Throughput Analysis and Design for Coexisting WLAN and ZigBee Network

Zigbee and wireless local area networks (WLAN), based on IEEE 802.15.4 and IEEE 802.11 standards, respectively, operate in overlapping unlicensed frequency bands. Therefore, one network can create harmful interference for the other if they are located in the same geographical area. The coexistence performance of the two networks has been analyzed mostly via computer simulation in the literature. In this paper, we develop a mathematical model to evaluate the throughput performance of coexisting 802.15.4 Zigbee network and 802.11 WLAN operating on the same channel. Our proposed analytical model is based on the analysis of a Markov chain for one pair of typical WLAN-Zigbee nodes, which capture detailed operations and interactions of the MAC protocols in the two networks. Moreover, we propose to employ the developed model for channel allocation that achieves fair throughput sharing among Zigbee nodes. Numerical results confirm the excellent accuracy of the proposed model and its usefulness for coexistence performance evaluation and design of the heterogeneous network.