Patent ID: 7321584
Filing Date: 2008-01-22
Classification: H04B

Abstract:
1. A cell search system for a mobile station in a time division duplex system, comprising: a primary synchronization code search module for searching primary synchronization codes for a predetermined search frame using received signals from a base station and generated primary synchronization codes, and comparing frame values of the primary synchronization codes to determine a position of the maximum value; a correlation module for estimating a phase value necessary for demodulation of secondary synchronization codes from the primary synchronization codes searched by the primary synchronization code search module, and detecting a correlation between the received signals and codes forming the secondary synchronization codes using the estimated phase value and the position of the maximum value determined by the primary synchronization code search module to acquire a first correlation value; a secondary synchronization code search module for generating determinative variables using the first correlation value of the correlation module, accumulating M slots based on the position of the maximum value, sorting, in the order of size, as many of the determinative variables of the respective M slots as can be sorted in a predetermined buffer size, and storing the sorted determinative variables; a comparison and decision module for detecting a maximum value of the determinative variables of the secondary synchronization code search module, comparing the maximum variable value with the values stored in the secondary synchronization code search module to count matching values, and comparing the counted value with a predetermined system value to decide whether slot synchronization and group acquisition is successful; and a base station determination module for detecting a correlation between the received signals and midamble codes in the group generated according to the decision result of the comparison and decision module to determine a second correlation value, and selecting a maximum of the second correlation values to determine the base station to which the mobile stations belongs, wherein the mobile station operates to search primary and secondary synchronization codes during initial acquisition without determining threshold values before entering checking mode to determine if synchronization is acquired, searches primary synchronization codes again when slot synchronization and group acquisition is not successful, and searches midamble codes only when slot synchronization and group acquisition is successful.