| Summary: | 碩士 === 國立交通大學 === 資訊科學系所 === 93 === Power management is a critical issue for portable devices. To reduce power consumption of a portable device, our basic idea is to switch a node from active state to sleep state when its transmission finishes. In this thesis, we propose a power efficient MAC protocol (PEMP) for IEEE 802.11 multihop ad hoc networks. Most of related work targeted at single hop ad hoc networks. In PEMP, when a node intends to transmit data, it will piggyback a data profile, including data size, on ATIM* and ATIM-ACK*. ATIM* and ATIM-ACK* are ATIM and ATIM-ACK with a piggybacked data profile, respectively. In this way, senders and receivers can inform their neighbor nodes of the data profiles. Then, each node calculates its transmission priority according to the collected data profiles. Based on transmission priorities, PEMP can schedule a better transmission sequence. In addition, similar to DPSM [11], PEMP also adjusts the ATIM window dynamically. By decreasing the idle time in active state and adjusting the ATIM window dynamically based on network conditions, the power consumption of PEMP is 20 % less than that of DPSM. PEMP is suitable for multihop ad hoc networks and can achieve a better tradeoff between power consumption, throughput and delay.
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