Adaptive Load Control For Zigbee-Based Wbans With Coexisting Wi-Fi Networks

The development of health tele monitoring through wireless body area networks (WBANs) is an evolving direction in personalized medicine and home-based mobile health care. In a health tele monitoring system, a WBAN consists of a number of lightweight miniature sensors. The sensors measure physiological parameters such as electrocardiography (ECG), electroencephalogram (EEG), body temperature, and blood pressure. These measurements are transmitted to an external data aggregation device called a coordinator via wireless communication networks, and are then sent to a health tele monitoring center (e.g., a hospital) via the Internet. One of the most widely used wireless technologies in WBANs is ZigBee because it is targeted at applications that require a low data rate and long battery life. However, ZigBee-based WBANs face severe interference problems in the presence of Wi-Fi networks. This problem is caused by the fact that most ZigBee channels overlap with Wi-Fi channels, severely affecting the ability of healthcare monitoring systems to guarantee reliable delivery of physiological signals. To solve this problem, adaptive load control algorithm that controls the load in Wi-Fi networks to guarantee the delay requirement for physiological signals, especially for emergency messages, in environments with coexistence of ZigBee-based WBAN and Wi-Fi. Since Wi-Fi applications generate traffic with different delay requirements, the focus is mainly on Wi-Fi traffic that does not have stringent timing requirements .A adaptive load control algorithm for ZigBee based WBAN/Wi-Fi coexistence environments has been proposed, with the aim of guaranteeing that the delay experienced by ZigBee sensors does not exceed a maximally tolerable period of time. Simulation results show that the proposed algorithm guarantees the delay performance of ZigBee-based WBANs by mitigating the effects of Wi-Fi interference in various scenarios.