How to deal with noisy signals? Signals from commercial WiFi n 75 devices are very noisy 60 Time (Seconds) 12 12.5 Original 75 Traditional filter based denoising approaches not work "wwwpylo- 11.5 12 12.5 Time (seconds) Low-pass filter Analysis based approach in our MobiCom 15 paper 11.5 12 12.5 Time (seconds) PCA 8/968/96 How to deal with noisy signals? § Signals from commercial WiFi devices are very noisy § Traditional filter based denoising approaches not work § We proposed a Principal Component Analysis based approach in our MobiCom 15 paper 11 11.5 12 12.5 60 65 70 75 CSI Time (seconds) Original 11 11.5 12 12.5 65 70 75 CSI Time (seconds) Low-pass filter 11 11.5 12 12.5 −10 −5 0 5 10 Time (seconds) CSI PCA