I/Q multiplexed code assignment for fast cell search in asynchronous DS/CDMA cellular systems

For flexible system deployment, we consider asynchronous cell site operation which requires much longer cell search time than in synchronous operation. A new code assignment scheme is proposed to minimize the cell search time in which a group code is assigned to the in-phase pilot channel and a cell-specific code assigned to the quadrature pilot channel. Simulation results show that cell search can be accomplished in less than about 200 ms at 90% of the locations when the pilot code of length 1024 and eight group codes (64 cell-specific codes/group) are used.