Improved assessment of interference limits in cellular radio performance

Reuse distance aid cluster size are evaluated for cellular mobile radio systems. Rayleigh fading, log-normal shadowing, and area mean power (which is inversely proportional to the fourth power of propagation distance) are considered, using the technique of Schwartz and Yeh (1982) for determining the probability density function of the sum of several log-normal variables in order to obtain the cochannel interference probabilities. These results are used for analyzing the radio spectrum efficiency, taking traffic intensity into consideration. Different modulation methods, namely, analog FM with 30 kHz and 12.5 kHz channel spacing, SSB (single sideband) with 5 kHz spacing, and digital modulation with 25 kHz channel spacing, with adequate protection ratios are compared. An example of the calculation of system bandwidth and cluster size using this procedure is presented.<
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