, even though the RSRP level may only drop by a few decibels (say 3-5 dB). This is because UEs are operated in their near exponential operating regions. For example, during one trial, RSRP levels dropped from -110 dBm to approximately - 115 dBm by moving the UE by a few centimetres. This resulted in a 12% power consumption increase during a Skype video call. 3 Power consumption with video calling varies according to the motion of the subject being filmed. Consumption is lower when subject is stationary/still. Smartphone Optimization Macrocell Smallcell RSRP (dBm/15 KHz) Macrocell Smallcell RSRP (dBm/15 KHz) Figure 16.46 Cellular subsystem power consumption versus RSRP versus UE: (a) 'radio streaming profile'; (b) Skype video call profile LTE Small Cell Optimization (a) 3500 19% gain 10% gain Screen 'OFF' Screen 'ON' (b) 3500 Radio streaming Video streaming Video streaming Skype video Figure 16.47 Average smartphone (UE4) power consumption measured in field locations "A", "B" and "C". (a) Radio streaming power consumption VS. screen state, (b) Application power consumption with screen in 'active state'. Measurements accuracy is estimated at +2% and are performed over several 2-minute-long logs using 100 us time resolution In summary, several efforts are made to continuously improve smartphone battery life. Chipset vendors have managed to significantly reduce the intrinsic power consumption of the cellular subsystem over a short lapse of time. The use of advanced PA control schemes also helps improving power consumption at high output powers. The deployment of small cells is a promising solution to ensure the contribution of the cellular subsystem is minimal. Yet, the consumption savings accomplished in small cells can be partially, and in certain cases completely, masked by other contributors, such as application engine, encoding and decoding as well as screen activities. Smartphone Optimization 16.9 Summary Smartphones are the dominant source of data traffic in mobile broadband networks. This chapter showed that 