Optimization Of Low Power Protocols In Wireless Sensor Networks

Low-power protocol is of importance to determine the performance of wireless sensor networks (WSNs), network security and reliability of energy control technology is also key factors to influence low-power protocol. Wireless sensor nodes are energy constraints and how to establish a low-power multi-protocol network to reduce energy consumption is difficult in reality. Furthermore, how to control energy consumption and maximize the life of a low-power network protocol is an important challenge. In addition, the dynamic and unstable nature of WSNs and many protocols use link-layer retransmission mechanism to ensure the reliability of packet transmission remains challenge. Another important challenge for WSNs is how to lower the packet loss ratio under resource constraints environment.Firstly, the thesis introduces related concepts of low power protocols in wireless sensor networks, and surveys the approach of energy saving in sensor networks. Furthermore, we compare and analyze the performance of typical low power protocols in sensor networks.Secondly, the thesis concern on two key techniques in WSNs, namely energy control and reliability guarantee, respectively. For sake of delay constraints in real time WSNs, we propose DC-Gear (Duty Cycle Gearing) optimization policy, which adjust the duty cycle on the sensor node in order to meet the requirements of delay constraints and minimize energy consumptions.We then report SAR2 policy, aiming at deal with packet loss problems during the data transmission period. The SAR2 use RSSI to classify the reason of packet loss, then gear the transmission power, transmission rate and routing path as to relieve the packet loss situation.Finally, we implement the two optimization policy on TinyOS, and the real experiment is composing of TelosB motes to evaluate the optimization policy. The results show that our scheme works effectively.