DE102012008147A1 - Radio frequency identification (RFID) transponder has memory that is organized in RFID tag file system which is provided with own file allocation table that manages files independently, so as to read or delete files - Google Patents

Abstract

The radio frequency identification (RFID) transponder has RFID transponder main portion that is provided with sensor (7), transmitting antenna (1), analog communication unit (2), digital communication unit (3), command interpreter (5) executed in microprocessor (4) and an electronic data memory (8). The memory is organized in RFID tag file system (6). The RFID tag file system is provided with own file allocation table that manages the files written and telemetrically transmitted to the RFID transponder main portion independently, so as to read or delete the files.

Description

The invention relates to a novel organization of data on RFID (Radio Frequency Identification) transponders in a self-sufficient file system and a method for accessing this data via the radio interface.

RFID transponders are electronic devices which, together with a product, enable identification of the goods in the sense of a clear identification via a non-contact radio interface over short distances. The radio interface is largely standardized, as well as the method for reading the identification number. In addition to the identification number, the RFID transponders allow to store further data. Again, there are different, partly company-specific standards.

RFID transponders can additionally be equipped with a sensor that allows further monitoring functions of the goods, in particular the monitoring of the temperature profile during storage and transport. These devices, referred to as "active RFID transponders", have special control electronics for controlling the data acquisition, corresponding sensors, such as temperature sensors, a data memory for storing the recorded measured values and an energy source for electrical supply, for example a battery. Since the number of measured values to be recorded can be very large, the memory is designed much larger than in conventional RFID transponders, also the control electronics by the use of a microprocessor is considerably more efficient and it will be more economic subsidies to the system, such as adaptability to different application scenarios, the possibility to replace the control program of the control electronics (firmware update), access protection, counterfeit security and measures to protect the stored data. There is therefore an effort to improve the organization of the data in the mass storage as well as the transmission thereof.

File systems and access methods using RFID are known. The US Pat. Publication 2007/0082613 describes the integration of RFID transponders in the file system of a data processing system (host) by an adaptive program (middleware). However, the files are not integrated directly into the directory structure of the data processing system. Furthermore, the assignment table is not on the RFID transponder, but in the operating system of the data processing system. The publication "The RFID filesystem whitepaper" by Achilleas Anagnostopoulos, Athens University of Economics and Business, 2005, shows how an RFID transponder is integrated directly into the existing file system of a data processing system (Mounting). In this case, the RFID transponder is used as a data segment (cluster) of the file system. Again, there is no complete self-sufficient file system on the RFID transponder, but instead forms the RFID transponder only a cluster, so a subunit of the data arrangement.

In the International Patent Application 2007/065747 this application is extended to the interpretation of multiple RFID transponders to obtain a so-called distributed data memory. Again, the central management of the files on the data processing system (host) remains, that is, data mapping and protection mechanisms are implemented on the host.

Similar concepts to integrate an external mass storage in the file system of a data processing system are also known for other technologies. As an example, here is the US Patent 7039759 from May 2006 called, which colloquially as USB stick described devices describes. In this a so-called FLASH memory is integrated as a removable medium in the file system of a data processing system. The mass storage is electrically connected via a USB interface. A microprocessor (a so-called "USB mass storage controller device") mediates between the access protocol of the data processing system and that of the storage medium. The intelligence of the processor is largely limited to the management of read and write accesses. The data content must be interpreted by a data processing system. This can also determine which file system should be used.

Furthermore, the sequence of communication between RFID transponder and reader with prior authentication already in the International Patent 2005/098737 mentioned. However, an application to individual files does not take place.

The known solutions all relate to the widespread standard RFID transponders, which have only low storage options. For the application "active RFID transponder" with large mass storage no comparable solutions are known.

Furthermore, the known solutions which combine RFID with file systems are characterized by the assumption of a data memory with minimal local intelligence without further data sources. The organization of the data does not take place on the RFID transponder. The RFID transponders are instead integrated as memory blocks in an existing file system. The data allocation table (File Allocation Table) is thus located on at least one associated data processing system (host) and / or must be interpreted by them. The RFID transponder thus has no knowledge of the number of files, the occupancy of the memory and the access rights to them. Furthermore, the sharing of data across multiple devices poses risks, such as errors in disturbed transmissions, or mutual dependencies that must be weighed against the benefits of facilitating integration with the data processing system.

