CN108256365B - Test method for evaluating signal modulation characteristics of RFID reader - Google Patents

Test method for evaluating signal modulation characteristics of RFID reader Download PDF

Info

Publication number
CN108256365B
CN108256365B CN201810077067.3A CN201810077067A CN108256365B CN 108256365 B CN108256365 B CN 108256365B CN 201810077067 A CN201810077067 A CN 201810077067A CN 108256365 B CN108256365 B CN 108256365B
Authority
CN
China
Prior art keywords
rfid reader
signal
point
sig
searching
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201810077067.3A
Other languages
Chinese (zh)
Other versions
CN108256365A (en
Inventor
王洪君
申大雪
杨阳
许建华
王娜
彭新旺
王峰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shandong University
Original Assignee
Shandong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shandong University filed Critical Shandong University
Priority to CN201810077067.3A priority Critical patent/CN108256365B/en
Publication of CN108256365A publication Critical patent/CN108256365A/en
Application granted granted Critical
Publication of CN108256365B publication Critical patent/CN108256365B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/0095—Testing the sensing arrangement, e.g. testing if a magnetic card reader, bar code reader, RFID interrogator or smart card reader functions properly
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2218/00—Aspects of pattern recognition specially adapted for signal processing
    • G06F2218/02—Preprocessing

Landscapes

  • Engineering & Computer Science (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The invention relates to a test method for evaluating signal modulation characteristics of an RFID reader, which comprises the following steps: (1) setting the RFID reader signal to be tested as sig (n); (2) smoothing and filtering; (3) classifying the carrier waves into a plurality of classes, and counting the carrier wave amplitude; (4) setting a threshold readerThres, and circularly searching for a point which passes the threshold from sig (n); (5) for each pair of SOF and EOF, calculating the average value max of all maximum values and the average value min of all minimum values; (6) calculating the rising time and the falling time of each segment of reader pulse; (7) calculating the pulse width of each segment of reader pulse and judging according to a protocol; (8) and detecting linear regression of the rising edge and the falling edge of the reader signal. The invention weakens the influence of the burrs and the environmental noise on the signals and improves the calculation precision.

