Research On Forest Communication System Protocol

China has a vast territory,complex and diverse terrain and climatic conditions,and abundant forest resources.As the country has increased its protection of wild animals and plants in recent years,many wild animal and plant protection areas have been established.However,due to the complex geographical environment,communication in nature reserves has always been a thorny issue.As we all know,3G/4G/5G public networks belong to the GHz frequency band.This high-frequency electromagnetic wave is attenuated severely in a complex forest environment,and the protected area is sparsely populated.Setting up a public network not only is too expensive,but also wastes a lot of resources.Compared with the business scope of the conventional public network,the nature reserve business is relatively single,such as timely forecast of fire alarm information,automatic collection of wild animal photos captured by the infrared detection camera installed inside the reserve,and the ability for forest rangers to interact with each other in the reserve,and simple communication with the outside world,etc.Aiming at the above application requirements,design a forest communication system based on chain relay.The research content is summarized as followings:Firstly,from the perspective of application requirements,a dedicated forest communication protocol is proposed to solve two different needs.The first is a one-way information flow design scheme.The main application scenarios that are met include timely forecast of fire alarm information and automatic collection of internal installations in the protection area.The wild animal photos captured by the infrared detection camera and the forest ranger send status information to the monitoring center.The second is a two-way information flow design scheme.While satisfying all the first application scenarios,the forest ranger can also receive messages from the monitoring room in the forest.Secondly,starting from the physical layer of the agreement,the forest electromagnetic wave propagation model is introduced,and the factors affecting the propagation loss of electromagnetic waves in the forest environment are obtained,which are verified from the experimental level to provide a theoretical basis for the subsequent system hardware design.Thirdly,the upper-layer protocol design is carried out for the above design schemes,including frame format agreement,error control design,and priority design of different types of messages.How to switch between the uplink and the downlink in the two-way information flow.Finally,the specific design scheme of the three-antenna solution in one-way information flow and two-way information flow is given.At last,test the functions of each module on the RF front-end hardware platform EZR32WG_R69 developed by the laboratory students,the temperature sensor module DS18B20 and the master MCU Raspberry Pi 3B+,and conduct simulation experiments in the campus forest environment.At the same time,the chain-type relay communication system can be applied in many practical environments,such as power tower monitoring systems,real-time bus systems,and many communication systems with relay transmission.This research can provide a solution for these scenarios.