Enhanced Maximal Ratio Combining for Rake Receivers in Mobile Cdma Terminals

In this paper we propose an enhanced maximal ratio combining (MRC) scheme for RAKE receivers in mobile CDMA terminals. It is based on the original MRC scheme derived by Brennan, where the RAKE finger noise powers are used in the combining weights. This enhanced scheme performs nearly as well as Brennan's original MRC scheme, but unlike Brennan’s method, it does not require the estimation of the RAKE finger noise powers. In order to see what is the achievable performance we also analyze the gain obtained through the use of Brennan's MRC scheme for mobile CDMA terminals in various types of channels, and show that the Brennan's original MRC scheme results significantly larger signal-to-noise ratios than the conventionally used MRC scheme. Simulations are presented to show that also our proposed MRC scheme gives a significant performance gain as compared to the performance of the conventional MRC scheme.