The hottest RFID technology and its application

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Radio frequency identification (RFID) technology and its application

1 introduction

radio frequency identification (RFID), also known as electronic tag (e-tag), is a technology that uses radio frequency signals to automatically identify target objects and obtain relevant information. The earliest application of RFID can be traced back to the "friend or foe identification" system used to distinguish between coalition forces and Nazi aircraft in World War II [1]. With the progress of technology, the application field of RFID is expanding day by day, which has involved all aspects of people's daily life and will become a basic technology for the construction of the information society in the future. Typical applications of RFID include: warehouse management, production line automation and commodity sales in the field of logistics; In the field of transportation, it is used for container and parcel management, highway toll and parking charge; In agriculture, animal husbandry and fishery, it is used for the management of sheep, fish, fruits, etc., as well as the tracking of pets and wild animals; In the medical industry, it is used for drug production, patient care and medical waste tracking; In the manufacturing industry, it is used for visual management of parts and inventory [2,3]; RFID can also be used in book and document management, access control management [3], positioning and object tracking, environmental awareness [4,5] and check anti-counterfeiting [6] and other application fields

in March 2003, Gartner predicted on "Symposium itxpo 2003" that RFID (e-tags) technology is a technology that will gradually begin to be applied on a large scale in the last 2 to 5 years (2005 to 2008), as shown in Figure 1. According to the prediction of arc Consulting Group, by 2008, the market demand for RFID in the global supply chain field alone will reach $4billion, as shown in Figure 2

Figure 1 RFID technology trend forecast

(data source: Gartner, March 2003)

Figure 2 RFID system global market analysis and forecast

(data source: arc Consulting Group, July 2004)

at present, RFID has become a research hotspot in the IT industry and is regarded as the next "gold mine" in the IT industry. All major software and hardware manufacturers, including IBM, Motorola, Philips, Ti, Microsoft, Oracle, sun, BEA, sap, etc., have shown strong interest in RFID technology and its applications, invested a lot of research and development funds, and launched their own software or hardware products and system application solutions. In the application field, a large number of enterprises represented by Wal Mart, UPS, Gillette, etc. have begun to prepare to use RFID technology to transform their business systems, so as to improve the work efficiency of enterprises and provide customers with various value-added services

in the field of labels, bar code technology has been very mature and widely used. Now almost all products are pasted with bar codes. Due to the limitation of storage space, barcode can only identify the product type. Compared with bar code, RFID tag has many advantages, such as fast reading speed, large storage space, long working distance, strong penetrability, diverse shapes, strong adaptability to working environment and reusable. Fast reading speed: it can read the identification information of hundreds of items in an instant, so as to improve work efficiency; Large storage space: it can realize the whole process management and tracking of single items, and overcome the limitation that barcode can only manage certain types of items; Long working distance: it can realize long-distance management of goods; Strong penetration ability: it can obtain item information through paper, wood, plastic, metal and other packaging materials; Labels can be made into strip, card, ring, button and other shapes according to different applications. However, compared with the cost of a few cents or even a few cents of bar code, the cost of RFID tags is still high

the second section of this paper will introduce the basic composition of RFID system; The third section analyzes the current research status of RFID; Finally, it summarizes the full text and looks forward to the application prospect of RFID

2 overview of RFID system

the basic RFID system consists of RFID tags, RFID readers and application support software. Figure 3 shows a basic RFID system, showing three different forms of RFID tags

Figure 3 basic RFID system composition

RFID tags are composed of chips and antennas, and each tag has a unique electronic code. The label is attached to the object to identify the target object

rfid tags are divided into active and passive according to different ways of sending RF signals. Active tags actively send RF signals to readers and writers, which are usually powered by built-in batteries, also known as active tags; Passive tags without batteries, also known as passive tags, transmit radio waves and the energy required for the operation of the internal processor come from the electromagnetic waves generated by the reader. After receiving the electromagnetic wave signal sent by the reader, the passive tag converts part of the electromagnetic energy into energy for its own work. Table 1 compares the characteristics of active and passive labels. Among them, the active tag usually has a longer communication distance, and its price is relatively high. It is mainly used in the application fields such as remote detection of valuables. Passive tags have the advantage of low price, but their working distance and storage capacity are limited by energy sources. Table 1 Comparison between active tags and passive tags

RFID tags use different types of antennas according to different factors such as application, shape, working frequency and working distance. An RFID tag usually contains one or more antennas. The frequency used by RFID tags and readers when working is called RFID working frequency. At present, the frequencies used by RFID span many frequency bands, such as low frequency (LF), high frequency (HF), ultra high frequency (UHF), microwave, etc. The selection of RFID frequency affects the distance and speed of signal transmission, and is also limited by national laws and regulations

