CN101694699A - Method and device for improving reading/writing distance of RFID - Google Patents
Method and device for improving reading/writing distance of RFID Download PDFInfo
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- CN101694699A CN101694699A CN200910197203A CN200910197203A CN101694699A CN 101694699 A CN101694699 A CN 101694699A CN 200910197203 A CN200910197203 A CN 200910197203A CN 200910197203 A CN200910197203 A CN 200910197203A CN 101694699 A CN101694699 A CN 101694699A
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Abstract
The invention belongs to the technical field of radio frequency automatic identification (RFID) and particularly relates to a method and a device for improving the reading/writing distance of the RFID. The system comprises a RFID label and a RFID reading and writing device; when the reading and writing device reads and writes the memory in the label, whether the error correcting code is used and what error correcting code is used are determined according to the judgment to the error condition of the CRC16 in the returning information of the label. The error correcting code function can be configured and is extremely flexible for use. If the reading and writing device decides to use the error correcting code, the label is informed by the instructions; therefore, in the subsequent communication, the reading and writing device and the label code the sent data and decode the received data. The reading and writing device can close the coding and decoding by the instructions or change the type of the used error correcting codes. In the invention, the power dissipation and time expense due to unnecessary coding and decoding can be saved effectively.
Description
Technical field
The invention belongs to radio frequency automatic identification (RFID) technical field, a kind of method and apparatus that improves the RFID reading/writing distance of specific design.
Background technology
RFID (Ratio Frequency Identification) technology is a kind of important non-contact automatic identification technology.It utilizes radio frequency signal to realize the noncontact bidirectional data communication by space coupling (alternating magnetic field or electromagnetic field), and the information of passing through to be transmitted reaches identifying purpose.Compare traditional automatic identification technology, the RFID technology has a bit a lot, such as noncontact, remote, read-write, contain much information, need not artificial disturb etc., have a wide range of applications in fields such as supply chain management, burglary-resisting system, parking lot control, automatic assembly line, taking care of books, animal trackings.As accompanying drawing 1, rfid system generally is made up of read write line, antenna and label.
Error correcting code, or claim channel coding technology or error control coding (Error Control Coding) is a kind of technology that can find voluntarily or correct at receiving end after information makes a mistake in transmission course.Its research object is the Serial No. M (information sequence) that source encoder is exported, and these sequences are generally formed by 0/1.Error correcting code is exactly to increase some redundant code elements according to certain rule to information sequence, makes it to become Serial No. C (code word).Specific relation is arranged between redundancy symbol in the code word and the information sequence, and this point is exactly the basis of carrying out error-detection error-correction at receiving end.At receiving end, channel decoder is deciphered by this relation, promptly detects the Serial No. R that receives and whether meets the rule that coding adopts, thereby reach the purpose of error correcting and detecting.
Summary of the invention
The object of the present invention is to provide a kind of method and apparatus that can improve the RFID reading/writing distance.
The method that can improve the RFID reading/writing distance provided by the invention is a kind of RFID communication means based on error correcting code, this method is utilized the characteristics of error correcting code and RFID, when reaching identical reading/writing distance at last environment SNR (signal to noise ratio (S/N ratio)) level is required lower, the farther purpose of reading/writing distance under equal SNR (signal to noise ratio (S/N ratio)) level in other words.And this communication means can be according to the error situation of CRC check sign indicating number in the communication process, such as what of wrong figure place, and judges whether to use error correcting code and selects which kind of error correcting code.This intelligentized operation gives great dirigibility for the use of error correcting code, thereby can effectively save power consumption and time overhead that unnecessary encoding and decoding bring.
According to first aspect of the present invention, the method for a kind of RFID of control label reception and the information of transmission is provided, this RFID label is communicated by letter with rfid interrogator.This method is carried out in the RFID label, may further comprise the steps:
Receive the instruction of read-write class;
Execution command, return data then;
Receive instruction, this instruction is specified and whether is used error correcting code and use which kind of error correcting code;
Return the follow-up continued access of RN16 and receive the instruction of read-write class;
Decoding and execution command will be returned after the digital coding.
