Research Of Random Access Technology In Ad Hoc Network Based On Wireless Optical Communication System

Wireless optical communication technology has made great progress in 21 st century with its effectiveness and reliability enhanced.This thesis considers that wireless optical communication can be applied in ad hoc networks,combining high speed and convenience,and applying it to the light sensor networks and the light Internet of Things.The study in ad hoc network based on wireless optical communication is called light ad hoc network(LANET).The main research contents are as follows:Firstly,an ad hoc network which use light-emitting diodes and photodiodes as transmitter and receiver is studied.After analyzing the principle and structure of light-emitting diodes and photodiodes,it is concluded that such optoelectronic devices should have a limited field of view.Based on the limited field of view of optoelectronic devices,this thesis combines multiple light-emitting diodes and photodiodes to design an omnidirectional communication light ad hoc network node.Secondly,random access protocol for light ad hoc network is studied.After analyzing the original ALOHA random access protocol,an ALOHA-LANET protocol has been proposed based on the node model mentioned above.The throughput and delay of the protocol has been analyzed and be compared with ad hoc network in radio frequency.The improvement which use the directionality of the optical communication signal has greatly reduces the collision of data packets caused by the random-access process and can effectively increase the throughput and reduce the delay.In addition,a light ad hoc network has been designed based on an embedded system and constructs a sensor network.The experiment verifies the feasibility of the system.Finally,a solution of wireless optical communication for hidden terminal problem is studied.Due to the directionality of wireless optical communication,the omnidirectional communication light ad hoc network can separate the collision signal from different directions,and solve the hidden terminal problem.This thesis tests the typical scenarios of the problems,and verifies the above-mentioned solutions.This thesis provides theoretical basis and experimental support for the design and application of light ad hoc networks.