17, wherein the means for stopping hybrid automatic repeat request (HARQ) operation at SFN rollover time for one or more HARQs comprises:

means for sending an uplink grant message if roundtrip processing of a message can be finished before SFN rollover time, wherein the roundtrip processing of a message comprises transmitting the message and receiving a response to the message.

23. The apparatus of claim 17, wherein the means for stopping hybrid automatic repeat request (HARQ) operation at SFN rollover time for one or more HARQs comprises:

means for sending an uplink grant if a corresponding uplink transmission time ends before SFN rollover time.

24. The apparatus of claim 23, further comprising:

means for combining HARQ processes that did not have time to send ACK/NACK before SFN rollover; and

means for sending the combined HARQ process using a process identification (ID) after SFN rollover time;

wherein the process ID is similar to a process ID before the SFN rollover time.

25. A computer-program product for wireless communications, comprising a non-transitory computer-readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:

instructions for identifying a system frame number (SFN) rollover time, indicating when a system frame number rolls over from a first value to a second value, wherein the second value is smaller than the first value;

instructions for stopping hybrid automatic repeat request (HARQ) operation at or near SFN rollover time for one or more HARQs; and

instructions for restarting an uplink HARQ operation from the SFN rollover time.