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 a pilot symbol in {HEAD ~ the data packet} to calculate {TAIL ~ a symbol transition} of the data packet; and 
to calculate
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 a pilot symbol in { HEAD ~ the data packet } to calculate { TAIL ~ 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 OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH