Hierarchical wireless networks of body sensor networks for healthcare applications

Abstract

Conventional wired body sensor networks have been used in hospitals over the last decade; however, the tethered operation restricts the mobility of the patients. In the scenario considered in this chapter, the signals collected from the patients’ bodies are wirelessly transmitted to a base station, and then delivered to a remote diagnosis centre through a communication infrastructure, enabling full mobility of the patient in the coverage area of the wireless network. Healthcare applications require the network to satisfy demanding requirements in terms of quality of service (QoS) and, at the same time, minimize the energy consumption of the sensor nodes. The traffic generated by data-intensive healthcare applications may lead to frequent collisions between sensor nodes and the consequent loss of data, if conventional MAC protocols for wireless sensor networks are used. Therefore, this chapter presents LPRT and CCMAC, two MAC protocols that intend to satisfy the QoS requirements of these applications, but differ in the wireless topology used. Experimental results for an implementation of the LPRT using an IEEE 802.15.4 compliant wireless sensor platform are presented, as well as simulation results comparing the performance of direct communication (between wireless body sensor nodes and the base station) with two other approaches relying on a cluster-based topology (similar to the one proposed by the authors of LEACH), which demonstrate the benefits of using a cluster-based topology on wireless healthcare applications.