Passive discovery of IEEE 802.15.4-based body sensor networks
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.