The present disclosure is related to wireless telecommunications networks and in particular to measuring and determining performance of a wireless telecommunications network. The network may be a cellular network, a WiFi network, or a combination of both. The present disclosure is further directed to a method for determining a parameter indicating quality of service for a wireless connection. In the method, changes in latency over a connection are measured using probe packets and if an increase of latency that is over a predetermined relative threshold is observed, the wireless connection is determined to be congested.