Embed Size (px)
Citation preview
RFID Tag anti-Collision Protocols
Hamed Naeemaei
Problem Definition
R
T1
T2
T3
Existing Protocols for RFID Tag Anti collisionTag multiple access / Anti Collision Method
Time Division Multiple Access
DeterministicAloha Based
Dynamic Slotted Aloha
Accelerated Frame Slotted Aloha
Dynamic Slot Allocation – Tag Estimation Method
I-Code
STAC
Bit-Slot
Probability(Tree Based)
Tree Algorithm
Binary Tree Search Algorithm
QT-Protocol
Polling
Contactless Protocol
Code Division Multiple Access
Gold Code
Walsh Sequence
Walsh Code + Pseudo Random
Sequence Generator
Huffman Sequence
Spatial Division Multiple Access
Twice Digital Beam-Forming
STDMA
Beam Forming And Reader
Power Control
Minimum Distance
Constellation
Frequency Division Multiple
Access
FDMA Novel With Q-
Algorithm
Existing Protocols for RFID Tag Anti collision
OtherA tree slotted ALOHA (TSA) is proposed in (Bonuccelli et al. 2006),hybrid tag anti-collision scheme (Shin et al. 2007)…
Tree-based RFID protocols
Binary TreeDong-Her Shih 2006
1 2 3 4 5 6 7 8 9 10 11 12 13
C C E C T1 T3 C T4 C E C T2 T5
Query treeOkkyeong Bang 2009
An Example
Start
1,2,3
1,2
1 2
3
4,5
E 4,5
4,5
4 5
E
Tag ID
Tag 1 0000
Tag 2 0010
Tag 3 0101
Tag 4 1100
Tag 5 1101
0
0
0
0
0
0
1
1
1
1
1
1
Tag ID
Tag 1 0000
Tag 2 0010
Tag 3 0101Tag ID
Tag 1 0000
Tag 2 0010Tag ID
Tag 1 0000
Tag ID
Tag 2 0010
Tag ID
Tag 3 0101
Tag ID
Tag 4 1100
Tag 5 1101
Tag ID
Tag 4 1100
Tag 5 1101
Tag ID
Tag 4 1100Tag ID
Tag 4 1101
Tag ID
Tag 4 1100
Tag 5 1101
Problems
• average number of iterations that are required to retrieve one tag ID among N tags L(N) = + 1(Finkenzeller 2004)
• The value L(N) becomes large when there are many tags in the reader’s coverage.
Aloha based protocols
BFSA
DFSAAfter first broadcast determine three parameters:
1. Collision slots
2. Success slots
3. Empty slots
Then estimate unread tags:
If Collision slots> threshold then increase slots
Else : decrease slots
Problems
• Compared with the tree-search scheme, the slot ALOHA schemes usually interrogate tags faster.
• the optimal system performance (or throughput) of a slotted ALOHA scheme can achieve as 36.8% (that is, MAX(PSUCC)= 36.8%) when nframe = ntag (Proakis 1995; Finkenzeller 2004).
EDFSAAfter first broadcast determine three parameters:
1. Collision slots
2. Success slots
3. Empty slots
Then estimate unread tags:
If number of tags are large then the tags can be grouped and allowing only one group to respondNumber of groups (M)= , N Frame size
Else : DFSA method
An Anti-collision Algorithm for Multi-Tag RFIDGENG Shu-qin, WU Wu-chen, HOU Li-gang and ZHANG Wang
If number of tags are large then the tags can be grouped :
, Probability of Collision in Step i
number of frequency channels = N Frame size, ntotal= total tags
An Anti-collision Algorithm for Multi-Tag RFIDGENG Shu-qin, WU Wu-chen, HOU Li-gang and ZHANG Wang
Number of tags Max Frame size Frequency channels
88-210 64
210/64 = 3
P = 36%
An Anti-collision Algorithm for Multi-Tag RFIDGENG Shu-qin, WU Wu-chen, HOU Li-gang and ZHANG Wang
A Novel Anti-collision Protocol in Adaptive Framed Slotted Aloha about RFIDTagsDeng Zhongting, Wu Haifeng* , Liu Jing, Tan Yuan
SC = Slot numberRSC = Readable slot numberTSC = Tag slot numberframe length in a read cycle is set to the RSC’s value in the last cycleAdvantage : Reduce Time Of re-IdentificationDisadvantage : Increase Number Of Computaion
A Novel Anti-collision Protocol in Adaptive Framed Slotted Aloha about RFIDTagsDeng Zhongting, Wu Haifeng* , Liu Jing, Tan Yuan
SC = Slot CounterRSC = Readable slot number
frame length in a read cycle is set to the RSC’s value in the last cycle
Algorithm 1. ADFA Reader Operation1 Start2 % Initialize L and RSC % L is frame length.3 if RSC=NULL4 L=N % N is set by user (frame size)5 else6 L=RSC (frame size = readable s n)----------7 end if8 RSC=0-------------9 do {10 SC=0 % initialize SC11 Transmit the command starting a frame------------------12 do {13 Transmit the command starting a slot14 Receive tag response and detect a collision15 if tag collision16 f=collision17 Transmit f18 else if no tag response19 f=idle20 Transmit f21 else only a tag response22 Receive ID from tag and store it23 RSC=RSC+124 f=successful
25 Transmit f with RSC26 end if27 SC=SC+128 }while SC<L ( end do line 12)29 [E, S, C]=performCountSlot(L)30 % Counts empty, successful and collision slots in31 % a frame with L32 L=2C33 }while C>0 ( end do line 9)
A Novel Anti-collision Protocol in Adaptive Framed Slotted Aloha about RFIDTagsDeng Zhongting, Wu Haifeng* , Liu Jing, Tan Yuan
SC = Slot CounterTSC = Tag slot Counter increase by one
SSC = Selected Slot NumberSSC<TSC means : the tag has not been
identified in last cyclesframe length in a read cycle is set to
the RSC’s value in the last cycle
Algorithm 2. ADFA Tag Operation1 Energized by reader2 Enter Ready state3 while state=Ready & Receive the command starting a4 frame with reader's L5 do {6 Enter Active state7 if SSC=NULL or SSC>L or SSC<TSC8 SSC=random number from 0 to L9 End10 TSC=011 while state=Active & Receive the command12 starting a slot13 do {14 if TSC=SSC15 Transmit ID16 Receive feedback f (with RSC) from17 reader18 if f= successful19 SSC=RSC20 Enter Quiet state21 else22 TSC=TSC+123 end
24 else25 TSC=TSC+126 end27 }28 Receive the command terminating this frame29 form reader30 if state=Active31 Enter Ready state32 end33 }
?
