DEMODULATION AND DECODING OF TRELLIS-CODED CONTINUOUS-PHASE MODULATIONS IN AN INCOHERENT MOBILE RADIO ENVIRONMENT

Digital communication systems using Trellis Coded-Continuous Phase Mod ulations (TC-CPM) have been shown to be power efficient, both for cohe rent and incoherent detection. In this paper some techniques for the i ncoherent detection of TC-CPM signals in a radio-mobile environment ar e studied. Two different differential decoding algorithms for the dete ction of TC-CPM are presented. The first one is a Viterbi algorithm ch aracterised by a reduced number of states when compared with the class ical coherent Viterbi detector. The second one is a modified SAN(B) al gorithm for the incoherent detection of convolutionally encoded CPM ov er a mobile radio environment. Comparisons with the coherent Viterbi d ecoder show that the proposed algorithms are quite attractive, especia lly in the case of frequency non-selective radiomobile channels.