5.5.2 The optimum detector All the possibilities form a cloud centered at s1. Detector:estimate the sym from the observat The dense of the cloud is What is the problem in the detector higher at the center,and With observation r=(,..in hand, becomes less as departing from the center. r=s +n and picture it. R2 。r=s1+n R3 Digital Communications Prof李晓峰 6