According to the above method that provides, after returning, execution command can receive the instruction whether appointment is used error correcting code and used which kind of error correcting code, and this instruction is user's extended instruction, similar write command.The relevant zone bit of error correcting code is deposited in the conduct of a selected address in EEPROM in advance.This instruction is promptly carried out write operation to it.And in above second step: behind the execution command return data, extended instruction and command content that whether read write line sent in the 3rd step depend on the error situation that returns middle CRC16 check code that read write line receives.The mistake that do not have CRC16 then continues communication needn't send this extended instruction.
The alternative sign indicating number class that coding uses can be according to concrete applicable cases---such as consider the restriction of RFID to hardware power consumption expense, to the restriction of encoding and decoding time-delay---select, communication data is through coding, change data length and add redundant bit, be used for the decoding of back.
A kind of RFID label also is provided, comprises device according to the method work of above first aspect.See shown in Figure 2.It comprises a main control module 17, FM0/Miller codec 15, RF front end 18, the scrambler 13 of error correcting code and the demoder 14 of error correcting code, and the error correcting code zone bit 12 in EEPROM11.EEPROM11 is connected with main control module 17 by interface 16, and whether selected certain address is used encoding and decoding and used which kind of encoding and decoding when receiving transmission information to be controlled at as error correcting code zone bit 12 in EEPROM11.The scrambler 13 of embedded standby error correcting code and demoder 14 receive and send whether code coder 13 and the demoder 14 by error correction of data can be chosen in 17 of FM0/Miller codec 15 and main control modules under the control of error correcting code zone bit data stream.Label 01 with the read write line communication process in can accept extended instruction, rewrite error correcting code zone bit 12, can in the communication process of back, enable error correcting code scrambler 13 and error-correcting code decoder 14 like this, after the data that receive are through 15 decodings of FM0/Miller codec, need through error-correcting code decoder 14.Label 01 returns to the data of read write line and need launch by emitting antenna 19 via radio-frequency front-end 18 then through encoding by FM0/Miller codec 15 behind error correcting code scrambler 13 codings again.
According to second aspect of the present invention, provide a kind of rfid interrogator to handle method, this rfid interrogator and the RFID label communication of the information that reads and the information of transmission.This method is carried out in rfid interrogator, may further comprise the steps:
Send read write command;
Reception is returned and is judged the CRC16 error situation;
Send extended instruction, receive return data;
Coding sends read write command;
Reception is returned and it is decoded.
Provide in the method above, reception is returned and is judged and not necessarily sends extended instruction after the CRC16 error situation, does not read and write according to normal protocol regulation flow process if do not send then.Here for illustrate invention method be provided and send the situation of extended instruction emphatically.Certainly, send in the wrong environment, may need repeatedly to send the zone bit that extended instruction just can be rewritten the tab end error correcting code at CRC16.
A kind of rfid interrogator also is provided, comprises device according to second aspect method work.See shown in Figure 3.It comprises a main control module 25, FM0/Miller codec 24, RF front end 26, the scrambler 22 and the demoder 23 of realization error correcting code, CRC16 mistaken verdict device 21.CRC16 mistaken verdict device 21 is judged that to the error situation of CRC16 judged result is given main control module 25 and whether opened the error correcting code function with final decision, promptly starts scrambler 22 and the demoder 23 of realizing error correcting code in the read write line.Read write line 02 is receiving label 01 return data by receiving antenna 27, sending into FM0/Miller codec 24 through radio-frequency front-end 26 decodes, by CRC16 mistaken verdict device basis the data error situation is judged, whether use error correcting code and use which kind of encoding and decoding by main control module 25 decisions, use if need, then can carry out Code And Decode respectively to the data that receive and will send by the scrambler 22 and the demoder 23 of error correcting code.
According to the 3rd aspect of the present invention, the communication means of the rfid system of a kind of RFID of comprising label and rfid interrogator is provided, this method may further comprise the steps:
Read write line sends read write command;
Label receives execution command and return data;
Read write line receives return data and judges whether to send extended instruction and determine this command content according to the error situation of CRC16;
Read write line sends extended instruction;
Label receives, and returns RN16 after carrying out this extended instruction;
Read write line receives return data, and coding sends the read write command of back then;
Label receives the decoding execution command and with return data after the digital coding;
Read write line is to receiving return data, and the line data of going forward side by side decoding continues coding and sends instruction or stop read-write.
