Understanding Battery Life Testing

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Understanding Battery Life Testing


White Paper


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Table of Contents

Overview ...............................................................................................................................3

Introduction ............................................................................................................................3

Measuring Battery Power Consumption ................................................................................4

Test Setup ..............................................................................................................................5

The Network Simulator...........................................................................................5

The Power Supply ..................................................................................................6

The Battery Adaptor ...............................................................................................7

The Equipment Control Software ...........................................................................8

GSMA TS09 Specication: Test Parameters ..........................................................................9

Test Methods ........................................................................................................................11

Anritsu Test Solution.............................................................................................................11

Conclusion ...........................................................................................................................13

References ...........................................................................................................................13


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Overview

This guide details how Anritsu tools help designers and testers identify power consumption issues early in

the product development cycle, resulting in longer battery life.

The guide rst describes the fundamentals of lab battery testing measurement, then details the recentstandard GSMA TS09 dedicated to battery testing, and nally presents Anritsus automated system solution.

Introduction

Although smartphone users are quite satised with the multiple functionalities and the convenience brought

by their devices, some users express concerns about the rather poor battery life compared to the previous

generation of feature phones. For some customers, the battery life is one of the key factors involved in the

decision to purchase a smartphone.

The introduction of large touch screens played an important role in the current smartphone success. The

displays allow users to spend much more time browsing websites or using applications handling large

amounts of IP data.

This more frequent usage, as well as the new hardware required, naturally results in increased power

consumption, leading to a reduction of battery life for a given capacity.

The smartphone hardware capabilities are driven by the creativity of application developers (and vice-versa) to

bring a better user experience. In recent years, the terminals have seen a substantial increase in term of screen

size, processing power and memory size. On top of the 3GPP cellular radio evolution from 2G/3G to LTE/

LTE-A, new types of radio have been incorporated such as Wi-Fi, Bluetooth, GPS or NFC.

Previous feature phones were typically tted with a rechargeable battery with the capacity of about 800 mAh,

which would last for several days with typical use on a single. Nowadays, most smartphone embed at least a

1500 mAh battery, and up to 3000 mAh for larger devices such as phablet. However, even having a battery

capacity of twice the previous amount does not fully cover the amount of power required for a typical day of

smartphone usage.

Figure 1. Evolution of smartphone technologies.


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While the smartphone processing has followed Moores Law [1] that computer performance would

double every two years, the energy density in batteries has only increased ve times in about 100 years.

A revolution can be still expected in battery density; however the actual trend for the next 10 year is

the well-known lithium-ion discovered in Oxford in the 1960s. In the meantime, manufacturers will have

to focus on energy efciency optimizing smartphone, and also for M2M devices using Machine Type

Communication (MTC).

Measuring Battery Power Consumption

Scenario

Minimizing the power consumption of different smartphone parts requires established scenarios for

quantitative measurement. Dening those scenarios enables comparing reference measurements

to optimize specic part such as the baseband processing, radio frequency modulation, application

processing or screen consumption.

One typical way of dening scenarios is to dene different user prole. Each prole represents a certain

smartphone usage (voice, video streaming, web-browsing, chat ) based on typical users such as

Voice only, Teenager, Business User, Tethering . On top of the smartphone user usage, the network

conditions are to be dened for the scenario. The lab testing approach allows setup known and

repeatable radio conditions thanks to a network simulator.

UE makers tend to create their own scenario based on their priorities, however the GSMA has published

a standardized guideline to ensure a common understanding between industry players. This specication

is the so-called Battery Life Measurement and Current Consumption Technique and the current version

V7.6 published in June 2013 can be used as test methodology. In addition, the TS09 denitions are

cross-referenced with the 3GPP measurement items (Table 1).

The TS09 contents dene the following test specications for each cellular standard (GSM, W-CDMA,

LTE) and non-cellular (BT, Wi-Fi). It provides a handful reference framework for the industry.

Table 1. TS09 Test Specication Contents.


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Test Setup

In this section one basic lab test setup is described as a guideline for automating battery consumption testing

based on Anritsu solution. This composition is a sample case. It may be necessary to change the setup

according to the desired test environment.

Each component of the setup is described here:

The Network Simulator

This is the equipment that can simulate Basestation and some additional core network capabilities that cancover up to RRC, NAS, IMS and data transaction. Most network simulators are designed to perform various

tests for 3GPP conformance (RF or Protocol) test. If the equipment is mostly restricted to conformance test

without much possibility of tweaking its functionalities, it may not be the best t for the battery life testing.

It is recommended to choose equipment that would give you as much exibility (possibility of extending

functionalities) as possible. The Anritsu protocol tester MD8475A is a perfect versatile candidate. It has a

convenient GUI interface and SmartStudio, where parameters can be tweaked. It can also be easily automated

with GPIB command or using our dedicated automation software embedding the GSMA test cases.

