Adaptive arrays and MLSE equalization

Abstract

In digital cellular communication systems, receivers are designed to combat the problems of fading, time dispersion, and interference. Separately, these problems can be solved using antenna diversity, equalization, and adaptive array processing, respectively. Joint solutions have been proposed which combine adaptive array processing with either linear equalization (LE) or decision feedback equalization (DFE). However, LE is sensitive to spectral nulls and DFE has the problem of decision error feedback. In this paper, an algorithm is proposed which combines adaptive array processing with MLSE equalization to mitigate fading, time dispersion, and interference. The optimal metric for the MLSE structure is derived. The receiver reduces to well known forms for special cases. D-AMPS simulation results illustrate the potential performance of the proposed algorithm, including the case when the fading on the different antennas is correlated.