User equipment-specific hybrid automatic repeat request timeline offset
Wireless communications systems may support user equipment (UE)-specific hybrid automatic repeat request (HARQ) timeline offsets such that transmission time intervals (TTIs) reserved for uplink HARQ transmissions are reserved on a per UE basis (e.g., TTIs are not reserved or designated on a network level or aligned across all or many UEs within the system). That is, UEs within a wireless communications system may employ a UE-specific offset for their respective HARQ timelines. UE-specific HARQ timeline offsets may be derived, by the UEs, explicitly or implicitly. Further, the network (e.g., a base station) may configure UE-specific HARQ timeline offsets to be distributed in time to avoid uplink HARQ transmission collisions between UEs, to eliminate the loss of TTIs for a second carrier operation (e.g., such as NR uplink) on a network wide basis, etc. The base station may then communicate with the UEs according to their corresponding UE-specific offset HARQ timelines.
1. A method for wireless communication, comprising:
identifying, by a user equipment (UE), a reference hybrid automatic repeat request (HARQ) timeline;
identifying, by the UE, a UE-specific offset, wherein the UE-specific offset indicates a value specific to the UE;
determining, by the UE, a UE-specific HARQ timeline, wherein determining the UE-specific HARQ timeline comprises adding the UE-specific offset to uplink TTI indices in the reference HARQ timeline, wherein the reference HARQ timeline corresponds to a frequency division duplex (FDD) configuration; and
transmitting, by the UE, one or more acknowledgements in a transmission time interval (TTI) in accordance with the UE-specific HARQ timeline.
2. The method of claim 1 , wherein identifying the reference HARQ timeline comprises:
receiving an indication of the reference HARQ timeline for a cell in which the UE is communicating.
3. The method of claim 1 , wherein identifying the UE-specific offset comprises:
receiving an indication of the UE-specific offset from a base station.
4. The method of claim 3 , wherein receiving the indication of the UE-specific offset comprises:
receiving the indication via downlink control information (DCI) or via radio resource control (RRC) messaging.
5. The method of claim 1 , wherein identifying the UE-specific offset comprises:
determining the UE-specific offset based at least in part on rules known by the UE.
6. The method of claim 1 , wherein identifying the UE-specific offset comprises:
determining the UE-specific offset based at least in part on an identification (ID) of the UE.
7. The method of claim 1 , further comprising communicating with a base station using multiple radio access technologies (RATs) via time division multiplexing (TDM).
8. The method of claim 7 , wherein communicating with the base station using multiple RATs comprises communicating with the base station using both Long Term Evolution (LTE) and New Radio (NR) radio access technologies, and wherein the one or more acknowledgements are transmitted as LTE communications.
9. The method of claim 8 , wherein the LTE RAT is configured for communications.
10. The method of claim 1 , wherein the one or more acknowledgements in the TTI correspond to a plurality of previous downlink transmissions.
11. An apparatus for wireless communication, comprising:
a processor;
memory in electronic communication with the processor; and
instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
identify a reference hybrid automatic repeat request (HARQ) timeline;
identify a UE-specific offset, wherein the UE-specific offset indicates a value specific to the UE;
determine a UE-specific HARQ timeline by adding the UE-specific offset to uplink TTI indices in the reference HARQ timeline, wherein the reference HARQ timeline corresponds to a frequency division duplex (FDD) configuration; and
transmit one or more acknowledgements in a transmission time interval (TTI) in accordance with the UE-specific HARQ timeline.
12. The apparatus of claim 11 , wherein the instructions executable by the processor to cause the apparatus to identify the offset comprise instructions further executable by the processor to cause the apparatus to:
receive an indication of the UE-specific offset from a base station.
13. The apparatus of claim 12 , wherein the instructions executable by the processor to cause the apparatus to receive the indication of the UE-specific offset comprise instructions further executable by the processor to cause the apparatus to:
receive the indication via downlink control information (DCI) or via radio resource control (RRC) messaging.
14. The apparatus of claim 11 , further comprising the instructions executable by the processor to cause the apparatus to communicate with a base station using multiple radio access technologies (RATs) via time division multiplexing (TDM).