anti-collision algorithm in rfid system -...
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AntiAnti--Collision AlgorithmCollision Algorithmin RFID systemin RFID system
삼성삼성 종합기술원종합기술원
Dec. 14, 2004Dec. 14, 2004
김김 재재 현현
Wireless Information Wireless Information && Network Engineering Research (WINetwork Engineering Research (WINNNER) Lab.NER) Lab.School of Electrical EngineeringSchool of Electrical Engineering
AJOU UniversityAJOU University
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ContentsContents
RFID SystemTag-collision Problem & IssuesConventional Anti-collision AlgorithmsAnti-collision Algorithm in StandardsProposed Anti-collision AlgorithmsPerformance AnalysisConclusion
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RFID SystemRFID SystemRFID (Radio Frequency IDentification) system이란?무선환경에서여러개의물리적기기(tags)를인식하기위한무선센서네트워크의한형태
RFID 시스템의활용분야물류/유통 (SCM, 재고관리)교통 (교통요금, 전자화폐)동물관리(가축관리)병원환자관리
Hospital
Casino: i-coin
Cloth
Secret Document Pet, Cow ID, Credit card
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TagTag--collision Problem & Issuescollision Problem & Issues
Tag-collision Problem수동태그간의통신불가
리더는모든태그에게데이터전송요구
동시에리더의전송요구에두개이상의태그가응답하면충돌이발생
Tag-collisionTag-collision Problem을해결할수있는 Anti-collision Algorithm 필요
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Classification of Classification of AntiAnti--collision Algorithm collision Algorithm
ALOHA types Binary types
Kinds ofSlotted ALOHA,
Framed Slotted ALOHA, Dynamic Framed Slotted ALOHA
Binary Search algorithm, Binary Tree algorithm,
Bit-by-bit Binary Tree algorithm
StandardISO 18000-6 TYPE A, EPC CLASS 1 (HF),
EPC CLASS 1 G2
RFID HANDBOOK, ISO 18000-6 TYPE B,EPC CLASS 0 (UHF),
EPC CLASS 1 G2
StrengthGood for the moderate number of tags
( generally up to 256 )Better for the large number of tags
(not always)
weakness Worse for the large number of tags Many iterations may cause large overhead
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AntiAnti--collision Algorithm collision Algorithm -- ALOHAALOHA
Framed Slotted ALOHA Algorithm고정된크기의프레임사용
프레임크기보다태그수적으면슬롯의낭비발생
프레임크기보다태그수많으면성능저하
태그수에따른프레임크기의변화필요
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AntiAnti--collision Algorithm collision Algorithm --ALOHAALOHA사용된태그의 ID
TAG 1 1011TAG 2 1010TAG 3 0011TAG 4 0101
Framed Slotted ALOHA
TAG4(0101)
TAG3(0011)
TAG2(1010)
TAG1(1011)
STATE
2nd REQSlot4Slot3Slot2Slot 11st REQREADER
IDLE1011 COLL 0101
0011
1010
1011
0101
0011
1010
Frame Size = 4 Frame Size = 4
Frame Size fixed
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AntiAnti--collision Algorithm collision Algorithm -- ALOHAALOHA
Dynamic Framed Slotted ALOHA AlgorithmEPC CLASS 1 (HF)EPC CLASS 1 G2 (UHF)ISO 18000-6 TYPE A태그의수에따라프레임크기를가변
태그수에따른프레임크기의분석적근거자료미흡
[표준] 에서구체적인프레임크기의가변방법제시없음
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AntiAnti--collision Algorithm collision Algorithm -- ALOHAALOHA사용된태그의 ID
TAG 1 1011TAG 2 1010TAG 3 0011TAG 4 0101
Dynamic Framed Slotted ALOHA
TAG4(0101)
TAG3(0011)
TAG2(1010)
TAG1(1011)
STATE
2nd REQSlot4Slot3Slot2Slot 11st REQREADER
IDLE1011 COLL 0101
0011
1010
1011
0101
0011
1010
Frame Size = 4 Frame Size = ?
