Radio frequency tags are physical carriers of product electronic codes (EPCs) attached to traceable items that can be circulated globally and recognized and read and written. The RFID (Radio Frequency Identification) technology has received attention as a key technology for constructing the "Internet of Things" in recent years. RFID technology originated in the United Kingdom and was used to identify the enemy’s identity in the Second World War. It began commercial use in the 1960s. RFID technology is an automatic identification technology. The US Department of Defense stipulates that all military supplies must use RFID tags after January 1, 2005; the US Food and Drug Administration (FDA) recommends that drug makers use RFID to track Fake drugs. A series of actions such as Walmart and RFID in the retail industry of Metro promoted the application of RFID in the whole world. In 2000, the price of each RFID tag was $1. Many researchers believe that RFID tags are very expensive and can only be applied on a large scale by reducing costs. In 2005, the price of each RFID tag was around 12 cents, and the UHF RFID price is now around 10 cents. For large-scale applications of RFID, on the one hand, it is necessary to reduce the price of RFID tags. On the other hand, it depends on whether the use of RFID can bring value-added services. Statistics from the European Union Statistics Office show that in 2010, 3% of companies in the European Union applied RFID technology and their applications were distributed in identity documents and access control, supply chain and inventory tracking, car charging, security, production control, and asset management.
Radio Frequency Identification (RFID) is a wireless communication technology that can identify specific targets and read and write related data through radio signals without identifying the mechanical or optical contact between the system and a specific target.
The radio signal is transmitted through a radio frequency electromagnetic field and transmitted from a label attached to the item to automatically identify and track the item. Some tags receive energy from the electromagnetic field emitted by the recognizer when they are identified, and do not require a battery. Also, the tag itself has a power source and can actively emit radio waves (electromagnetic fields tuned to a radio frequency). The tag contains electronically stored information that can be identified within a few meters. Unlike the barcode, the radio frequency tag does not need to be within the line of sight of the identifier, but it can also be embedded within the object being tracked.
Many industries use radio frequency identification technology. Attaching the tag to a car in production, the factory can easily track the progress of the car on the production line. The warehouse can track where drugs are located. RFID tags can also be attached to livestock and pets to facilitate positive identification of livestock and pets (active recognition means preventing the same identity from being used by several animals). RFID identification cards allow employees to access locked building parts, and RF transponders on cars can also be used to collect toll roads and parking fees.
Some radio frequency tags are attached to clothing, personal belongings, and even implanted in the body. Because this technology may read personal information without my permission, this technology also has the infringement of personal privacy concerns.
Conceptually speaking, RFID is similar to bar code scanning. For bar code technology, it attaches an encoded bar code to an object and uses a dedicated scanning reader to transmit information from bar magnetic to scan and write using optical signals. RFID, on the other hand, uses a dedicated RFID reader and a dedicated RFID tag that can be attached to the target, and uses frequency signals to transmit information from the RFID tag to the RFID reader.
Structurally speaking, RFID is a simple wireless system with only two basic components. The system is used to control, detect and track objects. The system consists of an interrogator and many transponders.
Initially in the technical field, transponders are electronic modules that can transmit information to reply information. In recent years, due to the rapid development of radio frequency technology, transponders have new ideas and meanings, and are also called smart labels or tags. The reader of the RFID electronic tag communicates wirelessly through the antenna and the RFID electronic tag, and can read or write the tag identification code and memory data. RFID technology can identify high-speed moving objects and can identify multiple labels at the same time. The operation is quick and easy.
In the future, the rapid development of RFID technology is of great significance to the progress in the field of Internet of Things.
Transponder: It is composed of an antenna, a coupling element and a chip. Generally speaking, a tag is used as a transponder. Each tag has a unique electronic code and is attached to an object to identify a target object.
Reader: A device that consists of an antenna, a coupling element, and a chip that reads (sometimes writes) tag information. It can be designed as a handheld RFID reader or a stationary reader.
Application software system: It is an application layer software. It mainly deals with the collected data and is used by people.
