RFID system performance prediction method under condition of label linear distribution

Abstract

The invention discloses an RFID system performance prediction method under the condition of linear distribution of tags, and the method comprises the following steps: S1, carrying out the linear array distribution of RFID tags, and recording the number n and spacing of the tags; s2, recording the working wavelength lambda of the label, and calculating the wavelength number d lambda of the label interval; s3, solving the mathematical model of the tag linear array distribution RFID system performance according to the number n of the tags and the wavelength number d lambda, and obtaining the performance attenuation at the most obvious position of the system performance attenuation; and S4, determining the transmitting power increasing multiplying power required for activating all the tags through the performance attenuation amount. The performance prediction method has the advantages of being small in calculation amount, high in calculation speed, universal in adaptability and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency identification electronic tags, and in particular to a method for predicting RFID system performance under a situation where tags are linearly distributed. Background Art

[0002] Radio frequency identification (RFID) technology can realize contactless communication between readers and tags. Due to its advantages such as long reading distance, fast reading speed and long service life, it is widely used in various fields of social and economic development, such as logistics, transportation, collections, production, etc. However, in these actual application scenarios, tags are often densely distributed and densely deployed at a distance of several wavelengths from each other. Each tag is easily interfered by the backlink scattered signals of other tags, destroying the impedance matching relationship between the chip and the tag antenna, resulting in a significant reduction in the performance of the tag and RFID system. Therefore, it is necessary to examine this influence through the corresponding model, so as to provide a theoretical basis for the future application of small, passive, densely distributed RFID tags.

[0003] The existing technology often uses electromagnetic simulation software to simulate the working condition of the target tag under the interference tag to analyze the impact of the mutual coupling effect on the RFID system link. The following problems still exist:

[0004] (1) There is a lack of research on the impact of the overall distribution status of the RFID system on system performance.

[0005] (2) The simulation calculation is large and time-consuming. When the type of analysis label needs to be changed, the workload required for modeling is large. Summary of the invention

[0006] Based on the technical problems existing in the background technology, the present invention proposes a method for predicting the performance of an RFID system under the condition of linear distribution of tags, which has the advantages of small calculation amount, fast calculation speed and universal adaptability.

[0007] The present invention proposes a method for predicting RFID system performance under a linear distribution of tags, and the method steps are as follows:

[0008] S1: Distribute the RFID tags in a linear array and record the number n and spacing d of the tags;

[0009] S2: Record the tag working wavelength λ and calculate the number of wavelengths d between tags λ ;

[0010] S3: According to the number of tags n and the number of wavelengths d λ Solve the mathematical model of the RFID system performance of the linear array of tags to obtain the performance degradation at the location where the system performance degradation is most obvious;

[0011] S4: Determine the transmission power increase ratio required to activate all tags based on the performance degradation.

[0012] Preferably, the number of wavelengths d in S2 is λ The calculation method is:

[0013]

[0014] Among them, d λ >0.16.

[0015] Preferably, the mathematical model of the performance of the tag linear array distribution RFID system in S3 is as follows:

[0016]

[0017] A2=1.45-25.98e -1.56n

[0018] Among them, τ min n,d λ Indicates the power transmission coefficient at the location where the performance of the tag group system degrades most significantly.

[0019] Preferably, the calculation method of the performance degradation amount Δη at the position where the system performance degradation is most obvious is:

[0020] Δη(%)=1-τ min n,d λ .

[0021] Preferably, the calculation method of the transmission power increase ratio ΔP* in S4 is:

[0022]

[0023] Beneficial technical effects of the present invention:

[0024] The present invention proposes a method for predicting RFID system performance under the condition of linear distribution of tags. The power transmission coefficient is used as an indicator for predicting the performance of the RFID system, and a transmission model for the power transmission coefficient is constructed. The model can be used to determine the position where the system performance of the tag group is most obviously attenuated and the attenuation at the position, thereby determining the transmission power increase factor required for the reader to activate all tags under the influence of the performance attenuation caused by the mutual coupling effect. The performance prediction method has the advantages of small calculation amount, fast calculation speed and strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flowchart of a method for predicting RFID system performance under a linear tag distribution situation.

