The effect of path loss models on the simulated performance of portable radio systems

Computer simulations of portable radio access were made to compare access performance using two dissimilar path loss models. One model corresponds to a residential environment, where customers are served by external radio ports (fixed radios). The other model was published by Ericsson Radio Systems from measurements in one office building. The results of the study quantify the impact of the contrasting service assumptions on the spectral allocation required for reliable portable radiotelephone service. Simulation results show that these quite different path loss models produced radically different predicted performance in cochannel interference-limited operation. In the residual environment, with a path loss exponent of 4 and a log-normal standard deviation of 10-dB for shadowing, a reuse factor of at least 25 is required for a 10-dB uplink SIR (signal to cochannel interference ratio) at the first percentile. With Ericsson´s in-building model, a reuse factor of 4 with 30-m interport spacing or a reuse factor of 2 with 45-m interport spacing results in equal quality and reliability