Research On Adaptive Neighbor Discovery Approaches In Wireless Ad Hoc Networks

Wireless ad hoc network consists of multiple nodes that can communicate with each other equally.Since the nodes in ad hoc network are usually mobile,the network topology of the network usually changes constantly.Therefore,in order to maintain effective communication between nodes on the network,the nodes need to periodically discover their neighbors to maintain the network neighbor list in real-time,which provides a reliable guarantee for subsequent network functions such as route discovery and data transmission.Current research on neighbor discovery in wireless ad hoc networks is mainly focused on reducing the latency of the neighbor discovery process under the given energy consumption.Most studies of neighbor discovery algorithms assume that nodes can successfully discover each other by turning on the radio at the same time.However,in practical applications,beacon collision may occur when multiple nodes transmit beacons at the same time,resulting in increased neighbor discovery latency or even failed discovery.In addition,existing neighbor discovery algorithms pay little attention to the error between the given duty cycle and the actual duty cycle,which may cause extra energy consumption during the actual operation,thus affecting battery quality management.In order to solve the beacon collision problem and the fine-grained duty ratio problem in the process of neighbor discovery,this dissertation carries out the following three aspects of work from the perspective of practical application:(1)For the problem of robot network neighbor discovery in robotic collective motion,a comprehensive neighbor discovery framework is proposed in this paper,which includes network condition prediction,working schedule,and beacon collision in neighbor discovery.Based on this framework,a low-latency adaptive neighbor discovery method ND-ACA for robotic collective motion is proposed.ND-ACA can intelligently estimate the number of nodes within the communication range according to the beacon transmission,reception,and collision information of the node in the process of a round of neighbor discovery,so as to select the appropriate slot length and backoff window for the neighbor discovery and collision avoidance.The simulation results show that the beacon collision probability of the proposed method is less than 8%.The simulation results also show that the proposed method can ensure that the convergence ratio of the robotic collective motion algorithm within 1000 seconds is higher than98%,which means that ND-ACA has strong practicability.(2)For the problem of beacon collision in node-dense networks,a neighbor discovery beacon collision avoidance method i.e.,FGSLC is proposed,which is capable of adjusting the slot length intelligently when beacon collision is detected to alleviate beacon collision in the network.Through theoretical analysis,it is proved that the proposed method can guarantee the bounded neighbor discovery under an arbitrary duty cycle when it is applied to the prime-based,Quorum-based,and prime-Quorum-based neighbor discovery protocols.The simulation results show that FGSLC achieves a neighbor discovery rate of more than 98% in the given time under symmetric duty cycle,which performs better than other neighbor discovery algorithms,In addition,FGSLC achieves a neighbor discovery rate of more than 60% in a given time under asymmetric duty cycle when the number of nodes reaches 200,which means that the neighbor discovery latency is reduced significantly.(3)For the problem of the low granularity of the duty cycle in the existing neighbor discovery protocols,a novel neighbor discovery framework BR-ND is proposed.This framework is inspired by the idea of multi-channel blind rendezvous algorithms.In this framework,the blind rendezvous schedule can be transformed into the neighbor discovery schedule.According to BR-ND,a neighbor discovery algorithm JS-ND,which is based on an intelligent selection mechanism of energy consumption parameters is proposed in wireless ad hoc network.JS-ND makes the actual duty cycle of the neighbor discovery schedule closer to the given duty cycle,thus to reduces the energy consumption and battery quality management problems.Simulation experiments show that the duty cycle relative error of JS-ND algorithm is less than 0.02 under any duty cycle,which is better than that of other algorithms.