An evaluation of frequency diversity performance in microwave frequency mobile radio communication systems

The present UK cellular radio system currently uses a frequency spectrum which limits both the number of users for speech communication and the range of services that may be offered. The introduction of millimetric frequencies will offer a larger amount of bandwidth and allows higher capacity services. One drawback of using short wavelength is the increase in the number of fades in a multipath environment. Frequency diversity is a technique already present on fixed services to combat multipath fading. Being a frequency spectrum consumer, this technique is not worthwhile for the current mobile communication system. Nevertheless the use of higher frequency bands may render frequency diversity attractive. Measurements made at different frequency spacings as well as a 3-D ray tracing model are presented. The objective of this investigation is to characterise the performance of frequency diversity in an indoor environment. An analysis of the correlation as functions of frequency spacing and distance is also presented.