Description

Test method for evaluating signal modulation characteristics of RFID reader
Technical Field
The invention relates to a test method for evaluating signal modulation characteristics of an RFID reader, and belongs to the technical field of radio frequency identification.
Background
Radio Frequency Identification (RFID) is a non-contact automatic identification technology implemented by using a radio frequency communication method, and is a research hotspot in the field of information technology. The RFID technology has wide application prospect in the aspects of entrance guard, retail, logistics, automatic charging and the like. Because the RFID technology has the characteristics of high-speed moving object identification, multi-target identification, positioning and tracking, non-contact identification and the like, the RFID technology increasingly shows great development potential and application space, and is considered to be one of the information technologies with the most development prospects in the 21 st century. The complexity of the application environment and the diversity of RFID products make RFID testing very important.
The existing RFID testing method mostly depends on international standard protocols formulated by International organization for standardization EPCglobal and ISO, performs functional tests on readers and labels under different frequencies and different protocols, belongs to qualitative tests, and does not accurately perform quantitative tests. Moreover, the existing testing technology mainly focuses on the aspects of non-safety functions such as collision prevention, identification rate and the like, and does not test whether the signal per se meets the specification or not, and cannot meet the production and test requirements of readers and tags in practical application.
The reader is an important component of the RFID communication, and the difference in the performance of the reader has a very great influence on the system performance. Whether the reader supports simultaneous reading and writing of multiple cards, whether the reading and writing distance is proper, the directivity of the reader, the modulation characteristic of the reader, the relation between the transmitting power and the receiving sensitivity of the reader and the like play an extremely important role in the architecture, construction and type selection of the whole RFID system. The modulation characteristic of the reader signal is an important index for judging the performance of the reader, and is a basis for evaluating the integrity of the reader signal.
Chinese patent document CN104281861A discloses a RFID mobile test system and a corresponding method, wherein the detection method includes the following steps: a. guiding the motion of the motion carrier by the guide rail, and carrying the RFID label to move by the motion carrier; b. speed sampling is carried out on the moving carrier by a speed measuring radar; c. identifying, by the card reader, the RFID tag as it passes through its valid identification zone; d. and receiving the speed sampling data from the speed measuring radar by the computing equipment connected with the speed measuring radar, and determining the movement speed of the RFID label when the RFID label passes through the working range of the card reader according to the speed sampling data so as to judge whether the RFID label meets the RFID mobile test requirement. However, the patent only focuses on the identification function of the reader for the tag, ignores the characteristics of the reader signal, and cannot ensure that the reader signal meets the specification and meets the standard requirements.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a test method for evaluating the signal modulation characteristics of an RFID reader;
the invention carries out quantitative test on the performance of the reader on the market, and is used for guiding the production of the reader, improving the product performance and reducing the risk in the application process of the product.
Interpretation of terms:
1. a reader: is a very important infrastructure in RFID systems. The reader and the tag establish connection through near field communication, read the tag identification number and the stored data in the memory, or write data into the tag.
2. RFID reader signal: and monitoring the communication process of the reader and the tag by the monitoring antenna, and sampling the monitored signal to obtain an RFID signal. Wherein the part belonging to the reader transmission is the reader signal.
3. Envelope amplitude: also referred to as amplitude, the reader signal is divided into a real part I and an imaginary part Q,
Figure BDA0001559895970000021
i.e. the envelope magnitude.
4. Labeling: the tag and the reader-writer are communicated by utilizing the principle of electromagnetic wave backscattering, namely electromagnetic coupling, and the tag acquires energy from a space electric field and is activated to work when communication is needed.
5. Carrier wave: the unmodulated periodic oscillating signal is referred to as a carrier wave, which may be a sine wave or a non-sine wave (e.g., a periodic pulse train), and the carrier wave is modulated and referred to as a modulated signal, which contains the full-wave characteristics of the modulated signal. The frequency of the sinusoidal carrier is generally required to be much higher than the bandwidth of the modulated signal, otherwise aliasing occurs, distorting the transmitted signal.
6. Rise time: the time required for the signal to rise from 10% to 90% of the pulse peak amplitude.
7. The falling time is as follows: the time required for the signal to fall from 90% to 10% of the pulse peak amplitude.
8. Pulse width: the leading and trailing edges of the pulse are each equal to the time interval at which 50% of the pulse amplitude is measured, based on the bottom of the pulse.
The technical scheme of the invention is as follows:
a test method for evaluating signal modulation characteristics of an RFID reader comprises the following steps:
