Patent ID: 7120192

Claim:
A synchronization establishing apparatus in a spectrum spread communication system, comprising: a search section which calculates correlation values from a received spectrum spread signal, calculates power values as addition values of symbols corresponding to said correlation values and power addition values of said power values, and selects larger ones of said power addition values to output together with timing data corresponding to said selected larger ones of said power addition values; a frequency offset estimating section which estimates frequency offsets from said power values and demodulation timing data, and calculates phase change quantities from the estimated frequency offsets to output to said search section; and a demodulation path selecting section which selects path timings from said timing data based on said selected larger ones of said power addition values and outputs said demodulation timing data indicative of said path timings to said frequency offset estimating section, wherein during the calculation of said power values, said search section corrects phases of either said symbols or said power values based on said phase change quantities calculated by said frequency offset estimating section.