Figure 18
From: Removing non-stationary noise in spectrum sensing using matrix factorization
Validation: first AGC removal step. The PDF after AGC removal step 1 versus the PDF of the field-strengths of the raw monitoring data (with AGC) and the PDF of the actual monitoring data (i.e., without AGC). The focus is on the leftmost distribution peak which is in the field-strength range of P r x ={170,-155} dBm/Hz. For the actual field-strength data this corresponds to thermal noise only whereas for the raw monitoring data also AGC noise is included. As a consequence the difference in distribution width between these two leftmost peaks equals the AGC noise contribution. Due to NMF the thermal noise and the lower AGC contribution (G AGC=3.5 dB) become separated and turn visible as distinguishable distributions.