Exact error rate estimation of optimum diversity combining with finite-length equalization in digital cellular mobile radio

This paper is devoted to the precise and fast performance assessment of Quadriphase-shift keying modulation (QPSK) transmission using optimum space diversity combining and a finite-length equalizer in a mobile radio channel with frequency-selective fading. The length of the equalizer may not be sufficient to compensate for the severe channel distortion, thus resulting in significant ISI. With the residual ISI, the evaluation of the error probability is fairly complicated and extremely time-exhausting through computer simulation. To resolve this issue, we devise the Gaussian quadrature rule (GQR) to calculate the error probability efficiently instead of the upper bound approach which was widely used in the previous study. The GQR method is capable of offering significant accuracy as well as considerable saving of computer time while other methods fail.