The Research Of Multi-relay Cooperative Handover Mechanism Based On Network Coding In Wireless Network

Wireless network has a rapid development in the recent ten years. In order to ensure that the mobile terminals execute smooth handover timely and effectively between the multiple wireless network, mobile terminal which accesses to the wireless network must adapt to a variety of different wireless network protocols. The defect of traditional multi-hop handover is that once the mobile terminal initiates a handover connection to the destination network, multi-hop connection will bring the corresponding handover to connect the new network access point. Terminal moves so frequently that the handover connection between the terminal and destination network will be established frequently, this way not only increases the cost of maintaining the handover connection, but also reduces the reliability of the handover. To solve the problems of multi-hop handover in wireless network, a cooperative communication technology which is called multi-relay cooperative handover mechanism is proposed, through the cooperation between multiple relay nodes, mobile terminal builts the handover connection with multiple destination network access points, which greatly improves the reliability of the handover. Because network coding can improve system throughput, balance the network load, that it is gradually applied to the system of wireless communication. So the network coding technology combines with multi-relay cooperative communication technology, has become the current research hot spot. Wireless network is a network which has the limited resource, so the problem that how to use limited resource to improve the performance of system needs to be considered. In order to save the wireless network resource and reduce system overhead, this paper mainly aimes at network coding based multi-relay cooperative handover system and studies it, the main contents and innovations points are as follows:Firstly, introduces three kinds of typical handover control mechanisms in wireless network: vertical handover mechanism, handover mechanism based on network hierarchical, multi-relay cooperative handover mechanism based on network coding, and analyzes them. Then to compare with the three kinds of handover mechanisms in such aspects handover delay, the block rate of handover and so on.Secondly, the network coding theory is studied, introduces the physical layer network coding briefly, and analyzes model of multi-relay cooperative handover mechanism based on network coding, points out the shortcomings of it. Then for some of these shortcomings, a new handover mechanism:multi-relay cooperative handover mechanism based on feedback network coding is proposed. Introduces the background of the handover mechanism, analyzes the principle of the handover mechanism. Then analyzes performance and simulate the handover mechanism respectively from two aspects of system outage probability and power consumption, and compares with the traditional multi-relay cooperative handover mechanism based on network coding and Takeover handover mechanism. Comparison results show that, under the condition of without affecting the system performance, the new handover mechanism is better than the other two in the system overhead and the rate of resource utilization.Finally, for the scenarios of node mobility in wireless network, on the basis of analyzing the multi-relay cooperative handover mechanism based on feedback network coding, this paper proposes a algorithm which is called the pivotal relay node detection algorithm based on potential energy field. Then introduces background of the algorithm which is proposed, analyzes algorithm principle, gives algorithm process and algorithm pseudo-code, and analyzes the performance of algorithm. Simulating the rate of detection accuracy and the overhead of detection time of algorithm respectively from the number of node、the speed of node and the density of node, and compares the simulation results between the algorithm proposed in this paper and traditional node detection algorithm. Comparison results show that, algorithm of this paper is superior to the traditional node detection algorithm on the overall performance.