Uplink ACK transmission for SDMA in a wireless communication system

A method for wireless communication, comprising:

• receiving at a user equipment (UE) a data transmission sent to multiple UEs with spatial division multiple access (SDMA);
• processing the data transmission to recover data sent to the UE;
• determining acknowledgement (ACK) information for the recovered data;
• determining ACK resources for the data transmission, the ACK resources comprising a plurality of subframes, wherein each subframe comprising a plurality of slots, and wherein each slot being divided into a plurality of subcarriers with multiple symbol periods;
• mapping the ACK information to a portion of the ACK resources allocated to the UE, wherein the multiple UEs are multiplexed on the ACK resources over both the plurality of subcarriers and multiple symbol periods in the plurality of slots;
• and
• performing modulation on the mapped ACK information based on single-carrier frequency division multiplexing (SC-FDM).

An apparatus for wireless communication, comprising:

• means for receiving at a user equipment (UE) a data transmission sent to multiple UEs with spatial division multiple access (SDMA);
• means for processing the data transmission to recover data sent to the UE;
• means for determining acknowledgement (ACK) information for the recovered data;
• means for determining ACK resources for the data transmission, the ACK resources including a plurality of subframes, wherein each subframe includes a plurality of slots, and wherein each slot is divided into a plurality of subcarriers with multiple symbol periods;
• means for mapping the ACK information to a portion of the ACK resources allocated to the UE, wherein the multiple UEs are multiplexed on the ACK resources over both the plurality of subcarriers and multiple symbol periods in the plurality of slots;
• and
• means for performing modulation on the mapped ACK information based on single-carrier frequency division multiplexing (SC-FDM).

A non-transitory machine-readable storage medium comprising instructions which, when executed by a machine, cause the machine to perform operations including:

• receiving at a user equipment (UE) a data transmission sent to multiple UEs with spatial division multiple access (SDMA);
• processing the data transmission to recover data sent to the UE;
• determining acknowledgement (ACK) information for the recovered data;
• determining ACK resources for the data transmission, the ACK resources including a plurality of subframes, wherein each subframe includes a plurality of slots, and wherein each slot is divided into a plurality of subcarriers with multiple symbol periods;
• mapping the ACK information to a portion of the ACK resources allocated to the UE, wherein the multiple UEs are multiplexed on the ACK resources over both the plurality of subcarriers and multiple symbol periods in the plurality of slots;
• and performing modulation on the mapped ACK information based on single-carrier frequency division multiplexing (SC-FDM).

An apparatus for wireless communication, comprising:

• at least one processor configured to:
• send a data transmission to multiple user equipments (UEs) with spatial division multiple access (SDMA);
• determine acknowledgement (ACK) resources for the data transmission;
• determine multiple portions of the ACK resources allocated to the multiple UEs;
• perform demodulation on single-carrier frequency division multiplex (SC-FDM) signals received from the multiple UEs to obtain received symbols;
• process received symbols from each of the multiple portions of the ACK resources to obtain ACK information sent by a corresponding one of the multiple UEs, wherein for each UE the at least one processor is configured to:
• obtain at least one received pilot symbol from at least one resource element in the portion of the ACK resources allocated to the UE;
• derive channel gain estimates based on the at least one received pilot symbol;
• obtain received ACK symbols from remaining resource elements in the portion of the ACK resources allocated to the UE;
• perform detection on the received ACK symbols with the channel gain estimates to obtain detected symbols;
• and
• process the detected symbol to obtain the ACK information sent by the UE;
• and
• a memory coupled to the at least one processor.

A method for wireless communication, comprising:

• sending a data transmission to multiple user equipments (UEs) with spatial division multiple access (SDMA);
• determining acknowledgement (ACK) resources for the data transmission;
• determining multiple portions of the ACK resources allocated to the multiple UEs;
• performing demodulation on single-carrier frequency division multiplex (SC-FDM) signals received from the multiple UEs to obtain received symbols;
• and
• processing received symbols from each of the multiple portions of the ACK resources to obtain ACK information sent by a corresponding one of the multiple UEs, wherein the processing the received symbols includes, for each UE:
• obtaining at least one received pilot symbol from at least one resource element in the portion of the ACK resources allocated to the UE;
• obtaining received ACK symbols from remaining resource elements in the portion of the ACK resources allocated to the UE;
• deriving channel gain estimates based on the at least one received pilot symbol;
• performing detection on the received ACK symbols with the channel gain estimates to obtain detected symbols;
• and
• processing the detected symbol to obtain the ACK information sent by the UE.

An apparatus for wireless communication, comprising:

• means for sending a data transmission to multiple user equipments (UEs) with spatial division multiple access (SDMA);
• means for determining acknowledgement (ACK) resources for the data transmission;
• means for determining multiple portions of the ACK resources allocated to the multiple UEs;
• means for performing demodulation on single-carrier frequency division multiplex (SC-FDM) signals received from the multiple UEs to obtain received symbols;
• and
• means for processing received symbols from each of the multiple portions of the ACK resources to obtain ACK information sent by a corresponding one of the multiple UEs, wherein the means for processing the received symbols includes, for each UE:
• means for obtaining at least one received pilot symbol from at least one resource element in the portion of the ACK resources allocated to the UE;
• means for obtaining received ACK symbols from remaining resource elements in the portion of the ACK resources allocated to the UE;
• means for deriving channel gain estimates based on the at least one received pilot symbol;
• means for performing detection on the received ACK symbols with the channel gain estimates to obtain detected symbols;
• and
• means for processing the detected symbol to obtain the ACK information sent by the UE.

A non-transitory machine-readable storage medium comprising instructions which, when executed by a machine, cause the machine to perform operations including:

• sending a data transmission to multiple user equipment (UEs) with spatial division multiple access (SDMA);
• determining acknowledgement (ACK) resources for the data transmission;
• determining multiple portions of the ACK resources allocated to the multiple UEs;
• performing demodulation on single-carrier frequency division multiplex (SC-FDM) signals received from the multiple UEs to obtain received symbols;
• and
• processing received symbols from each of the multiple portions of the ACK resources to obtain ACK information sent by a corresponding one of the multiple UEs, wherein the processing the received symbols includes, for each UE;
• obtaining at least one received pilot symbol from at least one resource element in the portion of the ACK resources allocated to the UE;
• obtaining received ACK symbols from remaining resource elements in the portion of the ACK resources allocated to the UE;
• deriving channel gain estimates based on the at least one received pilot symbol;
• performing detection on the received ACK symbols with the channel gain estimates to obtain detected symbols;
• and
• processing the detected symbol to obtain the ACK information sent by the UE.