Control of microcellular re-use statistics using directional antennas in the presence of scattering

In ideal homogeneous urban environments, microcellular systems may be planned using regular frequency re-use patterns. These patterns take advantage of the site shielding effect of buildings to allow channel re-use in adjacent streets. These regular patterns are rarely achieved in practice due to the effects of shadowing and scattering. The case of re-use within a linear microcellular GSM system is first examined and the effect of shadowing and directional antennas on the useful re-use pattern is established. Subsequently, a diffraction based model of site shadowing is used to evaluate the potential for re-use between adjacent streets. It is shown that discrete scatterers can produce significant deterioration in the attainable re-use patterns, but that this effect may be mitigated by the use of simple directive antennas.