secured operating regions of slotted aloha in the presence of interfering signals from other...

Secured Operating Regions of Slotted ALOHA in the Presence of Interfering Signals from Other Networks and DoS Attacking Signals

Jahangir H. Sarker and Hussein T. Mouftah

School of Information Technology and Engineering (SITE), University of Ottawa, Ottawa, Ontario, Canada K1N 6N5

E-mail: [email protected]

J. H. Sarker / SITE.uOttawa.ca/~jsarker

mailto:[email protected],

http://wisense.ca/

WiSense Seminar November 3, 2011

Outline of the Presentation• Potential applications of Slotted ALOHA.

• GSM-the most successful cellular system.• Slotted ALOHA and GSM system.

• Radio Frequency Identification (RFID)-next most widely used technology.

• Slotted ALOHA and RFID system.• Applications of RFID technology.• Slotted ALOHA in the presence of interfering signals from other

networks and the DoS attacking signals.• Security problem of Slotted ALOHA system in the presence of

interfering signals from other networks and the DoS attacking signals.• Security improvement using multiple channels and capture. • Security improvement by limiting the number of retransmission trials.• Security improvement using new packet rejection. • Conclusions

2J. H. Sarker / SITE.uOttawa.ca/~jsarker

http://wisense.ca/

Potential Applications of Slotted ALOHA

• The random access channels (RACH) of Global System for Mobile (GSM) communications

• The random packet access channels (RPACH) General Packet Radio Services (GPRS)

• Wideband Code Division Multiple Access (WCDMA) system

• cdma2000• IEEE 802.16 • IEEE 802.11

3J. H. Sarker / SITE.uOttawa.ca/~jsarkerWiSense Seminar November 3, 2011

http://wisense.ca/

GSM-the Most Successful Cellular System 1/(2)

4

http://www.dailywireless.org/2009/08/21/4-billion-gsm-users-sept-2009/

J. H. Sarker / SITE.uOttawa.ca/~jsarkerWiSense Seminar November 3, 2011

http://wisense.ca/

http://www.3gamericas.org/index.cfm?fuseaction=page&pageid=378

GSM-the Most Successful Cellular System 2/(2)

5

http://www.dailywireless.org/2009/08/21/4-billion-gsm-users-sept-2009/


http://wisense.ca/

http://www.3gamericas.org/index.cfm?fuseaction=page&pageid=565

Slotted ALOHA and GSM System 1/(7)

6

• Mainly 3 elements– MS– BS– MSC


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8

UPLINK DOWNLINK 25 MHz 25 MHz

200 kHz

TDMA burst, time slot, 0.557 ms

8 x 0.557 msTDMA frame

3 58 bit 26 bit 58 bit 3 8.25

TB message test sequence message TB GP

FDMA

GSM CHANNEL ALLOCATION• 890-915 MHz for uplink • 935-960 MHz for Downlink• 200 kHz carrier spacing• This gives 124 possible carriers in UL

and DL.• Fu(n)=890.2+0.2(n-1) MHz

1<=n<=124• Fu(n) =Fu(n)+45 MHz


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9


200 kHz



3 58 bit 26 bit 58 bit 3 8.25


FDMA

GSM CHANNEL ALLOCATION


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10


200 kHz



3 58 bit 26 bit 58 bit 3 8.25


FDMA

GSM CHANNEL ALLOCATION

Random accesschannels

Traffic channels

R BR1

BR 11

BR 111

2

x

x/

x/

x/S

S

S

Sx

R

Rx/1

Rx/

Rx/

rejection

success

blocked

RSx 1


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11

Random accesschannels

Traffic channels

R BR1

BR 11

BR 111

2

x

x/

x/

x/S

S

S

Sx

R

Rx/1

Rx/

Rx/

rejection

success

blocked

RSx 1


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12

There are five different structures of the RACH [24, 25] with approximately 400,000 and n*780,000 RACH slots per hour (n= 1, 2, 3, 4). It is interesting to know the exact choice of these five different possibilities. According to specifications, a maximum of r retransmissions is allowed for each mobile call during the access period. The parameter r can be set to four different possible values 1, 2, 4 or 7


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How Slotted ALOHA Works 1/(2)?


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How Slotted ALOHA Works 2/(2)?


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How Mobile RFID Works 1/(4)?


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+

Success =

Channel

1st Failure

Ret

rans

mis

sion

s

Active

RT1

RT2

RTr

2nd Failure

rth Failure

(r+1)th Failure

Rejected

G

GGe

Ge 1

Geqn 11

Gr eqn 11

qn1

qn2

qnr

Gr eqn 1


Future Store Checkout with RFID tagged items


Video Show

http://www.youtube.com/watch?v=zBz3aoikLpU


RFID Technology in Construction 1/(3)


RFID chips are tied to the rebar at apredetermined location before concrete is poured. The encapsulated RFID tag is placed in the area shown by the red circle.

