5.5.3 The optimum detector Using Bayes'rule, P(sr)=f(rIs)P(s) f(r) where,f(rs,)is the condi pdf of r given s; P(s)is prob of transmittings,called priori probability Let PM(r,s)=f(rls)P(s) MAP is equivalent to:sm=arg max、PM(r,sm） The Optimum Detector: Maximum a posterior probability (MAP):to s MAP: Max a posterior probability s,that max the P(sr).Denoted by, ML: Maximum-likelihood Min-Dist Minimum-distance s=arg maxs.(P(s Ir) Max-Corr:Maximum Correlation Note that P(s,r)is often called a posterior probability. UESTC-Digital transmission through the AWGN channel Prof李晓峰 10