Research On Neighbor Discovery Technology With Directional Antenna In Wireless Ad Hoc Networks

In recent years,due to its flexible,high-survivability,easy to quickly expand and low system cost,wireless ad hoc networks has been widely used in military tactical network and emergency rescue network.Wireless communication mode with directional antenna due to its advantages such as anti-intercept ability and anti-jamming ability,which can improve network capacity,increase transmission distance and reduce energy consumption.These features make it especially suitable for military communication.However,neighbor discovery with directional antennas in wireless ad hoc network becomes more challenging.Compared with neighbor discovery with omni-directional antennas,close cooperation is needed between neighbors when using directional antennas.Due to the mobility of nodes,their positions are difficult to determine in advance.It is necessary to design robust neighbor discovery algorithm and acquire orientation of neighboring nodes dynamically and instantly in order to make the directional antenna beam point at each other and ensure the directional communication between neighboring nodes.One key performance measure of neighbor discovery algorithm is how long it takes to discover all the neighbors given that nodes do not have prior knowledge the number of nodes in the network and where their neighbors are.Most of the existing researches on neighbor discovery problem are under the condition of single beam,there is almost no study of neighbor discovery with multi-beam directional antenna.Furthermore,the traditional single beam directional antenna neighbor discovery algorithm is difficult to directly promote to the case of multi-beam directional antenna.For this purpose,this paper proposes corresponding multi-beam directional antenna neighbor discovery algorithm for different network scenarios and constraints.The main tasks are as follows:Firstly,two deterministic pure directional neighbor detection algorithms are proposed for the synchronous network,which are called “one-transmit-one-receive” algorithm and “row-transmit-column-receive” algorithm.These two algorithms both utilize the quorum system and the multi-beam directional antenna technology.Unlike existing synchronous neighbor discovery algorithm,these two algorithms are dependent on neither omni-directional antenna nor the information of nodes number in the network,each node according to the algorithm design of sector scan sequence and sector transceiver model sequence to complete neighbor discovery.In the algorithm of “row-transmit-column-receive”,the method of single handshake between nodes can shorten the time of the neighbor discovery process compared with the traditional multiple handshake.Simulation results show that the performance of the two algorithms is better than the existing neighbor discovery algorithm.Secondly,the “one-transmit-one-receive” algorithm is extended to the asynchronous network,its performance in the asynchronous network is analyzed,prove that the algorithm can be applied directly to some asynchronous networks.Furthermore,a two-cycle asynchronous algorithm is proposed,which is more adaptive,but it takes longer to complete neighbor discovery than the “one-transmit-one-receive” algorithm.The two algorithms apply to different asynchronous network scenarios.Finally,the correctness of the two algorithms is verified by simulation.