A Study On Cooperative MAC Protocol Based On Network Coding Aware For Ad Hoc Network

Network coding was first proposed by Ahlswede in 2000, whose main idea is that network node not only as relay intermediate node to store and forward frames, but also allowing the intermediate node perform coding processing operation on the incoming frames. Since, it can increase the amount of information in single forwarding. Cooperative communication technology is a new distributed spatial diversity technology, whose main idea is to regard the nodes in the network as distributed antennas. Since, nodes can cooperate with each other for distributed data processing and transmission. The cooperative communication technology is very suitable for the wireless network because of the unreliability of wireless link and the broadcast characteristic of the data frame transmission. When the source node needs cooperative transmission, relay node can also send its own frame data with network coding technology while retansmittiong the original frame data. So in recent years, it has become a hotspot to improve the transmission efficiency and throughput by combining the network coding and cooperative communication technology.It can effectively improve the frame data forwarding times and throughput by combining the network coding and cooperative communication technology. This thesis is based on the netrwork coding aware cooperative MAC protocol for ad hoc network, and the main research content include two aspects: firstly, network coding aware cooperative MAC protocol without totally collision; secondly, a rate adaptive cooperative MAC protocol based on network coding. The achievements of this thesis are as follows:Firstly: to address the problems lying in the current NCAC-MAC(network coding-aware cooperative MAC protocol), the collision of selecting relay node and the unsuccessfully decoding the coding frame with the decoding method of random linear network coding, a network coding aware cooperative MAC protocol without totally collision(NCAC-WTC) is proposed. Secondly, to solve the problems lying in the traditional network coding protocols that not considering the improvement of rate adaption in unicast transmit mode and lying in the protocols using RTS/CTS control frames to estimate channel which generate additional expenses, a cooperative MAC protocol with rate adaption based on network coding(RACNC) is proposed.The main innovation of this paper are: NCAC-WTC protocol mainly proposes two optimized schemas, the one is the mechanism of relay node selection without totally collision, which was proposed to ensure the completely collisionless relay selection, the other is the adaptive decoding mechanism, target node can choose the decoding method for decoding the encoding frame adaptively based on the link between target node with source node and the link between relay node with source node to improve the decoding efficiency and decoding rate of success. RACNC protocol mainly proposes a rate adaptive mechanism based on ACK frame, which estimate channel with modified ACK frame instead of RTS/CTS frames and reduce network overhead. This mechanism can further improve the network throughput while combined with network coding technology.Finally, we have the conclusion about this thesis and further research directions are given.