Need to vary the Frame Size using the number of collided slots or other methods
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AntiAnti--collision Algorithm collision Algorithm -- BinaryBinary사용된태그의 ID
태그 1 1011태그 2 1010태그 3 0011태그 4 0101
Binary Search AlgorithmRFID HANDBOOKUse the position of collided bit to identify tags
REPLY
TAG
2nd REQ.<= 0111
READER
REPLY
TAG READERTAGREADERTAGREADERREADER
TAG4(0101)
TAG3(0011)
TAG2(1010)
TAG1(1011)
STATE
2nd REQ.<= 0111
REPLY1st REQ.<= 1111
REPLY3rd REQ.<= 0011
1st REQ.<= 1111
1010
1011
0011
0101
XXXX
0011
0101
0011
1010
1011
0101
0XX1 0011 XXXX
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AntiAnti--collision Algorithm collision Algorithm -- BinaryBinary
Binary Tree Algorithm ISO 18000-6 TYPE BEPC CLASS 1 G2CRP (Collision Resolution Protocol) Use internal counter and random generator to identify tags
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AntiAnti--collision Algorithm collision Algorithm -- BinaryBinaryQuery Tree Algorithm
Use Prefix to identify tagsMemory-less tag structureLow cost
REPLY
TAG
00
READER
REPLY
TAG READERTAGREADERTAGREADERREADER
TAG4(1100)
TAG3(1000)
TAG2(0011)
TAG1(0001)
STATE
1REPLY001REPLY0000
011
001
0X1
01
11
1 1
X1 0001 0011
사용된태그의 ID태그 1 0001태그 2 0011태그 3 1000태그 4 1100
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AntiAnti--collision Algorithm collision Algorithm -- BinaryBinaryBit-by-bit Binary Tree Search Algorithm
EPC CLASS 0 (UHF)태그는리더의전송요구에고유번호중한비트정보전송
태그로부터수신된비트정보가충돌이면알고리즘에의해하나의그룹 (비트정보가 0인그룹)을선택
사용된태그의 ID태그 1 001태그 2 011태그 3 100
REPLY
TAG
X(0)
READER
REPLY
TAG READERTAGREADERTAGREADERREADER
TAG3(100)
TAG2(011)
TAG1(001)
STATE
X(0)REPLYCMDREPLYX(0)CMD
0
0
X
0
1
1
0
X 001 X
1 1
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Reader to tag communication Reader to tag communication in Standards (1)in Standards (1)
충돌방지알고리즘Serial Number
(bits)태그메모리
23, 24, 34 and 36 (EPC)
Read-only
EPCCLASS1
(HF)
Probabilistic(Dynamic Framed Slotted
ALOHA)
23, 24, 34 and 36
(EPC)Read-only Avg. : 200 tags/s
UserProgrammable
UserProgrammable
Userprogrammable
23, 24, 34 and 36
(EPC)
64
64
태그 인식개수
EPCCLASS0(UHF)
Deterministic(Bit-by-bit Binary Tree)
Avg. : 200 tags/sMax : 800 tags/s
EPCCLASS1(UHF)
Deterministic(Binary Tree – Bin Slot) Not specified
ISO 18000-6TYPE A(UHF)
Probabilistic(Framed Slotted ALOHA)
Avg. : 100 tags/s
ISO 18000-6TYPE B(UHF)
Probabilistic (Binary Tree)
Avg. : 100 tags/s
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Reader to tag communication Reader to tag communication in Standards (2)in Standards (2)
동작주파수
(Mhz)에어인터페이스
(상/하향)전송속도 (상/하향)
(kbps)
비트전송시간
(상/하향)(us)
태그리셋시간
(us)
EPCCLASS0(UHF)
902-928FM0 /
AM Pulse width mod.40 or 80 /40 or 80
25 or 12.5 /25 or 12.5
800
EPCCLASS1
(HF)13.56
Manchester ASK / AM Pulse width mod.
