Hardware Design And Implementation Of Remote Cellular IoT System

Cellular Internet of Things（CIo T）,as an important research field of wireless communication system of the Internet of Things,has attracted wide attention for its service characteristics of low power consumption,wide coverage,low delay and high reliability.Radio Frequency Identification,as a key technology in the construction of the Internet of Things system,has the characteristics of fast scanning,large data memory capacity and low application cost.It has important application value in the logistics link,especially in the field of transportation and warehousing.However,it still cannot meet the market demand for large-capacity access and long-distance reliable communication.This thesis aims to design a cellular Internet of Things system capable of long-distance communication.By adding auxiliary base station networking and acting as relay and forwarding,the reliable communication identification distance between base station and label is improved,and the coverage range and access capacity of label are further expanded.The main work and achievements of this thesis are as follows:1.The path loss of energy transmission in free space is used to analyze the effective distance of the upper and lower communication links of the UHF RFID system.The main factors limiting the communication distance of the current RFID system are described.The system architecture of the cellular Internet of Things is proposed and its working principle is analyzed.The communication distance of the cellular Internet of Things system is improved by introducing auxiliary base stations and improving the system architecture.2.A technical implementation scheme of remote cellular Internet of Things system is proposed.The cellular Internet of Things is constructed through network communication between the base station and several auxiliary base stations,and the working state of several auxiliary base stations is controlled.The energy supply of the label end is increased and the communication mechanism of spatial diversity is utilized to significantly improve the communication distance and expand the coverage of the system.And greatly increase the cellular Internet of Things system tag access capacity.3.The hardware circuit of high-performance base station and auxiliary base station meeting the ISO/IEC 18000-6C protocol is designed and realized by using RF reader chip,RF transceiver chip and general-purpose microprocessor chip,and on this basis,the testing and verification platform of cellular Internet of Things system is built.The prototype functions of the base station and auxiliary base station and the main performance indexes of the system are tested and analyzed,and the feasibility of the cooperation between the base station and auxiliary base station in the remote cellular iot system is verified.The results show that the P_{1d B} compression point of the base station and the auxiliary base station is 31d Bm,the maximum output power is 32 d Bm,and the communication identification distance of the system to the access label can reach 100 m.By configuring the multi-cell network of the auxiliary base station,the access communication of the large-capacity label can be realized.The remote cellular Internet of Things system studied in this thesis doubles the coverage distance of the traditional ultra-high frequency RFID system,and supports large-capacity label leak-free identification communication.It has high application value in logistics management,public transport and other fields.