Hybrid indirect transmissions (HIT) for data gathering in wireless micro sensor networks with biomedical applications

Sensor networks have many potential applications in biology, physics, medicine, and the military. One major challenge is to maximize network life under the constraint of an extremely limited power supply. This is especially true for biomedical applications, which require large numbers of nodes that may be implanted in a subject; frequent battery changes are impractical. The paper proposes a new data gathering protocol, and analyzes a potential application in biomedical sensing technology. The protocol, named hybrid indirect transmission (HIT), is based on an architecture consisting of one or more clusters that cooperatively compute multiple, multi-hop, indirect transmission routes. In order to minimize both energy consumption and network delay, parallel transmissions with a collision avoidance guarantee are used throughout the network; adjacent clusters do not prevent this mechanism from working. To accomplish this, each sensor independently computes a medium access controlling TDMA schedule. HIT was simulated along with three existing protocols; a comparison of their performance in terms of energy efficiency, delay, and network lifetime is provided. Results show that HIT greatly reduces both energy consumption and network delay; it also maintains longer network life compared to the other three protocols. The proposed protocol is promising and would contribute to the use of wireless micro sensor networks in future biomedical technologies.