Autocorrelation characteristics for received signal level in a wide-band mobile radio channel

With the advent of diversified multimedia services in mobile communication systems, the trend in mobile transmission is to use digital and wide-band channels. It is reported that the instantaneous received signal level fluctuates in wide-band transmission channels, behaving very differently from narrow-band channels. The basic characteristics of the instantaneous received signal-level fluctuation are the distribution of the received signal level, the autocorrelation, and the frequency correlation. This paper discusses the autocorrelation characteristics, which are the most important in the design of the antenna spacing and other parameters in a mobile station for a space diversity system. As the first step, the autocorrelation coefficient is analyzed based on the wide-band propagation model, and an expression for the autocorrelation coefficient is derived. It is seen that the autocorrelation coefficient is not affected by the receiver bandwidth and can be represented by a zeroth-order Bessel function of the first kind, as in the case of the autocorrelation function in narrow-band transmission. In order to verify the above result, a computer simulation is performed. The instantaneous received signal-level fluctuation is generated by simulation for narrow-band and wide-band reception, and the autocorrelation coefficient is calculated based on the resulting received signal-level fluctuation. The received signal level is also measured by experiment for narrow-band and wide-band transmission, and the autocorrelation coefficient is calculated from the result. It is verified by the simulation as well as the experiment that the autocorrelation coefficient does not depend on the receiver bandwidth and can be approximately represented by a zeroth-order Bessel function of the first kind. (C) 1999 Scripta Technica.