Radio frequency technology
The most important advantage of radio frequency identification systems is non-contact recognition, which can read through the harsh environment where snow, fog, ice, paint, dust, and bar codes cannot be used, and the reading speed is extremely fast, in most cases less than 100 milliseconds. The ability to write active RFID systems is also an important advantage. Can be used for process tracking and maintenance tracking and other interactive services.
The main issue that hampers the development of RFID systems is incompatible standards. The main manufacturers of radio frequency identification systems provide dedicated systems, resulting in different applications and different industries adopting different vendors' frequency and protocol standards. This confusion and segregation have already constrained the growth of the entire RFID industry. Many European and American organizations are working to solve this problem and have achieved some success. Standardization will certainly stimulate the significant development and widespread application of radio frequency identification technology.
The essence of logistics management is to achieve the two goals of reducing costs and improving service levels through the management of the entire logistics process. How to ensure that the right customers get the right products at the right time and in the right place with the right cost and the right conditions has become the highest goal pursued by logistics companies. In general, the value of an enterprise's inventory accounts for about 25% of the total assets of the company and accounts for more than 50% of the company's current assets. Therefore, the core of logistics management is the management of inventory in the supply chain.
The use of radio frequency identification technology in transport management requires only the installation of electronic tags on the outer packaging of goods, and the installation of readers at transport checkpoints or transit stations to enable the visual management of assets. At the same time, the owner can access the on-site visualization web page according to his authority to understand the specific location of the goods, which is of great significance to improving the service level of logistics companies.
1. Quick scan. The RFID reader can recognize and read several RFID tags at the same time!
2. The size is small and the shape is diversified. RFID is not limited by size and shape in reading, and does not need to match the fixed size and print quality of the paper for reading accuracy. In addition, RFID tags can be developed in smaller and more diverse forms to be applied to different products.
3. Pollution resistance and durability. The carrier of traditional bar code is paper, so it is easily contaminated, but RFID is very resistant to substances such as water, oil and chemicals. In addition, because barcodes are attached to plastic bags or over-wrapped cartons, they are particularly vulnerable to breakage; RFID tags store data in the chip and are therefore protected from contamination.
4. Can be reused. Now that barcodes cannot be changed after printing, RFID tags can repeatedly add, modify, and delete data stored in RFID tags to facilitate information updates.
5. Penetrating and non-barrier reading. When covered, RFID can penetrate non-metallic or non-transparent materials such as paper, wood, and plastic, and is capable of penetrating communication. Barcode scanners must read barcodes at close range and without object obstruction.
6. The data memory capacity is large. The capacity of one-dimensional bar code is 50 Bytes, the maximum capacity of 2D bar codes can store 2 to 3,000 characters, and the largest capacity of RFID is MegaBytes. With the development of memory carriers, the data capacity has also been continuously expanding. The amount of data required to carry future items will increase, and the demand for the capacity of the labels to expand will increase accordingly.
7. Security. Since RFID carries electronic information, its data content can be protected by passwords, making its content less susceptible to counterfeiting and alteration.
RFID has attracted attention due to its features such as remote reading and high storage capacity. It can not only help a company significantly increase the efficiency of goods and information management, but also allow sales companies and manufacturing companies to interconnect, so as to receive feedback information more accurately, control demand information, and optimize the entire supply chain.
How it works
The basic working principle of RFID technology is not complicated: After the tag enters the magnetic field, it receives the RF signal from the reader, and the energy obtained by the induced current sends out the product information (passive tag or passive tag) stored in the chip, or The tag actively sends a signal (Active Tag, active tag or active tag) at a certain frequency. After the reader reads the information and decodes it, it sends it to the central information system for data processing.
A complete RFID system is composed of three parts: a reader and an electronic tag, namely a so-called transponder and an application software system. The working principle is that Reader emits radio wave energy of a specific frequency to drive the circuit. The internal data is sent out. At this point, the Reader receives the interpretation data in sequence and sends it to the application program for processing.
The communication between the RFID card reader and the electronic tag and the energy sensing method can be roughly divided into two types: inductive coupling and backscatter coupling. Most low-frequency RFIDs use the first type, and higher frequencies use the second method.
