Abstract

In CDMA systems, existence of large number of equally strong pilot signals is not desirable. As a consequence, this would create pilot pollution interference (PPI). Additionally, the limited number of fingers in the RAKE receiver adds a different dimension to the problem. The PPI has the influence of overloading the mobile station's RAKE receiver with excessive amount of signaling on the dedicated control channels. Therefore, the pilot signal's orthogonality erodes dramatically, and the system suffers from dropping of ongoing calls, blocking of originating fresh calls and decrease in the system capacity. In this paper, we demonstrate the power of using a novel multi-carrier chip shaping to alleviate the impact of the PPI. Consequently, the mobile's RAKE receiver will have the capability to perform frequency diversity rather than multipath diversity. This will make efficient use of the received signal energy in the frequency domain and boost the performance of the system. Simulation studies have been carried out to verify the appropriateness of the proposed approach and we have obtained very promising results. Copyright © 2003 John Wiley & Sons, Ltd.