Design And Implementation Of IoT Sensor Access Scheme Based On RFID

With its advantages of low power consumption,low cost,and ease of deployment,the RFID tags have a wide range of applications in logistics management,intelligent transportation,medical health,animal breeding and other fields,and have become one of the most rapidly growing applications of the Internet of Things(IoT).After years of industrial development,the actual RFID system is no longer satisfied with identifying and tracking items,but also requires RFID tags to have environmental sensing ability,thereby further expanding the application scope of RFID systems.The current design of RFID sensing tags is mainly based on the traditional embedded architecture,using processor module to achieve sensor control and data processing.However,there are two main problems.First,the computing power consumption of the processor far exceeds the power supply capability of the tag,resulting in short communication distance and poor performance of the tag.Second,traditional embedded development is difficult to meet the various application requirements of the IoT,and customized development leads to high cost of tags,lost the low-cost commercial advantage of traditional RFID tags.This thesis envisages that the next generation of RFID tags should have the following characteristics: first,it has both identification and perception capabilities.Second,it can be easily customized for different sensors to meet different application needs.Third,it has close to traditional RFID tags.performance and price.To this end,this thesis proposes a universal sensor tag: remove the processor module in the traditional architecture,and float the bus control to the sensor to the RFID gateway,thereby simplifying the RFID tag design and allowing existing commercial readers to directly control the sensor.To achieve the above design will face the following three challenges.First,how the RF signal is converted into a bus signal recognizable by the sensor.For this reason,this thesis uses a two-stage integral discriminator to realize the conversion of radio frequency signal to bus signal without processor,and implements a protocol state machine to input the command of controlling the sensor in the bus signal to the sensor.Second,how to use the RFID protocol for efficient data exchange between the gateway and the sensor.To this end,this thesis proposes an efficient data transmission scheme based on the UHF Gen2 protocol.Compared with the traditional method,the downlink transmission efficiency is improved by 93.6%,and the uplink transmission efficiency is improved by 54.5%.Third,how to control the universal sensing tag based on RFID protocol and endow it with unique functions.To this end,this thesis proposes a Sensing Control Protocol running on the upper layer of the Gen2 protocol,which provides tags with functions such as tag discovery,storage control,and sensing control.Through experiments and analysis,the communication distance of the tag prototype in passive and active states can reach 3.6 meters and 18 meters respectively; the probability of the tag prototype and traditional RFID tags being found in the same environment is almost the same; the overall average power consumption of the tag is about 361.15 microwatts,much lower than the milliwatt-level power consumption of traditional embedded architectures.