METHOD AND APPARATUS FOR PERFORMING SEARCH ACQUISITION IN CODE DIVISION MULTIPLE ACCESS COMMUNICATIONS SYSTEM

摘要

PURPOSE: An apparatus for performing a search acquisition in a code division multiple access(CDMA) communication system is provided to maximally reduce a false alarm probability and a miss detect probability caused by power changes of a CDMA receiving signal, without being affected by distortions included in the CDMA receiving signal in a process of acquiring an initial synchronization code among spread code adjusting processes, so as to decrease time for acquiring the initial code synchronization. CONSTITUTION: A parallel complex correlator(11) performs a complex correlation between an inputted 'dk' data sample signal(101) and a 'ck' vector signal(105) in N parallel. The 'ck' vector signal(105) is an internally-generated N parallel complex pseudo-noise(PN) code. A parallel complex accumulator(12) accumulates K consecutive samples according to each component of an 'rk' vector signal(102) outputted from the parallel complex correlator(11). A parallel energy detector(13) finds energy according to each complex component relating to an 'sk' vector signal(103) outputted from the parallel complex accumulator(12). An adaptive rate decider(14) inputs an 'ek' vector signal(104) outputted from the parallel energy detector(13) and a deciding threshold 'Vth'(111), and decides whether a code synchronization is performed, by using statistics characteristics of the 'ek' vector signal(104). A PN code generator(16) controls operations of a parallel complex PN code generator(17) by using a SEARCH_FLAG signal(107) among output signals of the adaptive rate decider(14). A parallel complex PN code generator(17) generates the 'ck' vector signal(105) having N code phases under control of a PN_CNTL signal(108) outputted from the PN code generator(16).