Performance Analysis of Cognitive Transmission in Dual-Cell Environment and its Application to Smart Meter Communications

摘要

ZigBee based smart meter communication system may suffer from severe interference from WiFi hot spots. To avoid the interference, smart meter communication systems can adopt a cognitive implementation strategy, while treating the WiFi system as primary user (PU) of the spectrum. In this paper, we investigate the performance of secondary system (SU) operating in an interweave fashion to explore the spectrum opportunities. We consider the scenario that the secondary system is subjected to two independent PUs. Under the assumption of Poison traffic for PU activities, we apply Markov chain model to characterize the dynamics of the spectrum opportunities for both single and multiple channel cases. Based on these models, we derive the exact mathematical expressions for the performance metrics of average service time and average waiting time of SU transmission. Through selected numerical examples, we examine the effect of different operation parameters on SU system performance. The analytical results can be applied to predict the performance of ZigBee based on smart meter communications under strong WiFi interference.