Modeling mobility and psychological stress based human postural changes in wireless body area networks

Mobility models play a vital role on the performance accuracy of simulations in Wireless Body Area Networks (WBANs). In this article, we propose a mobility model for the movement of nodes according to the posture patterns formed either because of psychological stress or any kind of mobility. During routine activities, body exhibits different postures like, standing, sitting, laying, etc. We form a mathematical model for the movement of nodes according to the posture pattern. In walking and running postures, the nodes placed on the limbs move in a defined trajectory repeatedly. In these postures, the nodes placed on trunk of the body are minimally mobile. On the other hand, in sitting and laying positions, the movement of limbs is nondeterministic. However, we can locate an area in which the node's presence is most probable. Postures change from one state to another depending upon probabilities. During movement, the distance between nodes and sink is changed. As energy consumption, delay, and path loss depend on distance, so they also change due to mobility. We implement the proposed mobility model in multi-hop and forwarder based routing techniques. In multi-hop routing technique, nodes send data to the sink using neighboring nodes. Whereas, in forwarders based scheme, two forwarders are selected in each round to transmit, alongwith their own data, the received data of neighboring nodes. Simulation results show that forwarder based routing schemes has increased stability period, network lifetime and throughput.