Furthermore, in RFID systems, common problems, such as restricted, protected access, data consistency and data security, are usually solved in an application-specific manner. A solution of the requirements on a general abstract level does not take place.

The invention has for its object to simplify the management of the arranged on the RFID transponder mass memory to the effect that on the RFID transponder a simple, realizable with small resources self-sufficient file system is implemented so that the wireless communications with the RFID transponder in addition to the standardized RFID commands on the transmission of files is reduced.

This object is achieved by an RFID transponder according to claim 1. The other claims relate to preferred embodiments of the file system according to the invention and corresponding access methods.

Organizing data in a self-sufficient file system has the advantage of not requiring a data processing facility to manage the data. The limited memory of the RFID transponder can be used efficiently. The organization of the data in files makes it possible to keep different types of data such as system information, sensor data and telemetry files in the same memory segment. The RFID transponder can manage data from any number of sensors or other data sources without the need for fundamental intervention in the memory structure and in the instruction set of the RFID transponder. The interface becomes independent of the content of the data.

Furthermore, common problems such as restricted, protected access, data consistency and data security can be solved on an abstracted file screen on the RFID transponder. The consistency of data is ensured with checksums in the files. The files can be provided with header headers, which considerably simplify the evaluation of the data on a data processing system. Access rights can be flexibly organized on the file level. By a so-called "mapping", the actual organization of the memory, even the configuration of several memories, no longer needs to be revealed. Copying between different storage units of the RFID transponder, as well as between RFID transponder and data processing system, can be made safe. Incoming files can be stored and checked in non-functional memory areas. Also called the firmware control program of the microprocessor on the RFID transponder can be transmitted as a file from the data processing system and thus forms the basis for a secure, against interference on the radio interface protected, customization of the control program (firmware update).

An embodiment of the invention is shown in Figure 1. The connection to the transmission medium takes place via antenna 1 , From the induced voltage of the antenna is from the analogue communication unit 2 generates a clock signal with the carrier frequency of the transmission medium. Also, the amplitude-modulated received signal is converted to a digital signal (down-link). Towards the transponder reader, the data is transmitted in a known manner via load modulation (up-link). The processed data are from a digital communication unit 3 decoded, and processed for further processing in the microprocessor. The digital communication unit may advantageously be implemented as a complex programmable logic device (CPLD), but may also be implemented by discrete circuit elements or by an application-specific integrated circuit. The data generated by the CPLD is from a microprocessor 4 which takes the command interpreter 5 implemented digitally as a program. The command interpreter, in turn, communicates with the file system routines 6 to answer external requests and to perform data operations. As another interface is on the microprocessor 4 a serial data bus (I2C or SPI) is available. On this bus are an external intelligent sensor 7 and an electrical mass data storage 8th (EEPROM, or Flash-PROM or FRAM) connected.

• – Index: Laufende Nummer der Datei
• – Attribut: Enthält in binärer Form Angaben über Belegung, Zugriff, Authorisierung u. a.
• – Name: Name der Datei mit Extension, getrennt durch einen ,.'. Die Extension gibt den Typ der Datei an.
• – Zeit: Ein Bitfeld mit der verschlüsselten Zeit und Datum im C-Standard
• – Adresse: Adresse im EEPROM-Speicher, wo die Datei beginnt
• – Größe: Länge der Datei in Blockeinheiten.

The first sector of Electrically Erasable Programmable Read-Only Memory (EEPROM) stores the data allocation table (FAT) as a file. For example, the table contains 16 entries as shown in Table 1. Each entry in the table, that is, each row contains multiple data fields, the together contain all information about the stored file. These are for example:

• - Index: Serial number of the file
• - Attribute: Contains information about occupancy, access, authorization, etc. in binary form
• - Name: Name of the file with extension, separated by a,. '. The extension specifies the type of the file.
• - Time: A bit field with the encrypted time and date in the C standard
• - Address: Address in the EEPROM memory where the file starts
• - Size: Length of the file in block units.