(1) setting the RFID reader signal to be tested as sig (n), n as the number of points of the RFID reader signal, and the data 0 reference time interval of the signal sampling frequency fs and sig (n) as Tari
(2) Performing smooth filtering on the RFID reader signal sig (n) to be tested;
(3) classifying the RFID reader signals sig (n) to be tested into a plurality of classes based on a simple clustering algorithm, and counting the amplitude of a carrier wave;
(4) setting a threshold readthrees 0.5, circularly searching points which pass the threshold readthrees from the initial position to the end of the reader signal, and seeing that all obtained threshold-passing points are positioned on the rising edge or the falling edge of the RFID reader signal, and the threshold-passing points have a corresponding relation, namely: the odd points are positioned on the falling edge of the signal of the RFID reader and marked as SOF, and the next point appears on the rising edge of the same section of the pulse of the RFID reader and marked as EOF;
(5) and (4) for each pair of SOF and EOF obtained in the step (4), searching the position marked as the SOF forwards to the first maximum value, searching backwards to the first minimum value, searching backwards to the first maximum value and searching forwards to the first minimum value, and solving the average value max of all the maximum values and the average value min of all the minimum values.
(6) Calculating the rising time and the falling time of each section of reader pulse, and the method comprises the following specific steps:
A. searching the position of each RFID reader signal marked as SOF obtained in the step (4) forwards to find a point of (max-min) 0.9+ min and a point of (max-min) 0.1+ min and a point of (max-min) 0.9+ min and a point of f0.1；
B. Calculating the falling time of the RFID reader signal:
Figure BDA0001559895970000031
C. for all the fall times of the resulting RFID reader signals, if Tf <0.33 x Tari, the fall time test is considered passed, otherwise it is not passed;
D. searching the position of each RFID reader signal marked as EOF obtained in the step (4) forwards to find the point of (max-min) 0.1+ min, and marking the position as r0.1, searching backwards to find the point of (max-min) 0.9+ min, and marking the position as r0.9；
E. Calculating the rise time of the RFID reader signal:
Figure BDA0001559895970000032
F. for all the rise times of the resulting RFID reader signals, the rise time test is considered passed if Tr <0.33 x Tari, otherwise not passed.
(7) Calculating the pulse width of each segment of reader pulse and judging according to a protocol;
G. setting ave as (max + min) × 0.5, judging the size of signals Sig (SOF) and ave of the SOF position for each pair of SOF and EOF obtained in the step (4), and if Sig (SOF) is less than ave, searching the point where the RFID reader signal passes ave forward; if Sig (SOF) > ave, searching backward the point of the signal ave of the RFID reader; if the two are equal, the point of the SOF position is the point of the RFID reader signal over ave, and the position of the obtained point is recorded as be;
H. judging the size of signals sig (EOF) and ave of the EOF position, and if sig (EOF) is less than ave, searching a point of the signal ave of the RFID reader backwards; if sig (EOF) > ave, forward searching for the point of the signal ave of the RFID reader; if the two are equal, the position of the EOF is the point of the RFID reader signal passing ave, and the obtained position of the point is marked as end;
I. calculating the pulse width of each segment of reader pulse:
Figure BDA0001559895970000033
J. for all pw, if there is MAX (0.265 × Tari,2) < pw <0.525 × Tari, the pulse width test is considered to pass, otherwise, the pulse width test does not pass, MAX () is a MAX function, and the function of the MAX function is to take the maximum of the two;
(8) detecting linear regression of rising and falling edges of a reader signal, comprising:
K. establishing a linear regression model y which is kx + b and is used for approximating the rising edge and the falling edge of the signal of the RFID reader, wherein x is the position of the signal of the RFID reader, and y is the theoretical value of the signal of the RFID reader;
l, representing the sampling points of the falling edge or the rising edge of the RFID reader signal as (Xi, Yi), wherein Xi is the position of the sampling points of the RFID reader signal, Yi is the actual value of the sampling points of the RFID reader signal, and m represents the number of the sampling points (Xi, Yi); order to
Figure BDA0001559895970000034
Substituting linear regression model y into kx + b and sampling point coordinates
Figure BDA0001559895970000035
To obtain
Figure BDA0001559895970000036
M, finding Sigma (y-Yi)2Minimum value of (d):
using functions
Figure BDA0001559895970000041
Calculating the partial derivatives of k and b to make the partial derivatives zero; namely, it is
Figure BDA0001559895970000042
Finishing to obtain the compound shown in the formula (I):
k*∑(Xi2)+b*∑Xi＝∑(Xi*Yi) (Ⅰ)；
Figure BDA0001559895970000043
finishing to obtain a compound shown in the formula (II):
k*∑Xi+m*b＝∑Yi (Ⅱ)；
and (3) simultaneously solving the formula (I) and the formula (II) to obtain a formula (III) and a formula (IV):
Figure BDA0001559895970000044
Figure BDA0001559895970000045
substituting k and b obtained in the step M into y ═ kx + b to obtain a linear regression equation;
o, substituting k and b obtained in the step M into
Figure BDA0001559895970000046
The minimum error sum is obtained.
According to the invention, preferably, in the step (2), the weighted average filtering algorithm is adopted to smoothly filter the to-be-tested RFID reader signal sig (n), so as to filter out unnecessary components in the signal and reserve useful components, so as to reduce the influence of noise and glitches on the signal. The method comprises the following steps:
