Abstract
We study the Short-Time Cell Outages (STCO) phenomena affecting Base Stations (BSs) in a mobile cellular operator network. The STCO is defined as a short-time outage of all or some BS cells (sectors) that lasts up to 30 min in a day, thus still guaranteeing more than 98% of operation. It is type of outage which cannot be detected directly through an operator network monitoring system. Although a complete characterization of STCOs has never been reported in the literature, such events are affecting the cellular network of every mobile operator. In particular, a statistical analysis of STCOs based on BSs measurements of a complete operator mobile network is performed. Our results show that: (i) STCOs impact everyday life of an operator network, (ii) high load of cells corresponds to an increase in the number of STCOs and their duration, (iii) the impact of STCOs to single sectors and whole BSs is not negligible, (iv) most of STCOs are recorded in urban areas compared to rural ones, (v) the impact of STCOs on users is higher in rural areas compared to urban ones, and (vi) the STCOs are correlated with the transferred traffic rather than the outside air temperature.
6. Conclusions and future work
We have presented a realistic study driven by operator measurements on the impact of STCOs on a cellular network. This study has been motivated by the need of having a deeper insight in these hidden events that may affect the operators revenue and network maintenance. Our results shown that STCOs are affecting the everyday behavior of the network, and their impact tends to be higher during peak traffic hours and in the presence of adverse weather conditions. In general, we have inferred the possible causes of outages, being STCOs triggered either by severe weather impacting all the three sectors of a BS, or the user load on a single sector. Moreover, we have estimated that the duration of STCOs is less than 2 min on average, thus imposing challenges on how to properly detect STCOs in real time. Additionally, STCOs occurrence is different in different morphologic areas, where urban areas experience larger number of the STCOs, while STCOs in rural areas have stronger impact on users. Finally, we have shown that STCOs are strongly correlated with the amount of transferred traffic rather than the outside air temperature. As next steps, we will consider the impact of heterogeneous BSs on STCOs. In particular, we will study a scenario composed of different technologies (i.e., 2G/3G/4G) in which BSs differ in terms of BSs hardware and software components. Additionally, we will extend our analysis over multiple data sets.