52.969 / 26.48 18.87 / 37.76 Not specified
EPCCLASS1(UHF)
902-928Pulse Interval AM /
AM Pulse width mod.140.35 / 70.18 7.13 / 14.25 64
ISO 18000-6TYPE A(UHF)
860-930 FM0 /
Pulse Interval ASK40 / 33 25 / 20 or 40 300
ISO 18000-6TYPE B(UHF)
860-930FM0 /
Manchester ASK40 / 8 or 40 25 / 25 or 125 400
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EPC CLASS 0 (UHF)EPC CLASS 0 (UHF)
A Reset Signal : Power UP
Oscillator Calibration SignalsTo allows the tag to adjust its oscillator frequency Ready itself for the next calibration pulse
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EPC CLASS 0 (UHF)EPC CLASS 0 (UHF)
Data Symbol Calibration SignalA sequence of three pulse cycles Inform the tag how to interpret the reader-to-tag link symbols 0, 1, and Null. As well as the time point where backscatter should stop
Previous O
csillatorC
allibration Pulses
Next S
ymbols
Data 0, 1, N
ull
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EPC CLASS 0 (UHF)EPC CLASS 0 (UHF)
Data Calibration and Data Transmission signals
3 us, Typ.
6 us, Typ.
9.5 us, Typ.
W1(4.5 us, Typ.)
W2(7.75 us, Typ.)
W3(11.5 us, Typ.)
Tag Tx offmid 0/1 bit mid 0/null bit
12.5 us bit time, Typ.
Data0
Data1
DataNull
Calib.‘T0
Calib.‘T1
Calib.‘T2
Timing for Data Event Points
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EPC CLASS 0 (UHF)EPC CLASS 0 (UHF)
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EPC CLASS 1 (UHF)EPC CLASS 1 (UHF)
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ISO 18000ISO 18000--6 TYPE A6 TYPE A
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ISO 18000ISO 18000--6 TYPE B6 TYPE B
Power OFF
IDREADY
DATA EXCHANGE
Power OnSelect
UnselectInitialize
Read
Data Read
Read
Collision Arbitration
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Ideas or ProposalIdeas or Proposal
ALOHAEstimation Function of number of tags
Estimate the number of tag to use the number of collided slots
Optimal Frame Size Determination AlgorithmUse tag transmission delay
BinaryModified
When tag ID is sequentialWhen there are two tags whose last bit is only different
ImprovedRequest selectively only the collided bit
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Proposed Algorithm Proposed Algorithm -- ALOHAALOHA
Estimation Function of number of tag [est(L,n)]Use the information of idle, successful, and collision slotUse the ratio of the number of collided slots for the frame size
L : Frame Size, n : Number of tags
1( , ) 1 1 11
n nest L nL L
Number of Collided SlotFrame Size
⎛ ⎞ ⎛ ⎞= − − +⎜ ⎟ ⎜ ⎟−⎝ ⎠ ⎝ ⎠
=
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Proposed Algorithm Proposed Algorithm -- ALOHAALOHAEstimation Function of number of tag [est(L,n)]
Example- L = 256
- est(L,n) = 0.5
