Robust multiuser detection based on minimax m-beamforming for mobile communications

In this paper, a new robust m-estimation technique is developed for combating impulsive noise and multiuser interference in code-division multiple-access (CDMA) communication systems with a receiver antenna array. A power function of the proposed robust estimator is obtained by minimizing a nonquadratic residual function derived from the Huber´s minimax robust estimation theory. Maximum peaks of this power function are used for estimation of communication signals as well as DOA. A strong advantage of the proposed robust m-estimation algorithm is a decreased sensitivity of the estimates with respect to an actual unknown distribution of random noises and interferences. Simulation results demonstrate that the proposed robust algorithm offers significant performance gain, in terms of BER and maximum user capacity, over the conventional least squares (LS) based estimator.