RFID chips are read with a handheld scanner.




Tunnel segments stored in theWoodstock plant all contain RFID chips that can be scanned through the concrete.

The application of RFID for tracking construction materials can provide an accurate and efficient means for reducing time and resources being spent collecting and managing data.

In a recent example, the NRC in collaboration with Armtec, has developed a system for tracking precast tunnel liner segments manufactured in Armtec’sWoodstock, Ontario plant.

The commercially availableencapsulated RFID tags which,during the fabrication process, areembedded in the liner segments.




• As the segments move through the plant, their status (i.e., fabrication, quality,storage and shipping) and associated data are updated by the field crewusing mobile computers.

• Armtec is using the system in its Woodstock plant to track the fabrication and inventory data for 58,000 tunnel liner segments being supplied for the York-Spadina subway extension project in Toronto, for two 6.5 km tunnels.

•The system helps reduce time and resources spent locating concrete units in the storage yard and managing production and quality control data.

• Another key benefit of the system is that it generates the product handover documentation in electronic format that many asset owners are now requesting. •For example, the product handover documentation is currently used by Toronto Transit Commission (TTC) construction contractors working at the subway site to validate the materials received.Source: http://www.nrc-cnrc.gc.ca/eng/ci/v16n2/9RFID-based life cycle tracking of precast concrete units


RFID Technology and Printed Electronics 1/(3)


Electronic devices can be printed on commercial off-set machines. (Source: pmTUC)

Reel-to-reel flexographic printing ofelectronic devices. (Source: Acreo)

Dimatix Materials Printer(DMP) DMP-2800 Series PrinterFUJIFILM

RFID can be used widely in almost all items Printed electronics opened that door




Printed RFID tags (Source: PolyIC)Printed RFID tag.(Source: PolyIC)




RFID can be used widely in almost all items Price per tag is an important issue


Success of Printed Electronics


Intelligent Packaging Application


Biomedical Applications of RFID


Wearable RFID-Enabled Sensor Nodes for Biomedical Applications

Source: Wearable RFID-Enabled Sensor Nodes for Biomedical Applications, Li Yang, Rushi Vyas, Amin Rida, Jonathan Pan, and Manos M. Tentzeris, IEEE 2008


Biosensor and Indicator & RFID


Inkjet printed oxygen indicator

Source: VTT 2008

Printed enzymatic power supply with integrated capacitor

Active RFID tag is better


Organic RFID


Source: Design and manufacturing of organic RFID circuits Coping with intrinsic parameter variations in organic devices by circuit design, Jan Genoe, Kris Myny, Soeren Steudel, and Paul Heremans, IEEE 2010


Multi-channel Slotted ALOHA System in the Presence of Interference from other Net. & Attacking Signals


+

Success =

Channel

1st FailureR

etra

nsm

issi

ons

Active

RT1

RT2

RTr

2nd Failure

rth Failure

(r+1)th Failure

Rejected

G

GGe

Ge 1

Geqn 11

Gr eqn 11

qn1

qn2

qnr

Gr eqn 1

Application of Slotted ALOHA with retransmission cut-off is huge

Interference from other Net.

DoS attacking signals


Security Improvements of Slotted ALOHA System


Four ways of improving the security

1 & 2. Security improvement using multiple channels and capture . 3. Security improvement by limiting the number of retransmission trials4. Security improvement using new packet rejection


Security Problem under DoS Attacking Signal & Interference from Other Networks


Message packet generation rate G

Thr

ough

put p

er s

lot S

1

J=00.10.20.30.5

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6

mfa zzz , ,

I=0, L=1

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6

Message packet generation rate GT

hrou

ghpu

t per

slo

t S

mfa zzz , ,

I=0.3, L=1

1

J=0

0.10.2

0.30.5

+

Success =

Channel

1st Failure

Ret

rans

mis

sion

s

Active

RT1

RT2

RTr

2nd Failure

rth Failure

(r+1)th Failure

Rejected

G

GGe

Ge 1

Geqn 11

Gr eqn 11

qn1

qn2

qnr

Gr eqn 1

Interference from other

Net.