Occupancy and access can be attributed to the attributes 9 be removed. The file name 10 is used to service queries on the file. The entries index 11 , Start address 12 and size 13 describe the data area reserved for the file. The index 11 a file and its current read-write address 14 can be summarized to a file pointer (file pointer), of which several can exist.

Two file pointers ( 15 and 16 ) are located in the data memory of the microprocessor. Each allows the file system to open a file. It is thus possible to write and read sensor data as well as telemetrically transmitted data in two different files.

A memory fragmentation is done by appropriate division of the electronic data memory 8th and the data allocation table (FAT) 17 avoided. The lower sector of the storage medium and the data allocation table contain system-relevant data 18 that are specially protected. The acquired measured values close to these 19 of the sensor as measurement data files. The upper part of the memory contains the data 20 which were transmitted via the telemetric interface. Files can be written until the file pointers overlap, previously aborted.

The files exist as in 21 shown, from file header 22 , User data 23 and file-foot 24 , In the illustration, , the header starts with the lowest address of the file. The file evolves from low to high addresses. A reverse development is also possible, depending on the processor and mass storage controller used. The file header stores information that makes it easier for a data processing system to interpret the file. At the bottom of the file is a checksum according to the Cyclic Redundancy Check (CRC) method in the same format as specified for the telemetric interface. Changes to the contents of the file are thereby recognizable or, if necessary, also correctable with appropriate coding. The actual user data is located in the middle part of the file. These are binary coded and clearly interpretable via the header. The contents of the file can also be encrypted.

• – Systemdateien, welche vom RFID-Transponder generiert werden um den Status des Systems wiederzugeben,
• – Messdatendateien, in denen erfasste Sensorwerte gespeichert werden und
• – Dateien die von einer Datenverarbeitungsanlage auf den RFID-Transponder geschrieben werden.

The file system distinguishes three groups of file types:

• - System files generated by the RFID transponder to reflect the status of the system
• - Measurement data files in which recorded sensor values are stored and
• - Files that are written by a data processing system on the RFID transponder.

• – die Dateizuordnungstabelle *.SYS,
• – die Konfigurationsdatei *.CFG und
• – die Historie *.LOG.

As a rule, system files can not be written by a data processing system. The files contain process variables that provide information about the assignment, configuration and use of the RFID transponder. The system files belong in the current version

• - the file allocation table * .SYS,
• - the configuration file * .CFG and
• - the history * .LOG.

The file allocation table is itself executed as a file as described above. It basically consists of 16 Fixed entries according to Table 1. The execution of the file allocation table as a file enables a data processing system to read the memory allocation completely by reading out the file. It is thus possible to implement a so-called DIR or LIST command.

The configuration of the RFID transponder is also kept in a file. This eliminates any special commands that query the configuration of the RFID transponder via the interface. A distinction is made between static and dynamic configuration values. Static configurations do not change during operation of an RFID transponder. These include, but are not limited to, the identification number, manufacturing status, memory structure information, sensor calibration, and date of manufacture. Dynamic configurations can be changed as often as you like. In the described application of an active RFID transponder with sensors, these data include, inter alia, the sampling intervals and guidelines for evaluating the measurement result. From this information, the current application profile can be determined.

Furthermore, in the current version, there is a history, a tabular logbook, in the memory of the RFID transponder. All Noteworthy events are included in this. Using the file, it is possible to draw conclusions about the use of the RFID transponder by a user. It is thus possible to use older transponders to optimize future transponders.

