a symbol transition calculation unit configured to perform forward and backward metric operations using the initial phase information calculated by the initial phase calculation unit and {TAIL ~ a pilot symbol} in the data packet to calculate {HEAD ~ a symbol transition} of the data packet; and 
a symbol transition calculation unit configured to perform forward and backward metric operations using the initial phase information calculated by the initial phase calculation unit and { TAIL ~ a pilot symbol } in the data packet to calculate { HEAD ~ a symbol transition } of the data packet ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH