off Pico on Location Location Location Location Location Location Downlink Uplink Figure 9.11 User data rate in selected indoor locations that the small cell was able to improve the network quality leading to higher data volumes. The results also indicated that the small cell was able to offload traffic from the macro cell. Figure 9.13 shows the physical resource block (PRB) utilization in the macro cell before and after small cell installation. The result shows that the macro cell PRB utilization has decreased with the small cell which leaves more room for other users in the macro cell. 9.6.4 KPIs in Network Statistics The network quality in terms of setup success rate and drop rate must be maintained after the small cell installation. The accessibility is shown in Figure 9.14 and the drop rate in Figure 9.15. Both performance indicators are on very good level in the macro cell and in the Data volume Macro Figure 9.12 Data volumes before and after small cell installation LTE Small Cell Optimization PRB usage distribution Lower PRB usage with small cell Before After Figure 9.13 Physical resource block (PRB) utilization in the macro cell small cell. The accessibility is clearly more than 99% and the drop rate below 0.1%. The macro and the small cells have approximately similar values. 9.6.5 Mobility Performance The small cell covers only a limited geographical area which can cause potential issues with the mobility performance at high velocities. If the small cell signal fades too rapidly, it may lead to radio link failure before the handover has been completed to the macro cell. Figure 9.16 shows inter-eNodeB handover success rate in the small cell and it is more than 98%. In this case, the small cell provides even higher success rate than the macro cell. More than 50% of e-RAB accessibility Macro Figure 9.14 Enhanced radio access bearer (eRAB) accessibility Learnings from Small Cell Deployments e-RAB drop rate Macro Figure 9.15 Enhanced radio access bearer (eRAB) drop rate the outgoing handovers from the small c