RLS-based adaptive multicode CDMA system

A single-user adaptive multicode CDMA system over AWGN channels is presented. The adaptive system involves joint transmitter-receiver adaptation which allows the desired user to achieve a designated signal-to-noise ratio (SNR) with minimum transmission power. We assume that the adaptive transmitter and receiver have no prior knowledge of the spreading sequences of other users. During the training period, the receiver weights are adapted based on the RLS algorithm. Information about the MMSE error and weights collected at the receiver is employed to update the spreading sequences, which are fed back to the transmitter for the transmission of the next block of data. Simulation results show that both the transmitter and receiver can converge to the optimal solution. The proposed implementation is also shown to be immune to feedback delay