An Adaptive Coexistence Mechanism between WLAN and WBAN in Wireless Medical Environments

Abstract

Electronic health (E-Health) is being recognized as a method to improve the overall health status of the population. For this reason, medical wireless communication technology has been actively studied to realize E-health. Unlike wired communication, the use of wireless communication remains to provide ubiquitous connectivity; it allows better access and enables greater physical mobility to patients. Among the various wireless technologies, WLAN (IEEE802.11/WiFi) and WBAN (IEEE 802.15.4/ZigBee) are widely used for e-healthcare system. However, interoperability and coexistence between these two heterogeneous networks are becoming key issues. ZigBee is potentially vulnerable to interference by WiFi in the same unlicensed ISM band. Most of all, the significantly different power level and asynchronous time slots result in significant unfairness between WLAN and WBAN. In this thesis, we focus on the coexistence environment beween WLAN and WBAN for e-healthcare systems in the ISM band. We propose an adaptive coexistence CSMA mechanism which can mitigate interference and achieve efficiency channel sharing. By using an efficient throughput model, we control and find an appropriate adaptive contention window size of WLAN in order to give transmission opportunities to WBAN. This proposal can guarantee the required medical-grade QoS of WBAN without any significant degradation of the throughput of WLAN. The simulation results using MATLAB confirm that the proposed algorithm operate to make efficient channel sharing compare with conventional approach. As a result, the proposed coexistence CSMA protocol guarantee reliable healthcare system and provide better QoS of WLAN and WBAN in medical environments. ⓒ 2013 DGIST