Versions with integrated measured value acquisition also generate measurement data files * .DAT. It is possible to collect the data of several sensors in one file. In further embodiments of the invention, it is also conceivable to create a separate file for each sensor. The number of file pointers would have to be scaled accordingly. A measurement data file is designed so that each file can be interpreted without further context. Parts of the configuration are repeated in the header of the file, so in the current version the measured value file contains the identification number of the RFID transponder, the sensor calibration as well as the sampling interval and evaluation guidelines. Furthermore, process data is entered which was transferred when the measurement was started. So there is also a process code and the time of the start in the file. The data area is filled with the raw data of the sensor. These are continuously entered into the file (streaming). Further information, such as the measured value index and the time of measurement, are redundant because a file represents a closed data record. It is not mandatory to save the raw data. The data can also be stored in a more readable data format or in compressed form in a Huffman code.

The data processing system can also store data on the RFID transponder. For example, the use of text files * .TXT is intended to transport process parameters during a collection cycle between several data processing systems. However, it is generally possible to store any type of files on the RFID transponder, as long as the RFID transponder does not have to interpret the content of the data. It is thus possible to cache executable files of the data processing system or media files on the RFID transponder to execute this on another data processing system.

The ability to store data from the data processing system on the RFID transponder is not just used to transport files. File formats are also implemented which can be interpreted by the RFID transponder. It is thus possible to transfer a program for the microprocessor * .BIN or a profile file * .PRO for more complex processes. The interpretation of the data is done by sending another interface command after completing the file transfer.

• – LOGIN, erlaubt einen autorisierten Zugang zum RFID-Transponder,
• – INIT, stellt einen definierten Anfangszustand her,
• – PUT FILE, überträgt eine Datei (File) von der Datenverarbeitungsanlage zum RFID-Transponder,
• – GET FILE, überträgt eine Datei vom RFID-Transponder zur Datenverarbeitungsanlage,
• – DEL FILE, löscht eine Datei auf dem RFID-Transponder,
• – COPY FILE, kopiert eine Datei innerhalb des Speichers des RFID-Transponders ohne das die Daten über die Luftschnittstelle transportiert werden müssen,
• – UPDATE, kopiert eine Datei in den ausführbaren Speicherbereich und startet den RFID-Transponder neu,
• – LOGOUT, erlaubt den Zugang definiert zu beenden.

The organization of the transmission interface corresponds to that Standard ISO-15693 or a comparable RFID standard. The instruction set of the RFID interface allows the standard commands to be extended by so-called customer commands (customer commands), which is used here to additionally insert the following commands:

• - LOGIN, allows authorized access to the RFID transponder,
• - INIT, creates a defined initial state,
• - PUT FILE, transfers a file (file) from the data processing system to the RFID transponder,
• - GET FILE, transfers a file from the RFID transponder to the data processing system,
• - DEL FILE, deletes a file on the RFID transponder,
• - COPY FILE, copies a file within the memory of the RFID transponder without the data having to be transported via the air interface,
• - UPDATE, copies a file into the executable memory area and restarts the RFID transponder,
• - LOGOUT, allows access to finish defined.

The commands are according to ISO standard 15693 inserted in the optional instruction set. For all commands, an extended latency is given until the response is received, as already provided in the standard for write operations.

A read or write access from a reader 25 on the RFID transponder 26 takes place according to the flowchart , First, the RFID transponder is selected 27 , The user authenticates 28 , Subsequently, depending on the writing or reading process, a command 29 for opening a read or write channel. In this process, the RFID transponder becomes a pointer 30 (Address) and additionally the size of the file returned. This is followed by a series of basic write and read operations 31 , The ones from ISO standard 15693 specified commands, "Read Multiple Block" or "Write Multiple Block", are used, and extensions of these commands are also possible. The process continues until the selected file has been completely written to the RFID transponder or loaded into the data processing system. Upon termination of the communication by logout and / or deselection of the RFID transponder 32 the write-read access to the RFID transponder is closed.

