Decision feedback-MLSE adaptive equalization of the mobile radio channel

This paper presents an analysis of the behavior of different equalization techniques, focusing on the performance of the MLSE (maximum likelihood sequence estimator) by reducing the number of states in the trellis by means of decision feedback in the Viterbi algorithm (DFSE algorithm). The performance of 4 and 16-QAM outdoor mobile radio systems that use adaptive channel equalization techniques is investigated in outdoor environments taking into account a cellular structure. The influence of various system and channel parameters, such as the bit rate, the vehicle speed, the impulse response estimation, the adaptive algorithm (RLS) and the effect of decision feedback in the Viterbi algorithm performance have been studied. Performance results have been compared with those obtained by means of less complex DFE (decision feedback equalizer) structures in terms of bit error rate.