Soft output equalization techniques for /spl pi//4-DQPSK mobile radio

The concatenation of an equalizer and a Viterbi decoder is a powerful means for improving the performance of mobile radio. The best system performance is obtained when the Viterbi algorithm is used with soft decisions. The soft output equalizer enables the use of soft decision Viterbi decoding. This paper proposes new soft output adaptive equalization techniques based on the SOVA and the modified-MAP algorithm for /spl pi//4-DQPSK mobile radio over multipath fading channels. Simulation results were obtained by using a modified version of the common functional blocks which were used previously by Hamied and Stuber (1996). A complexity analysis is also presented.

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