The interests in health care have considerably increased these days as the aging population becomes larger. Health care has grown to the one of most active research areas especially in the area of wireless, mobile health monitoring systems. The wireless network technologies have advanced to the point where they can enable and help deploy a very broad gamut of systems suitable for medical applications. Several researches have proposed to replace the wired connections among medical devices with wireless connections. Wireless network technologies interwork with sensor equipped BodyLANs. Wireless personal area networks (WPANs) are well positioned to support health care applications in limited geographic areas. In particular, the characteristics of Bluetooth and its popularity make it the preferred network infrastructure for HealthNet environments. However, Bluetooth has the "bad reputation" of long connection delays, which may be disastrous in some health applications. In this paper we address the connection delay and propose a new data transfer protocol based on Bluetooth version 2.1. The 2.1 version was published very recently and offers new features that are interest to our application. Among the new features we leverage extended inquiry response (EIR) and secure simple pairing (SSP) to solve the delay problem. Extensive simulation results show that the proposed system significantly improves data delivery as well as power consumption. It solves a well known problem in Bluetooth based wireless networks. Using our proposed scheme, Bluetooth devices are now adequate to support sophisticated scenarios such as emergencies and urgent data dissemination requirements.

ZigBee is popular for Wireless Sensor Network (WSN) devices because of its low power consumption, built-in security method and ratified specifications. With these features, it is also suitable to be used with medical sensor devices. Medical sensors in a human body self organize a ZigBee Personal Area Network (PAN). These PANs are interconnected and form a HealthNet. For the interconnection, a ZigBee PAN detects existence of another PAN with beacon detection or active channel scan. Different ZigBee interconnection schemes are used after detection. PAN bridge method uses special bridge node that works for different PANs with time division method. PAN merge method temporarily changes PAN coordinator's role as bridge node and merges two PANs. Peer-to-peer network temporarily share all resources when two PANs are met, but all PANs have to use the same channel and operate as an ad-hoc network. In this paper, we perform extensive evaluations using NS-2 simulations to compare PAN interconnection methods. Results show that the PAN bridge is the most useful method because it is not affected by router/node ratio and is applicable to different channel usages.

In a large scale Bluetooth network, scatternet is regarded as the only interconnection method among piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. We propose overlaid Bluetooth piconets (OBP) to interconnect piconets and form a virtual scatternet. Every piconet continuously changes its stages and collects metadata of piconets in the communication range. If metadata shows existence of data to transfer, an inter-piconet connection is made and data is transferred. We compared throughput and efficiency of OBP with those of scatternet. Results show the feasibility of OBP usage instead of scatternet

In this work, we determine an analytical relationship between the average path length of traffic connections of a Bluetooth scatternet and the overall throughput and power consumption of the network. Results obtained implementing this analytical relationship to different scatternet topologies are presented and discussed. By reducing the hop count in a scatternet we can achieve better performance in terms of throughput and power consumption. Therefore, the issue of minimizing the hop count in the presence of mobility, changing traffic flows and varying interference receives an important role. In our analysis we also show the impact of the link quality on the overall throughput. The obtained results motivate the importance of heuristics aimed at reducing the communication path length in a scatternet.

Previous work analytically showed that communication path length reduction is an efficient way for improving the performance of Bluetooth scatternets. Maintaining short communication paths is mainly important in dynamic scatternets with changing traffic flows, mobile nodes and in the presence of interference, when the network topology changes continuously. In this work we aim at demonstrating through simulations that in such dynamic scatternets by periodically reducing the path length (i.e. hop count) between the communicating nodes, the overall throughput supported by the network can be significantly increased and the available energy of nodes can be consumed more efficiently. For this purpose, we present a distributed technique for repeatedly re-configuring the scatternet topology such that to support the current traffic flows between all of the communicating peers with a small number of hops.