Radio Frequency Identification (RFID) technology steadily infiltrated many aspects of our daily lives. From the supermarket to the rapid collection inventory management, the technology is changing the number of existing applications and support new applications. Rfid in the front end, the "signal chain" from an effective device to start a small label, the information will be sent to one or more of the rfid reader, when the labels appear in a specific region, the reader detection. Rfid in the back-end, server-based system to maintain and update the database labels. rfid system block diagram shown in Figure 1.
Today, most of the rfid reader use multiple processors to meet the application requirements. One of which is usually connected analog to digital converter (adc) and digital to analog converter (dac) signal processor. The other is local or remote server communications network processor for use in information storage and recovery. However, blackfin processor family, and so be able to manage these different functions - signal conversion and network connectivity.
Figure 1 rfid system block diagram
This article first introduced rfid technology, and it can support current and future applications. Then, for rfid reader functions, this article will look at the running rfid readers and servers needed to connect the basic components of the software.
Rfid System
rfid is a use of radio frequency (rf) transmission, the identification code, and classification code (or) to track the target's communication system. Each has its own objectives rfid tags (also known as transponders). The total system with a tag reader to receive the label of each rf signal. Reader's embedded software management information, to receive and decode the label information processing and storage systems as well as communications, data collection tags and other relevant information.
Rfid applications
rfid technology to allow monitoring of a number of items at the same time, there is no need to "touch" each item (for example, a hand-held bar code scanners), so that it can support many new applications. To take advantage of this automatic identification technology covering a wide range of areas such as management control, logistics management, security monitoring and access charges. The following are now using rfid some of the common application system.
● food in the supermarket shelves and boxes, labels the ability to write (may include additional information, such as no later than the date of sale) so that food can be seen on the shelves of goods and better management. In addition, it can be automatically re-arranged to keep the shelves of inventory in the right order.
● Library in the management information automatically with the return of the loan. In the past, these items are used to identify the label article, each must use scanners to read bar codes.
● clothing trademark in the identification of the source of their goods. The use of the ID tag (id), can be identified by the goods are counterfeit or genuine.
● in the pharmaceutical industry to prevent counterfeit drugs.
● In sports, precisely tracking the process of marathon runner
rfid reader
rfid reader to provide the tag and end with the management system to track the connection between. Although it may take a variety of different-sized package, but are usually small in order to be installed on the wall or tripod. In addition, according to different applications and working conditions, you can use a number of readers in order to cover fully the provisions of the region. For example, in the warehouse, there may be covered by a network in order to ensure that goods from the point when a mobile point b, through all the goods to 100% of the inquiries and records.
In short, the reader has three main functions of the component. The first part is to send and receive functions, and used to label and the separation of the individual items to keep in touch; the second part is to receive initialization information processing; the third part of the server is a link to information will be sent to the authorities.
rfid reader system must be able to deal effectively in the region at the same time there are a number of labels, in this limited space in memory than the regional label applications is very important.
In the presence of a number of tags and readers, the main problem is the conflict, as a number of reader inquiries issued, there will be a number of labels at the same time response. There are many ways to avoid this problem. The most commonly used method is to adopt some kind of time-division multiplexing algorithm. Reader can be set up at different times inquiries, and the label can be set to go through a random intervals after the response. If the embedded software has the ability to achieve this function, can increase flexibility.
Rfid transponder
Rfid tags, including a piece of integrated circuit chip (which tags for the preservation of individual items of information), an antenna (usually printed circuit antenna for receiving from the reader's information and send a message rf) and contain labels A shell.
Rfid tags can be used many different objects, from a range of items to the animals, including people. Tag reader to the distance is a very important system variables, which directly affected by the tag technology. Commonly used in a variety of technologies have the following label.
1 passive tag
The simplest type of label is the passive tags. Its use of specialized readers to send the rf energy to electricity, so it does not have integrated battery size and cost. Passive tags are very cheap, good mechanical robustness, and very small size (about the size of a nail). However, because passive tags to receive its power to the rfid reader proportional to the physical distance, so the shortcomings of this type of label is limited in scope to read.
Talking about the scope, frequency rf selection of links with the actual scope of a great relationship. Low frequency (lf) label usually 125 ~ 135khz band, as they limited the scope, so its main use is access control and animal tags. High-frequency (hf) in 13.56mhz major label band to allow the scope of work of about a foot or two feet. hf tags are mainly used for simple one-on-one to read the object, such as access control, library fees, as well as to track the books and other items.
