Waveform Design for Sum Rate Optimization in Time-Reversal Multiuser Downlink Systems
Utilizing channel reciprocity, the traditional time-reversal technique boosts the signal-to-noise ratio at the receiver with very low transmitter complexity. However, the large delay spread gives rise to severe Inter-Symbol Interference (ISI) when the data rate is high, and the performance is further degraded in the multiuser downlink due to the Inter-User Interference (IUI). In this paper, the authors study the weighted sum rate optimization problem in the time-reversal multiuser downlink using waveform design. By exploiting the relation between the allocated power and the SINR targets, an iterative algorithm is proposed to optimize the waveform design through a new power allocation algorithm. Simulation results are shown to demonstrate the superior performance of the proposed algorithm in comparison with other traditional methods.