Objective-alternance optimization of wireless body area sensor network

In this paper the optimization process of a wireless body area network is presented. The optimization goal is to improve the performance of the body area sensor network with respect to the on-body transmission channel and off-body link performance. The sensor network consists of one node with fixed position (1) towards the ear and two sensor nodes that are located on the chest (2) and the back (3), respectively. The position coordinates of the nodes on the trunk are the design variables. The objective function in the design process includes two components: one that controls on-body data transmission between the 3 sensor nodes and another one controlling off-body transmission between the nodes and the remote receiver. The on-body component of the objective function is the maximum value of the path loss while the off-body component controls the gain of two antennas located in nodes 2 and 3 that are used for transmitting the data to the remote receiver. The optimization procedure utilizes EStra that is an evolutionary strategy optimization algorithm linked with finite-difference time-domain method based full-wave XFdtd simulator for obtaining the objective function value. Considering the two on-body and off-body components, the objective-alternance approach applied in this research yields a solution of the problem that is a compromise between on-body and off-body optimal solution.