1. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
Studies on Route Sustenance and Outage
Probability in Cognitive Mobile Secondary User
Networks
M.K. KAUSHIK
DEPARTMENT OF ELECTRICAL ENGINEERING
BITS PILANI HYDERABAD CAMPUS, INDIA

2. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
ELECTROMAGNETIC SPECTRUM

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SPECTRUM UNDERUTILIZATION

4. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
WITH COGNITIVE RADIO..

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WITH COGNITIVE RADIO..
Primary Users
Secondary User

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Definition
“ A wireless system where unlicensed users explore the spectrum
to transmit in a frequency band without causing harmful
interference to licensed users”

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Objectives
• Use of mobile Secondary users as relays in cognitive networks
is becoming popular.
• Dynamic nature of the mobile secondary users
• Route sustenance time, Throughput and Outage of
the network will be of importance for successful
secondary network operation.

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Objectives
• In this work we studied the route sustenance duration and
outage probability for a synthetic network of cognitive users.

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Contributions
• What is the probability that there is at least one feasible relay
for a given out-of-coverage end user?
• Route Sustaining time- the shorter the route sustaining time,
the more often a new feasible relay must be identified.
• Connection Sustaining time- Assuming re-routing, by making
use of relay handover, is allowed, how long will a connection
last

10. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
Probability of finding a feasible CU relay with path loss
exponent α=3 and ϒ1=ϒ2= 3 dB
10 20 30 40 50 60 70 80 90 100
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Average number of relays in the cell coverage area
SuccessRate
r=1.05
r=1.10
r=1.15
r=1.20

11. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
The probability of finding a feasible relay as a function of
relay SNR at unit distance ϒ2, with path loss exponent
α=3 and r=1.1
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
gama2(dB)
SuccessRate
gama1=5dB
gama1=4dB
gama1=3dB
gama1=2dB

12. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
The average route sustenance time for relays moving at
pedestrian and vehicular speed, with pass loss exponent
α=3 and ϒ1= ϒ2=3dB
1 1.02 1.04 1.06 1.08 1.1 1.12 1.14 1.16 1.18 1.2
0
100
200
300
400
500
600
700
Normalized distance from the base station
Routesustainingtime(sec)
Pedestrain speed
Vehicular speed

13. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
The average connection sustenance time given the
current number n of feasible CU’s for different speeds
and mobile relay CU densities(r=1.1)
0 1 2 3 4 5 6 7 8 9 10
10
2
10
3
10
4
10
5
10
6
current number of feasible relays n
Averageconnectionsustainingtime(sec)
High density,pedestrain speed
Low density,pedestrain speed
High density,vehicular speed
Low density,vehicular speed

14. ELECTRICAL ELECTRONICS COMMUNICATION INSTRUMENTATION
The average connection sustaining time given the current
number n of feasible relays for different speeds and
mobile relay densities(r=1.2)
0 1 2 3 4 5 6 7 8 9 10
10
1
10
2
10
3
10
4
current number of feasible relays n
Averageconnectionsustainingtime(sec)
High density,pedestrain speed
Low density,pedestrain speed
High density,vehicular speed
Low density,vehicular speed

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Future scope
• Set of Su relay nodes helping in retransmission of failed
packets from both Pu’s and Su’s

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Thank you