Radio propagation measurements and channel characterisation pertinent to urban microcellular communications systems incorporating relay links

The future use of cellular radio systems incorporating relay links is viewed [1-3] as key to the satisfaction of ever-increasing demands for greater capacity, while maintaining installation and operating costs at manageable levels. However, because of the scarcity of published propagation measurements on relay channels, channel models that have heretofore been used to support the claimed advantages of systems incorporating relays must be considered as only provisional until more measured results are available. This paper therefore reports radio propagation measurements that were made to observe quasi-simultaneous characteristics on direct and indirect (relay) radio links in base-relay-mobile terminal configurations that result in an emulation of radio links in urban microcells. Statistics for both wide and narrowband channel parameters, models for narrowband fading, and comparisons of results for direct and indirect links pertinent to both amplify and forward (AF) and decode and forward (DF) relay systems are reported.