An energy efficient, high throughput MAC protocol using packet aggregation

In wireless sensor networks, most MAC protocols switch radios off periodically, employing the so-called duty cycle mechanism, in order to conserve battery power that would otherwise be wasted by energy-costly idle listening. In order to minimize the various negative side-effects of the original scheme, especially on latency and throughput various improvements have been proposed. The novel Aggregation MAC or AG-MAC protocol presented in this paper combines two of the most promising improvements into one protocol. Firstly, the idea to forward packets over multiple hops within one duty cycle as initially introduced in RMAC. Secondly, a packet aggregation scheme that not only increases throughput but also reduces power consumption that would otherwise be incurred by additional control packets. Since data packets in sensor networks are comparatively small significant gains are to be expected. Furthermore, AG-MAC incorporates our previously presented idea of scheduling data transmissions with minimum latency, thereby performing packet aggregation together with the multi-hop transmission mechanism in a most efficient way. We evaluated AG-MAC using the prominent network simulator ns-2 and the results show that our protocol can outperform state of the art protocols both in terms of energy efficiency and throughput.