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Site speciJ'ic planning tools will become increasingly important as microcellular communication systems continue io evolve. These tools will enable system planners to design their systems far more rapidly and to minimise t,he cost of their development. In this paper, a new method for microcellular system capacity evaluation is presented, which proposes the use of the site specific ray-tracing propagation models developed at the University of Bristol. The propagation model includes the effects of (urban shielding & shadowing in site specific environments.To simpltfy the processing procedure, a statistical propagation model is used to generate the signal coverage of a Rayleigh fading environment. Taking into account the particular system requirements, such as the modulation scheme, BER and outage probability, the propagation results for a given area can be extensively analysed tlo produce its system capacity. Obviously, site specific propagation coverage will provide a more accurate e:rtimation of system capacity.

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This paper evaluates the effects of modulation and urban shielding for modern microcellular systems. The capacity analysis makes use of the site specijic ray-tracing propagation models previously developed at the University of Bristol.For a given microcellular location a site specijic building database has been used to predict the signal coverage as a result of rejlection, dgfraction and scattering in the local environment. Taking into account a number of system parameters, such as modulation type, antenna pattern, SNR, C/I, and outage probability, the ray-traced propagation data has been extensively analysed to provide an accurate estimation of system capacity. Using this model, the impact of higher level modulation schemes such as 16-QAM is examined for microcellular networks.