Feedback timing management for low latency communications

Patent metadata

Field	Value
Publication number	US-10492094-B2
Application number	US-201715706059-A
Country	US
Kind code	B2
Filing date	Sep 15, 2017
Priority date	Feb 1, 2017
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Low latency transmission time interval (TTI) structures and feedback configurations allow for a downlink transmission, a feedback indication indicating successful or unsuccessful reception of the downlink transmission, and a retransmission of the downlink transmission, within a same subframe or 1 ms time period. A TTI structure may include a number of shortened TTIs (sTTIs) that are transmitted in a subframe, and timing for feedback transmissions may be identified based at least in part on the TTI structure. The TTI structure and configurations for feedback timing may be dynamically or semi-statically determined by a user equipment (UE). In some cases, the TTI structure may include an identified partial sTTI allocated to a UE that may span fewer than all of the resources of a sTTI and allow for faster processing and generation of feedback information, and for faster retransmissions of unsuccessfully received transmissions.

First claim

What is claimed is:

1. A method for wireless communication, comprising:
identifying a first downlink transmission time interval (TTI) and a feedback configuration, based at least in part on a structure of the first downlink TTI, wherein the feedback configuration comprises a feedback timing spanning a first set of orthogonal frequency division multiplexing (OFDM) symbols and a rescheduling timing spanning a second set of OFDM symbols;
receiving, unsuccessfully, a first downlink transmission in the first downlink TTI;
generating, following the feedback timing, a negative acknowledgement (NACK) as a first feedback indication associated with the first downlink TTI according to the identified feedback configuration;
transmitting the first feedback indication in an uplink transmission during a first uplink TTI; and
receiving, based at least in part on the first feedback indication and following the rescheduling timing, a retransmission of the first downlink transmission in a second downlink TTI, wherein the first downlink TTI and the second downlink TTI are located within a same subframe or within one millisecond.

2. The method of claim 1 , further comprising:
identifying an uplink TTI structure for a plurality of uplink TTIs based at least in part on the structure of the first downlink TTI.

3. The method of claim 1 , wherein the identifying the structure of the first downlink TTI comprises:
dynamically identifying the structure of the first downlink TTI based at least in part on a number of OFDM symbols of the first downlink TTI.

4. The method of claim 3 , wherein the structure of the first downlink TTI is identified based at least in part on a number of control symbols in a control region associated with the subframe.

5. The method of claim 4 , wherein the number of control symbols in the control region is indicated in a physical control format indicator channel (PCFICH) transmission.

6. The method of claim 1 , wherein the identifying the structure of the first downlink TTI comprises:
semi-statically identifying the structure of the first downlink TTI based at least in part on radio resource control (RRC) signaling received from a base station.

7. The method of claim 1 , wherein the identifying the feedback configuration comprises:
identifying the feedback timing for transmitting the first feedback indication based at least in part on the structure of the first downlink TTI; and
identifying the rescheduling timing for receiving a subsequent retransmission of the first downlink transmission following the first feedback indication.

8. The method of claim 7 , wherein the feedback timing is different than the rescheduling timing.

9. The method of claim 7 , wherein the structure of the first downlink TTI comprises a plurality of TTIs that each span two or three OFDM symbols.

10. The method of claim 9 , wherein:
the feedback timing corresponds to a duration of three OFDM symbols, and
the rescheduling timing corresponds to a duration of two OFDM symbols.

11. The method of claim 9 , wherein:
the feedback timing corresponds to a duration of one OFDM symbol, and
the rescheduling timing corresponds to the duration of one OFDM symbol.

12. The method of claim 1 , further comprising:
identifying one or more of a maximum transport block size (TBS) or a maximum timing advance (TA) for the uplink transmission based at least in part on the feedback configuration.

13. A method for wireless communication, comprising:
identifying a first portion of a first downlink transmission time interval (TTI) and a feedback configuration, based at least in part on a structure of the first portion, wherein the feedback configuration comprises a feedback timing spanning a first set of orthogonal frequency division multiplexing (OFDM) symbols and a rescheduling timing spanning a second set of OFDM symbols;
identifying a first uplink TTI for transmitting a feedback indication associated with the first downlink transmission based at least in part on the feedback configuration;
receiving, unsuccessfully, the first downlink transmission in the first portion of the first downlink TTI;
generating, following the feedback timing, a negative acknowledgement (NACK) as a first feedback indication associated with the first downlink transmission;
transmitting the first feedback indication in an uplink transmission during the first uplink TTI; and
receiving, based at least in part on the first feedback indication and following the rescheduling timing, a retransmission of the first downlink transmission in a second portion of a second downlink TTI, wherein the first downlink TTI and the second downlink TTI are located within a same subframe or within one millisecond.

14. The method of claim 13 , wherein the identifying the first portion of the first downlink TTI comprises:
identifying a first OFDM symbol of two or more OFDM symbols of the first downlink TTI for receiving the first downlink transmission.

15. The method of claim 14 , wherein the first downlink TTI comprises two or three OFDM symbols.

16. The method of claim 13 , wherein the retransmission is unsuccessfully received, and wherein the method further comprises:
generating a second NACK as a second feedback indication associated with the retransmission;
transmitting the second feedback indication in a second uplink transmission during a second uplink TTI; and
receiving, based at least in part on the second feedback indication, a second retransmission of the first downlink transmission in a third portion of a third downlink TTI, wherein the first downlink TTI, the second downlink TTI and the third downlink TTI are located within the same subframe or within one millisecond.

17. The method of claim 13 , wherein the identifying the first portion of the first downlink TTI comprises:
receiving user equipment (UE) specific signaling or cell-specific signaling indicating the first portion of the first downlink TTI.

18. The method of claim 13 , wherein the identifying the first portion of the first downlink TTI comprises:
dynamically identifying the first portion of the first downlink TTI based at least in part on a number of OFDM symbols of the first downlink TTI.

19. The method of claim 18 , wherein the first portion of the first downlink TTI is identified based at least in part on a number of control symbols in a control region associated with the subframe.

20. The method of claim 19 , wherein the number of control symbols in the control region is indicated in a physical control format indicator channel (PCFICH) transmission.

21. The method of claim 13 , wherein the identifying the first portion of the first downlink TTI comprises:
semi-statically identifying the first portion of the first downlink TTI based at least in part on radio resource control (RRC) signaling received from a base station.

22. The method of claim 13 , wherein the first portion of the first downlink TTI is pre-specified.

23. The method of claim 13 , wherein the identifying the first uplink TTI comprises:
identifying the feedback timing for transmitting the first feedback indication based at least in part on a location of the first portion within the first downlink TTI.

24. The method of claim 13 , wherein the identifying the first uplink TTI comprises:
identifying the feedback timing for transmitting the first feedback indication based at least in part on a user equipment (UE) capability.

25. Th

Assignees

• Qualcomm Inc

Inventors

• Chen Wanshi
• Hosseini Seyedkianoush
• Sun Jing
• Gaal Peter

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04L1/1825

  Adaptation of specific ARQ protocol parameters according to transmission conditions · CPC title

• H04W56/0045

  compensating for timing error by altering transmission time · CPC title

• H04L1/0028

  Formatting · CPC title

• H04L5/0037

  Inter-user or inter-terminal allocation · CPC title