L-MAC: Location-aware MAC Protocol for Wireless Sensor Networks

This paper presents the design, implementation and performance evaluation of a location MAC protocol, called L-MAC, for wireless sensor networks. L-MAC is a combination of TDMA and CSMA while offsetting the high overhead of time slot assignment by allocating the time slots to sensor nodes based on their location information. This design avoids high computation complexity of time slot assignment incurred by node mobility and node failure. The area which the wireless sensor network occupies is divided into blocks and each block is associated with an inter-block time slot and an intra-block time slot. In the inter-block time slot, the sensor nodes stay active and receive the packets from nodes outside of the block. In the intra-block time slot, the sensor nodes communicate with peer nodes in the same block under CSMA. Sensor nodes stay sleep in all other time slots unless they have traffic to send. L-MAC is implemented and evaluated in NS-2.