s that small cell battery life savings may reach very high levels. In this example, operating UEs 3, 4 and 5 at this location increases power consumption by 25%, 20% and 13%, respectively, compared to the performance obtained at location B. Relatively, UE 5 provides lower savings. This is due to the extended range of transmit power over which battery consumption is minimal. In the case of Skype video calling, small cells still deliver superior performance despite operating UEs at 10 dB higher average total power. In this example, UEs 3, 4 and 5 only consume 4-7% more power at location B than at location A. At location C one can see the benefits of Envelope Tracking in UEs 4 and 5 over UE 3. Operating UEs at location B versus location C could bring savings in the range of 30-45%. This is due to the near exponential rise in power consumption as UE is operated closer to its maximum output power. However, in practice these gains are moderated by two factors: cDRX and transitions to idle state lower the consumption. Screen activity and application processor may dominate and flatten these theoretical savings. Figure 16.47 illustrates the actual performance of UE 4 at the three static locations for the case of radio streaming, two different video streaming applications and Skype video calling. Figure 16.47a shows that listening to radio with screen off at location B delivers a near 20% better power consumption than at location C. Turning 'on' the screen halves the gain. The impact of screen and application engine is more visible in Figure 16.47b. Video application 2 drains less battery than application 1. But battery savings achieved with both video streaming applications are in the same order of magnitude in small cells than those experienced with music/radio streaming, ie approximately 10% savings. On the contrary, Skype two-way video calling power consumption profile flattens the cellular subsystem savings. 3 Note that at location C, a small change in UE position may induce a significant increase in power consumption