In this section, we briefly describe the WM framework, based on the techniques introduced in 11 (11). In that work, we demonstrated two serious drawbacks of using a single sniffer: each sniffer experiences severe loss in captured frames, and each sniffer only observes its local view, that is, the frames observed by one sniffer, which may differ from the AP's global view. Our framework aims to improve the capture performance by using multiple sniffers, placed according to SNR measurements.