s on their websites. Also, the regulator may oblige telecom operators to send such information about the QoS audit periodically to subscribers (e.g. with their bills. QoS information examples that should be published include QoS results from the audit campaign (e.g. drive test, consumer survey). 9.6.2 KPI Measurements in Mobile Networks Regarding KPI measurements in mobile networks there can be variations in measure- ment metrics and methodologies in different countries. Such variations may lead to [6]: difficulty in comparability of mobile coverage, which may result in difficulties in com- parison; inconsistency regarding the measurements of different mobile operators; inconsistency from the point of view of new and innovative digital services for vertical use cases such as 5G applications and services (e.g. massive and critical IoT services). 9 QoS Regulatory Framework Table 9.2 Main KPIs for mobile voice and IAS services. Mobile Internet access Mobile voice service KPIs service (mobile IAS) KPIs Coverage [%] Coverage [%] Call success rate [%] Speed downlink/uplink [Mbit/s] Call block rate [%] Data transfer cut-off rate [%] Dropped call rate [%] IP service access failure rate [%] Speech quality [MOS] IP service access time [s] Call setup time [s] Session failure rate [%] Handover success rate [%] Session time [s] Ping round trip time [ms] However, in the mobile networks in the 2010s and the early 2020s the main KPIs are in fact service-independent KPIs such as 3G, 4G, or 5G mobile network coverage, as well as KPIs for two main service types in mobile broadband networks, mobile voice (over managed IP networks) and mobile IAS (Table 9.2). Various KPIs are measured using different methods. The speed (bitrate) measurement is based on multiple parallel HTTP connections (it is also possible to use FTP connec- tions). Regarding coverage, it is also related to type of service in the mobile network. For example, voice coverage can differ from mobile IAS (i.e. mobile data) coverage because voice can be provided also via 