Exploiting Interference Diversity for Event-Based ... - Semantic Scholar
Exploiting Interference Diversity for Event-Based Spectrum Sensing Anant Sahai presenting joint work with:
Arash Parsa
Amin Aminzadeh Gohari
BWRC and Wireless Foundations Center U.C. Berkeley
IEEE DySpAN 2008 Chicago, IL
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
1 / 15
Motivation: recovering spectrum holes
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
2 / 15
Motivation: recovering spectrum holes
Occupied Space/Time
Anant Sahai (UC Berkeley)
Unusable Part of Spectrum Hole
Exploiting Interference Diversity
Usable Part of Spectrum Hole
10/15/2008
2 / 15
Perspectives A A B
B
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
3 / 15
Perspectives
A
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
B
A
B
A
10/15/2008
B
3 / 15
Outline
Motivation The limits of existence-based detection Cooperative event-based detection The limits to event-based detection
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
4 / 15
Limits induced by noise uncertainty Min Noise Energy
Max Noise Energy
Min Signal +Noise Energy
Max Signal +Noise Energy
0
Reduced Signal Energy
0
Overlaping regions
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
5 / 15
Max-Min eigenvalue detector and noise uncertainty
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
6 / 15
Max-Min eigenvalue detector and noise uncertainty
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
6 / 15
Outline
Motivation The limits of existence-based detection Cooperative event-based detection The limits to event-based detection
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
7 / 15
The idea Traditional Existence-based High-power vs low-power
Detector statistic: False alarms:
Received power-level Noise higher than expected
Event-based Increased vs decreased vs unchanged power 8 < H− [n] : negative edge at time n; H+ [n] : positive edge at time n; : HI [n] : otherwise. Change in received power-level “Noise” increases suddenly
Missed detections:
Noise lower than expected
“Noise” drops suddenly
Dom. uncertainty:
Number of active interferers
Activity pattern of interferers
Detector: Hypotheses:
Anant Sahai (UC Berkeley)
H0 [n] : primary on at time n; H1 [n] : primary off at time n;
Exploiting Interference Diversity
10/15/2008
8 / 15
Edge-detection: a simple approach to sensing events
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
9 / 15
Insensitive to uncertainty in the level of energy
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
10 / 15
Distinguishing primaries and interferers: cooperation
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Distinguishing primaries and interferers: cooperation 4 -4 4 4 -4 -4
No Primary
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Distinguishing primaries and interferers: cooperation 4 -4 4 4
-4
-4
Signal Strength = 0.6
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Distinguishing primaries and interferers: cooperation
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Outline
Motivation The limits of existence-based detection Cooperative event-based detection The limits to event-based detection
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
12 / 15
Revisiting interference diversity 4 -4 4 4 -4 -4
No Primary
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Revisiting interference diversity 4 -4 4 4
-4
-4
Signal Strength = 0.6
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Revisiting interference diversity 2 -2 2 2 -2 -2
Signal Strength = 0.3
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Revisiting interference diversity 1 -1 1 1 -1 -1
Signal Strength = 0.15
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Footprints don’t stay “local”
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
14 / 15
Footprints don’t stay “local”
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
14 / 15
Mobility and interference diversity
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
15 / 15
Mobility and interference diversity
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
15 / 15
Arash Parsa
Amin Aminzadeh Gohari
BWRC and Wireless Foundations Center U.C. Berkeley
IEEE DySpAN 2008 Chicago, IL
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
1 / 15
Motivation: recovering spectrum holes
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
2 / 15
Motivation: recovering spectrum holes
Occupied Space/Time
Anant Sahai (UC Berkeley)
Unusable Part of Spectrum Hole
Exploiting Interference Diversity
Usable Part of Spectrum Hole
10/15/2008
2 / 15
Perspectives A A B
B
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
3 / 15
Perspectives
A
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
B
A
B
A
10/15/2008
B
3 / 15
Outline
Motivation The limits of existence-based detection Cooperative event-based detection The limits to event-based detection
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
4 / 15
Limits induced by noise uncertainty Min Noise Energy
Max Noise Energy
Min Signal +Noise Energy
Max Signal +Noise Energy
0
Reduced Signal Energy
0
Overlaping regions
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
5 / 15
Max-Min eigenvalue detector and noise uncertainty
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
6 / 15
Max-Min eigenvalue detector and noise uncertainty
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
6 / 15
Outline
Motivation The limits of existence-based detection Cooperative event-based detection The limits to event-based detection
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
7 / 15
The idea Traditional Existence-based High-power vs low-power
Detector statistic: False alarms:
Received power-level Noise higher than expected
Event-based Increased vs decreased vs unchanged power 8 < H− [n] : negative edge at time n; H+ [n] : positive edge at time n; : HI [n] : otherwise. Change in received power-level “Noise” increases suddenly
Missed detections:
Noise lower than expected
“Noise” drops suddenly
Dom. uncertainty:
Number of active interferers
Activity pattern of interferers
Detector: Hypotheses:
Anant Sahai (UC Berkeley)
H0 [n] : primary on at time n; H1 [n] : primary off at time n;
Exploiting Interference Diversity
10/15/2008
8 / 15
Edge-detection: a simple approach to sensing events
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
9 / 15
Insensitive to uncertainty in the level of energy
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
10 / 15
Distinguishing primaries and interferers: cooperation
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Distinguishing primaries and interferers: cooperation 4 -4 4 4 -4 -4
No Primary
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Distinguishing primaries and interferers: cooperation 4 -4 4 4
-4
-4
Signal Strength = 0.6
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Distinguishing primaries and interferers: cooperation
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
11 / 15
Outline
Motivation The limits of existence-based detection Cooperative event-based detection The limits to event-based detection
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
12 / 15
Revisiting interference diversity 4 -4 4 4 -4 -4
No Primary
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Revisiting interference diversity 4 -4 4 4
-4
-4
Signal Strength = 0.6
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Revisiting interference diversity 2 -2 2 2 -2 -2
Signal Strength = 0.3
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Revisiting interference diversity 1 -1 1 1 -1 -1
Signal Strength = 0.15
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
13 / 15
Footprints don’t stay “local”
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
14 / 15
Footprints don’t stay “local”
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
14 / 15
Mobility and interference diversity
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
15 / 15
Mobility and interference diversity
Anant Sahai (UC Berkeley)
Exploiting Interference Diversity
10/15/2008
15 / 15
