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Keysight Technologies
Power-Consumption Measurements
for LTE User Equipment




Application Note




If you are designing smartphone chipsets or operating a mobile
network, you need to determine how certain parameters affect a
speciic smartphone's power consumption and igure out how to
adjust the parameters to improve battery life. In this application
note we show how to use the Keysight Technologies, Inc. E6621A
PXT wireless communications test set and the Keysight N6705B
DC power analyzer to establish a power consumption model for
LTE user equipment (UE). The model is useful when you need to
examine the UE battery life in system-level simulations.

We will explain how the Keysight equipment can be used in
manual tests, but we do not discuss how to make automated
tests (for example, using VEE software).

In this application note, we analyze smartphones adhering to the
3GPP LTE standard [1].
Introduction

Modern smartphones have limited battery life, and this affects user satisfaction. Chipset manufac-
turers and mobile network operators will want to evaluate a smartphones' power consumption in a
realistic setup and establish a power consumption model based on the evaluation. The model helps
you determine how certain parameters affect a speciic smartphone's power consumption and how
you can adjust the parameters to improve battery life.

The key parameters are uplink (UL) and downlink (DL) data rates (R), transmit (Tx) and receive (Rx)
power levels (S), cell bandwidth (BW), and discontinuous reception (DRX). The parameters affect
the smartphone's modem, and more speciically, the Rx and Tx base band (BB) and Rx and Tx radio
frequency (RF) components. A power consumption model that includes these components has been
proposed in an article entitled Empirical LTE Smartphone Power Model with DRX Operation for Sys-
tem Level Simulations [2]. It covers the contribution from each parameter on the related component,
as illustrated in Figure 1.




Figure 1. UE power consumption model, based on Figure 1 in [2]




The model is made by measuring how each parameter affects the power consumption, but the
model does so by capturing major trends and not implementation-speciic peculiarities.
03 | Keysight | Power-Consumption Measurements for LTE User Equipment - Application Note



Setup description Proposed list of measurements
The measurements were performed in the laboratory using The goal is to estimate how the Rx and Tx BB and RF components
the Keysight E6621A PXT wireless communications test set contribute to the total modem power consumption. This goal is
[3] and the N6705B DC power analyzer [4] with the N6781A achieved by varying one key parameter, for example DL data rate
2-quadrant source/measure unit [5] module installed. for Rx BB examination, while keeping other parameters constant.
Table 1 contains the test cases. The varied parameter of each test
The UE is connected to is marked with brackets.