Classification of RFID technology
Table of Contents
- Classification of RFID technology
In reality, people see RFID products, but the use of RFID technology to provide the functionality of RFID products. RFID products are the tangible appearance of RFID technology, RFID technology is the invisible inside of RFID products. RFID products carry RFID technology, RFID technology continues to develop, promoting the continuous updating of RFID products. The classification of RFID products is closely related to the classification of RFID technology. Here, first of all, based on the concept of RFID system, focus on the classification of RFID technology.
RFID system includes two basic components of electronic tags and readers. Although the electronic label individual in the general sense price is much lower than the read-write individual, but because the electronic label is the item identifies the information carrier, follows the item which identifies to go all over the world, spreads in the item resides in each corner, but the read-write is mainly distributes in the electronic label information collection point. Thus, people see more is the electronic label, the quantity most is also the electronic label, the identification item most direct RFID system component unit is also the electronic label, and in the big world, because various specific application and the demand is different, there are a lot of different type and the mutual incompatibility electronic label. Even in the collection of mutually compatible electronic tags, but also because of the application of different needs, product development manufacturers are different, different inspiration of designers, different production process, resulting in the final application of a variety of products.
Because the electronic label quantity is large, the individual is relatively small, the value is relatively low, thus in the RFID system design time, usually in order to achieve the RFID system comprehensive goal, the most priority is how to design a simple but effective performance of the electronic label, and will complete the RFID system relatively complex some adaptability aspects of the problem left to the read-write side to complete. Thus decided in the RFID system, the electronic label is the dominant party of the technology. In more cases, is the design read-write to adapt to one or more kinds of electronic label read-write need.
In the above intrinsic reason drive, also has the view directly will the electronic label technology equals to the RFID technology, will the electronic label technology classification equals to the RFID technology classification. This paper adopts and supports this view.
In the subsequent discussion, for the sake of discussion convenience, will be directly to the discussion of electronic tag technology to refer to the discussion of RFID technology, the classification of electronic tag technology to refer to the classification of RFID technology.
1. The basis of RFID technology classification
Through the previous discussion, comprehensive extracted the most important RFID technology classification based on three: one is the electronic label power supply method; another is the electronic label work frequency, that is, the electronic label contactless transmission of identification information used by the frequency of radio frequency carrier; the third is the electronic label work when the internal state.
In addition, the other division basis also has the electronic label and the read-write between the communication method is one way, the half duplex or the full duplex; The electronic label data whether may rewrite, the wired rewrite or the wireless rewrite; The electronic label storage data quantity and so on, does not do the detailed discussion here.
2. According to the classification of the electronic label power supply method
According to the electronic label work when the power supply method to get the RFID technology / electronic label technology classification as shown in Figure 1. According to the classification of Figure 1, the basic definitions of passive electronic tag, semi-passive electronic tag and active active electronic tag are as follows.
(1) the basic definition of the passive electron label: the electronic label has no built-in battery, the power required for its work comes from the radio frequency field constructed by the read-write.
Active electronic label refers to the electronic label with built-in battery, detailed classification can be divided into semi-passive electronic label and active active electronic label.
Figure.1 According to the power supply classification of RFID technology / electronic label technology
(2) the basic definition of semi-passive electronic tags: electronic tags have built-in batteries, electronic tags to transmit information to the outside of the realization of the way to follow the principle of load reflection modulation technology to achieve. That is to say, the built-in battery energy does not transform into the electronic label outgoing information required radio frequency energy, the label outgoing information required radio frequency energy still depends on the carrier energy signal issued by the read-write.
(3) active electronic label basic definition: electronic label has built-in battery, and the electronic label has the ability to use its own battery energy to send out information.
3. According to the classification of the electronic label working frequency
The classification of RFID technology/electronic label technology obtained according to the working frequency factor of the electronic label is shown in Figure 2.
Figure.2 RFID technology/electronic tag technology according to the working frequency
The low frequency class RFID technology/electronic label technology’s characteristic is the electronic label and the read-write between the contactless coupling generally through the alternating magnetic field realization. The typical frequency boundary is the frequency is below 30MHz, the current mainstream RFID technology concentrates in the frequency is below 135kHz animal recognition application and the frequency is 13.56MHz card (including the flexible film sticker method) recognition aspect.
High frequency class RFID technology / electronic label technology is characterized by the electronic label and read-write between the contactless coupling generally through the propagation of electromagnetic field to achieve. The typical working frequency includes: 433MHz, 860-960MHz, 2.45GHz and 5.8GHz etc.
4. Classification according to the internal state of the electronic label
The internal state of the electronic label when working largely determines the working mode and design scheme of the read-write, such as whether the RFID system supports the multi-label read-write function in the same reading area, etc. According to the electronic label internal state RFID technology / electronic label technology classification as shown in Figure 3.
Figure.3 RFID technology/electronic label technology classified according to internal state
No built-in state machine model of the electronic label refers to the electronic label does not have time memory function, the most typical case is the electronic label work externally presents the nature of the pure combination circuit, some complex cases include the electronic label built-in random number generator for the control of the electronic label work state. For example, the electronic label after the power up namely enters the cycle sends the built-in complete storage information state, the railroad car number automatic diagnosis application uses the electronic label technology that belongs to this situation.
In general, does not have the built-in state machine model electronic label corresponding RFID system does not have the multi-label recognition function, but also has the exception situation. If the electronic label has built-in random number generator, even if no built-in state machine, also can be caused by the random number generator role at the same time obtains the stimulus electronic label interleaved information, thus can realize the multi-label recognition function.
No built-in state machine model electronic label usually also has WORM (WriteOnce, ReadMany) characteristic, namely once completes the electronic label information writing, many times repeatedly reads the electronic label information. The corresponding RFID system in the read-write generally only needs to configure read function, thus can simplify the corresponding read-write design.
Has the built-in state machine model electronic label is refers to the electronic label has the time memory function, the most typical situation is the electronic label work externally presents the nature of the time sequence circuit. Has the built-in state machine model electronic label usually has the multi-label recognition function. Generally speaking, has the built-in state machine model electronic label the number of state for 3-5, the complex some also may expand the concept of the state machine for the built-in programmable microprocessor. For example: ISO/IEC 18000-6B defines the built-in state machine model of the electronic tag can be represented in Figure 4.
As seen in Figure 4, the built-in state machine of the electronic tag defined by ISO/IEC 18000-6B has four independent states, including the down state when no excitation is obtained.
For the electronic tag containing the built-in state machine model, the built-in state machine is equivalent to the brain of the electronic tag and must ensure its uniqueness and consistency. Therefore, the original design must ensure that no two independent state machines are allowed to exist in the same electronic label. Otherwise, it will not guarantee the normal operation of the electronic label.
Figure.4 ISO/IEC 18000-6B definition of the electronic label built-in state machine model
The analysis and research work of this paper continues the content of “RFID Classification Study General”, and analyzes and studies the issues related to RFID technology classification in detail. The main points are summarized as follows.
- (1) The basic view that RFID technology can be directly classified as the same as electronic tag technology from the perspective of technology classification is confirmed and agreed.
- (2) Through the overall study of RFID technology, the classification of RFID technology is based on the classification of the power supply method of the electronic tag, the classification of the operating frequency of the electronic tag, and the classification of the internal state of the electronic tag. The classification of other unimportant factors is omitted.
Source: China RFID System Manufacturer – Actility Technologies Company Limited (www.tractility.com)