CN104008356A - Filtering method for RFID system in dense environment - Google Patents
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Abstract
The invention provides a filtering method for an RFID system in a dense environment. The air interface filtering method includes the first step of obtaining bounding boxes of all rectangular frames including antennas of all readers in a region according to the transmitting antenna gain and the transmitting power of the readers, and filtering out redundant information in tag clouds through the bounding boxes, wherein when filtering reading exists within scope boundaries of the tag clouds, the bounding boxes are considered invalid, the second step of finding out intersections between boundaries of rectangular frame groups through horizontal scanning lines and perpendicular scanning lines so as to isolate overlapping portions of the rectangular frame groups, selecting multiple independent isolating bounding boxes after the overlapping portions of the rectangular frame groups are found out, and allowing the readers to filter out the redundant information in each isolating bounding box through Select instructions, and the third step of repeating the second step until a smaller redundant information region is obtained in each isolating bounding box. Compared with a filtering reading method, the filtering method for the RFID system in the dense environment has the advantage that the filtering efficiency is improved by 50%.
Description
Technical field
The present invention relates to REID field, particularly relate to rfid system filtering method under a kind of intensive environment.
Background technology
Internet of Things utilizes the information sensing equipment such as radio-frequency (RF) identification (RFID), wireless sense network, object is connected with internet, and the functions such as intellectuality identification, location, monitoring and the management of realization to object.The restriction of rfid system, database and network data processing ability, makes filtering redundancy label information from magnanimity RFID label data become the problem of needing solution in RFID application badly.
Intensive environment rfid system is in deployed with devices environment, to have multiple readers and a large amount of label, and supports terminal user and the application of larger amt.Wherein, air interface layer is carried out pre-filtering, and middleware is made response to pre-filtering.Reader layer and middleware layer are carried out rear filtering.Rear filtering starts by reading filtering, and reads filtering and be subject to terminal user and application controls.Filter task after part is distributed to reader by middleware, to reduce middleware calculated amount and reader and middleware network payload.
RFID tag data structure, according to ISO/IEC 18000-6C standard, generally comprises version number, domain name supervising person, object classification and sequence number four parts.Code length is divided into 64,96 and 256 three kinds, and taking GID-96 as example, in tag data structure, four parts are respectively 8,28,24 and 36.Reader receives after label data, based on by bit pattern, label data being read to filtering processing.For example, the product G ID-96 of Coca-Cola is encoded to 35.00009F1.*.*, wherein the object classification code of the canned cola of 355ml is 000200, can utilize 35.00009F1.000200.* from label data, to leach the canned laughable product of 355ml, reads filtering thereby realize.
According to ISO/IEC 18000-6C standard, reader utilizes Select(to choose), Inventory(makes an inventory) and Access(access) three instruction Management label groups.Reader selects specific label group to carry out Inventory instruction by one or more Select instructions.Carry out after Select instruction, only have coupling label that mark is set, other label is not carried out Inventory process.When coupling population of tags is while receiving Query instruction, the Inventory beginning that circulates.Access process is that reader carries out read-write operation to the label of specifying in Inventory process.
" IEEE Network ", in " Algorithms for packet classification " literary composition of the 2nd phase of calendar year 2001 the 15th curly hair table, introduced typical network data packet classification method; Park H S and Kim J D, in " Design and Implementation of a High-speed RFID Data Filtering Engine " book of writing for 2006, have discussed the similarity of RFID filtering and network data packet classification method; The Reader Protocol that EPCglobal issued in 2006, in Version1.1, has provided RFID reader and has read filtering algorithm; Bai Y, Wang F and Liu P are in " Efficiently Filtering RFID Data Streams " book of writing for 2006, and Wang F and Liu P are in " Temporal Management of RFID Data " literary composition of delivering for 2005, all proposed the RFID filtering method based on reading filtering, emphasis has solved and in practical application, has removed noise and the repeating data problem with Obtaining Accurate Target id data.But, because the above-mentioned label data source quantity of reading filtering method is large, cause real-time poor, filtration efficiency is lower, does not meet the application demand of quick filter.
Summary of the invention
Technical matters to be solved by this invention is, overcomes the above-mentioned deficiency of prior art, provides a kind of real-time good, rfid system filtering method under the high intensive environment of filtration efficiency.
