Modified multi-rate detection for frequency selective Rayleigh fading CDMA channels

A LMMSE multi-rate detector for synchronous CDMA frequency selective Rayleigh fading channels is proposed. A comparative study between the conventional multi-rate RAKE receiver and suboptimal multi-rate detector is presented. The conventional multi-rate RAKE receiver is severely limited by the near-far effects in the multiuser environment. Both suboptimal multi-rate receiver and LMMSE multi-rate detector have the near-far resistance while preserving the multipath diversity gain. The simulation results show that the proposed LMMSE multi-rate detector can improve the performance compared to the proposed suboptimal multirate receiver.