LAUSR

The point coordination function (PCF) of the IEEE 802.11 standard represents a well-known medium access control (MAC) protocol providing quality-of-service guarantees in wireless local area networks (WLANs). However, few papers theoretically analyze energy efficiency. This paper presents a Parallel Gated Poll (PGP) access mechanism that exploits the PCF defined in the IEEE 802.11. The basic idea is, during the contention free period, idle stations can save energy by turning into sleep and active stations exchange data packet under a gated service polling scheme to improve the energy efficiency. Besides, the mean cycle analysis model is setup to evaluate the energy efficiency of a typically PCF protocol and PGP protocol. By applying the classic 1-limited and parallel gated polling model, the closed expressions of energy efficiency of PCF and PGP are formulated respectively. Simulations show that our analytical results are very accurate with the simulation results. Both analytical and simulation results show the high energy efficiency of PGP.