a. selecting a weight matrix, the weight matrix being symmetric; considering the influence of the positions of the neighborhood points on the center point, the weight of the center should be larger than the weights of the two sides.
b. Performing convolution operation on the RFID reader signal sig (n) to be tested and the weight matrix to obtain weighted values of all sampling points in a neighborhood window of each point of the RFID reader signal sig (n) to be tested; the size of the neighborhood window is determined by the order of the filter. For example, in the case of a fifth-order filter, the size of the neighborhood window includes a central point and two points before and after the central point, i.e., the size of the neighborhood window is 5.
c. And d, replacing the value of each point of the to-be-tested RFID reader signal sig (n) with the weighted value of all sampling points in the corresponding neighborhood window obtained in the step b.
According to the preferable embodiment of the present invention, in the step (3), the RFID reader signals sig (n) to be tested are classified into a plurality of classes based on a simple clustering algorithm, and the counting of the carrier amplitude envelope includes:
d. aiming at known determination signals of a protocol ISO18000-6C, a large number of experiments are carried out to obtain a threshold thres and an initial amplitude tmpThres which can attribute signal points to a certain class;
e. setting an array for storing the average value of the classification points as cluster, (j) belonging to the cluster, calculating from the initial position of the signal according to the thres obtained in the step a, judging whether each point of the to-be-tested RFID reader signal sig (n) belongs to any existing class, and if not, adding new classification; sig (i) is any point of the RFID reader signal to be tested; if | sig (i) -cluster (j) | < thres is satisfied, the point sig (i) is classified as this class cluster (j) and the average value of this class cluster (j) is recalculated; otherwise, point sig (i) is not classified as cluster (j);
f. and finding the cluster with the value larger than tmpThres and the maximum number of points, and determining the average value as the carrier amplitude envelope.
The invention has the beneficial effects that:
1. according to the test method for evaluating the signal modulation characteristics of the RFID reader, smooth filtering is utilized, the influence of burrs and environmental noise on signals is weakened, and the calculation precision is improved; the simple clustering algorithm is utilized to help search the position of the reader pulse, and a foundation is provided for the subsequent calculation of modulation parameters such as rise time and fall time.
2. The test method for evaluating the signal modulation characteristics of the RFID reader can realize the automatic test of the modulation parameters of the reader, reduces the manual participation, and has simple method and low algorithm complexity.
3. The test method for evaluating the signal modulation characteristics of the RFID reader focuses on the parameters of the reader signal and judges the standard conformity, and can be used for guiding the product production of the reader, improving the product performance and reducing the risk in the product application process.
Drawings
Fig. 1 is a schematic diagram of a reader and tag communication process in an RFID system.
FIG. 2 is a schematic diagram of an RFID raw signal.
Fig. 3 is a schematic diagram of a smoothed filtered signal.
FIG. 4 is a diagram showing the rise time and fall time of the reader.
FIG. 5 is a flow chart of a test method for evaluating signal modulation characteristics of an RFID reader according to the present invention.
Detailed Description
The invention is further defined in the following, but not limited to, the figures and examples in the description.
Example 1
A test method for evaluating signal modulation characteristics of an RFID reader, as shown in fig. 5, includes:
(1) setting the RFID reader signal to be tested as sig (n), wherein n is the number of points of the RFID reader signal, the signal sampling frequency is fs, and the reference time interval of data 0 is Tari as shown in FIG. 2;
(2) performing smooth filtering on the RFID reader signal sig (n) to be tested; the smoothed signal is shown in fig. 3.
(3) Classifying the RFID reader signals sig (n) to be tested into a plurality of classes based on a simple clustering algorithm, and counting the amplitude of a carrier wave;
(4) setting a threshold readthrees 0.5, circularly searching points which pass through the threshold from sig (n) to the end, and seeing that all points which pass through the threshold are positioned on the rising edge or the falling edge of a reader signal, wherein the points which pass through the threshold have a corresponding relation, the odd points are positioned on the falling edge of the reader signal and are marked as SOF, and the next point is positioned on the rising edge of the same reader signal and is marked as EOF;
(5) and (4) for each pair of SOF and EOF obtained in the step (4), searching the position marked as the SOF forwards to the first maximum value, searching backwards to the first minimum value, searching backwards to the first maximum value and searching forwards to the first minimum value, and solving the average value max of all the maximum values and the average value min of all the minimum values.
(6) Calculating the rise time and the fall time of each segment of the reader pulse, as shown in fig. 4, the specific steps are as follows:
A. searching the position of each reader signal marked as SOF obtained in the step (4) forward, and searching a point (max-min) 0.9+ min, wherein the position is marked as f0.9And search backwards to searchFind the point of (max-min) × 0.1+ min, and mark the position as f0.1；
B. Calculating the fall time of the reader signal:
Figure BDA0001559895970000061
C. for all tfs, if Tf < (0.33 x Tari), the fall time test is considered passed, otherwise it is not passed;
