Effects of Relaying on Network Lifetime in 2.4GHz IEEE802.15.4 Based Body Area Networks

Relaying is a major technique to increase network lifetime in wireless sensor networks (WSNs) and body area networks (BANs). The results of relaying studies highly depend on power consumption model of relay´s transmitter and receiver radio, channel and mobility models. In this work, we study the effect of relaying with 2.4GHz IEEE802.15.4 modules on network lifetime. We analytically derive the energy expenditure of relays in which we use the path loss probability distribution function (PDF) over links, which is derived from our link characterization using micaZ motes, and the existing power consumption models. It turns out that in order for relaying to be beneficial to network lifetime and for the same transmitter power amplifier efficiency, receive power consumption of IEEE802.15.4 widely used RF modules, e.g., micaZ motes are required to be decreased. For instance, receive power of 17mW helps us achieve 25% more lifetime with 3-relay scheme than single-hop transmission over ankle-waist link during walking, whereas with the current receiver, we achieve 12% less lifetime compared to single-hop scenario.