METHOD FOR OPTIMALLY SEARCHING FOR DS-CDMA SIGNAL COMPOSED OF PILOT SYMBOL AND CONTROL SYMBOL IN TIME DIVISION AND APPARATUS THEREBY

摘要

PURPOSE: A method for optimally searching for a DS-CDMA signal composed of a pilot symbol and a control symbol in time division and an apparatus thereby are provided to maximize the performance of a receiver in the case of searching for a signal or measuring the SIR(Signal to Interference Ratio) using a direct sequence band-spread signal. CONSTITUTION: Despreaders(24A-24M) execute complex despreading as much as symbol length using code phases for M numbers of hypotheses. In case that the field of the currently despread signal is a pilot symbol field, the output of each decimator(25A-25M) is inputted to each coherent accumulator(26A-26M). If the field of the currently despread signal is a control symbol field, the output of each decimator(25A-25M) bypasses each coherent accumulator(26A-26M). Each square combiner(27A-27M) squares the real part and imaginary part of the output of each decimator(25A-25M) or the output of each coherent accumulator(26A-26M) respectively and adds up them. Each multiplier(28A-28M) multiplies the output signal of each square combiner(27A-27M) by a weight corresponding to the slot format of the present mobile station's transmitting signal. Each non-coherent accumulator(29A-29M) accumulates the values received from each multiplier(228A-28M) or each square combiner(27A-27M) through many slot lengths. These accumulated values are inputted to a decision device(30).