D. searching the position of each reader signal marked as EOF obtained in the step (4) forward, searching a point (max-min) 0.1+ min, and marking the position as r0.1And searching backwards to find the point of (max-min) × 0.9+ min, and recording the position as r0.9；
E. Calculating the rise time of the reader signal:
Figure BDA0001559895970000062
F. for all Tr, if Tr < (0.33 × Tari), the rise time test is considered passed, otherwise it is not.
(7) Calculating the pulse width of each segment of reader pulse and judging according to a protocol;
G. setting ave as (max + min) × 0.5, judging the size of the signal of the SOF position and ave for each pair of SOF and EOF obtained in the step (4), and if Sig (SOF) < ave, searching forward the point where the reader signal passes ave; if Sig (SOF) > ave, searching backward for the point of the ave of the reader signal; if the two are equal, the point of the SOF position is the point of the reader signal over ave, and the obtained point position is recorded as be;
H. judging the size of the signal of the EOF position and ave, and if sig (EOF) is less than ave, searching a point of the reader signal passing ave backwards; if sig (EOF) > ave, searching forward for the point of the reader signal passing ave; if the two are equal, the point of the EOF position is the point of the reader signal passing ave, and the obtained point position is recorded as end;
I. calculating the pulse width of each segment of reader pulse:
Figure BDA0001559895970000063
J. for all pw, if there is MAX (0.265 × Tari,2) < pw <0.525 × Tari, the pulse width test is considered to pass, otherwise, the pulse width test does not pass, MAX () is a MAX function, and the function of the MAX function is to take the maximum of the two;
(8) detecting linear regression of rising and falling edges of a reader signal, comprising:
K. establishing a linear regression model y which is kx + b and is used for approximating the rising edge and the falling edge of a reader signal, wherein x is the position of the reader signal, and y is the theoretical value of the reader signal;
l, representing the sampling points of the falling edge or the rising edge of the reader signal as (Xi, Yi), wherein Xi is the position of the sampling points of the reader signal, Yi is the actual value of the sampling points of the reader signal, and m represents the number of the sampling points (Xi, Yi); order to
Figure BDA0001559895970000071
Substituting linear regression model y into kx + b and sampling point coordinates
Figure BDA0001559895970000072
To obtain
Figure BDA0001559895970000073
M, finding Sigma (y-Yi)2Minimum value of (d):
using functions
Figure BDA0001559895970000074
Calculating the partial derivatives of k and b to make the partial derivatives zero; namely, it is
Figure BDA0001559895970000075
Finishing to obtain the compound shown in the formula (I):
k*∑(Xi2)+b*∑Xi＝∑(Xi*Yi) (Ⅰ)；
Figure BDA0001559895970000076
finishing to obtain a compound shown in the formula (II):
k*∑Xi+m*b＝∑Yi (Ⅱ)；
and (3) simultaneously solving the formula (I) and the formula (II) to obtain a formula (III) and a formula (IV):
Figure BDA0001559895970000077
Figure BDA0001559895970000078
substituting k and b obtained in the step M into y ═ kx + b to obtain a linear regression equation;
o, substituting k and b obtained in the step M into
Figure BDA0001559895970000079
The minimum error sum is obtained.
The reader and tag communication process in an RFID system is shown in fig. 1. Wherein, the abscissa is the number of points of the signal, and the ordinate is the amplitude of the signal.
Example 2
The test method for evaluating the signal modulation characteristics of the RFID reader in the embodiment 1 is characterized in that in the step (2), the weighted average filtering algorithm is adopted to carry out smooth filtering on the RFID reader signal sig (n) to be tested, unnecessary components in the signal are filtered out, and useful components are reserved to reduce the influence of noise and burrs on the signal. The method comprises the following steps:
a. selecting a weight matrix, the weight matrix being symmetric; considering the influence of the positions of the neighborhood points on the center point, the weight of the center should be larger than the weights of the two sides.
b. Performing convolution operation on the RFID reader signal sig (n) to be tested and the weight matrix to obtain weighted values of all sampling points in a neighborhood window of each point of the RFID reader signal sig (n) to be tested;
c. and d, replacing the value of each point of the to-be-tested RFID reader signal sig (n) with the weighted value of all sampling points in the corresponding neighborhood window obtained in the step b.
Example 3
The method for evaluating the modulation characteristics of the RFID reader signals according to embodiment 1 is characterized in that, in the step (3), the RFID reader signals sig (n) to be tested are classified into a plurality of classes based on a simple clustering algorithm, and the counting of the carrier amplitude envelope includes:
d. aiming at known determination signals of a protocol ISO18000-6C, a large number of experiments are carried out to obtain a threshold thres and an initial amplitude tmpThres which can attribute signal points to a certain class;
e. setting an array for storing the average value of the classification points as cluster, (j) belonging to the cluster, calculating from the initial position of the signal according to the thres obtained in the step a, and judging whether each point of the to-be-tested RFID reader signal sig (n) belongs to any existing type; sig (i) is any point of the RFID reader signal to be tested; if | sig (i) -cluster (j) | < thres is satisfied, the point sig (i) is classified as this class cluster (j) and the average value of this class cluster (j) is recalculated; otherwise, point sig (i) is not classified as cluster (j);
f. and finding the cluster with the value larger than tmpThres and the maximum number of points, and determining the average value as the carrier amplitude envelope.

