Error rate performance improvement for a decorrelating CDMA receiver by introducing additional dummy pilot response

A pilot assisted CDMA system which uses extended spreading sequences with guard sequences under a quasi-synchronous condition is capable of separating the interference components included in the input of a decorrelating receiver by solving a system of linear equations. The performance of such a system, however, depends on the property of the de-correlating matrix made of the pilots responses. The regularity of the matrix often tends to degrade due to primarily the multipaths, resulting in the solutions vulnerable to AWGN. This paper proposes an effective technique to solve this problem by introducing a dummy pilot associated with a virtual user into a group of the real users to be served. The simulation indicates a remarkable improvement in the bit-error-rate performance. In addition, it proves a RAKE like function with power-sum-characteristics.