A method and the detector to the differential a maximum of - probability of detection

摘要

The phase of received waves is detected at every symbol period T by means of a phase detector (12) on the basis of the phase of a local signal and the detected phase is inputted to a serial circuit of delay circuits (151-15N) each of which lags a signal by a delay time T. Then signals with phases Γn (n=0, 1,..., N) delayed by 1 to N symbols are outputted and supplied to a metric calculating section (16). By adding the sum of a partial sequence (ΔΖi; i=n+1-q, n+2-q,..., n) out of the candidates (ΔΖn; n=0, 1, ..., N) of an N-symbol phase-difference sequence to the phase Γn-q detected at a point of time (n-q)T (q=1, 2, ..., N), to determine the estimated value of the phase Γn of the received waves. The v-th power of the absolute value of the difference νn(q) between the estimated value and the phase of the received waves is used as the metric of the q-symbol phase-difference detection. Σ|νn(q)|v=μ¿n?, the sum of the metric from q=1 to q=n is used as a branch metric at a point of time nT for the candidates of the phase-difference sequence. A pass metric Μ=Σμn are found by calculating the sum of the branch metrics from a point of time 1T to a point of time NT for all the candidates of the N-symbol phase-difference sequence, and the sequence candidates which give the minimum value is used as a decoding sequence.