A Multi-Radio Interface for Dependable Body Area Network Communications

Body Area Networks (BANs) are emerging as a convenient option for patient monitoring. They have shown potential in improving health care services through a network of external or implanted biosensors and actuators collecting real-time physiological data. Advancements in wireless networking and sensor development are expediting the adoption of BANs. However, real-time patient monitoring still remains a challenge due to network failures and congestion. In order to improve channel loss resilience and thus link availability, a multi-radio systems approach is adopted incorporating Bluetooth and Wi-Fi. In this work, we propose a multi-radio interface designed for a BAN to improve end-to-end communications. A multi-radio BAN controller is introduced to interface between the two wireless protocols (Wi-Fi and Bluetooth), control inter-radio handovers, manage a shared transmission buffer, and overall, route data accordingly through the protocol stacks. Simulations are conducted to study the performance of the system by adjusting handover timing and its effect on link availability. Advancing a handover has the benefit of a higher throughput at the cost of an increase in power consumption and timing overhead. Furthermore, various human mobility models, AP placement arrangements, and network densities are simulated to evaluate the performance of the BAN multi-radio interface. Sparse networks were found to have the most gain from the addition of the secondary Bluetooth radio system, as primary AP coverage was already very limited. Simulation results for various combinations of simulation parameters are presented to illustrate the improvement in BAN dependability through a multi-radio interface

A Novel Approach for Survivability of IEEE 802.11 WLAN Against Access Point Failure

In the last decade, wireless networks have become increasingly popular as powerful and cost-effective platforms for mobile communications. Unfortunately, current wireless networks are notoriously prone to a number of problems, such as the loss of link-level connectivity due to user mobility and/or infrastructural failures, which makes it difficult to guarantee their reliability. Today’s users are mostly satisfied with the ability to access wired networks/resources conveniently from mobile stations, even if the access is unreliable. However, as wireless networks become more ubiquitous and start to support more critical applications, users will expect wireless networks to provide the same guarantees of reliability as their wired counterpart are often able to ensure. Research is ongoing to extend the scope of services made available to mobile users to achieve the “anytime, anyplace, any form” communications vision. This vision is to provide voice, data, and multimedia services to users regardless of location, mobility pattern, or type of terminal used for access. In IEEE 802.11 Wireless LAN, if an access-point fails, then, all the mobile stations connected to a wired network via the access-point may lose connectivity. In this thesis work, the problem of enhancing the survivability of IEEE 802.11 WLAN focusing on tolerating Access Point (AP) failures is addressed. In particular, focus on the problem of overcoming these APs failures working with reconfiguration of the remaining APs by changing parameters like the neighboring AP’s MAC address is done. This approach consists of two main phases: Design and Fault Response. In Design phase, we deal with quantifying, placement and setting up of APs according to both area coverage and performance criteria. In Fault Response phase we consider the reconfiguration of the active APs in order to deal with AP fault in the service area