Research On LEACH Protocol In Wireless Sensor Networks Based On Cooperation Communication

Wireless sensor networks is a new self-organizing network, with the developing of electronics and communication technology, wireless sensor networks has been rapidly developed, whether in military or civilian fields it all has been widely used. Compared with the traditional network, wireless sensor networks have many features:Firstly, sensor networks are often used in harsh environment, it is difficult for staff to reach. Secondly, the nodes are very limited in size and energy, they often get energy from the battery, and battery replacement is not easy; Finally, the distribution of nodes is very dense, each node maintains global information is not possible. Due of the above characteristics, when we research routing protocol, energy efficiency is one of the key problems. Therefore the design of energy-efficient routing protocol for wireless sensor networks is the key issue. To save the energy consumption of wireless sensor networks and extend the network's lifetime, wireless sensor network routing protocols are analyzed and researched in this thesis.Firstly, the thesis analyzes the structure,characteristics and key technologies of wireless sensor networks.Secondly, analyzing some typical routing protocols, and based the analysis, we compare the characters of them.Thirdly, we analyze and discuss the cooperation communication technology and its closely related space-time coding techniques.Finally, we focus on LEACH, LEACH-MH and LEACH-COOP. The protocol of LEACH use single-hop, it causes the energy consumption of remote nodes too fast. LEACH-MH is a cluster heads multi-hop transfer protocol, and bases on the protocol of LEACH, The remote cluster heads don't directly communicate with sink node, they sent data through the intermediate cluster head nodes. Although it can save the remote node's energy, but also cause the energy consumption of middle cluster heads, and frequent updates of routing will also have a part of the energy consumption. LEACH-COOP is a LEACH protocol that bases on cooperation, it takes the cooperation technology into the protocol of LEACH, the cluster heads don't sent data to the sink node, but using the cooperation nodes to sent, This can not only balance the energy consumption of nodes, but also reduce the energy consumption which caused by frequent routing updates. In order to verify the superiority of LEACH-COOP protocol, we have a simulation with MATLAB, Compared with other two protocols, results show that LEACH-COOP protocol not only reduces the average power consumption but also extend the life of the entire network.