Multichannel maximum-likelihood sequence estimation (MLSE) equalizer for GSM using a parametric channel model

We propose a novel algorithm for the maximum-likelihood sequence estimation (MLSE) equalizer for the Global System for Mobile Communications (GSM) system. Specifically, we use a parametric model for the channel, along with a modified phase pulse-shaping function of Gaussian minimum shift keying (GMSK) modulation to obtain the modified Viterbi equalizer which we refer to as the parametric channel-Viterbi equalizer (PC-VE). In contrast to the conventional Viterbi equalizer with a finite impulse response (FIR) channel description, the PC-VE avoids the linear approximation error. The PC-VE also has a lower computational complexity if the number of the propagation paths is less than the number of the FIR channel taps multiplied by the number of antennas. The proposed algorithm is applicable to both single and multiantenna receivers. An analytical expression for the BER as a function of the SNR, path delays, and path DOAs has been derived. Some simulation results that illustrate the performance of the proposed algorithm are presented.