New methods for reliable packet transfer and energy balancing in wireless sensor networks

In this paper some novel unicast protocols are developed for wireless sensor networks (WSNs) in order to ensure reliable packet transmission and maximize the lifespan at the same time. The optimal transmission energies and the optimal numbers for repeated packet transfers are derived which guarantee that the packets are received by the base station (BS) with a given probability, subject to achieving the longest possible lifespan. These protocols can be applied in biomedical applications where energy consumption and longevity are of crucial importance. The optimization has been carried out for the chain protocol (when nodes are forwarding the packets toward the BS via the neighbouring nodes) and for the shortcut type of protocols (when packet is handed down to neighbours in the chain until on certain node it gets transmitted directly to the BS). The reliability of information transfer is enhanced by repeated low-energy packet transmissions. The new results have been tested by extensive simulations which also demonstrated that the lifespan of WSN can significantly be increased by the new unicast protocols.