Impact of propagation effects on an adaptive TDMA network

An experimental TDMA network consisting of four stations located within different (CCIR-rain climatic zones) has been successfully operated in the 20/30-GHz frequency range. To improve system availability limited by link attenuation due to rain, an up-grade of the network by a fade countermeasure protocol is planned applying up-link power control and common resource sharing, techniques. Ideal performance of these techniques is degraded by the occurrence of 'false alarms' and the allocation of the resources to other stations suffering from concurrent attenuation. To optimise the switching protocol for the network configuration the influence of propagation on the performance of the switchover routine as well as on the availability of the resources has to be evaluated. Results of a simulation based on one-year of propagation data and estimates of the influence of correlation between attenuation events are presented.<
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