Adaptive algorithm based on pilot-channel for multiuser detection

A novel adaptive algorithm for MMSE multiuser detection in downlink CDMA is proposed in this paper. This algorithm uses the information in the pilot channel to compute the desired MMSE solution directly. Compared with conventional adaptive algorithms and previously proposed blind algorithms, it does not require training sequences or channel estimation. Analysis shows that the MMSE detector obtained by the algorithm converges to the Wiener solution globally, and the computational complexity is O(N²). Simulation examples illustrate that the algorithm can rapidly reach the steady state. The steady state performance can be enhanced by increasing the transmitted power in the pilot channel, but is worse than that of a conventional recursive least-square (RLS) algorithm in decision-directed mode