An Approach of Optimizing Power in WSN with Random Topology under Rayleigh Channels

The paper proposes an approach of optimizing transmit power in wireless sensor networks with random topology in order to prolong node lifetime. It defines optimal transmit power as the minimum transmit power used by all nodes necessary to guarantee end-to-end bit error rate (BER) requirement. Assuming Rayleigh fading channels and two- dimensional Poisson topology, we bring nearest with forward progress (NFP) routing strategy and enhanced Aloha protocol into the SINR model. On the basis of the SINR model, we derive the expression of optimal transmit power and investigate the tradeoff among the average lifetime of nodes, transmit power and node density. The numerical results demonstrate that optimal transmit power can try its best to prolong node lifetime in the precondition of guaranteeing end-to-end bit error rate (BER) requirement. Besides, increasing the forwarding angle epsiv can decreases the optimal transmit power.