The reader can be a read or read/write device depending on the structure and technology used, and is an RFID system information control and processing center. The reader is usually composed of a coupling module, a transceiver module, a control module, and an interface unit. Half-duplex communication is generally used for information exchange between the reader and the transponder, and the reader is coupled to the passive transponder to provide energy and timing. In practical applications, management functions such as collection, processing, and remote transmission of object identification information may be further implemented through Ethernet or WLAN. The transponder is the information carrier of the RFID system, and the transponder is mostly composed of coupling originals (coils, microstrip antennas, etc.) and microchips constituting a passive unit.
Product Category Editor
The products derived from RFID technology are roughly classified into three categories: passive RFID products, active RFID products, and semi-active RFID products.
The development of passive RFID products is the earliest, and it is also the product with the most mature development and the most widely used market. For example, bus cards, cafeteria meal cards, bank cards, hotel access cards, second-generation ID cards, etc., which can be seen everywhere in our daily lives, are close-contact type recognition. The main operating frequency of its products are low frequency 125KHZ, high frequency 13.56MHZ, UHF 433MHZ, UHF 915MHZ.
Active RFID products have been gradually developed in recent years. Their long-distance automatic identification characteristics determine their enormous application space and market potential. In the field of long-distance automatic identification, such as smart prisons, smart hospitals, smart parking, intelligent transportation, smart cities, smart world and the Internet of things, there are major applications. Active RFID has emerged in this field and belongs to the category of long-distance automatic identification. The main operating frequency of the product is UHF 433MHZ, microwave 2.45GHZ and 5.8GHZ.
The different characteristics of active RFID products and passive RFID products determine different application fields and different application modes, and also have their own advantages. However, in this system, we focus on introducing semi-active RFID products between active RFID and passive RFID. This product integrates the advantages of active RFID and passive RFID in the management of access control and accurate positioning of personnel. , Regional positioning management, perimeter management, electronic fences and security alarms and other fields have great advantages.
Semi-active RFID products, combined with the advantages of active RFID products and passive RFID products, enable microwave 2.45G to take advantage of the low-frequency 125KHZ frequency trigger. Semi-active RFID technology, also known as low-frequency activation trigger technology, uses low-frequency, near-distance precise positioning, microwave remote identification, and uploading data to solve the problems that simple active RFID and passive RFID have no way to achieve. Simply put, it is to activate positioning, identify and upload data at a short distance.
RFID is a flexible application technology that is easy to operate, simple and practical, and particularly suitable for automation control. Freedom to work in all kinds of harsh environments: Short-range RF products are not afraid of bad environment such as oil stains and dust pollution. They can replace bar codes, such as tracking objects on the factory's assembly line; long-range RF products are mostly used for traffic, and the distance can be identified. Up to tens of meters, such as automatic charging or identification of vehicle identities. The radio frequency identification system mainly has the following system advantages:
Reading is quick and easy: The reading of the data does not require a light source, and can even be performed through the outer packaging. The effective identification distance is larger. When the active label with its own battery is used, the effective identification distance can reach more than 30 meters;
Fast recognition speed: When the tag enters the magnetic field, the reader can instantly read the information, and can process multiple tags at the same time to realize batch identification;
Large data capacity: The two-dimensional barcode (PDF417) with the largest data capacity can only store up to 2725 digits; if it contains letters, the amount of storage will be less; RFID tags can be expanded to 10K according to the needs of users;
Long service life and wide range of applications: Its radio communication means can be used in dusty, oily and other highly polluted and radioactive environments, and its closed packaging greatly extends the life span of printed barcodes;
Tag data can be dynamically changed: The programmer can write data to the tag, giving the RFID tag the capabilities of an interactive portable data file, with less write time than the printed bar code;
Better security: not only can be embedded or attached to different shapes and types of products, but also can set password protection for reading and writing of tag data, thus having higher security;
Dynamic real-time communication: The tag communicates with the reader at a frequency of 50 to 100 times per second. Therefore, as long as the RFID tag is attached to an object within the effective recognition range of the reader, it can dynamically track and monitor its position. .