322
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Proposed Algorithm Proposed Algorithm -- ALOHAALOHA
Optimal Frame Size Determination AlgorithmUse transmission delay (D) to obtain the optimal frame sizeRetransmission (R)
Delay (D) =Retransmission (R) * Frame Size (L)
Optimal Frame Size ( )
111n
LD
L
−=⎛ ⎞−⎜ ⎟⎝ ⎠
optimalL n=
optimalL
1111
nR −=⎛ ⎞−⎜ ⎟⎝ ⎠L
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Proposed Algorithm Proposed Algorithm -- BinaryBinaryModified Bit-by-bit Binary Tree Search Algorithm (MBBT)마지막비트가다른두개의태그를동시에인식
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Proposed Algorithm Proposed Algorithm -- BinaryBinaryImproved Bit-by-bit Binary Tree Search Algorithm (IBBT)충돌이발생한비트의위치에따라선택적전송요구
마지막비트가다른두개의태그를동시에인식
사용된태그의 IDTag1 0001
Tag2 0010
Tag3 1010
Tag4 1011
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Performance Analysis Performance Analysis -- ConventionalConventional
Iteration (반복회수) : 리더와태그간의 Request와 Response의전송반복회수
( ) 1(2)BSlog nI log= +
2
2( 1)( 1)1 2[1 (1 ) ]
n kSBT k kk
n kI nk p p⎛ ⎞⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠=
− −= + ≥− − −∑
BBTI n j= ×
Conventional Algorithms Number of Iteration
Binary Search Algorithm (BS)
Binary Tree Algorithm (BT)
Bit-by-bit Binary Tree Algorithm (BBT)
n = the number of used tags
j = the length of tag ID
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Performance Analysis Performance Analysis ––Proposed MBBT( Iteration )Proposed MBBT( Iteration )
Modified Bit-by-bit Binary Tree Search Algorithm태그의개수(n)가짝수일때사용된태그의개수가총태그개수 (2m) 의 50% 이하일때
사용된태그의개수가총태그개수 (2m) 의 50% 초과일때
2( )
0
22( )
(2 )22
m km
MBBTk
n n kk m k
I m knm
−
=
−⎛ ⎞⎛ ⎞⎜ ⎟⎜ ⎟−⎝ ⎠⎝ ⎠= × −
⎛ ⎞⎜ ⎟⎝ ⎠
∑
2( )
2
22
(2 )22
m km
MBBTk m n
n n kk k m n
I m knm
−
= −
−⎛ ⎞⎛ ⎞⎜ ⎟⎜ ⎟− +⎝ ⎠⎝ ⎠= × −
⎛ ⎞⎜ ⎟⎝ ⎠
∑
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Performance Analysis Performance Analysis ––Proposed MBBT( Iteration )Proposed MBBT( Iteration )태그의개수 (n) 가홀수일때사용된태그의개수가총태그개수(2m)의 50% 미만일때
사용된태그의개수가총태그개수 (2m) 의 50% 초과일때
(2 2 1)1
0
22 2 1
(2 1 )2
2 1
m km
MBBTk
n n kk m k
I m kn
m
− −
−
=
−⎛ ⎞⎛ ⎞⎜ ⎟⎜ ⎟− −⎝ ⎠⎝ ⎠= × − −
⎛ ⎞⎜ ⎟−⎝ ⎠
∑
(2 2 1)1
2 1
22 1
(2 1 )2
2 1
m km
MBBTk m n
n n kk k m n
I m kn
m
− −
−
= − −
−⎛ ⎞⎛ ⎞⎜ ⎟⎜ ⎟− + +⎝ ⎠⎝ ⎠= × − −
⎛ ⎞⎜ ⎟−⎝ ⎠
∑
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Performance Analysis Performance Analysis ––Proposed IBBT( Iteration )Proposed IBBT( Iteration )
Improved Bit-by-bit Binary Tree Search Algorithm제안한 Improved Bit-by-bit 이진트리알고리즘
Tag의개수(m)가짝수일때
( )
( )
( )
( )
2
2
0
2
2
2
22 221 , 0
2
2 22
1 2 ,2
m km
k
IBBT
m k
m
nk m
n n k
k m k nm k mnmm
I nn k
nk k m nm k m nnmm
−
=
−
= −
⎧ ⎛ ⎞⎛ ⎞−⎪ ⎜ ⎟⎜ ⎟⎪ ⎜ ⎟⎜ ⎟⎜ ⎟⎜ ⎟−⎪ ⎝ ⎠⎝ ⎠∏× × ⋅ − < ≤⎪ ⎛ ⎞⎪ ⎜ ⎟⎪ ⎝ ⎠⎪= ⎨ ⎛ ⎞−⎛ ⎞⎪ ⎜ ⎟⎜ ⎟⎪ ⎜ ⎟⎜ ⎟⎪ ⎜ ⎟⎜ ⎟− +⎜ ⎟⎝ ⎠⎪ ⎝ ⎠∏× × ⋅ − < ≤⎪
