 (and by extension UE 5) at its maximum downlink throughput whenever possible is beneficial from an energy efficiency point of view. These measurements also show that single input single output (SISO) mode saves on average 100 mW over 2x2 MIMO operation. Note that the earlier measurements in Figure 16.9 showed a clear difference in the power consumption between 10 and 20 MHz bandwidths while Figure 16.41 shows that the number of received PRBs with the given bandwidth has only a minor impact of the power consumption. An even more pronounced pattern can be observed in Figure 16.41c (TC4) which shows that transmitter baseband performance is nearly independent of the number of transmitted physical resource blocks (PRB). Figure 16.41d shows that, with the exception of UE 1, using 16QAM has no impact on transmitter power consumption. The consumption step in UE 1 is believed Launch date June 2012 April 2013 July 2014 August 2014 October 2014 Operating system Android 4.0.4 Android 4.1.2 Android 4.4 Android 4.4 Android 4.4 Modem and CPU Part #A Part #B Part #C Part #D Part #D Modem CMOS node 28 nm LP 28 nm LP 28 nm LP 28 nm HPM 28 nm HPM RF transceiver Part #E Part #F Part #G Part #F Part #F Transceiver CMOS node 65 nm 65 nm 65 nm 65 nm 65 nm Band 4 PA control Gain switching (GS) + average power tracking (APT) GS + APT + envelope tracking (ET) LTE bands 4, 17 1, 2, 4, 5, 17 2, 4, 7, 17 4,7,17 1, 2, 3, 4, 5, 7, 8, 12, 17 UE category Figure 16.40 Smartphones under test (CPU = central processing unit, LP = lower power, HPM = high-performance mobile) PRxBB PRxBB SISO downlink data rate, MCS is varied (Mbit/s) MIMO downlink data rate, MCS is varied (Mbit/s) PTxBB PTxBB Uplink number of PRB - MCS=6 Uplink Data rate - MCS is varied (Mbit/s) PRxRF PTxRF Total RX power in 100 PRBs (dBm) Transmit power (dBm) PTxRF at -40 dBm PTxRF Transmit power (dBm) Figure 16.41 Band 4, 20 MHz cell bandwidth, LTE subsystem consumption benchmark (UE 5 results are restricted to SISO operation due to lack of RF Rx diversity test port) LTE Small Cell