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