⎛ ⎞⎪⎜ ⎟⎪ ⎝ ⎠⎩
∑
∑
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Performance Analysis Performance Analysis ––Proposed IBBT ( Iteration )Proposed IBBT ( Iteration )
Tag의개수(m)가홀수일때
Where
( )
( )
( )
( )
21
2
0
2
12
2
22 221 , 0
2
2 22
1 2 ,2
m km
k
IBBT
m k
m
nk m
n n k
k m k nm k mnmm
I n
nk k m nm k m nnmm
−−
=
−
−
= −
⎧ ⎛ ⎞⎛ ⎞−⎪ ⎜ ⎟⎜ ⎟⎪ ⎜ ⎟⎜ ⎟⎜ ⎟⎜ ⎟−⎪ ⎝ ⎠⎝ ⎠∏× × ⋅ − < <
⎛ ⎞⎪ ⎜ ⎟⎪ ⎝ ⎠⎪= ⎨ ⎛ ⎞⎪ ⎜ ⎟⎜ ⎟⎪ ⎜ ⎟⎜ ⎟⎪ ⎜ ⎟⎜ ⎟− +⎜ ⎟⎝ ⎠⎪ ⎝ ⎠∏× × ⋅ − < <⎪
⎛ ⎞⎪⎜ ⎟⎪ ⎝ ⎠⎩
∑
∑
⎪
n k−⎛ ⎞
2
max
2log 1
max1
2 21 12( 1 ) 1 ( 1) 1 ( ),
2 2
rr r
mn r
k kk
m mn n
r k m r r kn
⎛ ⎞−⎜ ⎟⎜ ⎟
⎝ ⎠
=
⎛ ⎞⎛ ⎞ ⎛ ⎞− −⎜ ⎟⎜ ⎟ ⎜ ⎟⎛ ⎞⎝ ⎠ ⎝ ⎠⎜ ⎟∏ = + − + × + + + − −⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎜ ⎟⎜ ⎟
⎝ ⎠
∑
( 1)max 2
2[log 1 ], 2 2 , 0 35r
r rk m n rn
+⎛ ⎞= − < ≤ ≤ ≤⎜ ⎟
⎝ ⎠
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Simulation EnvironmentSimulation EnvironmentOPNET models
Project model
무선채널에러는고려하지않음
알고리즘비교에초점을맞춤
Tag 인식시간은전송된 bit 수에
비례
Tag의 ID는 36bits 로가정
OPNET을시뮬레이터로사용
Reader Tag
Node model
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Simulation Result Simulation Result -- ALOHAALOHA태그수에따른인식시간
Result from SimulationBound : 16 ~ 256
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Analytic Result Analytic Result -- BinaryBinary
20 40 60 80 100 120 140 160 180 2000
1
2
3
4
5
6 x 104
사용된 태그의 개수
태그가
보낸
총 비트
수
Binary Search AlgorithmBinary Tree Algorithmbit-by-bit Binary Tree AlgorithmModified bit-by-bit Binary Tree AlgorithmImproved bit-by-bit Binary tree Algorithm
Tag 개수에대한 tag가보낸총비트수(Analysis)
:
:
total I
I
Bit Bit I
I
Bit tag
= ×
알고리즘의반복횟수가전송한비트수
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Analytic and Simulation Result Analytic and Simulation Result --BinaryBinary
Tag의개수에대한반복회수(Analysis + Simulation)
20 40 60 80 100 120 140 160 180 2000
1000
2000
3000
4000
5000
6000
7000
8000
사용된 태그의 개수
반복
회수
BBT 수학적분석BBT 모의실험MBBT 수학적분석MBBT 모의실험IBBT 수학적분석IBBT 모의실험 MBBT : 태그의 ID가순차적일때
최대 100%의성능향상
IBBT : 태그의 ID가순차적일때
최대 839% 성능향상
⇒ 태그의수가증가함에 따라더좋은성능을보임
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Analytic and Simulation Result Analytic and Simulation Result --BinaryBinary
Tag의개수에대한반복회수(Analysis + Simulation)
⇒ 태그의 ID가순차적일경우태그ID의길이에상관없이동일한성능을보임
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Conclusion (1)Conclusion (1)Anti-collision Algorithms
ALOHAISO 18000-6 TYPE AEPC CLASS 1 (HF)EPC CLASS 1 G2
BINARYRFID HANDBOOKISO 18000-6 TYPE BEPC CLASS 0 (UHF)EPC CLASS 1 G2
Anti-collision IssuesDynamic Framed Slotted ALOHA최적의프레임크기를얻기위한구체적인방법제시필요
Bit-by-bit Binary Tree Search Algorithm태그 ID의모든비트를한비트씩수신태그를인식하기위한정확한인식시간계산가능
태그의인식시간은태그 ID 길이와태그개수에비례
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Conclusion (2)Conclusion (2)