• – INIT
• – PUT FILE (inklusive Write Multiple Blocks beziehungsweise Write Single Block)
• – GET FILE (inklusive Read Multiple Blocks beziehungsweise Read Single Block)
• – DEL FILE
• – COPY FILE
• – UPDATE
• – START, RESUME und STOP LOGING
• – CHANGE ACCESS RIGHT

Whether a user can access the RFID transponder from the data processing system is determined on the basis of user profiles. Currently there are five adjustable profiles in the Microprocessor of the RFID transponder provided, two user and administrator, guest and manufacturer profile. The user is authenticated via the profile number and password during the LOGIN command and is valid for the duration of the file access. A user with the guest profile does not have access to files of the RFID transponder. Only elementary functions of the RFID transponder are accessible to it. The profile manufacturer on the other hand is above the rights management of the RFID transponder. This user has write and read access to all files of the RFID transponder. On the other hand, the administrator only has read-write access to own files (* .TXT, * .BIN) and only read access to the system files (* .SYS, * .LOG, * .CFG) and measured value files (* .DAT ). However, he is able to edit his profile and password as well as the rights of the two user profiles and thus to adjust the access rights on the system. So the following operations concerning the file system in the profile can be allowed or forbidden:

• - INIT
• - PUT FILE (including Write Multiple Blocks or Write Single Block)
• - GET FILE (including Read Multiple Blocks or Read Single Block)
• - DEL FILE
• - COPY FILE
• - UPDATE
• - START, RESUME and STOP LOGING
• - CHANGE ACCESS RIGHT

The administrator is able to specifically allow or prohibit read / write accesses to a user group. The profile controls which group is allowed to manipulate the contents of the memory and who can initiate the process of updating the control program (update).

Using the UPDATE command, a copy process can be triggered in an executable memory of the RFID transponder. For this purpose, the executable program is first transmitted in the form of a file via the radio interface to the memory of the RFID transponder. Then, by means of a permanently programmed reload routine (UPDATE loader), the program of the microprocessor is replaced by the one present in the file and the new program is started. With this measure, a change in the program of the RFID transponder even after production and encapsulation is possible, for example, to adapt to new requirements or to implement new functionalities.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2007/0082613 [0004]
• WO 2007/065747 [0005]
• US7039759 [0006]
• WO 2005/098737 [0007]

Cited non-patent literature

• Standard ISO-15693 [0029]
• ISO standard 15693 [0030]
• ISO standard 15693 [0031]

Claims (11)

An RFID transponder, equipped with at least one sensor, a transmitting antenna, an analog and digital communication unit, a executed in a control unit command interpreter and an electronic data storage, characterized in that the organization of the memory via an implemented on the RFID transponder file system, wherein the RFID transponder has its own file allocation table and manages it autonomously and files can be written to, read from or deleted from the RFID transponder by telemetric transmission. An RFID transponder according to claim 1, characterized in that the files consist of a header, the user data and a file foot, the header containing information for the interpretation of the file, the file foot a checksum according to the usual standards. An RFID transponder according to claim 1, characterized in that the files have a type designation in the name, wherein the same types are interpreted in the same way. An RFID transponder according to claim 1 to 2, characterized in that the consistency of the files is ensured by calculating a checksum from the file data on a data processing system and by comparison with the transmitted checksum. An RFID transponder according to claim 1 to 3, characterized in that the access to a file requires authentication and in this case the access rights are set via a profile, wherein access is allowed only if the attributes in the data allocation table allow and / or the type of file is shared. An RFID transponder according to claim 1, characterized in that the RFID transponder prevents fragmentation of its storage medium by creating measurement data files with ascending addresses in the lower part of the mass memory, while telemetry data written in the upper part of the memory with descending start Addresses are created whereby the writing direction of the files remains the same. An RFID transponder according to claim 1, characterized in that an adaptation of the control program of the RFID transponder (Update) takes place in that first a file with the new control program is transmitted, the file then by a running in the RFID transponder Nachladeroutine (Update Loader), which is activated by a command provided for this purpose, copied into the executable memory and then started. An RFID transponder according to claim 1, characterized in that a plurality of electronic data storage on the RFID transponder are present and managed by the file allocation table, wherein from the point of view of the data processing system, a continuous address space is available. An RFID transponder according to claim 1, characterized in that the file allocation table is also stored as a file on the memory. An RFID transponder according to claim 1, characterized in that the measurement data files are data coded by known compression methods. An RFID transponder according to claim 1, characterized in that individual or all files are stored encrypted on the RFID transponder according to a known method.

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