DoS attacking signals


Security Improvement Using Capture



Thr

ough

put p

er s

lot S

1

J=00.10.20.30.5

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6

mfa zzz , ,

I=0, L=1

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6


Thr

ough

put p

er s

lot S

mfa zzz , ,

I=0.3, L=1

1

J=0

0.10.2

0.30.5

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6


Thr

ough

put p

er s

lot S

I=0.3, L=1J=0

0.1

0.2

0.3

0.5

1 , , mfa zzz

1

Improvement with capture 1

1 ,1 , mfa zzz

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6

I=0.3, L=1

J=0

0.1

0.2

0.3

0.5

Thr

ough

put p

er s

lot S


1

Improvement with capture 2


Security Improvement using Multiple Channels

34

1-channel system5-channel system


0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6


Thr

ough

put p

er s

lot S

mfa zzz , ,

I=0.3, L=1

1

J=0

0.10.2

0.30.5

0 3 6 9 12 150

0.1

0.2

0.3

0.4

0.5

0.6


Thr

ough

put p

er s

lot S

mfa zzz , ,I=0.3, L=5

1

J=00.10.20.30.5

Improvement with multi-channel


Security Improvement using Multiple Channels

35

ActiveL-parallel channels

Retransmission trials <=r

+

+

Total rejection

Retransmission rejection=

Retransmissions=

Yes

No

Success

G/L

1L

L

L

r

i

iPL 1

)Su(11

1)Su(11 rPL

Attacking signal with rate J


Number of channels L

Thr

ough

put p

er s

lot S

opt

J=0

1

52

1020

0 ,

,

Iz

zz

m

fa

0 10 20 30 40 500

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8


Thr

ough

put p

er s

lot S

opt

510

20

0 10 20 30 40 500

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

J=0 1 2

2 ,

,

Im

fa

z

zz


Security Improvement using Multiple Channels & Capture


Interfering signal rate I

Thr

ough

put p

er s

lot S

opt

L=20

25

3

10

1

0 1 2 3 4 50

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 ,

,

Jz

zz

m

fa

Interfering signal rate I

Thr

ough

put p

er s

lot S

opt

L=20

25

3

10

1

0 1 2 3 4 50

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

2 ,

,

Jz

zz

m

fa

Interfering signal rate IT

hrou

ghpu

t per

slo

t Sop

t

L=20

2

5

3

10

1

0 1 2 3 4 50

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

2 ,1

1 ,1

Jz

zz

m

fa


Security Improvement by Limiting the Number of Retransmission Trials


1 11 21 31 41 510

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4

Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

ot


mfa zzz , ,

Secured region without limiting r

I = 0, J = 0

Secured region with limiting r

Unsecured operating region

r

0r

Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

otNumber of channels L

1 11 21 31 41 510

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4

mfa zzz , ,

I = 2.5, J = 0

r

0r




1 11 21 31 41 510

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4


Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

ot

mfa zzz , ,


I = 2.5, J = 2.5



r

0r

1 11 21 31 41 510

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4



I = 2.5, J = 2.5

1 , , mfa zzz

Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

ot

0r

r



1 11 21 31 41 510

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4


Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

ot

1 ,1 , mfa zzz

I = 2.5, J = 2.5



r

0r


1 11 21 31 41 510

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4

mfa zzz ,1 ,1

I = 2.5, J = 2.5

r

0r




Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

ot



Security Improvement using New Packet Rejection


1 10 1000

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

Opt

imum

new

pac

ket g

ener

atio

n

rat

e pe

r sl

ot

Retransmission trials r+1


X*



Sopt

Gopt

The y-axis should be multiplied by

1opt*

GX

Source: Secured Operating Regions of Slotted ALOHA in the Presence of Interfering Signals from Other Networks and DoS Attacking Signals, Journal of Advanced Research – Elsevier, 2011, Vol. 2, Issue 3, July 2011, pp. 207-218. Available at http://www.sciencedirect.com/science/article/pii/S2090123211000488


Conclusions

39

• The potential application of Slotted ALOHA based technologies are presented• The security improvement of Slotted ALOHA in the presence of interference from other networks and

DoS attacking signals is studied• The current security protected measures such as encryption makes the packets unreadable by

unauthorized users. The authentication technique is used to protect the system from illegal users and authorization separates the legal users.

• In a Slotted ALOHA based network, the interference from other networks and DoS attacking noise packets may collide with message packets and reduces the secured transmission.

• We have used four different techniques to improve the security of Slotted ALOHA.• Security improvement using multiple channels

– The use of multiple channels in the Slotted ALOHA protocol reduces the packet collisions• Security improvement using capture effect

– Capture effect reduces the packet collisions– 3 types of captures are considered

• Security improvement by limiting the number of retransmission trials.– The retransmissions cut-off technique can limit the aggregate packet flow– It is possible that the 3rd technique retransmissions cut-off technique is not enough to control the

flow of message packets.• Because of that the 4th technique called new packet rejection probability is introduced.

– The system is secured or stable with almost any high value of new packet generation rate.


Thank you

40

Thanks a lot for

your kind attention


Questions?


secured operating regions of slotted aloha in the presence of interfering signals from other...

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jsarkerwisense seminar

gsm system

rfid system

successful cellular

mobile gsm communications

security improvement

multiple channels

access period