INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, vol.30, no.3, 2017 (SCI-Expanded)
Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 is a protocol operating in media access control and physical layer, and it is commonly used in low-power and low data-rate wireless communications. In this paper, we develop a stochastic model for unslotted operations of IEEE 802.15.4 networks. Signal fading is an important factor in mobile communications. According to the level of fading, signal-to-noise ratio gets dynamically changing values. Given a pair of nodes communicating to each-other in a mobile channel, the model calculates frame sizes providing maximum data-rate of successful IEEE 802.15.4 transmissions. The experimental results in various environments are given in the paper to discuss the success of the model. In the consideration of real-time operations, the model is improved to be operated in a low-complexity hardware/software unit. According to experimental results presented in the paper, the proposed model seems to be suitable in mobile environments by achieving high data-transfer rate for unslotted IEEE 802.15.4 protocol. Copyright (c) 2015 John Wiley & Sons, Ltd.