Research On Working Vacations Strategy Of WLAN MAC Layer

Wireless local area networks (WLAN) have been widely used in many different fields for its flexibility and expandability. IEEE 802.11 defined two kinds of media access control methods:Distributed Coordination Function (DCF) and Point Coordination Function (PCF). Each of them has its merits and demerits, so it is a key problem to use both functions reasonably in order to meet the requirements of integrated service.In this thesis, we analyze the DCF and PCF schemes deeply, and study some conventional MAC algorithms systemically. For the purpose of satisfying requirements of data transmission in integrated services, a new MAC algorithm based on working vacations is proposed in the thesis. We discuss the physical operation characteristic of wireless local area networks. Combining queuing theory, the queuing model of the algorithm proposed above and steady performance parameters of mathematics model are obtained. The results show that the algorithm based on working vacaions has an advantage over single PCF or DCF scheme in some indices such as mean queue length, mean delay time and system throughput.Using the continuous system simulation strategy, we design the simulation experiment of MAC algorithm. Simulation results prove that the MAC algorithm based on working vacations has a better performance than the PCF function or the DCF function.