| As the application of mobile ad hoc networks becomes more and more extensive,the neighbor discovery technology to ensure its normal operation is also gaining more attention.However,as the requirements become more and more complex,a node with a single function can no longer meet the requirements,which requires a single node to have multiple functions,which is called a multi-role node in this paper.Multiple different cycles often run on multi-role nodes,such as broadcast cycle,scan cycle,and data exchange cycle.These cycles will conflict with each other.How to ensure the performance of neighbor node discovery without the conflict of their own cycles? It has become the primary problem to be solved in multi-role node discovery.Most of the existing neighbor node discovery technologies analyze the node discovery process based on time slots,which will obscure the multi-role node scheduling process.Therefore,it is necessary to seek a new scheduling scheme to solve the above problem.In addition,as the number of nodes increases,there will inevitably be a pair of nodes with the same parameters but need to discover each other.The existing neighbor node discovery technology basically guarantees unidirectional discovery with the same parameters,and the protocol itself does not provide a high success rate of bidirectional discovery.Therefore,how to improve the success rate of bidirectional discovery of two multi-role nodes under the same parameters becomes the second problem to be solved in multi-role node discovery.In this paper,related researches have been carried out on these two issues.In response to the first problem,this paper first analyzes the conflict between different periods of the node itself.The main reason is that different periods will conflict at the place of the least common multiple.According to this reason,the necessary and sufficient conditions for avoiding self-period conflict are proved.Based on this condition and the node discovery conditions of the BLE-Circle model,a multi-role neighbor discovery model is proposed,and a multi-role neighbor discovery parameter configuration scheme is given.The scheme splits the broadcast period and scan period into two types of parameters: basic multiplier and scan multiplier,and gives the theoretical maximum discovery delay and duty cycle of the model.Then,the discovery performance of the model is tested through experiments,and a conclusion is drawn that the discovery delay decreases with the increase of node duty cycle by comparing the simulation results,experimental results and theoretical results.The results also verify that the model can make multi-role nodes avoid its own cycle conflicts,and guarantee the discovery performance.For the second problem,this paper firstly analyzes the difficulty of bidirectional discovery of a pair of nodes with the same parameters,and gives four main reasons for the failure of discovery.Then,the feasibility of the Quorum mechanism in the Circle protocol is discussed,and its bidirectional discovery performance is analyzed.According to the results,a multirole neighbor discovery protocol based on the Quorum mechanism is proposed,and the calculation method of the bidirectional discovery success rate of the protocol is given.It is concluded that in the case of the same pair of node parameters,the bidirectional discovery success rate is only related to the base multiplier and proportional to the base multiplier.Finally,the bidirectional discovery performance of the protocol is tested through experiments.The results verify the above conclusions and show that the protocol has a good bidirectional discovery success rate. |
