OPTIMUM DIVERSITY COMBINING AND EQUALIZATION IN DIGITAL DATA-TRANSMISSION WITH APPLICATIONS TO CELLULAR MOBILE RADIO .1. THEORETICAL CONSIDERATIONS

In this paper, Part I, a comprehensive theory for Nth-order space diversity reception combined with various equalization techniques in digital data tranmission over frequency-selective fading channels is developed. The channels are characterized by N arbitary impulse responses possessing random parameters as well as N additive Gaussian noise sources. Various combiner-equalizers which minimize the mean-squared error are determined. Formulas are presented for the attainable least-mean-squared errors and upper bounds on average probabilities of error. The theory is applied to optimize system parameters and to predict performance for QAM data transmission operating over the following model for the mobile radio channel: The diversity paths are statistically independent and each is characterized by the sum of two delayed and independently Rayleigh fading beams. For this model we provide estimates of average attainable error rates and outage probabilities as functions of system parameters. In these channel models the uncoded data rates as well as Shannon capacity are regarded as random variables. In another paper, Part II, we study the probability distributions of the data rates that can be supported by the optimum receiver structures as well as the distribution of the Shannon capacity. The dependence among the important system parameters are there exhibited graphically for several illustrative examples including QPSK.