A Survey of Key Performance Indicators for Generic Cellular Networks

The increasing offer of advanced services in cellular networks forces operators to provide stringent quality of service (QoS) guarantees. The contentment level of different customers depends on different QoS levels based on key performance indicators (KPIs). Monitoring QoS of any telecommunications network requires continuous processes that estimate values of the KPIs in real-time that determine the quality of service rendered to the subscribers. System coverage, trunking efficiency, spectrum efficiency, carrier-to-interference ratio (C/I), drop-call probability and call blocking probability are some of the important KPIs used to estimate the performance of cellular networks. The system coverage in an area is dependent on the area covered by the signal. Trunking efficiency relates to the number of customers per channel to the number of channels per cell for a particular grade of service. Spectrum efficiency is a measure of how efficiently space, frequency and time are used. The C/I factor arises because wireless users communicate over the air and there is significant interference between them. Call dropping refers to the event described by the termination of calls in progress before either involved party intentionally ends the call. Blocking occurs when a base station has no free channel to allocate to a mobile user. In this paper, the KPIs' concepts are reviewed and presented in a more coherent and unified manner than have been previously done including the illustration of the concepts in an experimental context for an operative cellular network.