than four times during the event from average prior to the event hours and compared to the normal day. Similarly the downlink data volume per subscriber decreases during the event to around one-third and one-fourth compared to prior the event hours and normal day, respectively. The analysed mass event starts at around sample 76 and ends at around sample 91. Similar to the uplink and downlink data volume per subscriber, the uplink and downlink data volume per setup E-RAB changes a lot during the mass event hours. Figure 13.3 shows that the uplink data volume per setup E-RAB increases during the event hours five times compared Average DL data volume per subscriber (KB) Average UL data volume per subscriber (KB) Average DL data volume per subscriber (KB) Average UL data volume per subscriber (KB) Figure 13.2 Average uplink and downlink traffic volume per subscriber in mass event area during (a) normal day and (b) mass event day per 15-minute data samples LTE Small Cell Optimization DL KB per E-RAB UL KB per E-RAB DL KB per E-RAB UL KB per E-RAB Figure 13.3 Average uplink and downlink traffic volume per E-RAB in mass event area during (a) nor- mal day and (b) mass event day per 15-minute data samples to hours prior the event and compared to normal day. The downlink data volume per setup E-RAB is lower throughout the event hours compared to the normal day and reduces to around one-third from prior event hours. During the mass event there is slight increase in signalling in terms of E-RAB setups per subscriber as indicated in Figure 13.4, that is, during the event hours each subscriber makes 7 E-RAB setups and during the normal day the amount is around 6.5. Therefore, the main increase in signalling traffic comes from increase in subscribers during the mass event hours. The amount of E-RAB setups increases six times during the event compared to lowest during the event day and that increase is roughly three times more compared to the normal day. During the mass event the session time per E-RAB (the time the UE occupies 