Research On Anti-jamming Dynamic Access For Multi-channel Wireless Networks

Multi-channel wireless communication network enables multiple nodes to access interference-free channels and communicate parallelly.It has been proposed as a promising technology to solve the severe competition problem in traditional single-channel wireless communication networks.Multi-channel dynamic access can play important role in anti-jamming networks due to its abundant application prospects.On one hand,when there exists malicious jamming,the nodes can dynamically choose the channel exposed to less interference to perform reliable communications.On the other hand,even when no jamming exists,the nodes can dynamically choose the channel,which less nodes compete for,to avoid collisions with other nodes.Under both these two conditions,the nodes can achieve better throughput performance by using multi-channel dynamic access.Based on aforementioned background,this thesis focuses on the design and implementation of multi-channel dynamic access MAC protocol with the objective of improving the reliability of multi-channel communication and efficiency of link-building.More specifically,a dedicated control channel(DCC)based multi-channel dynamic access MAC protocol and a channel-hopping(CH)based blind rendezvous algorithm are proposed.Main contributions of this thesis are summarized as follows.First,considering the high complexity of the channel sensing algorithm and the poor instantaneity of the protocol implementation in traditional HC-MAC,a DCC based multi-channel MAC protocol is designed for better instantaneity and easier implementation in hardware device.The proposed protocol uses the same channel structure with the other DCC based protocols.However,the channel sensing algorithm in our proposal is more practical while the instantaneity of the protocol implementation is evidently improved.The design of this proposed protocol forms the foundation for the design and realization of further network simulation system.Second,combining with the discrete-event technique,we discretize our protocol to several system state points.By analyzing the process of propelling between these system state points and parameter variation of the process,a discrete simulation model of multi-channel network is designed,which is suitable for DCC based protocols.Then,we optimize some parameters in the model by simulating the protocol.It can not only reflect the impact of the channel structure on the protocol as well as the network performance,but also make the simulation of multi-channel networks more efficient.Third,to solve the bottleneck problem of DCC based multi-channel access protocol while reducing the negotiation overload of the networks,a CH based blind rendezvous algorithm which allows the parallel negotiating rendezvous is proposed.All source and destination nodes can reach rendezvous over different co-channels efficiently without foreseeing CH sequence of nodes.The implementation of the protocol does not require either DCC or synchronization.By guaranteeing full diversity of rendezvous,our proposal improves the anti-jamming performance of multi-channel communication,the efficiency of communication link build and the robustness of communication network.Finally,using GNU Radio software tool and USRP2 hardware devices,a simulation platform for multi-channel wireless communication system is designed.To improve the reality of multi-channel networks simulation,a hardware-in-loop simulation platform based on the designed discrete simulation model is built.The platform improves the facticity and configurability of networks simulations,and as a result it can make the real communication simulation with plenty of nodes possible.Simulation results validate the accuracy of the network model.Moreover,we take the blind rendezvous algorithm into practice with the communication system platform and the results prove the advancement and feasibility of the algorithm.