Implementation of a conjugate matched filter adaptive receiver for DS-CDMA

The implementation of a conjugate matched filter receiver based on adaptive noise cancellation (CMF-ANC) techniques for asynchronous direct sequence code division multiple access (DS-CDMA) mobile radio is described. The system employs a recursive least squares (RLS) minimisation in the form of a modified QR-decomposition algorithm, which is ideally suited to running on a triangular systolic array. The highly pipelined systolic array has many features which make it attractive for parallel processing architectures and very large scale integration (VLSI). Simulation results are presented for the systolic CMF-ANC receiver performance in the mobile fading environment. It is shown that the QRD-RLS version of the CMF-ANC receiver has a significantly better performance in the multiple access interference limited environment than the conventional linear correlating receiver and out-performs other adaptive strategies not based on noise cancellation techniques, such as the standard RLS algorithm. In addition, the systolic array algorithm offers greater numerical stability than the CMF-ANC receiver employing the conventional RLS adaptive solution and has a much lower computational complexity per processor