A cooperative MAC providing alternate path for the poor link

We exploit helper-to-helper (h-2-h) cooperation using the broadcast nature of wireless sensor networks. The potential helpers overhear the packet from the transmission of previous hop and the helper transmits the packet in the current hop on behalf of the assigned node (sender). We call it friendship relaying cooperative medium access control (FRC-MAC) protocol. This mechanism eliminates the sender transmission phase, improving the energy efficiency and end-2-end delay. Our innovative proposed MAC protocol provides alternate path when a link is poor temporarily, hence no need to find a new path frequently. In this protocol, each node manages a helper queue in additional to its data queue to store cooperative data so that the helper can transmit cooperative data with higher priority than its own data. We performed a simulation study to investigate network performance and compared with existing protocols. We found that FRC-MAC outperforms existing protocols in terms of end-to-end delay and energy efficiency.