Ultra-high frequency (uhf) major label in 850 ~ 950mhz band to allow 10 feet beyond the scope of work. In addition, the reader can at the same time a number of inquiries uhf labels, and one-on-one to read labels hf different process. This feature will also help meet the region for a limited number of readers. Because of this feature, uhf tags in very common in industrial applications for inventory tracking and control. But the label uhf one of the main shortcomings is not effectively penetrate the liquid. This can not be used to make them full of liquid objects, such as beverages and the human body. In tracking these objects, usually used to replace the label hf.
2 semi-active tags
As passive tags, semi-active tags will be returned to rf energy label reader to send identification information. However, it also contains a battery for the label in some of the power supply ic so that it can support a number of interesting applications, such as placing labels on each sensor. This approach, each transponder can send not only a static logo, can also send some of the real-time attributes, such as temperature, humidity and the time and date. Ic only through the use of sensors and battery-powered, semi-active tags can be achieved in terms of cost, size and scope of the compromise between.
3 Active tags
Active tags used for labels integrated battery ic (as well as all the sensors) and the rf transmitter power supply, so that it more than half of active tags has taken one step further. Active tags to expand the scope of the work of a great deal (to reach more than 100 m), which means that the goods through the reader than the speed of passive and semi-active label system, the speed is much higher. In addition, active tags can carry more product information, not just a simple product id code.
Rfid reader's software architecture
Rfid described above is the basic functions of the reader, the following will explore how to use a processor to achieve these functions. rfid reader software architecture of the three units are: the back-end server interface, middleware and front-end label reader algorithm. Although the software architecture of the units vary, they can run in a blackfin processor.
And back-end server connectivity
Usually, rfid readers, including a network element, is used to read a rfid events connected to the central server. This back-end network interface may be wired Ethernet (ieee802.3), Wireless Ethernet (ieee802.11a/b/g), for example, or zigbee (ieee802.15.5) Ethernet. Central server running a database system and its features include matching, tracking and storage. In many applications, there will be a "warning" function. For the supply chain and inventory management systems, which may be re-arranged to remind; for security applications is one of the guards to report to the police.
When the back-end servers and communications, the use of high-performance operating system to run uclinux embedded processor to build reader with a great advantage. tcp / ip protocol stack robustness and sql database engine, such as the availability of the key factors in reducing the development process can be a huge burden on the development and integration.
Middleware
Rfid in the unit, is in the range of middleware rfid reader front-end and back-end enterprise systems software translation layer. Reader's middleware to filter data so as to ensure that many do not read or invalid data. Early in the rfid system, middleware running on the server. However, rfid reader to complete filtering of data have become more popular in prior to sending data through the corporate network. This enhanced functionality is embedded processor to the application of such a benefit.
Front-end reader
Signal Processing reader on the front-end system. This signal processing is usually contains a large number of filtering and transform operations, which is why the need to adopt a strong signal processing performance of the processor.
Rfid reader for the processor
blackfin processor to provide wired and wireless network connections. adsp-bf536 / 7, such as the processor chip inside a 10/100baset Ethernet mac-layer. In the wireless connection, through sport and spi interface peripherals directly connected to the ieee 802.11 and 802.15.4 zigbee chipsets, processors do not consume all the bandwidth they can achieve the rate of transmission lines.
The external processor parallel interface (ppi) can be connected directly to the above-mentioned adc / dac. Some processors, including the two ppi, the system can be further expanded.
In addition, the above-mentioned functions of the processor makes it one-dimensional and two-dimensional bar code applications particularly attractive because it can be completed on the same device control systems, network connectivity and image processing.
From the perspective of software processors, rfid reader products include mixed-signal front-end connected to the necessary driver. In addition, there is a dma drive in the transmission of data through the system is very useful. In addition operating uclinux also based on the network protocol stack, as well as sql database engine. From the system point of view, additional features, such as the 802.11 wifi card, usb thumb drive and compactflash card interface, and so on, can be quickly integrated with the blackfin devices together.
