Several distributed routing algorithms for wireless networks were described recently, based on location information of nodes available via Global Positioning System (GPS

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In a localized routing algorithm, each node currently holding a message makes forwarding decision solely based on the position information about itself, its neighbors and destination. In a unit graph, two nodes can communicate if and only if the distance between them is no more than the transmission radius, which is the same for each node. This paper proposes localized routing algorithms, aimed at minimizing total power for routing a message or maximizing the total number of routing tasks that a network can perform before a partition. The algorithms are combinations of known greedy power and/or cost aware localized routing algorithms and an algorithm that guarantees delivery. A shortcut procedure is introduced in later algorithm to enhance its performance. Another improvement is to restrict the routing to nodes in a dominating set. These improvements require two-hop knowledge at each node. The efficiency of proposed algorithms is verified experimentally by comparing their power savings, and the number of routing tasks a network can perform before a node loses all its energy, with the corresponding shortest weighted path algorithms and localized algorithms that use fixed transmission power at each node. Significant energy savings are obtained, and feasibility of applying power and cost-aware localized schemes is demonstrated.

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This paper presents a distributed sleep scheduling protocol that can be used for implementing synchronous interface sleep for energy conservation in wireless Ad Hoc networks. Central ida of this protocol is to distribute a common sleep-awake cycle schedule among all nodes within a connected partition so that the nodes can turn their interface off during the sleep section of the agreed upon schedule, and they can communicate during the wake section of the schedule. By turning the interface off, the nodes can avoid idle listening consumption, which is a known reason for nonessential energy drainage in random-access network interfaces such as those running IEEE 802.11. This protocol is suited for low to moderate network loading conditions. The proposed distributed protocol employs a novel schedule synchronization technique that can work without any local time synchronization and can deliver low convergence latencies. Another notable feature of the protocol is its ability to work with unmodified existing MAC layer protocols such as 802.11. We present an ns2 based simulation model of the proposed distributed scheduling and sleep protocols for evaluating and comparing their energy performance with those of plain 802.11 MAC and a centralized scheduling mechanism. Experimental results show that with 50% wake-sleep duty cycle and 1 second wake-sleep cycle period, the protocol can achieve up to 50% energy gain within the feasible network loading situations, with a maximum packet drop rate of less than 5%.