Research On Cooperative Communication Based On Network Coding In Wireless Sensor Networks

The network resources of wireless sensor networks(WSN) are constrained. Therefore, low-power transmission to reach a reliable communication is very important in WSN. Cooperation communication combining the advantages of both diversity and rely transmission is a virtual MIMO technology. The transmission reliability and the channel capacity can be improved by applying cooperative communication. Network coding is an important break-through in the field of network communication which increases network capacity and reduces the cost of network transmission. The relay nodes in the network not only store and forward packets, but also encode the information that passes by. In this way, the transmission efficiency and the network capacity are increased. Aiming at reducing the transmission energy consumption in WSN, this dissertation studies cooperative communication based on network coding in WSN, which achieves some results. The major works include:(1) A network coded cooperation scheme combining network coding and cooperative communication based on WSN is presented. The sensor nodes encode the received data by network coding and forward the combination to the sink node to help improve the network performance. Besides, the transmission block error rate and energy consumption is analyzed. Simulation results show that the energy consumption of network coded cooperation scheme is 80.9% lower than the single routing scheme and 43.7% lower than the cooperation scheme to reach the target average block error rate of 10-2.(2) The optimal source-partner power allocation for the network coded cooperation scheme focusing on node position and system block error rate is studied. An energy allocation algorithm based on minimum block error rate is presented. In the algorithm, the energy allocation factorαis adjusted according to the position of the cooperative node to achieve the minimum block error rate. Simulation results show that when the cooperative node is further from the source node, the value ofαis greater.(3) The network coded cooperation scheme is extend to multi-node model. The transmission energy consumption is analyzed and the transmission energy consumption performances of 2,4,8,12 nodes coded cooperation is proposed by computer simulations. Numerical results show that the more nodes the network contains, the less transmission energy each node consumes. Besides, an improved random network coding algorithm which can reduce the encoded coefficient cost is presented to ease the defect of general random network coding algorithm. Network coded cooperation scheme with the improved random network coding algorithm consume 13.6% less than the general network coded cooperation scheme when the fading coefficient is 30dB.