en 21% when the background activity is only four times per hour and up to 50% if there are 12 events per hour. DRX Impact on Active Profile Performance When users are actively interacting with smartphone there are other factors which contribute to the battery consumption besides the radio transmission, and it is often the case that the display actually consumes significant amount of battery. Therefore, when trying to estimate the real impact of cDRX during active usage it is important to model a realistic mix of typical services, break intervals and usage of the display. Figure 16.16 shows an example of the evolution of power consumption during a predefined data session with a mix of different services and periods of inactivity. A similar current LTE Small Cell Optimization Battery life NoDRX 320 ms cycle 640 ms cycle 1280 ms cycle Nr keep-alive events per hour Figure 16.15 Impact of cDRX on standby battery life (2600 mAh capacity, 10 ms OnDuration) consumption pattern is observed in both cases, driven not only by radio transmission but also by the display usage and processor utilization. However, the current consumption averaged over the whole period still reflects significant savings when cDRX with long DRX cycle is used. Long DRX cycle adapts well to bursty applications with relatively long silence periods between data transfers. When using short DRX cycle and smaller DRX inactivity timers, it is possible to obtain additional gains by getting into DRX sleep state sooner. Figure 16.17 shows the average current consumption gain when using cDRX with 320-ms-long cycle and a combination of 320-ms-long cycle and 80-ms-short cycle for an extended traffic pattern over 20 minutes duration. 1 min user 1 min user 1 min user 1 min user 1 min user inactivity, inactivity, inactivity, inactivity, screen off screen off screen off inactivity, screen off screen off Take a picture Send and Check Browse Make min and upload to receive weather Skype call Facebook emails UE current without DRX 343 mA (time 8:20,88) UE current with D