Method and Apparatus for Hybrid Automatic Repeat Request Signaling

A method at a User Equipment (UE) of generating Hybrid Automatic Repeat reQuest (HARQ) feedback for transmission in a wireless communication network in an uplink (UL) subframe n, wherein the UE is configured with two or more serving cells according to a carrier aggregation configuration, and wherein the UE is further configured with Time Division Duplex (TDD) Uplink/Downlink (UL/DL) configurations that define the association set for each serving cell as which DL subframes are associated with the HARQ feedback being generated for transmission at a given UL subframe, said method comprising:

• determining the largest association set size M among the two or more serving cells for the UL subframe n;
• and
• generating the HARQ feedback by:
• generating, for each of the serving cells, a HARQ-ACK bit according to an actual HARQ feedback state for each DL subframe that is associated with the serving cell for the UL subframe n;
• and
• for the serving cells having an association set size smaller than M, generating additional HARQ-ACK bits as Discontinuous Transmission (DTX) values, as needed, so that the number of HARQ-ACK bits generated for each serving cell equals M;
• and
• transmitting the HARQ feedback in the UL subframe n.

A User Equipment (UE) configured to generate Hybrid Automatic Repeat reQuest (HARQ) feedback for transmission in a wireless communication network in an uplink (UL) subframe n, wherein the UE is configurable with two or more serving cells according to a carrier aggregation configuration, and wherein the UE is further configurable with Time Division Duplex (TDD) Uplink/Downlink (UL/DL) configurations that define the association set for each serving cell as which DL subframes are associated with the HARQ feedback being generated for transmission at a given UL subframe, said UE comprising:

• processing circuitry and a memory, said memory containing instructions executable by said processing circuitry whereby said processing circuitry is operative to
• determine the largest association set size M among the two or more serving cells for the UL subframe n;
• and
• generate the HARQ feedback by:
• generating, for each of the serving cells, a HARQ-ACK bit according to an actual HARQ feedback state for each DL subframe that is associated with the serving cell for the UL subframe n;
• and
• for the serving cells having an association set size smaller than M, generating additional HARQ-ACK bits as Discontinuous Transmission (DTX) values, as needed, so that the number of HARQ-ACK bits generated for each serving cell equals M;
• and
• transmit the HARQ feedback in the UL subframe n.