INITIAL SYNCHRONIZATION METHOD FOR RECEPTION SYSTEM OF CODE DIVISION MULTIPLE ACCESS

PROBLEM TO BE SOLVED: To shorten the initial synchronization time and to secure the accurate initial synchronization by receiving some of segments included in a sequence of pseudo noise PN codes for several periods and calculating an inter-code phase difference in the segment of every period to obtain a receiving PN code. SOLUTION: The PN codes 2 of a single period of (n) pieces of PN code chips 1 which are received by a receiver via a radio charmel within a PN code period are repetitively received by M times. The received value of a j-th chip 1 or the PN code 2 of the i-th period is shown as Ri, J equal to (M×n) matrices. An element of every column consisting of the same chip 1 is repetitively received by M times. A phase difference is calculated for every row by a multiple symbol differential detection MSDD system, and the signals showing the chips 1 are obtained. The PN codes combined in every column are averaged by M. Thus, (n) pieces of chips 1 are and the codes 2 are decided. Thereby, the maximum likelihood symbols are detected to N pieces of symbols and the system performance is improved.