Interface Protocol Editor
Air interface communication protocol specification The information exchange between the reader and the electronic tag is aimed at producing interconnection and interoperability between devices from different manufacturers. ISO/IEC has developed five kinds of frequency band air interface protocols, this idea fully reflects the relativity of the standard, a standard is a common need for a wide range of applications, but not all applications
ISO/IEC 18000-1 Information technology - Radio frequency identification based on single product management - Reference structure and standardized parameter definitions. It regulates the communication parameters of readers and tags that are commonly observed in the air interface communication protocol, and the basic rules of intellectual property. In this way, the standard corresponding to each frequency band does not need to repeat the same content.
ISO/IEC 18000-2 Information technology - Radio frequency identification based on single product management - Suitable for intermediate frequency 125 ~ 134KHz, specifies the physical interface between the tag and the reader, the reader should have and Type A (FDX) and Type B (HDX) tag communication capabilities; provisions of the agreement and instructions plus multi-tag communication anti-collision method.
ISO/IEC 18000-3 information technology - radio frequency identification based on single product management - applies to the high frequency band 13.56 MHz, and specifies the physical interface, protocols, and commands between the reader and the tag plus anti-collision methods. About the anti-collision protocol can be divided into two modes, and Mode 1 is divided into basic type and two kinds of extended type protocol (no-slot non-terminated multi-transponder protocol and slot termination adaptive polling multi-transponder reading protocol) . Mode 2 uses the time-frequency multiplexed FTDMA protocol, a total of eight channels, and is suitable for a large number of tags.
ISO/IEC 18000-4 Information Technology - Radio Frequency Identification Based on Single Item Management - Suitable for microwave segments 2.45 GHz, which specifies the physical interfaces, protocols, and commands between the reader and the tag plus anti-collision methods. The standard includes two modes. Mode 1 is the passive tag working mode is the reader first; Mode 2 is the active tag, and the working mode is the tag first.
ISO/IEC 18000-6 information technology - radio frequency identification based on single product management - applies to the ultra-high frequency band 860 ~ 960MHz, and specifies the physical interface, protocol and command between the reader/writer and the tag plus anti-collision method. It contains the interface protocols of Type A, Type B, and Type C passive tags. The communication distance can reach up to 10 meters. Among them, TypeC was drafted by EPCglobal and approved in July 2006. It has greatly improved in terms of recognition speed, read/write speed, data capacity, anti-collision, information security, band adaptability, and anti-jamming. The draft V4.0 was submitted in 2006. It expands on the characteristics of electronic tags with auxiliary power supplies and sensors, including tag data storage and interactive commands. Active tags with batteries can provide a wider range of reading capabilities and stronger communication reliability, but they are larger in size and more expensive.
ISO/IEC 18000-7 applies to the ultra-high frequency band 433.92 MHz, which is an active electronic tag. The physical interface, protocols, and commands between the reader and the tag are added together with anti-collision methods. The scope of active tag reading is large, and it is suitable for tracking large-scale fixed assets.
Data content standards mainly specify the representation of data in tags, readers to hosts (that is, middleware or applications). Because of the limitations of tag capabilities (storage capabilities, communication capabilities), the data representation at each link must take full account of their respective characteristics and take different forms of expression. In addition, host access to tags can be independent of readers and air interface protocols, which means that readers and air interface protocols are transparent to applications. The application interface of the RFID data protocol is based on ASN.1, which provides a set of commands that are independent of the application program, operating system, and programming language and independent of the tag reader and tag driver.
ISO/IEC 15961 specifies the interface between the reader and the application , which focuses on the standard way of exchanging data between the application command and the data protocol processor, so that the application can read and write the electronic tag data. Modify, delete, and other operating functions. The protocol also defines error response messages.
ISO/IEC 15962 specifies data encoding, compression, and logical memory mapping formats , together with how to convert data from electronic tags into meaningful applications. The agreement provides a set of data compression mechanisms that can fully utilize the limited data storage space in electronic tags plus airborne communications capabilities.
ISO/IEC 24753 Extension ISO/IEC 15962 data processing capability  for electronic tags with auxiliary power and sensor functions. With the addition of sensors, the amount of data stored in the electronic tag, plus the management tasks for the sensor, has increased significantly. ISO/IEC 24753 specifies battery status monitoring, sensor setup and reset, and sensor processing. Figure 1 shows that ISO/IEC 24753, together with ISO/IEC 15962, regulate data processing and command interactions with auxiliary power and sensor-enabled electronic tags. Their role is to make ISO/IEC 15961 independent of electronic tags and air interface protocols.