[0026] Figure 2This is a schematic diagram of the applicable scenarios of the RFID system performance prediction method under the condition of linear tag distribution proposed by the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further explained below in conjunction with specific embodiments.

[0028] Reference Figure 1 and Figure 2 The performance prediction method of the linear array distributed RFID system proposed by the present invention has the following steps:

[0029] S1: Place 6 items with ALN-9662 RFID tags on a flat surface in a linear array with a tag spacing of 10 cm.

[0030] S2: The wavelength of the system working is 32.8cm through the working status of the reader / writer, and the number of wavelengths of the tag spacing is calculated.

[0031] Wavelength d λ The calculation method is:

[0032]

[0033] After calculation, the wavelength number of the label spacing in this embodiment is 0.305.

[0034] S3: Substitute the number of tags obtained in S1 and the number of wavelengths obtained in S2 into the mathematical model of the linear array distributed RFID system performance to obtain the performance attenuation at the location where the system performance attenuation is most obvious.

[0035] Among them, the mathematical model of the linear array distributed RFID system performance is as follows:

[0036]

[0037] A2=1.45-25.98e -1.56n

[0038] Among them, τ min n,d λ The power transmission coefficient at the location where the performance of the tag group system is most obviously degraded is calculated to be: τ min 6,0.305≈0.6638.

[0039] The performance degradation at the most obvious position of system performance degradation can be expressed as:

[0040] Δη(%)=1 min -τ min n,d λ .

[0041] Substitute τ min6,0.305 to obtain Δη(%)=1-τ min 6,0.305≈33.62%, that is, the tag performance at the location where the system performance decayed most significantly decayed by 33.62%.

[0042] S4: The performance degradation in S3 can be used to determine the transmission power increase factor ΔP* required for the reader to activate all tags while taking into account the performance degradation caused by the mutual coupling effect.

[0043]

[0044] Substitute τ min 6,0.305 is obtained

[0045] The present invention proposes a method for predicting RFID system performance under the condition of linear distribution of tags. The power transmission coefficient is used as an indicator for predicting the performance of the RFID system, and a transmission model for the power transmission coefficient is constructed. The model can be used to determine the position where the system performance of the tag group is most obviously attenuated and the attenuation at the position, thereby determining the transmission power increase factor required for the reader to activate all tags under the influence of the performance attenuation caused by the mutual coupling effect. The performance prediction method has the advantages of small calculation amount, fast calculation speed and strong adaptability.

Claims

1. A method for predicting RFID system performance under linear tag distribution, characterized in that: The steps are as follows: S1: Distribute the RFID tags in a linear array and record the number n and spacing d of the tags; S2: Record the tag working wavelength λ and calculate the number of wavelengths d between tags λ ; S3: According to the number of tags n and the number of wavelengths d λ Solve the mathematical model of the RFID system performance of the linear array of tags to obtain the performance degradation at the location where the system performance degradation is most obvious; S4: Determine the transmission power increase ratio required to activate all tags based on the performance degradation.

2. The method for predicting RFID system performance under the condition of linear distribution of tags according to claim 1, characterized in that: The number of wavelengths in S2 d λ The calculation method is: Among them, d λ >0.

16.

3. The method for predicting RFID system performance under a linear tag distribution situation according to claim 1, characterized in that: The mathematical model of the performance of the RFID system with linear array distribution of tags in S3 is as follows: <h2 style=";text-align:left;direction:ltr">A2 = 1.45-25.98e<h2 style=";text-align:left;direction:ltr"> -1.56n in, Indicates the power transmission coefficient at the location where the performance of the tag group system degrades most significantly.

4. The method for predicting RFID system performance under linear tag distribution according to claim 3, characterized in that: The calculation method of the performance degradation Dη at the position where the system performance degradation is most obvious is:

5. The method for predicting RFID system performance under linear tag distribution according to claim 3, characterized in that: The calculation method of the transmission power increase ratio DP* in S4 is:

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