Macrodiversity reception performance investigation in microcellular networks

Macroscopic diversity provides two or more independent copies of the transmitted signal which fade in an uncorrelated manner. The signals can be combined to fight against shadowing but also against fast fading avoiding the use of two antennas per site (microdiversity). It is suggested in this paper that macrodiversity can provide all the necessary fading protection (against fast as well as slow fading) in microcellular networks where the density of antennas is high. This paper investigates the performance of macrodiversity versus microdiversity from the radio coverage point of view. Two and four port combining are considered, firstly for a Rayleigh fading environment and later with a more elaborate microcellular channel model that includes Rician statistics for the received signal envelope, dual-slope path loss model and lognormal shadowing. The results show that macrodiversity is an effective fading countermeasure in microcellular environments. This work is motivated for the concept of a radio fibre microcellular network where optical fibre links are used for RF signal distribution from a central controller to remote antennae at cellsite. In these systems low-cost and compact radio access ports can be deployed anywhere. Therefore the question is how to obtain maximum radio coverage with minimum number of ports using diversity techniques