Analysis Of The CSM/CA Protocol For Ad Hoc Network

With the development of network communication, users nowadays have higher requirements. How to allocate and manage the network resource more efficiently and how to provide personalized and fair services based on the high Quality of Service become the main problems which are urgently to be solved.Since the1970s, ALOHA system appeared in university of Hawaii, random multiple access technology achieved by leaps and bounds development, formed the ALOHA multiple access technology, CSMA multiple access technology, CSMA/CD multiple access technology and CSMA/CA multiple access technology.Random multiple access is an efficient access technology, it uses a method that random access resources of users, competition, control flexibility and can guarantee transmission efficiency. In some conditions, it can use channel resources effectively and reduce the conversion time delay.So it is widely used in computer communication network, satellite communication, wireless communication network, the organization of wireless sensor network and so on. However, the performance of traditional random multiple access control system dramatically deteriorated, collision probability of random users’ competition increased and the augment of control signals during forwarding process made the channel transmisson worse.These inevitably lead to deep research on a new random multiple access control protocol.This paper is based on the random multiple access system.Consulted a lot of documents and books which were related to Ad hoc network technology and random multiple access technology.Summarized the characteristics, the topologies and structures,MAC protocols,route protocols and the analysis method of Ad hoc network.Introduced the CSMA/CA protocol’s working principle in detail.Evaluated many typical random access protocols.Then put forward a new Ad hoc network MAC protocol PCMAHN(Parallel Control protocol for Multi-Hop Ad Hoc Networks) according to the improvement of the communication efficiency between the nodes.Protocol placed importance on the characteristics of data transmission between the wireless Ad hoc network nodes. Modified the frame structure of CTS and ACK of IEEE802.11DCF protocol.Improved the exchanging way of handshake signals between Ad hoc network nodes.Use the CTS and ACK of upstream node as the handshake signal of next hop communication:downstream node listens the CTS and ACK signals of upstream node,then replies the CTS to upstream node after the communication of upstream nodes so that can establish data transmission quickly.It improved the throughput of data transmission and reduced the transmission delay.This paper uses the average cycle of mathematical modeling method to set up the normalization multi-hop system model.Concluded the throughput analysis formula of new protocol and IEEE802.11DCF. After theoretical analysis,calculated and simulated the protocol on MATLAB platform the according to the protocol’s working principle. Provided lots of throughput curve graphs. These analysis graphs well reflected the characteristics of the control protocol, summarized the important conclusions. It has important scientific significance for further improving and optimizing the wireless network CSMA/CA control protocol theoretic modeling analysis and the application of protocol.Finally, concludes the work of this thesis and also prospects the future research direction of the subject.