Abstract: To improve network performance in dynamic traffic condition, an adaptive and asynchronous MAC protocol called AX-MAC was proposed. Based on preamble sampling technique, AX-MAC halves the length of wakeup preamble by employing some early ACK listening periods intercepted into strobed preambles. It also allows nodes to adjust their polling intervals according to the traffic conditions quickly and accurately by employing a two-parameters-based traffic determining mechanism. A model based on Markov chain is set up to analyze the influence of these two parameters. The simulations illustrate that AX-MAC can significantly reduce network latency on dynamic traffic conditions. Moreover, it also provides an optimal energy-latency trade-off by selecting proper parameters couples carefully.

Key words:  wireless sensor networks, preamble sampling, adaptive, media access control (MAC)