  Monitoring the network performance experienced by the end-user is crucial for
managers of wireless networks as it can enable them to remotely modify the
network parameters to improve the end-user experience. Unfortunately, for
performance monitoring, managers are typically limited to the logs of the
Access Points (APs) that they manage. This information does not directly
capture factors that can hinder station (STA) side transmissions. Consequently,
state-of-the-art methods to measure such metrics primarily involve active
measurements. Unfortunately, such active measurements increase traffic load and
if used regularly and for all the STAs can potentially disrupt user traffic,
thereby worsening performance for other users in the network and draining the
battery of mobile devices.
  This thesis enables passive AP-side network analytics. In the first part of
the thesis, I present virtual speed test, a measurement based framework that
enables an AP to estimate speed test results for any of its associated clients
solely based on AP-side observables. Next, I present Uplink Latency Microscope
(uScope), an AP-side framework for estimation of WLAN uplink latency for any of
the associated STAs and decomposition into its constituent components. Similar
to virtual speed test, uScope makes estimations solely based on passive AP-side
observations. We implement both frameworks on a commodity hardware platform and
conduct extensive field trials on a university campus and in a residential
apartment complex. In over 1 million tests, the two proposed frameworks
demonstrate an estimation accuracy with errors under 10%.
