Energy efficient cross-layer design for Ad Hoc networks based on IEEE 802.11

Abstract

In the mobile wireless networks which use a battery as a power, because of limitation of battery capacity, reducing energy consumption is the important issue. This is also essential in the mobile ad hoc network that is composed of only stations without base station as an access point. This day, IEEE 802.11 Wireless LANs are widely deployed and exponentially grown. In the IEEE 802.11 power saving mode specified for DCF which can make ad hoc network, time is divided into Beacon Intervals to synchronize nodes and to be able to exchange data each other. At the start of each Beacon Interval each node in the power saving mode periodically wakes up for a duration called the ATIM Window. During the ATIM window, the nodes exchange control packets to determine whether they need to stay awake for the rest of the Beacon interval. In this thesis we suggest a Synchronized Hello Exchange Mechanism improve IEEE 802.11 DCF-PSM in Mobile Ad-hoc Network. When IEEE 802.11 Power Saving Mode works with AODV, Power Saving Mode would be inefficient. PSM turn off the power of RF antenna when a node does not have any data to transmit or receive. However, in AODV, a node may determine connectivity by listening for hello packet from the neighbors. In stand-by state, because of the periodical local connectivity information exchange, nodes do not go into doze state, regardless of no data to transmit or receive. The node would dissipate the power staying in awake state. To solve this problem, we propose a Synchronized Hello Exchange Mechanism which makes distributed hello packet exchange synchronize. This proposal improves the performance of IEEE 802.11 PSM in stand-by state.