Design, implementation and analysis of cognitive radio enabled intelligent WBAN gateway for cost-efficient remote health monitoring

Abstract

In this paper, we design and implement an intelligent gateway for Wireless Body Area Network (WBAN) that seeks opportunistic access of licensed Primary User (PU) channels using Cognitive Radio (CR) to facilitate spectral-efficient, cost-efficient and reliable Non-Real Time (NRT) backhaul transmission of WBAN data for ubiquitous healthcare monitoring. The controller is termed herein as BodyCog-BNC. We develop and implement a cross-layer based modified protocol stack at the BodyCog-BNC, comprising of BodyCog-BNC Management Entity (BME) and BodyCog-BNC CR Medium Access Control (BCR-MAC) units, to exploit cross layer message passing to support the novel idea of spectrum agility. A spectral agile BodyCog-BNC is capable of intelligently switching to conventional licensed Wide-Area Access Network (WAN) technology in case of lack of proper PU channels or occurrence of successive handoffs in multiple PU channels. Furthermore, the protocol stack facilitates session management and energy-efficient backhaul CR transmission over a PU channel employing a proposed Inter-Sensing Time Optimization (ISTO) algorithm. ISTO leverages on convex optimization to select the optimum inter-sensing time for a PU channel to maximize the energy-efficiency within a PU interference constraint under sensing uncertainties. Closed form analytical expressions are also derived to estimate the average consumed energy, switching probability, switching time and the cost-efficiency of BodyCog-BNC. Exhaustive performance analysis shows that the BodyCog-BNC (WBAN gateway), provides a cost-efficient solution for different healthcare applications under varied operating conditions and CR cost regimes. Finally, through a prototype implementation and proof of concept we validate the ability of BodyCog-BNC in enabling NRT remote healthcare monitoring.