The technical scheme that the present invention solves its technical matters employing is: rfid system filtering method under a kind of intensive environment, adopt air interface filtering method, and comprise the following steps:
(1) according to reader transmitter antenna gain (dBi) and emissive power, obtain the Bounding Box that comprises all rectangle frames of all reader antennas in region, utilize the redundant information in Bounding Box filtering population of tags, fall in Bounding Box, overlapped region is all considered as redundant information region between the region of outer rectangular frame and rectangle frame group; In the time that filtering is read in the existence of population of tags range boundary, be considered as Bounding Box invalid;
(2) utilize level and vertical scan line to find out the point of crossing between rectangle frame group border, with the lap of isolation rectangular frame group, after finding the lap of rectangle frame group, select multiple independent isolation boundary boxes, reader utilizes the redundant information in the each isolation boundary box of Select instruction filtering;
(3) repeating step (2), until obtain less redundant information region in each isolation boundary box.
Further, in step (1), the rectangle frame of described reader antenna is obtained by following formula,
In formula,
for wavelength,
for reader antenna gain,
for label antenna gain,
for reader antenna emissive power,
for label antenna sensitivity,
for reader antenna main lobe width.
Further, in step (2), it is to complete by following steps that described reader utilizes the redundant information in the each isolation boundary box of Select instruction filtering:
1) Select instruction select based on user define standard population of tags, start unit, intersect and based on label piecemeal negate;
2) reader sends and connects Select instruction execution start unit and intersect operation;
3) Select instruction can confirm or cancel confirm that the SL(of the label that is applicable to four calls is selected) mark, or can in one of them call of four calls, be set to A or B by the mark of dish of label;
4) reader and label protocol standard are carried out Select instruction, target is whether Select instruction is revised the SL mark of label or coiled mark, if in the situation that coiling mark, represent whether be that certain call is revised SL mark or coiled mark, carry out subsequently corresponding tag responses.
Further, in step (2), in the time finding point of crossing, should avoid overlapped between isolation boundary box, produce replication region.
The beneficial effect that the present invention compared with prior art has: in conjunction with reading filtering algorithm and Select instruction, utilize rectangle frame geometric format, provide air interface filtering method, with Obtaining Accurate target labels data, and utilize Inventory probability model and filtering time test method, proposed filtering method is carried out to emulation testing; Test result shows, compared to reading filtering method, institute's put forward the methods filtration efficiency improves 50%.
Brief description of the drawings
Fig. 1 is the effective schematic diagram of embodiment of the present invention Bounding Box;
Fig. 2 is the schematic diagram that embodiment of the present invention Bounding Box is invalid;
Fig. 3 is the schematic diagram of 3 isolation boundary boxes of the embodiment of the present invention;
Fig. 4 is the schematic diagram that embodiment of the present invention isolation boundary box produces replication region;
Fig. 5 is the schematic diagram in 6 redundant information regions of the embodiment of the present invention;
Fig. 6 is the schematic diagram in 3 redundant information regions of the embodiment of the present invention;
Fig. 7 is the schematic diagram of twice Select operation of the embodiment of the present invention;
Fig. 8 is embodiment of the present invention list reader environment
,
and
the schematic diagram of proportionate relationship;
Fig. 9 is the embodiment of the present invention read the to circulate schematic diagram of Inventory number of operations;
Figure 10 is the layout schematic diagram of reader under the intensive environment of the embodiment of the present invention;
Figure 11 is the intensive environment of embodiment of the present invention reader
,
and
the schematic diagram of proportionate relationship.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in further detail.
Rfid system filtering method under a kind of intensive environment, adopts air interface filtering method, comprises the following steps:
(1) according to reader transmitter antenna gain (dBi) and emissive power, obtain the Bounding Box that comprises all rectangle frames of all reader antennas in region, utilize the redundant information in Bounding Box filtering population of tags, fall in Bounding Box, overlapped region is all considered as redundant information region between the region of outer rectangular frame and rectangle frame group, with reference to Fig. 1; In the time that filtering is read in the existence of population of tags range boundary, can not improve filtration efficiency, be considered as Bounding Box invalid, with reference to Fig. 2.
Wherein, the rectangle frame of reader antenna is obtained by following formula,
In formula,
for wavelength,
for reader antenna gain,
for label antenna gain,
for reader antenna emissive power,
for label antenna sensitivity,
for reader antenna main lobe width.
(2) utilize level and vertical scan line to find out the point of crossing between rectangle frame group border, with the lap of isolation rectangular frame group, after finding the lap of rectangle frame group, select 3 independent isolation boundary boxes, with reference to Fig. 3; Reader utilizes the redundant information in 3 isolation boundary boxes of Select instruction filtering; And in Fig. 4, due to the appearance of new replication region, compared to Fig. 2, increased a small amount of redundant information region, therefore should avoid the generation of replication region.
