Research On Passive Cellular Internet Of Things Protocol

In the past decade,the Internet of Things industry has developed rapidly,and the scale of the industry and the number of IoT equipments have experienced explosive growth.Ultra-High Frequency Radio Frequency Identification(UHF RFID),which is one of the technology supporting the IoT,has also become increasingly developed.Currently,it has many applications in various fields such as personnel identification,asset management and smart home.But how to design and implement a UHF RFID-based passive cellular Internet of Things system,including cellular IoT base stations and passive terminals,as well as the corresponding protocol software compatible with the current mainstream protocol,and supports device to device(D2D)communication,will require further study.This paper first analyzes a typical cellular IoT application,the UHF RFID system,including its forward link and reverse link.Based on this,the D2 D communication based on backscatterring is analyzed from aspects of energy and signal.Finally,the overall design scheme of the passive cellular IoT system is proposed,including the hardware and software architecture of the cellular IoT base station and the passive terminal,the conventional communication protocol compatible with ISO/IEC 18000-63:2015,and the D2 D communication protocol.Starting from cellular IOT base stations and passive terminals,based on the existing Internet of Things protocols,the UHF RFID-based IoT protocol supporting D2 D is studied.In the cellular IoT base station part,it is mainly the embedded protocol software running on an ARM processor and the host computer control program running on PC.In the passive terminal part,it includes an energy harvesting and management circuit,a radio frequency transceiver front-end circuit,a baseband processing module,and a protocol software system running on a low-power microcontroller.Finally,the energy-harvesting test was performed on the passive terminal.And the entire system was tested for conventional communications between the Io T base station and passive terminals,and D2 D communications between passive terminals.Using protocol and system designed and implemented in this paper,users can configure and operate the cellular IoT base station through a host computer.The conventional communication mode is compatible with the ISO/IEC 18000-63:2015 protocol and multi-terminal anti-collision processing,inventory,read,write,and other commands are implemented.And in specially designed D2 D mode,passive terminals can directly exchange data without relaying through the cellular IoT base station,which a traditional UHF RFID cannot.Compared with UHF RFID,this protocol and system reduces the burden on the base station and communication delay and improves the data exchange efficiency between terminals.In the future,this system could be improved in the following aspects.In theory,multi-hop direct communication of passive terminals and roaming between multiple base stations can be realized.After combining with sensing technologies,indoor positioning and environmental monitoring functions can also be realized.