Design And Implementation Of Remote Education System Based On WebRTC Technology

In recent years,with the development of the Internet of Things technology,the application of the Internet of Things is increasing.In the IoT application scenario,many devices have limited computing and storage capabilities.In terms of application layer protocols,the relatively large traditional HTTP protocol cannot be very good.Applicable to existing IoT applications.In the scenario of limited storage capacity,limited network bandwidth,and limited power consumption in the Internet of Things,CoAP(Constrained APPlication Protocol)protocol and NB-IoT(narrow-band Internet of things,narrowband Internet of Things)have been proposed and designed.The CoAP protocol is a lightweight application layer protocol with a minimum packet size of only 4 bytes.It can be used in many IoT communication scenarios due to its adaptability to restricted devices,restricted networks,and low-power scenarios.Built on a cellular network,NB-IoT enables wide-area network coverage with low cost and low power consumption.NB-IoT is also one of the important branches of the development of the Internet of Things at home and abroad.This paper deeply studies the basic principle of CoAP protocol,designs and implements a terminal that communicates through NB-IoT platform,and adopts CoAP protocol in the communication application layer of the terminal.At the same time,considering the development cost and difficulty of the subject design,as well as the subsequent equipment upgrade and maintenance factors,the STM32 L series low-power processor is used as the main chip on the hardware device,and the communication module adopts the BC95 communication module of Shanghai Mobile.The ?C/OS-II operating system was ported on the STM32 L series processor.As a follow-up development platform,the CoAP protocol is developed.The CoAP packet data structure,framing and de-frameping,and packet retransmission are designed and implemented to implement the CoAP communication process between the terminal and the server.At the same time,the JSON data format is used as the payload of theCoAP protocol message.In order to improve the security of the CoAP protocol communication,the RC4 algorithm is used to encrypt the message content.In order to improve the stability of the terminal operation,the system management module is designed and implemented.When the device is abnormal,the system can be reset and restarted.In order to adapt to the low-power scenarios in the Internet of Things communication,the low-power of the terminal under ? C/OS-II is designed and implemented.Consumption mode.Finally,the task scheduling test and interrupt response test are performed on the terminal after the operating system is transplanted,and the CoAP communication between the terminal and the server is tested,and the low power consumption model of the terminal is tested and analyzed.The IoT communication terminal designed by this subject has ? C/OS-II operating system,supports CoAP protocol communication,supports low-power mode,can be used for secondary development of IoT applications,and provides IoT communication terminal design.Theoretical research and experimental basis.