It is to complete by following steps that reader utilizes the redundant information in the each isolation boundary box of Select instruction filtering:
1) Select instruction select based on user define standard population of tags, start unit, intersect and based on label piecemeal negate;
2) reader sends and connects Select instruction execution start unit and intersect operation;
3) the SL mark of confirming the label that is applicable to four calls can be confirmed or cancel to Select instruction, or can in one of them call of four calls, be set to A or B by the mark of dish of label;
4) reader and label protocol standard are carried out Select instruction, target is whether Select instruction is revised the SL mark of label or coiled mark, if in the situation that coiling mark, represent whether be that certain call is revised SL mark or coiled mark, carry out subsequently corresponding tag responses.
(3) repeating step (2), until obtain less redundant information region in each isolation boundary box.In Fig. 5, utilize 4 Select instructions to produce 6 redundant information regions; In Fig. 6, utilize 4 Select instructions to produce 3 redundant information regions.Redundant information region is much smaller than overall region.
Air interface filtering method utilizes Select instruction, in data source header, population of tags is carried out to filtering, thereby improves system data processing power.By assessment is proposed air interface filtering method efficiency, the present embodiment adopts the efficiency of Inventory probability model and the filtering time test method assessment air interface filtering method that proposes.
(1) Inventory probability model
Inventory probability model is: in definition ALOHA anti-collision algorithms, frame length is
, population of tags size is
.Formula (1) and formula (2) are document Lee S R, Joo S D, Lee C W. An Enhanced Dynamic Framed Slotted ALOHA Algorithm for RFID Tag Identification. International Conference on Mobile and Ubiquitous Systems, MobiQuitous, 2005:166-174. provides
probability model.The number of timeslots of supposing n label is
, wherein,
t n be n label, system effectiveness
for
（1）
For making system effectiveness maximum, to formula (1) differentiate, can obtain frame length and be
time optimal response number of tags
for
（2）
Suppose variable N obey about
, the binomial distribution of p, has
, wherein
, can obtain n according to probability mass function and be
（3）
, in the Inventory cycle, single label responds and idle probability
and
be respectively
（4）
Definition conflict response probability
comprise and removing
and
outer situation, convolution (3) and (4) can obtain
for
（5）
Can be obtained by formula (5), when
and
when larger, have
（6）
In read cycle, Inventory cycle index model is:
Suppose that the probability that c label enters new Inventory circulation is
,
（7）
From formula (7), in the time that reader does not receive label response within certain period, reader completes the read cycle.Can be obtained by formula (7)
（8）
Inventory cycle index in the read cycle
for
（9）
(2) filtering time test method
Suppose Select, Inventory and read the filtering time and be respectively
,
and
, t is the rfid system tag recognition time
（10）
Select time approximate treatment is: utilize two Select command calculations
, with reference to Fig. 7.Label is 0.5 by the probability of initial markers (Flag), therefore first Select instruction changes selected population of tags quantity, second Select instruction arrange dialogue mark (
).Supposing that Select instruction is consuming time is
, an air interface runtime of filtering is
.Suppose that air interface filter times is k,
for
（11）
Inventory time approximate treatment is: suppose to send in first Inventory circulation Query(inquiry) instruction, RN16, involves the agreement control time to be respectively continuously
,
and
,, first Inventory cycling time
for
（12）
Second Inventory circulation sends QueryRep(and repeats inquiry) instruction,
（13）
Can be obtained by formula (12) and (13), n Inventory is cycling time
（14）
Therefore
for
（15）
Reading the approximate treatment of filtering time is: suppose to have m reader in rfid system, and n label, reader and middleware filter times are
, when filtering adopts linear query, i.e. when logical “and” operation is carried out in step-by-step,
for
（16）
In the time that filtering adopts pre-paper mulberry algorithm,
for
（17）
(3) emulation experiment
Test reading filtering linear query (LS) and propose under air interface filtering method condition, rfid system tag recognition time t, and the two filtration efficiency relatively.Process to simplify the analysis, according to document Lee S R, Joo S D, Lee C W. An Enhanced Dynamic Framed Slotted ALOHA Algorithm for RFID Tag Identification. International Conference on Mobile and Ubiquitous Systems, MobiQuitous, 2005:166-174, supposes
, can be obtained by formula (2)
, wherein
.Three steps of the air interface filtering method that proposes be designated as respectively Step1, Step2, Step3.
