HYBRID AUTOMATIC REPEAT REQUEST MANAGEMENT METHOD FOR IMPROVING TRANSMISSION QUALITY

• US 20150106674A1
• Filed: 10/15/2013
• Published: 04/16/2015
• Est. Priority Date: 10/15/2013
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Chen, Yu-Ting, Yang, Shu-Huei
• Granted Patent: US 9,288,012 B2
• Time in Patent Office: Days
• US Class Current: 714/748
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1822 involving configuration of automatic repeat request [ARQ] with parallel processes
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/2458 Modification of priorities while in transit
• CPC Class Codes: H04L 47/2466 using signalling traffic
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/626 channel conditions
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

The present invention to provide methods and related controllers that manage HARQ processes in a wireless communications system. The present invention provides a method and related controller to map data units (e.g. PDU) of importance that is to be transmitted to a HARQ process having a higher transmission success rate to prevent the data units from being transmitted via a HARQ process having more transmission failures. In addition, the present invention also provides a method and a related controller to force a HARQ process to retransmit a data unit that has been correctly received by a receiving end to reduce the latency of retransmission caused by a possible transmission failure occurring between a MAC layer and a RLC layer at the receiving end.

Claims

1. A method of managing at least one Hybrid Automatic Repeat reQuest (HARQ) process in a wireless communications system, comprising;

determining a priority of the HARQ process according to a transmission success rate of the HARQ process;

determining a priority of a data unit to be transmitted; and

transmitting the data unit according to the priority of the data unit and the priority of the HARQ process.

2. The method of claim 1, wherein the priority of the data unit is selected from a group consisting of at least a first data priority and a second data priority lower than the first data priority, the priority of the HARQ process is selected from at least a group consisting of a first HARQ priority and a second HARQ priority lower than the first HARQ priority.

3. The method of claim 2, wherein the step of transmitting the data unit according to the priority of the data unit and the priority of the HARQ process comprises:

transmitting the data unit having the first data priority via the HARQ process having the first HARQ priority.

4. The method of claim 2, wherein step of transmitting the data unit according to the priority of the data unit and the priority of the HARQ process comprises:

transmitting the data unit having the second data priority via the HARQ process the second HARQ priority.

5. The method of claim 2, wherein the step of transmitting the data unit according to the priority of the data unit and the priority of the HARQ process comprises:

transmitting the data unit having the second data priority via the HARQ process having the first HARQ priority when there is no other data unit having the first data priority waiting to be transmitted.

6. The method of claim 2, further comprising:

transmitting dummy data unit via the HARQ process having the second HARQ priority when there is no other data unit waiting to be transmitted.

7. The method of claim 2, wherein and the step of transmitting the data unit according to the priority of the data and the priority of the HARQ process comprises:

transmitting the data unit having the first data priority via the HARQ process having the second HARQ priority when an amount of data units having the first data priority waiting to be transmitted reaches an upper limit.

8. The method of claim 2, wherein the step of determining the priority of the data unit comprises:

determining the data unit as having the first data priority when the data unit corresponds to retransmission data or control data.

9. The method of claim 2, further comprising:

after the priority of the HARQ process is determined based on the transmission success rate,

counting a period of reset time; and

when the period of reset time expires and the priority of the HARQ process is a second HARQ priority, resetting the priority of the HARQ process to a first HARQ priority.

10. The method of claim 1, wherein the step of determining the priority of the HARQ process comprises:

determining an average transmission success rate according to a plurality of transmission success rates of a plurality of HARQ processes including the HARQ process; and

determining the priority of the HARQ process according to the transmission success rate and the average transmission success rate.

11. The method of claim 10, wherein the step of determining the priority of the HARQ process according to the transmission success rate and the average transmission success rate comprises:

checking if a difference between the transmission success rate and the average transmission success rate exceeds a threshold; and

when the difference exceeds the threshold, determining the priority of the HARQ process based on the transmission success rate.

12. The method of claim 11, wherein the step of determining the priority of the HARQ process based on the transmission success rate comprises:

determining the HARQ process having the first HARQ priority when the transmission success rate of the HARQ process is greater than the average transmission success rate; and

determining the HARQ process having the second HARQ priority when the transmission success rate of the HARQ process is lower than the average transmission success rate.

13. The method of claim 10, wherein the step of determining the priority of the HARQ process according to the transmission success rate and the average transmission success rate comprises:

when none of differences, each between one of the transmission success rates and the average transmission success rate, exceeds a threshold, determining each of the HARQ processes as having a same HARQ priority.

14. The method of claim 1, wherein the step of determining the priority of the HARQ process comprises:

counting a period of time; and

determining the transmission success rate of the HARQ process according to numbers of HARQ negative acknowledgements (NACK) responses and HARQ acknowledgements (ACK) responses regarding the HARQ process that have been received during the period of time.

15. A method of managing at least one Hybrid Automatic Repeat reQuest (HARQ) process in a wireless communications system, comprising:

determining whether a number of HARQ acknowledgement (ACK)-to-Radio Link Control (RLC) negative acknowledgement (NACK) errors occurred on the HARQ process reaches a threshold; and

when the number of the HARQ ACK-to-RLC NACK errors occurred on the HARQ process reaches the threshold, configuring the HARQ process to perform at least one retransmission of a data unit even if a HARQ ACK corresponding to the data unit has been received.

16. The method of claim 15, wherein the step of configuring the HARQ process to perform the at least one retransmission on the HARQ process comprises:

setting a non-zero retransmission value for the HARQ process; and

configuring the HARQ process to perform retransmission of the data unit until a number of times that the data unit has been retransmitted reaches the non-zero retransmission value.

17. The method of claim 15, wherein the step of determining whether the number of the HARQ ACK-to-RLC NACK errors occurred on the HARQ process reaches the threshold comprises:

counting a period of time; and

collecting the number of the HARQ ACK-to-RLC NACK errors that have occurred during the period of time.

18. The method of claim 15, further comprising:

setting a retransmission value by a non-zero value for the HARQ process, wherein the retransmission value defines a number of times a data unit is required to be retransmitted;

counting a period of reset time; and

resetting the retransmission value as zero when the period of reset time expires.

19. The method of claim 15, further comprising:

collecting a number of HARQ ACK-to-the RLC NACK errors that have occurred on each of the HARQ processes during a period of time; and

generating the threshold by averaging a plurality of numbers of HARQ ACK-to-the RLC NACK errors corresponding to each of the HARQ processes.

20. A controller of managing at least one Hybrid Automatic Repeat reQuest (HARQ) process in a wireless communications system, comprising;

a first determination module, arranged to determine a priority of the HARQ process according to a transmission success rate of the HARQ process;

a second determination module, arranged to determine a priority of a data unit to be transmitted; and

a configuration module, coupled to a first determination module and the second determination module, arranged to transmit the data unit according to the priority of the data unit and the priority of the HARQ process.

21. A controller of managing at least one Hybrid Automatic Repeat reQuest (HARQ) process in a wireless communications system, comprising:

a determination module, arranged to determine whether a number of HARQ acknowledgement (ACK)-to-Radio Link Control (RLC) negative acknowledgement (NACK) errors occurred on the HARQ process reaches a threshold; and

a configuration module, coupled to the determination module, when the number of the HARQ ACK-to-RLC NACK errors occurred on the HARQ process reaching the threshold, arranged to configure the HARQ process to perform at least one retransmission of a data unit even if a HARQ ACK corresponding to the data unit has been received.