According to the method in the 3rd aspect of the present invention, the same extended instruction that whether sends with two aspects, front all relies on error situation with CRC16, and read write line can continue to send the instruction of read write command or other agreement supports or stop read-write under the situation of this instruction not needing to send.
The rfid system of realizing the 3rd the described communication means in aspect also is provided, comprises above-mentioned rfid interrogator and RFID label, communicate according to the 3rd method that the aspect is mentioned.See shown in Figure 5.Label 01 return data is given read write line 02, and read write line 02 receives data, and makes error situation by CRC16 mistaken verdict device 21 and judge, and the result is sent to 25 decisions of read write line main control module whether sends extended instruction and determine this command content.
Enable if desired error correcting code then read write line 02 send extended instruction notified tag 01 and enable error correcting code,
After read write line 02 received and returns, scrambler 22 codings were all passed through in the instruction that sends later, and the data that receive are all decoded through 23,
The data that label 01 receives are all passed through demoder 14 decodings, and the data of transmission are all passed through scrambler 13 codings.
After the communication that at every turn relates to the judgement of error in data situation, read write line 02 can send the error correcting code function is opened or closed to the extended instruction decision whether and which kind of error correcting code unlatching uses.
Effect of the present invention can obviously be weighed out by direct measure R FID reading/writing distance.
Description of drawings
Fig. 1: general rfid system constitutes.
Fig. 2: according to the schematic block diagram of the RFID label of first aspect present invention.
Fig. 3: according to the schematic block diagram of the rfid interrogator of second aspect present invention.
Fig. 4: according to the middle rfid system communication flow diagram of third aspect present invention.
Fig. 5: rfid system schematic block diagram.
Number in the figure: 01 is the RFID label, and 02 is rfid interrogator, and 11 is the EEPROM module, 12 is the error correcting code zone bit, and 13 is scrambler, and 14 is demoder, 15 is the FM0/Miller codec, and 16 is interface, and 17 is main control module, 18 is the RF front end, and 19 is antenna, and 21 is CRC16 mistaken verdict device, 22 is scrambler, and 23 is demoder, and 24 is the FM0/Miller codec, 25 is main control module, and 26 is the RF front end, and 27 is antenna.
Embodiment
The present invention will be described in detail below in conjunction with drawings and Examples.
Embodiment:
Present embodiment adopt BCH code commonly used in the linear block codes and during convolutional code is communicated by letter as RFID channel coding/decoding standby sign indicating number class.The scrambler of BCH code adopts the shift register structure of band feedback, and its hardware spending is quite little, and can accomplish not have encoding time delay, and decoding algorithm uses the Berlekamp-Massey algorithm, and this algorithm has ripe hardware configuration support.The expense and the performance of comprehensive encoding and decoding, BCH code is a kind of good selection.By the shift register coding of band feedback, classical Viterbi algorithm is used in decoding to convolutional code equally, and error-correcting performance is superior, and hardware spending is little, is the error correcting code s that is fit to very much the RFID communications applications equally.
Flow process as shown in Figure 4, in once traditional RFID communication process based on EPC C1G2 agreement, read write line is wished the content among the reading tag end EEPROM.Read write line sends a Query/QueryAdjust instruction, begins one time Inventory.Constantly send the instruction of Inventory class, be kept to 0 up to Slot counter, label returns a new RN16, after read write line received and returns, sending one was the ACK instruction of parameter with this RN16, if parameter was correct after label received, then label will be { PC, EPC} information returns to read write line.Read write line receives data, send a Req_RN (containing the RN16 identical) as parameter with ACK, label returns handle to effective Req_RN instruction, read write line is that order parameter sends the Read instruction with this handle then, label effectively instructs to handle subsequently and returns eeprom content, read write line carries out the inspection of crc error situation after receiving this content, if wrong then in the instruction of next bar call tag use error correcting code, arrange the error bit number in the present embodiment greater than selecting convolutional code at 3 o'clock for use.So detect CRC16 error bit number greater than 3 after, during communicating by letter in the back, uses by call tag of read write line transmission the extended instruction of convolutional code encoding and decoding, label returns handle after successfully receiving this instruction, read write line sends instruction and the label return data all passes through convolution coding in the communication of back then, and label receives instruction and read write line and receives and all carry out convolutional code decoder behind the label return data and operate.The error-correcting performance that convolutional code is superior has improved communication quality greatly.
