Optimizing Energy Efficiency of TDMA with Finite Rate Feedback

We deal with energy efficient time-division multiple access over fading channels with finite-rate feedback for use in the power-limited regime. Through FRP from the access point, users acquire quantized channel state information. The goal is to map channel quantization states to adaptive modulation and coding modes and allocate optimally time slots to users so that the average transmit-power is minimized. To this end, we develop a joint quantization and resource allocation approach, which decouples the complicated problem at hand into three minimization sub-problems and relies on a coordinate descent approach to iteratively effect energy efficiency. Numerical results are presented to evaluate the energy savings.