Research On Energy Balanced Adaptive Transmission Algorithm For Wireless Sensor Networks

With the rapid development of chip, communication and sensing technologies, wireless sensor network (WSN) has become the key technology in the new era of sensing technologies. In WSN, the tiny sensor nodes which consist of sensing, data processing and wireless communication components, form the network in a self-organization manner and send the data to the remote sink effectively and timely. WSN can be widely used in military sensing, environmental monitoring, anti-terrorism, medical treatment and traffic surveillance, etc.Sensor nodes must be left unattended e.g., in hostile even dangerous environments, which makes it difficult or impossible to recharge or replace their batteries. So prolonging the lifetime of WSN by designing effectively has become a hotspot all over the world.Based on the purpose of prolonging the network lifetime, in this article, the system structure, characteristic, application and key problems of WSN are first introduced. And then two low-energy strategies of WSN-data aggregation technology and routing protocol algorithm are stated in detail. Since the transmission of messages consume the most energy of the whole network, and the energy dissipation on radio signal is direct ratio to the square of the transmission distance, all data packets are usually forwarded to the remote base station via multi-hop routing in order to achieve high energy efficiency. However, there is an unavoidable problem of unbalanced energy dissipation among different sensor nodes in this model, that is, the sensor nodes closest to the base station are burdened with a heavy relay traffic load and die first.Meanwhile, for single-hop communication, the sensor nodes furthest away from the base station consume much more energy than other sensor nodes as network radius increases. So, in order to balance the energy dissipation among different sensor nodes in the whole network, two new routing protocols which combine the single-hop communication and multi-hop communication are presented-EBAT and EBMD. In EBAT, every sensor node either sends a data packet directly to the base station or sends the data packet to its successor node along a multi-hop path. For each sensor node, a proportion value of the multi-hop transmission times to the direct transmission times is calculated by the base station through using the centralized algorithm. According to the proportion value, each sensor node uses the distributed algorithm to decide its data packet delivery path every time. And in EBMD, a probability-based mathematical model is used to formulate the energy dissipated by sensor nodes. In this model, every sensor node can send the data packet to any other sensor node, including the base station. Genetic algorithm (GA) is proposed to explore the sub-optimal solutions of every routing probability of each sensor node, and finally the data propagation algorithm is implemented according to these probabilities. Simulation results demonstrate that these two protocols can both enable the sensor nodes to consume energy more uniform in the process of data transmission and prolong the system lifetime.