Here the Memory that just reads label with read write line is the application that example describes this method, and and unrestricted its range of application.Other makes instruction that tab end returns band CRC16 such as write, can insert extended instruction after the Req_RN, enables codec functions.
What deserves to be mentioned is in the communication process of back, whether to use encoding and decoding and use which kind of encoding and decoding still can change, help reducing system power dissipation like this, can make RFID application adaptation environment more flexibly in addition.
Accompanying drawing 2 is the schematic block diagram according to the embodiment of the RFID label of first aspect present invention.The data that all labels send are before carrying out FM0 or Miller coding, at first whether decision is encoded and is adopted which kind of coding according to error correcting code zone bit content, if need then to carry out through the error correcting code scrambler coding of institute's code selection class, and the data that all receive will be carried out the error correction decode of institute's code selection class according to error correcting code zone bit content too or do not decoded after FM0 or Miller decoding.
Accompanying drawing 3 is the schematic block diagram according to the embodiment of the rfid interrogator of second aspect present invention method execution, after receiving that the label that comprises CRC16 returns, the read write line end is checked the data of being returned by the crc error decision device, whether decision sends instruction and enables error correcting code encoding and decoding communication and use which kind of error correcting code according to the error situation of CRC16, if enable, all transmissions after the transmission extended instruction is just received label to return handle or the data of reception are all corresponding to scrambler or demoder.
The present invention adds the error correcting code function by very little hardware and power consumption expense in the RFID communication process, can effectively improve the reading/writing distance of rfid system.
Claims (6)
1. control that the RFID label receives and the method for the information of transmission for one kind, this RFID label is communicated by letter with rfid interrogator; This method is carried out in the RFID label, it is characterized in that may further comprise the steps:
Receive the instruction of read-write class;
Execution command, return data then;
Receive instruction, this instruction is specified and whether is used error correcting code and use which kind of error correcting code;
Return the follow-up continued access of RN16 and receive the instruction of read-write class;
Decoding and execution command will be returned after the digital coding;
According to above method, after returning, execution command receives the instruction whether appointment is used error correcting code and used which kind of error correcting code, and this instruction is user's extended instruction, similar write command; The relevant zone bit of error correcting code is deposited in the conduct of a selected address in EEPROM in advance; This instruction is promptly carried out write operation to it; And in above second step: behind the execution command return data, extended instruction and command content that whether read write line sent in the 3rd step depend on the error situation that returns middle CRC16 check code that read write line receives; The mistake that do not have CRC16 then continues communication needn't send this extended instruction.
2. realize the RFID label of method according to claim 1 for one kind, it is characterized in that it comprises a main control module (17), FM0/Miller codec (15), RF front end (18), the demoder (14) of scrambler of error correcting code (13) and error correcting code, and the error correcting code zone bit (12) in EEPROM (1) 1; EEPROM (11) is connected with main control module (17) by interface (16), and whether selected certain address is used encoding and decoding and used which kind of encoding and decoding when receiving transmission information to be controlled at as error correcting code zone bit (12) in EEPROM (11); Scrambler of embedded standby error correcting code (13) and demoder (14) receive and send data and be chosen in data stream code coder (13) and the demoder (14) by error correction whether between FM0/Miller codec (15) and main control module (17) under the control of error correcting code zone bit; Label (01) with the read write line communication process in accept extended instruction, rewrite error correcting code zone bit (12), in the communication process of back, enable error correcting code scrambler (13) and error-correcting code decoder (14), after the data that receive are through FM0/Miller codec (15) decoding, through error correction decode (device 14); The data that label (01) returns to read write line through error correcting code scramblers (13) coding after again by FM0/Miller codec (15) coding, launch by emitting antenna (19) via radio-frequency front-end (18) then.
3. a rfid interrogator is handled the method for the information that reads and the information of transmission, this rfid interrogator and RFID label communication; This method is carried out in rfid interrogator, it is characterized in that may further comprise the steps:
Send read write command;
Reception is returned and is judged the CRC16 error situation;
Send extended instruction, receive return data;
Coding sends read write command;
Reception is returned and it is decoded.
