Method and apparatus in a wireless communication system

Patent metadata

Field	Value
Publication number	US-9590704-B2
Application number	US-201314237144-A
Country	US
Kind code	B2
Filing date	Jun 13, 2013
Priority date	Sep 21, 2012
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

There is disclosed a method performed by a User Equipment, UE, for Hybrid Automatic Repeat Request, HARQ, retransmission of data in a multi-antenna wireless communication system. The method comprises, receiving Acknowledgement/Negative Acknowledgement, ACK/NACK, feedback information relating to data transmitted on two streams, and performing, upon rank reduction where only one stream is available for transmission, retransmission of data on a cancelled stream over the remaining stream. There is furthermore disclosed a UE configured for performing the method. A transmission method together with an arrangement for a UE is also disclosed.

First claim

The invention claimed is:

1. A method performed by a User Equipment, UE, for Hybrid Automatic Repeat Request, HARQ, retransmission of data in a multi-antenna wireless communication system, comprising:
receiving Acknowledgement/Negative Acknowledgement, ACK/NACK, feedback information relating to first data transmitted on a primary stream and second data transmitted on a secondary stream, wherein the first data transmitted on the primary stream is associated with a first HARQ process and the second data transmitted on the secondary stream is associated with a second HARQ process;
associating the received ACK/NACK feedback with a correct HARQ process, the correct HARQ process comprising either the first HARQ process or the second HARQ process; and
retransmitting the second data on the primary stream, upon rank reduction where the primary stream is available for transmission and the secondary stream has been cancelled.

2. The method according to claim 1 , wherein said rank reduction is a forced rank reduction from a rank 2 transmission mode, where data is transmitted over a primary stream and a secondary stream, to a rank 1 transmission mode, where data is transmitted over the primary stream, and said retransmitting step comprises retransmitting data associated with a NACK from the secondary stream over the primary stream.

3. The method according to claim 1 , wherein said associating step comprises the step of deciding which of either the first HARQ process or the second HARQ process should be targeted when the ACK/NACK information is received.

4. The method according to claim 3 , wherein the associating step comprises associating ACK/NACK feedback information representing a request for retransmission with the second HARQ process of the cancelled secondary stream so that the UE retransmits requested data on the primary stream instead of the secondary stream.

5. The method according to claim 1 , wherein said UE is configured for uplink Multiple Input Multiple Output, MIMO.

6. The method according to claim 1 , wherein said multi-antenna wireless communication system is a system supporting Multiple Input Multiple Output, MIMO, enabled High Speed Uplink Packet Access, HSUPA, with Frequency Division Duplex, FDD.

7. The method according to claim 1 , wherein said-primary and secondary streams are carried on Enhanced Dedicated Channels, E-DCH and said ACK/NACK feedback information is carried on E-DCH Hybrid ARQ indicator Channels, E-HICH.

8. A method performed by a User Equipment, UE, for Hybrid Automatic Repeat Request, HARQ, transmission of data in a multi-antenna wireless communication system, comprising:
transmitting transport blocks, TB, on two streams;
reducing a transmission rank;
receiving Acknowledgement/Negative Acknowledgement, ACK/NACK, feedback information relating to the two streams, wherein the first stream is associated with a first HARQ process and the second stream is associated with a second HARQ process;
associating the ACK/NACK feedback information with a correct HARQ process, the correct HARQ process comprising either the first HARQ process or the second HARQ process; and
retransmitting any requested TBs based on the association.

9. The method according to claim 8 , wherein the step of reducing the transmission rank comprises the step of reducing the rank from rank 2 , where said transmitting is performed over a primary stream and a secondary stream, to rank 1 , whereby the secondary stream is cancelled.

10. The method according to claim 8 , wherein said step of associating, in the case of a single feedback, comprises the steps of:
determining a number of transmission attempts for each of the first and second HARQ processes; and
determining that the HARQ process with the largest of said number of transmission attempts is the correct HARQ process requested for retransmission.

11. The method according to claim 8 , wherein said step of associating, comprises the steps of:
comparing buffer sizes of the first and second HARQ processes and assuming that the HARQ process with a largest buffer size is the correct HARQ process requested for retransmission.

12. The method according to claim 8 , wherein the step of associating, comprises the step of:
monitoring a parameter introduced in the second HARQ process, said parameter providing an indication of whether a retransmission of a transmission on a secondary stream is to be performed on a primary stream, and based on the state of said parameter, associate the ACK/NACK feedback information with the correct HARQ process.

13. The method according to claim 12 , wherein said parameter is a parameter whose default value is set to zero or false, indicating that no TBs initially transmitted on the secondary stream were transmitted on the primary stream, and whose value is set to one or true if TB(s) initially transmitted on the secondary stream are retransmitted on the primary stream.

14. The method according to claim 8 , wherein the step of associating is combined with the use of information about a signature of one or more channels carrying the ACK/NACK feedback information to target the correct HARQ process associated with said ACK/NACK feedback information.

15. An arrangement for a user equipment, UE, configured for HARQ transmission of data, comprising:
a transmitter unit configured to transmit transport blocks, TBs, over two streams;
a rank controller configured to reduce a transmission rank;
an Acknowledgement/Negative Acknowledgement, ACK/NACK feedback information receiver configured to receive ACK/NACK feedback relating to the transmitted transport blocks, wherein the first stream is associated with a first HARQ process and the second stream is associated with a second HARQ process;
an associating unit configured to associate ACK/NACK feedback information with a correct HARQ process, the correct HARQ process comprising either the first HARQ process or the second HARQ process; and
a retransmitting unit, configured to transmit any requested TBs based on the association.

16. The arrangement according to claim 15 , wherein said rank controller is further configured to reduce the rank from rank 2 , wherein transmission of TBs is performed over a primary stream and a secondary stream, to rank 1 , wherein the secondary stream is cancelled.

17. The arrangement according to claim 16 , wherein said associating unit is further configured to introduce and monitor a parameter in the second HARQ process, said parameter providing an indication of whether a retransmission of a transmission on the secondary stream is to be performed on the primary stream, and based on the state of said parameter associate the ACK/NACK feedback information with the correct HARQ process.

18. The arrangement according to claim 17 , wherein said associating unit is further configured to set a default value of said parameter to zero or false, said default value indicating that no data initially transmitted on the secondary stream was transmitted on the primary stream, and set the parameter to one or true if data initially transmitted on the secondary stream is retransmitted on the primary stream.

19. The arrangement according to claim 15 , wherein said rank controller is a rank unit.

20. The arrangement according to claim 15 , wherein said associating unit is further configured to determine a number of attempted retransmissions of the first and second HARQ processes.

21. The arrangement according to claim 15 , wherein said associating unit is further configured to

Assignees

• Ericsson Telefon Ab L M
• ERICSSON TELEFON AB L M (publ)

Inventors

• Lidian Namir
• Caverni Alessandro
• Konuskan Cagatay
• Larsson Erik
• Von Wrycza Peter

Classifications

• H04W72/563

  of the wireless resources · CPC title

• H04W72/20

  Control channels or signalling for resource management · CPC title

• H04L1/06

  using space diversity · CPC title

• H04L1/1816

  with retransmission of the same, encoded, message · CPC title

• H04L1/1874

  Buffer management · CPC title