Distributed Access Scheme for body area networks

Sensor networks are being researched and deployed in wide range of applications in healthcare. A number of tiny wireless sensors strategically placed on or in the human body, create a wireless body area network (WBAN) that can monitor various vital signs and provide real-time feedback to the medical personnel. In this paper we present the architecture of an ambulatory e-health system including a cluster-tree structured WBAN. In this WBAN, to achieve synchronization, the BAN coordinator and cluster heads (CHs) send beacon frames periodically. It is necessary to schedule the different beacon frames to avoid beacon collisions. We propose a Distributed Access Scheme (DAS) to solve the beacon collision problem. In Distributed Access Scheme, the CHs select their own contention-free time slot (CFTS) of the beacon-only period for sending its beacon frame to nodes in its cluster.