Design and analysis of Hybrid Indirect Transmissions (HIT) for data gathering in wireless micro sensor networks

Abstract

Sensor networks have many potential applications in biology, physics, medicine, and the military. One major challenge in sensor networks is to maximize network life under the constraint of limited power supply. The paper addresses energy-efficiency in the context of routing and data gathering. A new protocol is proposed: Hybrid Indirect Transmission (HIT). HIT is based on a hybrid architecture that consists of one or more clusters, each of which is based on multiple, multi-hop indirect transmissions. In order to minimize both energy consumption and network delay, parallel transmissions are used both among multiple clusters and within a cluster. This is made possible by having each sensor independently compute a medium access controlling TDMA schedule. The computation within each sensor is intelligent yet simple. Formal analysis shows that it requires O(n) space and O(n x logn) time complexities, and O(1) setup messages prior to the computation, where n is the total number of sensors. HIT does not require sensor nodes with CDMA capability, or the remote base station to compute a data gathering schedule. Performance is evaluated by simulating and comparing HIT with three other existing protocols, including Low Energy Adaptive Clustering Hierarchy (LEACH), Power Efficient Gathering for Sensor Information System (PEGASIS), and Direct Transmission. Results have shown that HIT greatly reduces both energy consumption and network delay; it also maintains longer network life compared to these three existing protocols. Security issues and a potential application of HIT in biomedical sensing technology are also rigorously discussed. This work is significant to the advancement of energy-efficient micro sensor networks; the proposed protocol is promising and would contribute to the use of wireless micro sensor networks in future biomedical sensing technologies.