MAC protocols for wireless networks: Spatial-reuse and energy-efficiency

Abstract

This thesis addresses the problem of developing MAC protocols for wireless networks, in particularly, wireless sensor networks and wireless ad-hoc network. Firstly, to provide energy-efficient and low-latency medium access in diverse traffic conditions and second, by exploiting multi-channel radio capability to provide concurrent transmissions in areas where traffic is dense or exhibits traffic funneling effect. The contributions of the thesis are as follows:- This thesis presents AMCM, a traffic-adaptive multi-channel MAC protocol that increases the capacity of wireless network by enabling multiple concurrent transmissions on orthogonal channels using a single half-duplex transceiver. AMCM is based on the IEEE 802.11 MAC but provides fine-grain,asynchronous coordination among locally interfering nodes for channel negotiation. The protocol has several key features. Firstly, the protocol does not requires network-wide synchronization nor does it requires any dedicated control channel for channel negotiation purposes. Next,by dynamically adapting the size of the control window to varying traffic load, our protocol mimics single-channel IEEE 802.11 MAC during low load, while enabling multiple concurrent transmissions during high load.- This thesis presents GMAC, an energy-efficient and low-latency convergecast MAC protocol for data gathering system. GMAC adopts a synchronized low duty cycling approach to minimize the cost of idle listening by allowing network nodes to sleep most of the time. GMAC adopts a simple, low-overhead reservation-based routeaware TDMA approach to facilitate low-latency packet forwarding along a route towards the sink, thus it also minimizes both packet collisions and overhearing.