Claims (3)

1. A test method for evaluating signal modulation characteristics of an RFID reader is characterized by comprising the following steps:
(1) setting the RFID reader signal to be tested as sig (n), n is the number of points of the RFID reader signal, the signal sampling frequency is fs, and the data 0 reference time interval of the sig (n) is Tari;
(2) performing smooth filtering on the RFID reader signal sig (n) to be tested;
(3) classifying the RFID reader signals sig (n) to be tested into a plurality of classes based on a simple clustering algorithm, and counting the amplitude of a carrier wave;
(4) setting a threshold readthrees of 0.5, wherein the envelope refers to the amplitude of a carrier wave, circularly searching points of the threshold readthrees from the beginning to the end of a reader signal, and all obtained threshold-passing points are positioned on the rising edge or the falling edge of the RFID reader signal, and the threshold-passing points have a corresponding relation, namely: the odd points are positioned on the falling edge of the signal of the RFID reader and marked as SOF, and the next point appears on the rising edge of the same section of the pulse of the RFID reader and marked as EOF;
(5) for each pair of SOF and EOF obtained in the step (4), searching the position marked as the SOF forwards to a first maximum value, searching backwards to a first minimum value, searching backwards to a first maximum value and searching forwards to a first minimum value, and solving an average value max of all maximum values and an average value min of all minimum values;
(6) calculating the rising time and the falling time of each section of reader pulse, and the method comprises the following specific steps:
A. searching the position of each RFID reader signal marked as SOF obtained in the step (4) forward, and searching a point with the position being marked as f and the position being marked as (max-min) × 0.9+ min0.9And searching backwards to find the point of (max-min) × 0.1+ min, and the position is marked as f0.1；
B. Calculating the falling time of the RFID reader signal:
Figure FDA0002658104370000011
C. for all the obtained fall times of the RFID reader signals, if Tf is less than 0.33 Tari, the fall time test is considered to pass, otherwise, the fall time test is not considered to pass;
D. searching the position of each RFID reader signal marked as EOF obtained in the step (4) forward, searching a point (max-min) 0.1+ min, and marking the position as r0.1And searching backwards to find the point of (max-min) × 0.9+ min, and recording the position as r0.9；
E. Calculating the rise time of the RFID reader signal:
Figure FDA0002658104370000012
F. for all the obtained rise times of the RFID reader signals, if Tr is less than 0.33 Tari, the rise time test is considered to pass, otherwise, the rise time test is not considered to pass;
(7) calculating the pulse width of each segment of reader pulse and judging according to a protocol;
G. setting ave as (max + min) × 0.5, judging the size of signals Sig (SOF) and ave of the SOF position for each pair of SOF and EOF obtained in the step (4), and if Sig (SOF) < ave, searching the point where the RFID reader signal passes ave forward; if Sig (SOF) is greater than ave, searching back for the point of passing ave of the RFID reader signal; if the two are equal, the point of the SOF position is the point of the RFID reader signal over ave, and the position of the obtained point is recorded as be;
H. judging the size of signals sig (EOF) and ave of the EOF position, and searching an ave passing point of the RFID reader signal backwards if sig (EOF) is less than ave; if sig (EOF) is greater than ave, forward searching for an ave passing point of the RFID reader signal; if the two are equal, the position of the EOF is the point of the RFID reader signal passing ave, and the obtained position of the point is marked as end;
I. calculating the pulse width of each segment of reader pulse:
Figure FDA0002658104370000021
J. for all pw, if there is MAX (0.265 × Tari,2) < pw <0.525 × Tari, the pulse width test is considered to pass, otherwise, the pulse width test does not pass, MAX () is a MAX function, and the function of the MAX function is to take the maximum value of the two;
