Design Energy-Efficient Low-Latency MAC Protocols in IEEE 802.11 Wireless Networks

To support mobility, most hand-held wireless devices are powered by battery that has only a limited amount of energy. Therefore, energy efficiency becomes one of most important design issues in wireless networks. However, our proposed mechanism is focused on power saving MAC protocol. A well-designed of energy-efficient MAC protocols should be realized with both minimum energy consumption as well as maximum data throughput while be compatible with currently defacto standards. IEEE 802.11 protocol is one of most deployed and popular WLAN system in the world. IEEE 802.11 standard has Infrastructure and Ad Hoc network, our MAC protocols are based on the two. When Power-Saving (PS) nodes which don』t transmission or receive data frames are wake up, the wireless network interface card is in received or idle state. It will waste their energy. And the frame collisions and lengthen the frame delay due to waiting backoff time especially in heavy network traffic. Thus, our plan reduce idle and collision times, increase throughput. This project aims to propose a three-year research work. In the first year, we propose a novel scheduling strategy to improve the energy utilization by avoiding the collision of PS-Poll transmitted by PS nodes in infrastructure WLAN. In ad hoc single-hop networks, we propose a protocol that lets PS nodes can be scheduled to transmit their data frames in order after the ATIM window, and change the ATIM window size dynamically to save more battery power. In the second year, PS node schedules their data frames according to the state switch times to further improve the energy efficiency. In the third year, we propose a strategy that can extend the battery lifetime of PS nodes by allowing that PS nodes can sleep in specific beacon intervals while can transmit and receive data frames normally. All of these protocols proposed by us will be evaluated by mathematic analyses and simulations and, depended on the evaluated results, will be further improved.

Project ID:PB9801-0548
External Project ID:NSC96-2221-E182-007-MY3