An improved differential detection scheme based on maximum likelihood sequence estimation

摘要

Although differential detection is a suitable demodulation scheme for mobile communications, its bit error rate (BER) performance in an additive white Gaussian noise (AWGN) channel is inferior to that of a coherent detection scheme. To remedy this deficiency, Mitsubishi Electric has developed an improved differential detection scheme using maximum likelihood sequence estimation based on the Viterbi algorithm. The resultant scheme achieves good BER performance not only in AWGN channels but also infast Rician fading channels and slow Rayleigh fading channels.The improved differential scheme developed by Mitsubishi Electric is a multiple differential detection scheme that improves the BER performance by estimating demodulation data from 1, N{sub}(22) differential detection signals. The method involvesdifferential detection of phase changes in the specified symbol interval of the received signal. We call the developed scheme a "multiple differential phase detection" (MDPD) scheme, since its algorithm only requires phase information of the receivedsignal.