Performance Analysis of Relay based Cooperative MAC Protocols

The incessant demand for access to information at ‘anytime’ and ‘anywhere’ has motivated researchers to look into Next Generation Networks (NGNs) which will be a of platform for co-existence of different technologies. Ad Hoc Networks (AHNs) being a vital component of the NGNs still need to address challenges such as throughput, energy consumption, latency and time varying channel conditions. Considering the drive to ‘go green’ and vendors’ commitments to reduce their energy emissions, NGNs must be environmentally friendly, and this underpins the importance of energy conservation. Cooperative communications has emerged as a promising solution which exploits the broadcast nature of wireless networks to yield higher throughput, achieve lower energy consumption, increase network lifetime and provide network resilience. This thesis aims at contributing to the field of cooperative AHNs. The focus of this research is on the relay based MAC layer: design of cooperative MAC protocols, performance modelling, and protocol enhancements. The first contribution of this thesis is dedicated to the modelling of energy consumption which aids MAC protocol developers in the design phase to devise efficient protocols and energy saving solutions. This model can predict energy consumption in an ideal and non-ideal environment. It is shown that using a relay results in not only better throughput but also higher energy efficiency. In the next contribution, we propose an Enhanced relay-enabled Distributed Coordination Function (ErDCF), which uses high data rate nodes to work as relays for the low data rate nodes. ErDCF in saturation achieves higher throughput, lower delay and lower energy consumption as compared to conventional 802.11 Distributed Coordination Function (DCF) in ideal conditions. The performance of ErDCF under