The main task of the RFID reader is to control the RF module to transmit reading signals to the tag, receive the response of the tag, decode the object identification information of the tag, and transmit the object identification information together with other relevant information on the tag to the host for processing. Depending on the application, the reader can be handheld or fixed. At present, the cost of readers is relatively high, the price is about $1000, and most of them can only work at a single frequency point. In the future, the price of the reader will be greatly reduced, and it supports multiple frequency points, which can automatically identify tag information of different frequencies

rfid application support software in addition to the software running on tags and readers, the middleware between readers and enterprise applications is an important part. This middleware provides a series of computing functions for enterprise applications and is called savant in the electronic product code (EPC) specification. Its main task is to filter, collect and calculate the tag data read by the reader, so as to reduce the amount of data transmitted from the reader to enterprise applications. Savant also provides interoperability with other RFID support systems. Savant defines two interfaces: reader and application

users can choose the RFID system suitable for their own application according to the working distance, working frequency, working environment requirements, antenna polarity, life cycle, size and shape, anti-interference ability, security, price and other factors

3 Analysis of the current situation of RFID research and mutual assistance

the current RFID research is mainly carried out around RFID technical standards, RFID tag costs, RFID technology and RFID application systems

3.1 RFID technology standard

as a technology that will deeply affect everyone's daily life, RFID technology must be standardized in order to realize the unified management of items around the world, but also to standardize the development of labels and readers, and solve the interconnection and compatibility problems of RFID systems. RFID standardization is an important problem that needs to be solved urgently at present. Countries and relevant international organizations are actively promoting the formulation of RFID technology standards. At present, there is no perfect international and domestic standard on RFID. The standardization of RFID involves many parts, such as identification coding specification, operation protocol and application system interface specification. The identification coding specification includes identification length, coding method, etc; The operation protocol includes specifications of air interface, command set, operation process, etc. At present, the main RFID related specifications include European and American EPC specifications, Japanese uid (ubiquitous ID) specifications and ISO 18000 series standards. The ISO standard mainly defines the air interface for interoperability between tags and readers

epc specification is formulated by auto ID center and later established EPCglobal [7]. Auto ID center was founded by Massachusetts Institute of Technology (MIT) in 1999. Its goal is to create a global "Internet of things". The center has received extensive support from the U.S. government and business circles. On October 26th, 2003, a new EPCglobal organization was established to take over the work of the former auto ID center and manage and develop EPC specifications. As for labels, EPC specifications have issued the first generation of specifications. The specification subdivides labels into Class 0, class 1 and class 2. Both Class 0 and class 1 tags are read multiple times at a time. Class 0 Tags can only be written by manufacturers and cannot be modified by users. Therefore, they are also called read-only tags and are mainly used for supply chain management; Class 1 provides more flexibility, and information can be written once by the user. Class 0 and class 1 Tags use different air interface standards for communication, so the two types of tags cannot interoperate. The class 2 tag has the ability to write multiple times, and part of the storage space is added to store the additional data of the user. Class 2 tag allows the addition of security and access control, perceptual network, ad hoc network and other functional support. At present, EPCglobal is developing the second generation label standard, namely UHF class 1 generation 2 (C1G2). C1G2 has the ability to update the label content at any time to ensure that the label always keeps the latest information. EPC specification version 1.0 currently includes EPC tag data specification, Class 0 (900MHz) tag specification, class 1 (13.56MHz) tag interface specification, class 1 (860mhz~930mhz) tag RF and logic communication interface specification, and physical markup language (PML)

uid (ubiquitous ID) specification is formulated by Japan ubiquitous ID center [8]. The ubiquitous ID center in Japan was founded by the t-engine forum. Its goal is to establish and promote the automatic identification technology of items and finally build a ubiquitous computing environment. The specification has no mandatory requirements for frequency bands. Tags and readers are multi band devices that can support 13.56MHz or 2.45GHz frequency bands at the same time. Uid tags generally refer to all devices containing ucode codes, such as bar codes, RFID tags, smart cards and active chips, and define nine different categories of tags. Related to RFID tags include: Class 1 read-only RFID tags, class 2 read-write RFID tags, and class 5 RFID tags with power supply. In addition to tags, uid network also includes two other key parts: one is the terminal that reads tags, called ubiquitous communicators (UCS), which can not only communicate with tags, but also provide 3G, PHS, 802.11 and other access methods to connect with information servers in the wide area; The other is ucode parsing server, which provides the function of obtaining the address of information server by ucode

epc code currently has three versions. The main difference is that the length of the code is different, which are 64 bits, 96 bits and 2 bits respectively. Through them, the effective supervision of business households can be achieved by 56 bits [11]. The purpose of using 64 bit encoding is to reduce tag storage and thus reduce tag production costs; 96 bit coding is to achieve a balance between performance and cost; But in order to meet the requirements of providing identification for any object in the world

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