For each received symbol, the receiver determines which of {TAIL ~ a plurality} of {HEAD ~ phase} sectors the phase angle lies in 
For each received symbol , the receiver determines which of { TAIL ~ a plurality } of { HEAD ~ phase } sectors the phase angle lies in
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH