CN102521627B - A Middleware-Based RFID System Reader De-redundancy Method - Google Patents

Abstract

The invention discloses a redundancy eliminating method of an RFID (radio frequency identification) system reader based on a middleware. The method relies on an EPC (electronic product code) network architecture to utilizes label information of an RFID middleware to judge a redundant reader. The method does not require system topology or require a reader to write information into a label, and has good flexibility and expandability. Compared with the typical method LEO+RRE (Layered Elimination Optimization+ Recurrence Risk Estimator), the method improves the detection rate of the redundant reader for 6.27-20.80%, and reduces data quantity of the labels to be obtained and processed by the system for 4.50-35.73%, so as to further optimize rationality of system deployment.

Description

A Middleware-Based RFID System Reader De-redundancy Method

technical field

The invention relates to the field of radio frequency identification (RFID) network technology, in particular to a middleware-based RFID system reader redundancy removal method.

Background technique

RFID (Radio Frequency Identification) is a system for automatic identification and wireless data acquisition. With the rapid development of the electronics industry, RFID technology has been widely used in supply chain management, medical monitoring, positioning and navigation, smart home and many other fields, and is regarded by the industry as one of the core technologies to realize the Internet of Things.

Redundant-reader Problem is one of the fundamental issues affecting the performance of RFID systems. In large-scale, especially densely deployed RFID systems, identifying and closing redundant readers can reduce the energy consumption of the RFID system, optimize system deployment, and reduce the amount of tag data that the system needs to acquire and process. Therefore, the research purpose of RFID reader de-redundancy is to optimize the overall performance of the system by minimizing the number of working readers in the coverage area, which is conducive to solving the problem of reader-level read and write conflicts, and can also be used to guide the planning and design of RFID systems. Two classic reader redundancy algorithms:

(1) RRE (Redundant Reader Elimination) algorithm: This algorithm is a greedy strategy-based RRE algorithm, which uses the number of tags in the reader RA as the weight to ensure that the reader with the largest weight "locks" all tags in the RA first. The "locking" process refers to the multiple read-write communication process between each reader and its RA tags. Each reader decides whether to write "lock" information to the tag by comparing its own weight with the weight of the tag's returned information, iteratively runs until all tags are "locked" by the reader, and the reader that does not "lock" any tag is Redundant reader. However, the RRE algorithm will fail in some system topologies. At the same time, the working characteristic of one-to-one writing of information between the reader and the tag may lead to the occurrence of multiple readers with the same weight, thus causing the RRE algorithm to miss redundant readers.

(2) LEO (Layered Elimination Optimization) algorithm: This algorithm is based on the "first come, first served" strategy. Each reader reads the tags in the RA hierarchically and successively, and ensures that each tag is "locked" by the reader that reads it for the first time. A reader that does not write information to any tag is a redundant reader. Compared with the RRE algorithm, in the LEO algorithm, the number of times the reader reads and writes the tags is greatly reduced, but the reading order of the reader is random, so the reliability of the algorithm is not good. On this basis, the authors of LEO further proposed the LEO+RRE algorithm, which combines the advantages of the above two algorithms and has better de-redundancy performance and reliability. However, the communication method of exchanging information between readers by reading and writing tags will cause the LEO (LEO+RRE) algorithm to miss redundant readers or fail to achieve the best performance of the algorithm.

At the same time, various algorithms including the RRE algorithm and the LEO algorithm require the reader to write "lock" information to the tag, and this information can also be read by other readers. Therefore, these algorithms all contain an implicit premise: the maximum distance a tag can be read by a reader (read distance) is equal to the maximum distance it can be written to (write distance). However, the chip characteristics of RFID tags determine that the reader needs to consume more power when writing information to the tag, so the writing distance of the reader is generally smaller than its reading distance. The working characteristics of the reader’s unequal reading and writing distance to the tag will cause the de-redundancy algorithm to miss and misjudge the redundant reader, so that it cannot ensure that the system can read all the tag information. Therefore, various reader de-redundancy algorithms that require the reader to write "lock" information to the tag, such as RRE, LEO, etc., are unreliable in the actual application environment. In addition, in large-scale, especially in wireless communication RFID systems, the resources of both readers and tags are generally limited, and the reader's multiple reading and writing of tags and the redundant discrimination function of the reader will increase the burden on the system.

Therefore, in the implementation process of the RFID system reader de-redundancy algorithm, the working characteristics of the RFID system have a greater impact on the performance and reliability of the algorithm. solved problem.

Contents of the invention

In order to solve the above-mentioned missed judgment of redundant readers, and in large-scale especially wireless communication RFID systems, the resources of readers and tags are generally limited. Function will increase the deficiencies of the prior art such as system burden, the present invention provides a kind of middleware-based RFID system reader redundancy that has higher detection rate of redundant readers and can reduce the amount of tags that the system needs to process method.

The technical scheme of the present invention is: a kind of middleware-based RFID system reader redundant method, comprises the following steps:

S1 defines the matrix MRT. The reader number R _i is the row number, and the tag number T _j is the column number. When the reader numbered R _i can read the tag numbered T _j , the matrix element MRT(R _i ,T _j ) has a value of 1, otherwise, let its value be 0;

S2 calculates the sum of the data values of each row element of the matrix MRT and the sum of the data values of each column element to obtain one-dimensional arrays MR and MT respectively;

S3 calculates the maximum value of the element data in the array MR, if there is only one element corresponding to the maximum value of the data, record the reader corresponding to the element number as R _min , otherwise record the set of element numbers corresponding to the maximum value of the element data in the array MR as RCS;

S4 records the number of the reader in the element numbering set RCS and its surrounding readers having the same label as RRF, and obtains the RRF value of each reader in the set RCS, and records the reader corresponding to the minimum value of RRF as _Rmin ;

S5 sets the reader R _min as a reader in the working state, and updates the element data values of all rows and columns corresponding to the reader R _min in the matrix MRT to 0;

S6 updates the element data in the array MR, and repeats steps S3 to S5 until the matrix MRT is an empty matrix. At this time, the readers that have not been designated as working status are redundant readers, and the redundant readers mentioned above are removed.

In the above scheme, the matrix element MRT(R _i , T _j ) is defined as follows:

$\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\begin{array}{cc}\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Subset;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&NotSubset;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right.& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; )</span>\end{array}<span\; class="notranslate">\; ,</span>$

Among them, RS and TS are respectively the reader set and the tag set stored by the middleware in a certain period of time, ì means that the reader can read the corresponding tag, otherwise it means that the tag is not within the recognition range of the reader.

Further, the one-dimensional arrays MR and MT are respectively defined as follows:

$\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; MR</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; ,</span>\end{array}$

$\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; MT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; ,</span>\end{array}$

The element number in the array MR is the reader number, and the element data value is the number of tags within the recognition range of the corresponding reader; the element number in the array MT represents the tag number, and the element data value is the number of readers that can read the corresponding tag.

Further, the element (reader) number set RCS corresponding to the maximum value of element data in the array MR is defined as follows:

RCS={R _i ∈ RSMR(R _i )=max(MR)}

Further, the RRF calculation method of the readers in the set RCS is as follows:

$\mathrm{<span\; class="notranslate">\; RRF</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; MT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; CoT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; CoT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RCS</span>}<span\; class="notranslate">\; ,</span>$

Among them, R _m is the reader located in the set RCS, and CoT is the comparison matrix of the matrix MRT, that is, CoT=MRT.

The R _min is defined as follows:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\underset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; min</span>}}\mathrm{<span\; class="notranslate">\; RRF</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

Among them, R _min represents that among all the reader sets RCS that contain the same maximum number of tags, the reader has the smallest number of the same tags as all surrounding readers, that is, the number of tags it contains alone is the largest.

The update formula of the reader R _min corresponding to the row and column element data values in the matrix MRT is as follows:

In the foregoing solution, the middleware-based RFID system reader de-redundancy method does not require the reader to read the tag multiple times, nor does the reader need to write any information to the tag during the de-redundancy process.

Compared with the prior art, the beneficial effect of the present invention is: relying on the EPC network architecture, the method utilizes the RFID middleware in the EPC network architecture to acquire tag information and identify redundant readers. Different from the existing de-redundancy method, this method does not require the reader to read and write information to the tag multiple times, so it will not be affected by the working characteristics of the RFID system. In addition, the method can also be applied to RFID systems in which tags do not have storage capabilities. Compared with the RRE algorithm and the LEO+RRE algorithm, the MRRE algorithm has a higher detection rate of redundant readers, and also effectively reduces the amount of tags that the system needs to process, and further optimizes the rationality of system deployment. Compared with the classic algorithm LEO+RRE, this method increases the detection rate of redundant readers by 6.27% to 20.80%, reduces the amount of tag data that the system needs to acquire and process by 4.50% to 35.73%, and further optimizes the deployment of the system. rationality.

Description of drawings

Fig. 1 is the schematic diagram of the EPC network framework that the present invention relies on;

Fig. 2 is a schematic flow chart of the method of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

The invention is a middleware-based RFID system reader redundant method, which utilizes the RFID middleware in the EPC network framework to obtain label information and distinguish redundant readers. EPC network is one of the typical applications of the Internet of Things based on RFID technology. It integrates RFID systems and Internet applications, and realizes real-time remote tracking of tags by obtaining and retrieving the unique EPC code (Electronic Product Code) of the tag. Its network architecture As shown in Figure 1. Among them, RFID middleware (Middleware) is an important part of the EPC network. It is a new type of software system that mainly obtains tag data through readers, and performs aggregation, filtering, and storage operations on the data to serve EPC applications and EPC Information Services (EPC IS) provides high-quality data streams.

The MRRE method proposed by the present invention does not need to know the system topology, and the method requires the RFID system as follows:

The reader can read all the tag information in the RA, and the reader does not need to write information to the tag;

·The RFID middleware can receive and store the tag information sent by each reader.

Let the storage format of RFID middleware tag information be <R, T, timestamp>, that is, the reader numbered R reads the tag information numbered T at a certain moment (timestamp). The MRRE method requires middleware to establish the "reader-tag" matrix MRT, which is defined as follows:

Note that the reader set and tag set stored by the middleware in a certain period of time are respectively RS and TS, the reader number R _i is the row number, the tag number T _j is the column number, and the matrix MRT is established, and the matrix element MRT( R _i , T _j ) is

$\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\begin{array}{cc}\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Subset;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&NotSubset;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right.& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; )</span>\end{array}$

in, It means that the reader can read the corresponding tag, otherwise it means that the tag is not within the recognition range of the reader, and the comparison matrix CoT=MRT is defined.

The MRRE method de-redundancy steps are shown in Figure 2:

(Step 201) Calculate the sum of the element data values in each row of the matrix MRT to obtain a one-dimensional array MR:

$\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; MR</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; ,</span>\end{array}$

Calculate the sum of the data values of the elements in each column of the matrix MRT to obtain a one-dimensional array MT:

$\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; MT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; ,</span>\end{array}$

The element number in the array MR is the reader number, and its element value is the number of tags within the recognition range of the corresponding reader; the element number in the array MT represents the tag number, and its element value is the number of readers that can read the corresponding tag.

(Step 202 ) Calculate the maximum value of element data in the array MR, and there may be multiple elements in the array corresponding to the maximum value. If there is only one element corresponding to the maximum value of the data, record the number of the element (reader) as R _min , otherwise record the set of element (reader) numbers corresponding to the maximum value of the element data in the array MR as RCS:

RCS={R _i ?RSMR(R _i )=max(MR)}

(Step 203) The number of readers R _m and its surrounding readers having the same label in the element number set RCS is RRF:

get

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\underset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; min</span>}}\mathrm{<span\; class="notranslate">\; RRF</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

Among them, R _min represents that among all the reader sets RCS that contain the same maximum number of tags, the reader has the smallest number of the same tags as all surrounding readers, that is, the number of tags it contains alone is the largest. Therefore, it is the least likely to be considered as a redundant reader and should be selected as the working reader first.

(Step 204) data in the update matrix MRT is:

(Step 205) Update the array MR data, repeat (step 202) ~ (step 204), until the matrix MRT is an empty matrix, at this time the readers that have not been designated as working status are redundant readers.

Compared with the classic algorithm LEO+RRE, this method increases the detection rate of redundant readers by 6.27% to 20.80%, reduces the amount of tag data that the system needs to acquire and process by 4.50% to 35.73%, and further optimizes the deployment of the system. rationality.

In a word, those skilled in the art can make various changes and deformations to a middleware-based RFID system reader de-redundancy method of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (7)

1. a middleware-based RFID system reader method for removing redundancy, is characterized in that, comprises the following steps: S1 defines the matrix MRT. The reader number R _i is the row number, and the tag number T _j is the column number. When the reader numbered R _i can read the tag numbered T _j , the matrix element MRT(R _i , The value of T _j ) is 1, otherwise, let its value be 0; S2 calculates the sum of the data values of each row element of the matrix MRT and the sum of the data values of each column element to obtain one-dimensional arrays MR and MT respectively; S3 calculates the maximum value of the element data in the array MR, if there is only one element corresponding to the maximum value of the data, record the reader corresponding to the element number as R _min , otherwise record the set of element numbers corresponding to the maximum value of the element data in the array MR as RCS; S4 records the number of the reader in the element numbering set RCS and its surrounding readers having the same label as RRF, and obtains the RRF value of each reader in the set RCS, and marks the reader corresponding to the minimum value of RRF as R _min ; S5 sets the reader R _min as a reader in the working state, and updates the element data values of all rows and columns corresponding to the reader R _min in the matrix MRT to 0; S6 updates the element data in the array MR, and repeats steps S3 to S5 until the matrix MRT is an empty matrix. At this time, the readers that have not been designated as working status are redundant readers, and the redundant readers mentioned above are removed. 2. the RFID system reader based on middleware according to claim 1 removes redundant method, it is characterized in that: described matrix element MRT (R _i , T _j ) is defined as follows: $\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\begin{array}{cc}\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Subset;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&NotSubset;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right.& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; )</span>\end{array}<span\; class="notranslate">\; ,</span>$ Among them, RS and TS are respectively the reader set and the tag set stored by the middleware in a certain period of time, It means that the reader can read the corresponding tag, otherwise it means that the tag is not within the recognition range of the reader. 3. the RFID system reader based on middleware according to claim 2 removes redundant method, it is characterized in that: described one-dimensional array MR and MT are respectively defined as follows: $\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; MR</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; ,</span>\end{array}$ $\begin{array}{ccc}\mathrm{<span\; class="notranslate">\; MT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; MRT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RS</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; TS</span>}<span\; class="notranslate">\; ,</span>\end{array}$ The element number in the array MR is the reader number, and the element data value is the number of tags within the recognition range of the corresponding reader; the element number in the array MT represents the tag number, and the element data value is the number of readers that can read the corresponding tag. 4. the RFID system reader based on middleware according to claim 3 removes redundancy method, it is characterized in that: in described array MR, the definition of element number set RCS corresponding with element data maximum value is as follows: RCS={R _i ∈ RS|MR(R _i )=max(MR)}. 5. the RFID system reader based on middleware according to claim 4 removes redundant method, it is characterized in that: the RRF calculation method of reader in the described set RCS is as follows: $\mathrm{<span\; class="notranslate">\; RRF</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; MT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; CoT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; CoT</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; RCS</span>}<span\; class="notranslate">\; ,</span>$ Among them, R _m is the reader located in the set RCS, and CoT is the comparison matrix of the matrix MRT, that is, CoT=MRT. 6. the RFID system reader based on middleware according to claim 5 removes redundant method, it is characterized in that: described R _min is defined as follows: ${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\underset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; min</span>}}\mathrm{<span\; class="notranslate">\; RRF</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$ Among them, R _min represents that among all the reader sets RCS that contain the same maximum number of tags, the reader has the smallest number of the same tags as all surrounding readers, that is, the number of tags it contains alone is the largest. 7. the RFID system reader based on middleware according to claim 5 removes redundant method, it is characterized in that: described reader R _min corresponds to row and column element data values update formula as follows in matrix MRT: MRT[R _i ,T _j |MRT(R _min ,T _j )=1]=0, R _i ∈RS, T _j ∈TS.