# A Modular Web-Based Software Solution for Mobile Networks Planning, Operation and Optimization
## 6 Case Studies
### Network Troubleshooting
#### 6.1.2 Analysis  
In the analysis setup, the RCA is performed subjected to different hypothesis, as root causes for the service drop: lack of coverage; high interference; cell accessibility (see Figure 9). For network metrics as RF coverage and interference, which are more stable than other indicators, the use of DT data is common, when available. Thus, a user trying to evaluate coverage in a given area can select this data source to be added to the map, as in Figure 11.  
The DT color scheme ranges from high-received power (red) to low power (black), thus identifying an area in the center of the interest area with the lowest received power. In this case, just the 4G DT measurements (best sever only) are represented, however the user is able to add or remove data, by filtering the relevant DT information. However, as the lower range of the received power corresponds to \(-105\) dBm in a 4G network, even though being a low value, do not justify by itself the service drop. So, the RCA moves into the interference domain, still based on DT data.  
Another possibility to visualize DT data, and gauge the corresponding QoS levels, is to represent it in histogram format, as in Figure 12. The user can visualize the abscissa values dynamically when crossing the mouse over the graph.  
As the 4G interference is the domain being considered, the select metric is the RSRQ (that has a reporting range between \(-19.5\) dB to \(-3\) dB [34]), where it can be stated that this area is characterized by high interference, with a considerable number of measurements below \(-14.5\) dB.  
To evaluate in detail the accessibility of a given network node, another data source is required: PM data. This data source, with multiple KPIs, is also available in the solution's network overview module, to be explored and visualized thought the cell objects represented in the map. A user by interacting with the cell attached to the service drop can select and visualize the available KPIs, as in Figure 13.  
Figure 11: The failure location (green circle) and available DT measurements as a function of the received power.  
Up to two KPIs can be represented in simultaneous, and a sliding window bar allows focusing on specific time spans. The available KPIs included information about the UE CQI (for all the possible CQIs) and the number of successful connection establishments. Also, several KPIs reporting the downlink traffic (volume and throughput) were available.  
With respect to this study case, a KPI with the occurrence of UE CQI 1, which corresponds to the use of the most robust modulation and codification, along with another KPI with the occurrence of successful establishments were selected. Furthermore, using the sliding window to focus on the failure time, a sudden rise of CQI 1 is reported while  
Figure 12: Histogram of the RSRQ with respect to the interest area DT.  
Figure 13: Visualization of cell KPIs centered at the failure time.  
the successful establishments drop. This erratic behavior, in an area with moderated RF conditions can be concluded as the cause of the service drop.