Conclusion
As we have seen, rfid applications no longer need a dedicated signal processor for adc and dac connection, as well as the use of micro-controller for network connection. blackfin processor family, and so can complete the network connection and control functions, in order to complete the converter to connect and pattern-matching algorithms sufficient room for performance. This also reduces the next generation rfid application materials costs and accelerate time-to-market product.
Today, most of the rfid reader use multiple processors to meet the application requirements. One of which is usually connected analog to digital converter (adc) and digital to analog converter (dac) signal processor. The other is local or remote server communications network processor for use in information storage and recovery. However, blackfin processor family, and so be able to manage these different functions - signal conversion and network connectivity.
Figure 1 rfid system block diagram
This article first introduced rfid technology, and it can support current and future applications. Then, for rfid reader functions, this article will look at the running rfid readers and servers needed to connect the basic components of the software.
Rfid System
rfid is a use of radio frequency (rf) transmission, the identification code, and classification code (or) to track the target's communication system. Each has its own objectives rfid tags (also known as transponders). The total system with a tag reader to receive the label of each rf signal. Reader's embedded software management information, to receive and decode the label information processing and storage systems as well as communications, data collection tags and other relevant information.
Rfid applications
rfid technology to allow monitoring of a number of items at the same time, there is no need to "touch" each item (for example, a hand-held bar code scanners), so that it can support many new applications. To take advantage of this automatic identification technology covering a wide range of areas such as management control, logistics management, security monitoring and access charges. The following are now using rfid some of the common application system.
● food in the supermarket shelves and boxes, labels the ability to write (may include additional information, such as no later than the date of sale) so that food can be seen on the shelves of goods and better management. In addition, it can be automatically re-arranged to keep the shelves of inventory in the right order.
● Library in the management information automatically with the return of the loan. In the past, these items are used to identify the label article, each must use scanners to read bar codes.
● clothing trademark in the identification of the source of their goods. The use of the ID tag (id), can be identified by the goods are counterfeit or genuine.
● in the pharmaceutical industry to prevent counterfeit drugs.
● In sports, precisely tracking the process of marathon runner
rfid reader
rfid reader to provide the tag and end with the management system to track the connection between. Although it may take a variety of different-sized package, but are usually small in order to be installed on the wall or tripod. In addition, according to different applications and working conditions, you can use a number of readers in order to cover fully the provisions of the region. For example, in the warehouse, there may be covered by a network in order to ensure that goods from the point when a mobile point b, through all the goods to 100% of the inquiries and records.
In short, the reader has three main functions of the component. The first part is to send and receive functions, and used to label and the separation of the individual items to keep in touch; the second part is to receive initialization information processing; the third part of the server is a link to information will be sent to the authorities.
rfid reader system must be able to deal effectively in the region at the same time there are a number of labels, in this limited space in memory than the regional label applications is very important.
In the presence of a number of tags and readers, the main problem is the conflict, as a number of reader inquiries issued, there will be a number of labels at the same time response. There are many ways to avoid this problem. The most commonly used method is to adopt some kind of time-division multiplexing algorithm. Reader can be set up at different times inquiries, and the label can be set to go through a random intervals after the response. If the embedded software has the ability to achieve this function, can increase flexibility.
Rfid transponder
Rfid tags, including a piece of integrated circuit chip (which tags for the preservation of individual items of information), an antenna (usually printed circuit antenna for receiving from the reader's information and send a message rf) and contain labels A shell.
Rfid tags can be used many different objects, from a range of items to the animals, including people. Tag reader to the distance is a very important system variables, which directly affected by the tag technology. Commonly used in a variety of technologies have the following label.
1 passive tag
The simplest type of label is the passive tags. Its use of specialized readers to send the rf energy to electricity, so it does not have integrated battery size and cost. Passive tags are very cheap, good mechanical robustness, and very small size (about the size of a nail). However, because passive tags to receive its power to the rfid reader proportional to the physical distance, so the shortcomings of this type of label is limited in scope to read.
Talking about the scope, frequency rf selection of links with the actual scope of a great relationship. Low frequency (lf) label usually 125 ~ 135khz band, as they limited the scope, so its main use is access control and animal tags. High-frequency (hf) in 13.56mhz major label band to allow the scope of work of about a foot or two feet. hf tags are mainly used for simple one-on-one to read the object, such as access control, library fees, as well as to track the books and other items.