Proposed AlgorithmFast Tag Identification using Dynamic Slot Allocation in RFID system
Estimation Function of number of tags (Estimate the number of tags using collided slots)Optimal Frame Size Determination Algorithm태그의수에따라최적의프레임크기결정
Modified Bit-by-bit Binary Tree Search Algorithm마지막비트의충돌감지로인식속도개선
순차적인태그의개수가많을수록성능향상
최대 100% 성능향상Improved Bit-based Binary Tree Search Algorithm충돌이발생한비트의위치에따라선택적전송요구
최대 839% 성능향상
Future StudyReader Collision / Security & privacy issues / Active Tag
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ReferenceReference[1] Harald Vogt, "Efficient Object Identification with Passive RFID Tags," Pervasive2002, pp.98-113, 2002.[2] Harald Vogt, "Multiple Object Identification with Passive RFID Tags," 2002 IEEE International Conference on Systems, Man
and Cybernetics, vol.3, pp.6-9, Oct., 2002. [3] K. Finkenzeller, RFID Handbook: Radio-Frequency Identification Fundamentals and Applications. John Wiley & Sons, Ltd.,
1999[4] M. Jacomet, A. Ehrsam, and U. Gehrig, "Contactless Identification Device With Anticollision Algorithm," IEEE Computer
Society CSCC’99, Jul. 4-8, Athens., 1999. [5] ISO/IEC FDIS 18000-6:2003(E), Part 6: Parameters for air interface communications at 860-960 MHz, Nov. 26, 2003. [6] Auto-ID Center., Draft Protocol Specification for a Class 0 Radio Frequency Identification Tag. , 2003.[7] Auto-ID Center, 13.56 MHz ISM Band Class 1 Radio Frequency Identification Tag Interface Specification : Candidate
Recommendation, Version 1.0.0, 2003. [8] 차재룡, 최호승, 김재현, "Ubiquitous ID시스템에서고속무선인식알고리즘," JCCI2004, pp.317, Apr. 28-30, 2004. [9] J. L. Massey, “Collision resolution algorithms and random-access communications,” Univ. California, Los Angeles, Tech.
Rep. UCLAENG -8016, Apr., 1980.[10] H. S. Choi, J. R. Cha and J. H. Kim, "Improved Bit-by-bit Binary Tree Algorithm in Ubiquitous ID System," in Proc
PCM2004, TOKYO, JAPAN Nov., 2004.[11] H. S. Choi, J. R. Cha and J. H. Kim, "Fast Wireless Anti-collision Algorithm in Ubiquitous ID System ," in Proc.
IEEE VTC 2004, L.A., USA, Sep., 26-29, 2004.[12] H. S. Choi, J. R. Cha and J. H. Kim, "Novel Bit-by-bit Binary Tree Algorithm in Ubiquitous ID System," in Proc.
WTC2004, Seoul, Korea, Sep., 12-15, 2004, pp. 51.[13] 차재룡, 김재현, "Ubiquitous ID 시스템에서고속충돌방지알고리즘," 한국통신학회논문지, 제29호, 8A, pp.942-949,
2004년 8월.[14] 최호승, 김재현, "Ubiquitous ID 시스템에서의 Enhanced bit-by-bit 이진트리알고리즘," 전자공학회논문지, 제41권,
제8호, pp581-588, 2004년 8월.[15] R. Glidden, C. Bockorick, S. Cooper, C. Diorio, D. Dressler, V. Gutnik, C. Hager, D. Hara, T. Hass, T. Humes, J. Hyde, R.
Oliver, O. Onene, A. Pesavento, K. Sundstrom, and M. Thomas, Impinj, inc., “Design of Ultra-Low-Cost UHF RFID Tags for Supply Chain Applications,” IEEE Commun. Mag., Aug. 2004, pp. 140-151.