Cell search scheme using I/Q multiplexed code assignment in asynchronous W-CDMA system

Synchronized base station operation simplifies the process of fast channel acquisition and call location. However, asynchronous operation has benefits also. For instance, it is desirable to have the system operate in geographic areas where accurate time synchronization is unavailable. Therefore inter-cell asynchronous operation provides the advantage of flexible system deployment from outdoors to indoors. In order to deploy asynchronous cell site, it is necessary to assign different long code into each cell. For realistic cell panning and operation, several hundreds of long codes are required and the cell search time is much longer than in synchronous cell site operation. To speed up acquisition, we propose a fast cell search scheme using the pilot channel of the I/Q multiplexed code assignment, i.e. group and cell-specific code, in inter-cell asynchronous DS-CDMA cellular system. And, we simulate the cell search scheme based on ITU-R channel model (Rec. M.1225), and simulation results demonstrate that the rapid cell search is achieved.