5.5.2 The optimum detector The dense indicates basically the probability density or r. What is a good detector ?----Make error as less as posible How to measure error ?----Probability of error Let R be the region in the space for which we select s, Re be the complement of R.They are decided by the criterion. R3 The average probability of errors is, E-P(e)=1-ES P(.Ir)f(r)dr P(successs)=P(s,Ir)f(r)dr where,P(s,r)is the prob that s has been transmitted on the reception of r f(r)is the unconditional pdf of r. Digital Communications Prof李晓峰