4. a realization is as the rfid interrogator of method as described in the claim 3, it is characterized in that it comprises a main control module (25), FM0/Miller codec (24), RF front end (26), realize the scrambler (22) and the demoder (23) of error correcting code, CRC16 mistaken verdict device (21); Read write line (02) is receiving label (01) return data by receiving antenna (27), sending into FM0/Miller codec (24) through radio-frequency front-end (26) decodes, by CRC16 mistaken verdict device (21) the data error situation is judged, whether use error correcting code and use which kind of encoding and decoding by main control module (25) decision, use if need, then, the data that receive and will send are carried out Code And Decode respectively by the scrambler (22) and the demoder (23) of error correcting code.
5. communication means that comprises the rfid system of RFID label and rfid interrogator, this method may further comprise the steps:
Read write line sends read write command;
Label receives execution command and return data;
Read write line receives return data and judges whether to send extended instruction and determine this command content according to the error situation of CRC16;
Read write line sends extended instruction;
Label receives, and returns RN16 after carrying out this extended instruction;
Read write line receives return data, and coding sends the read write command of back then;
Label receives the decoding execution command and with return data after the digital coding;
Read write line is to receiving return data, and the line data of going forward side by side decoding continues coding and sends instruction or stop read-write.
6. a realization is as the rfid system of method as described in the claim 5, it is characterized in that forming by described RFID label of claim 2 and the described rfid interrogator of claim 4, label (01) return data is given read write line (02), read write line (02) receives data, and make error situation by CRC16 mistaken verdict device (21) and judge, and the result is sent to read write line main control module (25) decision whether send extended instruction and determine this command content;
Enable if desired error correcting code then read write line (02) send extended instruction notified tag (01) and enable error correcting code,
Label (01) returns handle after receiving and carrying out this extended instruction,
After read write line (02) received and returns, scrambler (22) coding was all passed through in the instruction that sends later, and the data that receive are all passed through demoder (23) decoding,
The data that label (01) receives all through demoder (14) decoding, encode by the encoded device of the data of transmission (13);
After the communication that at every turn relates to the judgement of error in data situation, read write line (02) sends extended instruction and determines which kind of error correcting code is the words of whether opening or closing error correcting code function and unlatching use.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910197203 CN101694699B (en) | 2009-10-15 | 2009-10-15 | Method and device for improving reading/writing distance of RFID |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910197203 CN101694699B (en) | 2009-10-15 | 2009-10-15 | Method and device for improving reading/writing distance of RFID |
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| CN101694699A true CN101694699A (en) | 2010-04-14 |
| CN101694699B CN101694699B (en) | 2013-01-30 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106250796A (en) * | 2016-08-16 | 2016-12-21 | 成都市和平科技有限责任公司 | A kind of radio system possessing height anti-collision and method |
| CN106485291A (en) * | 2015-08-24 | 2017-03-08 | 瑞章科技有限公司 | Radio-frequency recognition system, label and read write line, and error correction method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6297734B1 (en) * | 1999-09-23 | 2001-10-02 | Northrop Grumman Corporation | Randomization of transmit time |
| GB0604341D0 (en) * | 2006-03-03 | 2006-04-12 | Wavetrend Technologies Ltd | Apparatus and methods for electromagnetic identification |
| CN101441703B (en) * | 2008-10-08 | 2012-05-30 | 湖南大学 | Coding and decoding circuit of super high frequency radio frequency personal identification system |
-
2009
- 2009-10-15 CN CN 200910197203 patent/CN101694699B/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106485291A (en) * | 2015-08-24 | 2017-03-08 | 瑞章科技有限公司 | Radio-frequency recognition system, label and read write line, and error correction method |
| CN106250796A (en) * | 2016-08-16 | 2016-12-21 | 成都市和平科技有限责任公司 | A kind of radio system possessing height anti-collision and method |
| CN106250796B (en) * | 2016-08-16 | 2019-02-01 | 日照山川电子信息技术有限公司 | A kind of radio frequency system and method having height anti-collision |
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| CN101694699B (en) | 2013-01-30 |
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