Fading depth dependence on system bandwidth in mobile communications - an analytical approximation

A simple and computationally inexpensive analytical approach is proposed for the evaluation of the dependence of short-term fading depth on system bandwidth and environmental characteristics. The approach, accounting for the maximum difference in propagation path length and having the Rice factor as a parameter, is derived by fitting simulated data from a model in the literature. Application examples are presented for GSM, UMTS, HIPERLAN, and mobile broadband systems (MBS), giving some insight into the fading depth observed under different conditions with regard to system bandwidth and environmental characteristics. Macro-, micro-, and picocell environments are considered. In the microcellular environment, the fading depth experienced by UMTS is below the one for GSM by 0.1 to 5.5 dB, while in the picocellular one, the difference between GSM and UMTS is not significant, being almost independent of environment characteristics. When considering HIPERLAN or systems with larger bandwidths, the fading depth, both in micro and picocellular environments, is smaller than the one verified by UMTS; however, there is an increased dependence on environmental characteristics. In the macrocellular environment, the fading depth experienced by UMTS is about 6 to 11 dB below the one for GSM. Hence, different short-term fading margins should be considered for each system and working environment.