be made for any coming mass event as 100,000 10,000 Average number of users with data in buffer in DL Figure 13.55 Downlink throughput per user as a function of number of users with data in downlink buffer per cell using 15-minute statistics LTE Small Cell Optimization -10-8 4 681012 14 16 18 20 22 Uplink average PUSCH SINR (dB) Figure 13.56 Average number of users with data in buffer in uplink versus uplink average PUSCH signal to interference ratio per cell per 15 minutes long as the increase in RRC-connected users is known per cell. Example of the increase of the cell-level average and maximum RRC-connected users between mass event and normal day is shown in Figure 13.59. As can be seen the average (averaged over the highest loaded cells) increase of average RRC-connected users per cell is up to 15 and up to 11 for maximum RRC-connected users for the event day compared to the normal day. When the maximum and average RRC-connected users are estimated per cell then all the other limitations can be estimated and possible bottleneck on cell level analysed. Average channel quality indicator Figure 13.57 Average number of users with data in buffer in downlink versus average channel quality indictor per cell per 15 minutes Capacity Optimization Average number users with data in UL buffer Average number users with data in DL buffer Average number of RRC-connected users Figure 13.58 Average number of users with data in buffer as a function of average number of RRC- connected users per cell based on 15-minute statistics 13.8 Summary Each cell can have different upper limits in terms of capacity. Some cells are uplink or downlink PRB utilization limited and therefore uplink or downlink end-user throughput limited. In case conservative-enough uplink power control is not used the cells typically become uplink interference limited. Also in case of poor physical layer performance the cells can become Event day to normal day ratio (ave) Event day to normal day ratio (max) RRC-connected users (max), normal day RRC-connected us