A Relay-Aided Transmission Power Control Method in Wireless Body Area Networks

Reliability is one of the most important communication metrics in wireless body area networks especially for medical applications. However, traditional one-hop transmission power control methods failed to guarantee the reliability when the transmission distance is large. Two-hop relaying transmission can provide reliable transmission but energy consumptions for relay nodes are high resulting in the reduction of network lifetime. In this paper, a relay-aided transmission power control method is proposed to provide reliable transmission and at the same time alleviate the relaying burden on relay nodes. The proposed method automatically switches transmitter's transmission strategy between the direct transmission and the relay-aided transmission based on the channel condition to address long distance problem and then adaptively adjusts the transmission power according to the received signal strength indicator feedback to guarantee the reliable transmission and conserve the energy of relay nodes as much as possible. In addition, parameters in the proposed method are tunable according to the application scenarios to make tradeoff between reliability and energy efficiency. The simulation results demonstrate that the proposed method can effectively guarantee the transmission reliability and conserve the energy of relay nodes, which in turn prolongs the network lifetime.