(8) detecting linear regression of rising and falling edges of a reader signal, comprising:
K. establishing a linear regression model y which is kx + b and is used for approximating the rising edge and the falling edge of the signal of the RFID reader, wherein x is the position of the signal of the RFID reader, and y is the theoretical value of the signal of the RFID reader;
l, representing the sampling points of the falling edge or the rising edge of the RFID reader signal as (Xi, Yi), wherein Xi is the position of the sampling points of the RFID reader signal, Yi is the actual value of the sampling points of the RFID reader signal, and m represents the number of the sampling points (Xi, Yi); order to
Figure FDA0002658104370000022
Make the linear backReturn model y as kx + b and sample point coordinate input
Figure FDA0002658104370000023
To obtain
Figure FDA0002658104370000024
Figure FDA0002658104370000025
M, finding Sigma (y-Yi)2Minimum value of (d):
using functions
Figure FDA0002658104370000026
Calculating the partial derivatives of k and b to make the partial derivatives zero; namely, it is
Figure FDA0002658104370000027
Finishing to obtain the formula (I):
k*∑(Xi2)+b*∑Xi＝∑(Xi*Yi) (I)；
Figure FDA0002658104370000028
finishing to obtain a compound shown in a formula (II):
k*∑Xi+m*b＝∑Yi (II)；
and (3) solving the formula (I) and the formula (II) simultaneously to obtain a formula (III) and a formula (IV):
Figure FDA0002658104370000029
Figure FDA00026581043700000210
substituting k and b obtained in the step M into y ═ kx + b to obtain a linear regression equation;
0. substituting k and b obtained in step M into
Figure FDA00026581043700000211
The minimum error sum is obtained.
2. The testing method for evaluating the signal modulation characteristics of the RFID reader according to claim 1, wherein the step (2) of performing smooth filtering on the RFID reader signal sig (n) to be tested by using a weighted average filtering algorithm comprises the following steps:
a. selecting a weight matrix, the weight matrix being symmetric;
b. performing convolution operation on the RFID reader signal sig (n) to be tested and the weight matrix to obtain weighted values of all sampling points in a neighborhood window of each point of the RFID reader signal sig (n) to be tested;
c. and d, replacing the value of each point of the to-be-tested RFID reader signal sig (n) with the weighted value of all sampling points in the corresponding neighborhood window obtained in the step b.
3. The testing method for evaluating the modulation characteristics of the RFID reader signals according to claim 1 or 2, wherein the step (3) of classifying the RFID reader signals sig (n) to be tested into a plurality of classes based on a simple clustering algorithm, and counting the carrier amplitude envelope comprises the following steps:
d. for the known determination signals of the protocol ISO180006C, a large number of experiments are carried out, obtaining a threshold thres and an initial amplitude tmpThres that attribute the signal point to a certain class;
e. setting an array for storing the average value of the classification points as cluster, (j) belonging to the cluster, calculating from the initial position of the signal according to the thres obtained in the step a, and judging whether each point of the to-be-tested RFID reader signal sig (n) belongs to any existing type; sig (i) is any point of the RFID reader signal to be tested; if | sig (i) -cluster (j) | < thres is satisfied, the point sig (i) is classified as the cluster (j) and the average value of the cluster (j) is recalculated; otherwise, point sig (i) is not classified as cluster (j);
f. and finding the cluster with the value larger than tmpThres and the maximum number of points, and determining the average value as the carrier amplitude envelope.
CN201810077067.3A 2018-01-26 2018-01-26 Test method for evaluating signal modulation characteristics of RFID reader Active CN108256365B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810077067.3A CN108256365B (en) 2018-01-26 2018-01-26 Test method for evaluating signal modulation characteristics of RFID reader

