Reduced state Viterbi receivers for digital mobile communications

In the context of the new North American TDMA standard for digital cellular, the problem the authors seek to address is the design of an adaptive detector and differential phase decoder. The technique used in the design is that of maximum likelihood sequence estimation, implemented by use of the Viterbi algorithm. Two solutions are proposed, the shifted Viterbi receiver and the differential Viterbi receiver. Each can be implemented using current hardware technology, with the tradeoffs presented. Both architectures simplify the signal constellation at the input of the Viterbi detector. The behavior of the shifted Viterbi receiver and the differential Viterbi receiver was simulated under various SNR, with or without fading, with pseudorandom or correlated data patterns and with various LMS algorithm gain