i recommends to use Matlab WSN tool download the sample scenario of WSN with tutorial from (http://wislab.cz/our-work/wireless-sensor-network-simulation-tutorial-for-matlab )
One of my MS students is using this recently. However we have also used OMENT++ and castalia for BAN . Have a look at my WSN papers full text on RG .
1) Application Specific Study, Analysis and Classification of Body Area Wireless Sensor Network Applications
2) Pest detection and control techniques using wireless sensor network
3) A class based QoS model for Wireless Body Area Sensor Networks