Ultra-high frequency (uhf) major label in 850 ~ 950mhz band to allow 10 feet beyond the scope of work. In addition, the reader can at the same time a number of inquiries uhf labels, and one-on-one to read labels hf different process. This feature will also help meet the region for a limited number of readers. Because of this feature, uhf tags in very common in industrial applications for inventory tracking and control. But the label uhf one of the main shortcomings is not effectively penetrate the liquid. This can not be used to make them full of liquid objects, such as beverages and the human body. In tracking these objects, usually used to replace the label hf.
2 semi-active tags
As passive tags, semi-active tags will be returned to rf energy label reader to send identification information. However, it also contains a battery for the label in some of the power supply ic so that it can support a number of interesting applications, such as placing labels on each sensor. This approach, each transponder can send not only a static logo, can also send some of the real-time attributes, such as temperature, humidity and the time and date. Ic only through the use of sensors and battery-powered, semi-active tags can be achieved in terms of cost, size and scope of the compromise between.
3 Active tags
Active tags used for labels integrated battery ic (as well as all the sensors) and the rf transmitter power supply, so that it more than half of active tags has taken one step further. Active tags to expand the scope of the work of a great deal (to reach more than 100 m), which means that the goods through the reader than the speed of passive and semi-active label system, the speed is much higher. In addition, active tags can carry more product information, not just a simple product id code.
Rfid reader's software architecture
Rfid described above is the basic functions of the reader, the following will explore how to use a processor to achieve these functions. rfid reader software architecture of the three units are: the back-end server interface, middleware and front-end label reader algorithm. Although the software architecture of the units vary, they can run in a blackfin processor.
And back-end server connectivity
Usually, rfid readers, including a network element, is used to read a rfid events connected to the central server. This back-end network interface may be wired Ethernet (ieee802.3), Wireless Ethernet (ieee802.11a/b/g), for example, or zigbee (ieee802.15.5) Ethernet. Central server running a database system and its features include matching, tracking and storage. In many applications, there will be a "warning" function. For the supply chain and inventory management systems, which may be re-arranged to remind; for security applications is one of the guards to report to the police.
When the back-end servers and communications, the use of high-performance operating system to run uclinux embedded processor to build reader with a great advantage. tcp / ip protocol stack robustness and sql database engine, such as the availability of the key factors in reducing the development process can be a huge burden on the development and integration.
Middleware
Rfid in the unit, is in the range of middleware rfid reader front-end and back-end enterprise systems software translation layer. Reader's middleware to filter data so as to ensure that many do not read or invalid data. Early in the rfid system, middleware running on the server. However, rfid reader to complete filtering of data have become more popular in prior to sending data through the corporate network. This enhanced functionality is embedded processor to the application of such a benefit.
Front-end reader
Signal Processing reader on the front-end system. This signal processing is usually contains a large number of filtering and transform operations, which is why the need to adopt a strong signal processing performance of the processor.
Rfid reader for the processor
blackfin processor to provide wired and wireless network connections. adsp-bf536 / 7, such as the processor chip inside a 10/100baset Ethernet mac-layer. In the wireless connection, through sport and spi interface peripherals directly connected to the ieee 802.11 and 802.15.4 zigbee chipsets, processors do not consume all the bandwidth they can achieve the rate of transmission lines.
The external processor parallel interface (ppi) can be connected directly to the above-mentioned adc / dac. Some processors, including the two ppi, the system can be further expanded.
In addition, the above-mentioned functions of the processor makes it one-dimensional and two-dimensional bar code applications particularly attractive because it can be completed on the same device control systems, network connectivity and image processing.
From the perspective of software processors, rfid reader products include mixed-signal front-end connected to the necessary driver. In addition, there is a dma drive in the transmission of data through the system is very useful. In addition operating uclinux also based on the network protocol stack, as well as sql database engine. From the system point of view, additional features, such as the 802.11 wifi card, usb thumb drive and compactflash card interface, and so on, can be quickly integrated with the blackfin devices together.
Conclusion
As we have seen, rfid applications no longer need a dedicated signal processor for adc and dac connection, as well as the use of micro-controller for network connection. blackfin processor family, and so can complete the network connection and control functions, in order to complete the converter to connect and pattern-matching algorithms sufficient room for performance. This also reduces the next generation rfid application materials costs and accelerate time-to-market product.
