Research On Networking Key Technologies Of Wide-area Directional MANET

Modern warfare becomes an omnibearing engagement in five-dimensional space composed of land,sea,sky,space and electromagnetism,where communication antijamming and jamming has been the most drastic combat.Due to the limited bandwidth,traditional antijamming methods such as hopping frequency and spread spectrum could not meet the requirements for the high-speed communication as well.Presently,to utilize the capabilities of the phased array antennas on energy gathering,space isolation and space filter has become a new way for antijamming communication.However,it brings other challenges on the network construction and management owing to the decrease scope of information broadcasting and promoted variation of the topology.Therefore,it is of important meanning and significant application value to study the networking technology on wide-area MANET.In this paper,graph theory,graph spectrum and pattern recognition were applized to analyse and resolve the networking problems,which was based on the characters of battlefield network,such as the broad distributed nodes,long rang transmissiom,high realtime mission and versatile wapon platform.The achievements are shown as follows:Since some nodes like AWACS in wide-area directed MANET has double-frequency for communication,an algorithm named DFDC(Double-Frequency Distributed Clustering)based on the MBNP was proposed.The DFDC adopted the double-frequency model and selected the nodes with the capbility to communicate on two frequencies to be cluster head,which meet the application requirement of the wide-area MANET.Besides,it decreased the influence to and increased the efficiency of the communication by adopting the dedicated channel for cluster maintaining.Theory analysis and simulation results showed the DFDC resolved the potential inconnection problem when there exist 3-hop distance between arbitrarily two cluster heads.To meet the gathering need for members in clustered wide-area directed MANET in some special applicaton like cooperated engagement,an algorithm named FNC(False-Nearest Clustering)based on geography was proposed.Most of the clustering algorithms are based on topology,as a result the clustering results can not based on the geography,or the clustering results are not adjustable.The proposed FNC adopted the fake nearest neighbor classification method that came from pattern recognition to classify the nodes,which put the nodes closed each other geographically into the same cluster and the clustering result of FNC was adjustable when it is not suitable.Besides,the FNC can balance the loads among the clusters.Wide-area directed MANET can fulfill the space division multiplexing access(SDMA)by using the capacity of directed antennas in space division.The SDMA can improve the throughput and decrease the transmission delay of wide-area directed MANET effectively.To meet the SDMA requirement of wide-area directed MANET,an algorithm named SDMAM(Space Division Multiplexing Access Mapping)based on subgraph isomorphism was proposed,which resolved the mapping problem between the pattern graph and the target graph in the design of SDMA.To decreased the computing complexity,it designed two filtering rules to limite the searching nodes of pattern graph within its mapping set,which avoided blind searching and reduced the computation complexity.Simulation and analyse showed that compared with typical Ullmann's subgraph isomorphism algorithm,the SDMAM had lower computation complexity and less graphs mapping time.To reduce the computation complexity further,another algorithm named CSDMAM(Clustering Based on Space Division Multiplexing Access Mapping)based on geographical clustering and subgraph isomorphism was proposed.The CSDMAM classified the nodes with FNC algorithm firstly,and then search the class mapping with SDMAM,If the class mapping was succed,the CSDMAM would continue to map the nodes in the mapping classes.The CSDMAM reduced the computation complexity of SDMAM.As there is a need for low delay of end-to-end data transmission in some particular application like cooperative strike,an algorithm named MNCR(MAC and Network Cross-layer Routing)based on cross-layer optimizing was proposed.It selected the routing path based on the SDMA(Space Division Multiple Access)timetable applicated and informed by MAC.When a packet arrived,the node computed all the possible paths and the corresponding delay according to SDMA timetable,then selected the path with the lowest delay,which ensured that the packets were transmitted to the destination timely.Simulations showed that the MNCR can decrease the end-to-end transmission delay and balance the node's loading.When wide-area directed MANET are focused on transmission insurance in some particular application of wide area battlefield,the reliability and management of the network are treated more seriously.Constructing virtual backbone network can not only improve the reliability and management of the network,but also decrease the overhead of routing computing and maintaining and improve the efficiency of data transmission.So an algorithm named DBCDS(Distributed Bidirectional-Link Connected Dominating Set)based on DGB(Disk Graph with Bidirectional Link)model was put forward.It modeled the topology of wide-area directed MANET with DGB and constructed the virtual network with CDS(connected dominating sets),then limited the computing and maintaining of routing within the CDS nodes set.Compared with the typical CDS construction algorithms,the DBCDS overcame the inaccurate modeling problem and decreased overhead by no spanning tree construction.Besides,the omnibearing request and directed reply of information transmission decreased the CDS size.To improve the reliability and fault-tolerance capacity,another algorithm named DKCDS(Distributed k-dominated Connected Dominating Set)was proposed.It constructed a CDS by the DBCDS firstly,then calculated k-dominating set iteratively and constructed cycle to make the virtual backbone network be 2-connected k-dominated.The DKCDS improved the stability and fault-tolerance of virtual backbone network by more dominated nodes.Besides,its overhead was not very high.