Dominant pilot recovery in IS-95 CDMA systems using repeaters

The term pilot pollution in IS-95 CDMA systems is used to indicate that a large number of equally strong pilot signals is present. Those pilots compete with each other to become the serving one and this causes a very high rotation of pilot leadership at the mobile station. As a consequence, the signaling rate on the traffic channel increases, thus degrading the call quality. We present a method of alleviating the pilot pollution problem by means of repeaters. Simulation studies have been carried out on an actual CDMA network suffering from pilot pollution and the results have been verified by field trials. They indicate that repeaters can effectively improve call quality by altering the spacial distribution of pilot signal strength.