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