A Slotted Aloha joint MAC - cum - Routing protocol for data gathering sensor network applications

In this paper we have proposed and implemented a joint medium access control (MAC) -cum- routing scheme for environment data gathering sensor networks. The design principle uses node dasiabattery lifetimepsila maximization to be traded against a network that is capable of tolerating: (a) A known percentage of combined packet losses due to packet collisions, network synchronization mismatch and channel impairments (b) Significant end-to-end delay of an order of few seconds We have achieved this with a loosely synchronized network of sensor nodes that implement slotted-aloha MAC state machine together with route information. The scheme has given encouraging results in terms of energy savings compared to other popular implementations. The overall packet loss is about 12%. The battery life time increase compared to B-MAC varies from a minimum of 30% to about 90% depending on the duty cycle.