A cooperative relaying scheme for real-time vital data gathering in a wearable wireless body area network

Wireless Body Area Network (WBAN) plays an important role in real-time data gathering by on-body vital sensors for athletes in a sports training scenario. However, the 2.4 G Hz Industrial, Scientific and Medical (ISM) band, which is one of candidate frequency bands for WBAN, is not rich in diffraction, so when a man putting on on-body sensor nodes and a BAN coordinator takes different postures and actions, the direct links between them are frequently blocked by parts of his body, resulting in a higher packet error rate (PER). This paper proposes a cooperative relaying scheme for lowering the PER in a WBAN. For each node on a human body, the proposed scheme autonomously assigns a node as a cooperator out of other nodes and the cooperator re-transmits packets from the node for a BAN coordinator instead when the direct link between them is blocked. The paper evaluates the performance of the proposed scheme in terms of average and worst outage rates using experimental data for three subjects in a mixed indoor/outdoor environment.