Noise calibration, delay coherence and SNR walls for ...sahai/Presentations/DelayCoherenceDySpAN08.pdfNoise calibration: cyclostationary feature detection AGC calibration: Yb[n] =

Noise calibration, delay coherence and SNR walls forsignal detection

Rahul Tandra Anant Sahai

Wireless Foundations CenterDepartment of Electrical Engineering and Computer Sciences

University of California, Berkeley

15th October, DySpAN 2008

UC Berkeley Wireless Foundations Rahul Tandra, Anant Sahai

Problem setup


Spectrum sensing: traditional picture






Spectrum sensing: noise uncertainty






Spectrum sensing: SNR walls


Impact of SNR walls — sensing overhead


Narrowband pilot signals






Cyclostationary signals


Cyclostationary feature detection






Feature detection: single-tap Gauss-Markov fading






Feature detection: multi-tap Gauss-Markov fading






Feature detection: finite-delay fading process


Feature detection: finite-delay fading process


Phase coherence vs Delay coherence








Noise calibration: pilot case

fp

Pilot

f

fp fm

f

Band pass filters


Noise calibration: cyclostationary feature detection

AGC calibration:

Y [n] =1√

1N

∑Nn=1 |Y [n]|2

Y [n]

As N →∞

1√1N

∑Nn=1 |Y [n]|2

→

{1σa

Under H01√P+σ2

a

Under H1


Robustness gains from noise calibration





Colored noise model:

W [n] = M [n]− βM [n− 1],

M [n] is iid white Gaussian noise, β ∈ [0, βmax].


Noise calibration, delay coherence and SNR walls for ...sahai/Presentations/DelayCoherenceDySpAN08.pdfNoise calibration: cyclostationary feature detection AGC calibration: Yb[n] =

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