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810077067.3A CN108256365B (en) 2018-01-26 2018-01-26 Test method for evaluating signal modulation characteristics of RFID reader

Publications (2)

Publication Number Publication Date
CN108256365A CN108256365A (en) 2018-07-06
CN108256365B true CN108256365B (en) 2021-01-15

Family

ID=62742731

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810077067.3A Active CN108256365B (en) 2018-01-26 2018-01-26 Test method for evaluating signal modulation characteristics of RFID reader

Country Status (1)

Country Link
CN (1) CN108256365B (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101236595A (en) * 2007-01-29 2008-08-06 国际商业机器公司 Radio frequency identification reader and its test method
US7847743B2 (en) * 2005-12-09 2010-12-07 Electronics And Telecommunications Research Institute Method for measuring inverse scattering wave, and apparatus for identifying inferior RFID transponder and reader using the same
CN102539970A (en) * 2012-01-04 2012-07-04 华北电网有限公司计量中心 RFID (radio frequency identification) equipment testing method and system
CN104125050A (en) * 2014-08-04 2014-10-29 江苏物联网研究发展中心 Ultrahigh-frequency RFID (radio frequency identification) reader protocol conformance testing method
CN104635067A (en) * 2013-11-07 2015-05-20 北京自动测试技术研究所 Radio frequency signal testing method
CN105656574A (en) * 2016-02-03 2016-06-08 上海坤锐电子科技有限公司 Detection device for sensitivity of NFC card reader
CN107220572A (en) * 2017-06-27 2017-09-29 天津市滨海新区军民融合创新研究院 The sensitivity of radio frequency reader and the method for testing of Packet Error Ratio, equipment and system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7847743B2 (en) * 2005-12-09 2010-12-07 Electronics And Telecommunications Research Institute Method for measuring inverse scattering wave, and apparatus for identifying inferior RFID transponder and reader using the same
CN101236595A (en) * 2007-01-29 2008-08-06 国际商业机器公司 Radio frequency identification reader and its test method
CN102539970A (en) * 2012-01-04 2012-07-04 华北电网有限公司计量中心 RFID (radio frequency identification) equipment testing method and system
CN104635067A (en) * 2013-11-07 2015-05-20 北京自动测试技术研究所 Radio frequency signal testing method
CN104125050A (en) * 2014-08-04 2014-10-29 江苏物联网研究发展中心 Ultrahigh-frequency RFID (radio frequency identification) reader protocol conformance testing method
CN105656574A (en) * 2016-02-03 2016-06-08 上海坤锐电子科技有限公司 Detection device for sensitivity of NFC card reader
CN107220572A (en) * 2017-06-27 2017-09-29 天津市滨海新区军民融合创新研究院 The sensitivity of radio frequency reader and the method for testing of Packet Error Ratio, equipment and system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
符合ISO/IEC 14443标准的RFID信号测试系统软件的设计和实现;蔡楠楠;《中国优秀硕士学位论文全文数据库 信息科技辑》;20160215;全文 *

Also Published As

Publication number Publication date
CN108256365A (en) 2018-07-06

Similar Documents

Publication Publication Date Title
EP2648131B1 (en) Method and device for locating RFID tags
CN102539970A (en) RFID (radio frequency identification) equipment testing method and system
CN107943887B (en) RFID tag sequencing method in conveyor belt environment
EP2457193A2 (en) A movement detection method and reader/writers in a radio frequency identification system
EP1760640A1 (en) System for measuring the distance between an RFID tag and a base station
CN101149783B (en) Rfid interrogator device
CN111541511B (en) Communication interference signal identification method based on target detection in complex electromagnetic environment
CN102998654A (en) Method and device of label phase information and based on passive wireless radio frequency recognition
CN108460304A (en) Lane discriminating method and system, data processing equipment residing for vehicle
CN109376820A (en) Books based on RFID technique are accurately positioned sort method
CN105550720A (en) RFID system capable of enhancing read-write distance and read-write method thereof and energy distribution optimization method
CN110954863A (en) RFID positioning method oriented to storage article positioning
CN107622290A (en) Radio frequency identification and radar linkage processing method and system, data processing equipment
CN110857979B (en) Anti-interference identification system and method for polarization frequency selection characteristic material based on coherent signal
CN103310172A (en) Echo frequency discrimination method for passive radio frequency identification temperature measurement system
CN112149436A (en) Portable RFID field tester
CN105515753A (en) RFID (radio frequency identification) lead code detection method based on FPGA (Field-Programmable Gate Array)
CN108256365B (en) Test method for evaluating signal modulation characteristics of RFID reader
CN110458257A (en) Label checking method and device based on RFID system
CN110764152A (en) Device and method for rapid detection and identification of unmanned aerial vehicle
CN109034313A (en) Parking stall use state detection method, system, reflective tape and anticollision strip
CN108549922A (en) A kind of ultra-high frequency RFID label accurate positioning method based on label coupling
CN113283258A (en) Method and reading device capable of automatically searching optimal working frequency point of electronic tag
CN106908709A (en) The system and method for electromagnetic distu during detection intelligent card non-contact communication
Li et al. Recovery of collided RFID tags with frequency drift on physical layer

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant