Per-TTI rank control within transmission opportunity for downlink comp

An apparatus configured for wireless communication, comprising:

• means for determining, by a base station at a beginning of a transmission opportunity, a rank and data rate for the transmission opportunity, wherein the transmission opportunity includes a plurality of transmission time intervals (TTIs);
• for each TTI of the plurality of TTIs:
• means for computing, by the base station, one or more channel quality indicator (CQI) back-offs using one or more outer loop adaptation processes per TTI;
• and
• means for updating, by the base station, the rank and the data rate using the one or more CQI back-offs;
• and
• means for transmitting, by the base station, data during each TTI of the plurality of TTIs according to the updated rank and the updated data rate,
• wherein the means for updating the rank includes:
• means for calculating an effective signal-to-interference-plus-noise ratio (SINR) for a plurality of available ranks at an associated TTI of the plurality of TTIs;
• means for adjusting the effective SINR with the one or more CQI back-offs of the associated TTI;
• means for estimating a throughput associated with each of the plurality of available ranks based on the adjusted effective SINRK;
• and
• means for selecting the updated rank of the plurality of available ranks, wherein the updated rank has a highest value of the estimated throughput.

A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

• program code executable by a computer for causing the computer to determine, by a base station at a beginning of a transmission opportunity, a rank and data rate for the transmission opportunity, wherein the transmission opportunity includes a plurality of transmission time intervals (TTIs);
• program code executable by the computer, for each TTI of the plurality of TTIs:
• for causing the computer to compute, by the base station, one or more channel quality indicator (CQI) back-offs using one or more outer loop adaptation processes per TTI;
• and
• for causing the computer to update, by the base station, the rank and the data rate using the one or more CQI back-offs;
• and
• program code executable by the computer for causing the computer to transmit, by the base station, data during each TTI of the plurality of TTIs according to the updated rank and the updated data rate,
• wherein the program code executable by the computer for causing the computer to update the rank includes:
• program code executable by the computer for causing the computer to calculate an effective signal-to-interference-plus-noise ratio (SINR) for a plurality of available ranks at an associated TTI of the plurality of TTIs;
• program code executable by the computer for causing the computer to adjust the effective SINR with the one or more CQI back-offs of the associated TTI;
• program code executable by the computer for causing the computer to estimate a throughput associated with each of the plurality of available ranks based on the adjusted effective SINR;
• and
• program code executable by the computer for causing the computer to select the updated rank of the plurality of available ranks, wherein the updated rank has a highest value of the estimated throughput.

An apparatus configured for wireless communication, the apparatus comprising:

• at least one processor;
• and
• a memory coupled to the at least one processor,
• wherein the at least one processor is configured:
• to determine, by a base station at a beginning of a transmission opportunity, a rank and data rate for the transmission opportunity, wherein the transmission opportunity includes a plurality of transmission time intervals (TTIs);
• for each TTI of the plurality of TTIs:
• to compute, by the base station, one or more channel quality indicator (CQI) back-offs using one or more outer loop adaptation processes per TTI;
• and
• to update, by the base station, the rank and the data rate using the one or more CQI back-offs;
• and
• to transmit, by the base station, data during each TTI of the plurality of TTIs according to the updated rank and the updated data rate,
• wherein the configuration of the at least one processor to update the rank includes configuration of the at least one processor:
• to calculate an effective signal-to-interference-plus-noise ratio (SINR) for a plurality of available ranks at an associated TTI of the plurality of TTIs;
• to adjust the effective SINR with the one or more CQI back-offs of the associated TTI;
• to estimate a throughput associated with each of the plurality of available ranks based on the adjusted effective SINR;
• and
• to select the updated rank of the plurality of available ranks, wherein the updated rank has a highest value of the estimated throughput.