Wherein single reader test is: experiment test reader carries out 5 times and reads filtering, and Q=4,5,6 and 7,
be respectively 24,25,26 and at 27 o'clock,
,
and
proportionate relationship.Compared to
and
,
affected by system deployment way and applied environment larger.According to document Park H S, Kim J D. Design and Implementation of a High-speed RFID Data Filtering Engine [M]. Proc.EUC Workshops, 2006, (LNCS, 4097): 423-434, in assumption (16) and (17)
for single is read the consumption of filtering minimum of computation.Utilize Select and Inventory link time parameter, obtain the mean value of 100 emulation.Test result is with reference to Fig. 8 and Fig. 9.Fig. 8 is
,
and
proportionate relationship; Fig. 9 is each Inventory number of operations of reading to circulate in Fig. 8.
As seen from Figure 8, the filtering of air interface filtering method non-target labels group;
for fixed value and much smaller than
therefore, although air interface filtering method has increased
time loss, but its filtration efficiency is still better than linear query.
for
major influence factors;
much smaller than
and
, LS, Step1, Step2 and Step3's
value is respectively 0.064,0.042, and 0.035 and 0.029, it is right
impact is minimum.As seen from Figure 9, read to circulate Inventory number with
increase and increase; In air interface filtering, Select instruction number of times is more, and the non-target labels group of filtering is more, and the Inventory number of operations of reading to circulate therefore each is fewer.
Intensive environmental testing is: experiment test system exists 32 readers, and reader is arranged as shown in figure 10, produce at random 1024 times and read filtering, and Q=11,12,13 and 14,
be respectively 2
11, 2
12, 2
13and 2
14time,
,
and
proportionate relationship, specific experiment data (unit: ms) as shown in table 1.
Under the intensive environment of table 1
,
and
the experimental data of proportionate relationship
From table 1 and Figure 11, under the intensive environment of reader, air interface filtering method filtration efficiency is higher than linear query method.For Step1, due to the whole label field of Bounding Box nearly cover space, therefore Step1 filtration efficiency and LS differ less; Adopt Step2 and Step3, system filter efficiency obtains larger raising, compares LS method, and system label recognition time reduces respectively 40% and 50%.For the intensive environment of reader, middleware receives 32 filter data, reads filtering and occurs in middleware, therefore compared to single reader environment, now
and
become impact
key factor;
size is fixing, and much smaller than
and
.
Claims (5)
1. a rfid system filtering method under intensive environment, is characterized in that, adopts air interface filtering method, comprises the following steps:
(1) according to reader transmitter antenna gain (dBi) and emissive power, obtain the Bounding Box that comprises all rectangle frames of all reader antennas in region, utilize the redundant information in Bounding Box filtering population of tags, fall in Bounding Box, overlapped region is all considered as redundant information region between the region of outer rectangular frame and rectangle frame group; In the time that filtering is read in the existence of population of tags range boundary, be considered as Bounding Box invalid;
(2) utilize level and vertical scan line to find out the point of crossing between rectangle frame group border, with the lap of isolation rectangular frame group, after finding the lap of rectangle frame group, select multiple independent isolation boundary boxes, reader utilizes the redundant information in the each isolation boundary box of Select instruction filtering;
(3) repeating step (2), until obtain less redundant information region in each isolation boundary box.
2. rfid system filtering method under intensive environment according to claim 1, is characterized in that, in step (1), the rectangle frame of described reader antenna is obtained by following formula,
In formula, being wavelength, is reader antenna gain, for label antenna gain, is reader antenna emissive power, is label antenna sensitivity, is reader antenna main lobe width.
3. rfid system filtering method under intensive environment according to claim 1 and 2, is characterized in that, in step (2), it is to complete by following steps that described reader utilizes the redundant information in the each isolation boundary box of Select instruction filtering:
1) Select instruction select based on user define standard population of tags, start unit, intersect and based on label piecemeal negate;
2) reader sends and connects Select instruction execution start unit and intersect operation;
3) the SL mark of confirming the label that is applicable to four calls can be confirmed or cancel to Select instruction, or can in one of them call of four calls, be set to A or B by the mark of dish of label;
4) reader and label protocol standard are carried out Select instruction, target is whether Select instruction is revised the SL mark of label or coiled mark, if in the situation that coiling mark, represent whether be that certain call is revised SL mark or coiled mark, carry out subsequently corresponding tag responses.
4. rfid system filtering method under intensive environment according to claim 1 and 2, is characterized in that, in step (2), in the time finding point of crossing, should avoid overlapped between isolation boundary box, produces replication region.
5. rfid system filtering method under intensive environment according to claim 3, is characterized in that, in step (2), in the time finding point of crossing, should avoid overlapped between isolation boundary box, produces replication region.
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| CN113554134A (en) * | 2021-07-23 | 2021-10-26 | 三一石油智能装备有限公司 | Fracturing pump monitoring method and device, storage medium and fracturing pump |
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