ISO/IEC 15963 specifies the coding standard for the unique identification of electronic tags , which is compatible with ISO/IEC 7816-6, ISO/TS 14816, EAN.UCC standard coding systems, INCITS 256 plus reservations for future expansion. Note the difference with the item code. The item code is the code of the item attached to the tag, and the standard identifies the tag itself.
The real-time positioning system can improve the transparency of the supply chain, fleet management, logistics and fleet safety. RFID tags can solve short-distance, especially indoor object positioning, and can make up for GPS and other positioning systems can only be applied to a wide range of outdoor deficiencies. GPS positioning, mobile phone positioning, together with RFID short-range positioning means and wireless communication means can achieve full tracking and monitoring of item positions. The standards being worked out are:
The ISO/IEC 24730-1 application programming interface API, which specifies the RTLS service function plus the access method, aims to allow the application program to easily access the RTLS system. It is independent of the low-layer air interface protocol of RTLS.
ISO/IEC 24730-2 applies to the RTLS air interface protocol at 2450 MHz. It regulates a network location system that uses radio-frequency (RTLS) transmitters to transmit radio beacons and receivers to solve locations based on several received beacon signals. Many parameters of the transmitter can be configured remotely and in real time.
ISO/IEC 24730-3 applies to the 433MH RTLS air interface protocol. Content is similar to Part 2.
In 2006, ISO/IEC began to pay attention to the standardization of RFID application systems, and adjusted ISO/IEC 24752 into 6 parts and renamed ISO/IEC 24791. The purpose of this standard is to provide a framework for RFID application systems, and to standardize data security and a variety of interfaces to facilitate information sharing among RFID systems; so that applications no longer care about the differences between multiple devices and different types of devices. It facilitates the design and development of application programs. It can support distributed coordination control and centralized management of devices and optimize the performance of dense readers. The main purpose of this standard is to solve the problem of sharing data between readers and between application programs. With the wide application of RFID technology, the sharing of RFID data information is increasingly important.
ISO TC 23/SC 19 is responsible for the development of animal management RFID standards, including ISO 11784/11785 and ISO 14223.
ISO 11784 encoding structure
It specifies the 64-bit encoding structure of the animal's radio frequency identification code. The animal's radio frequency identification code requires that the reader and the electronic tag can identify each other. The bitstream containing the data is usually added with the encoded data needed to ensure the data is correct. The code structure is 64 bits, of which 27 to 64 bits can be defined by each country.
According to estimates by retail analysts at Sanford C. Bernstein, using RFID, Wal-Mart can save $8.35 billion a year, mostly because of the labor cost savings that do not require manual viewing of incoming bar codes. Although some analysts believe that the $8 billion figure is overly optimistic, there is no doubt that RFID can help solve two of the biggest problems in the retail industry: commodity outages and losses (products lost due to theft and supply chain disruption) However, Wal-Mart’s loss alone is almost $2 billion a year. If a legitimate company's turnover can reach this figure, it can be ranked 694 in the list of the 1,000 largest companies in the United States. Research institutions estimate that this RFID technology can help reduce theft and inventory levels by 25%.
Logistics and Supply Management, Manufacturing and Assembly, Air Baggage Handling, Mail/Express Parcel Handling, Document Tracking/Library Management, Animal Identification, Sports Timing, Access Control/Electronic Ticketing, Automated Road Billing, Card, Storage in Plastic Trays , turnover baskets, etc.
Reading and writing equipment
RFID can play its role only when there are reading and writing devices. RFID readers have RFID readers, RFID readers, and so on. These devices can read or write RFID data. The identification system connected to the reader has a key chip that can do a good job of encryption.
Radio Frequency Identification
Radio Frequency Identification Technology
Radio frequency identification technology (2 photos)
Radio frequency identification technology is an emerging automatic identification technology developed in the 1980s. Radio frequency identification technology is the use of radio frequency signals to achieve non-contact information transmission through spatial coupling (alternating magnetic field or electromagnetic field) and reaching through the transmitted information. Identify the technology of purpose.