Figure 2. Guideline for automating battery consumption testing based on Anritsu Automation.


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The Power Supply

In battery consumption testing, the power supply plays an important role: It should be able to display both

voltage and current being drained by DUT and transfer the values to the PC to be collected by the remote

control software on real time basis.

Automation based on 3G voice call, rst peak being registration, second peak is the voice call starting at

maximum power, followed by TPC adapting power to the radio condition, with the nal plateau being the stable

voice call. (1s logging rate).

The choice of the power supply will depend on the accuracy of test requirements. Indeed, the changes of

chipset power consumption may vary quite quickly, in a magnitude of several milliseconds time scale, due to

status mode change, such as idle or connected, or Discontinuous reception or transmission.

The following features can be important selection criteria depending on the accuracy of the capture required:

The sampling rate of the instrument: how often the power supply can measure current (and/or voltage)?

The logging rate: At what pace the information measured can be stored in the internal memory in

function of the selected measurements?

The internal memory storage: How much measurement data can be stored in the power supply?

The reporting rate: How quickly can it send the measured data to control PC?

On one hand, if the focus of the measurement is a detail of current consumption changes on milliseconds scale,

a large storage capability as well as a fast internal logging is required. A real time basis reporting of these valuesto the control PC is limited.

On the other hand, if the measurement aims at an average current consumption over a long period such as

minutes or hour, the sampling rate may not be that relevant and a real time reporting to the control PC is then the

preferred solution.

Figure 3. Real time capture of power consumption on the SmartStudio Manager.


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The Battery Adaptor

It may not be perceived as a critical component for testing, however, the battery adaptor can be an essential

part if you are working on commercial devices. As you see in Figure 2, the UE battery port should be directly

connected to the power supply. A specially designed adaptor is required to t into UEs battery slot and should

have the extension cables to be connected to the power supply as per Figure 4.

The battery adaptors are usually available at UE maker, however, for the rest of the industry the adaptor may

have to be built.

Figure 4. Battery Adaptor example.


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The Equipment Control Software

Many tests can be done manually by pressing buttons on the equipment and writing down the measured value,

however automation software is highly recommended as the Battery Life Test involves reading the current value

with a fraction of second for a relative long period of time. Considering the number of elements involved in

automation system, the automation could be cumbersome.

Automation software embedding predened scenario dedicated for battery testing, such as the Anritsu

SmartStudio Manager (SSM), can easily automate network simulator and power supply measurement logging.

The Anritsu SSM, in Figure 5, embeds a set of test cases following TS09 recommendations (detailed later), which

can be easily executed or tted to different custom requirements. It uses high-level procedures blocks that can

be arrange in a graphical owchart interface.

Figure 5. Automation software Anritsu SSM functionalities.


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GSMA TS09 Specifcation: Test Parameters

In this section, in order to understand the principles of the GSMA TS09 specication, the LTE FDD test

parameters are outlined as an example.

The LTE FDD denes the Standby Time Test and Packet Switched Transfer Test.

The Packet Switched Transfer Test is composed of three sections: LTE Download, LTE File Upload,

and LTE FDD Parallel File Download and File Upload.

The LTE FDD Standby Time item denes recommended parameters for bearers. When testing

smartphones, TS09 denes both the test results and the data including these parameters.

Bearer items include DL EARFCN and Neighbor Cell settings, DRX Cycle and control channel power

ratio settings. Setting these test parameters requires determining the current and power consumptionwhen the smartphone is in Idle status.

The LTE Download item includes the UL settings in addition to the same test items as the Standby

Time Test items.

Since it is necessary to run a DL download test after establishing communications, not only the DL bandwidth

and TBS index must be dened, but also the UL EARFCN and Tx level, communications bandwidth, TBS

(Transmit Block Size) index and RB (Resource Block) settings must be set.

The LTE FDD Parallel File Download and File Upload test items are design to stress the device communications

performance to its maximum power consumption. In comparison to the LTE Download test parameters, the

RB and TBS index settings for both UL and DL are dened for performing settings required for U-Plane datacommunications in both directions.

The different parameters to be set are summed up in Table 2 for standby and for Packet Switched Transfer Test.

Those parameters are automatically set up in the simulator by the automation software:


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Table 2. TS09 Parameters for LTE network conguration.


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Test Methods

Battery Capacity

First the end of life voltage (EOLV) of the phone is measured by means of an external power supply and by

measuring the voltage at which the phone drops an active call. Measuring the battery capacity Cis done by

measuring the voltage Uover time tat a shunt resistor Rconnected to the battery as described in chapter 20 of

the specication [2]. The measurement lasts till a complete discharge of the battery. The battery capacity is than

calculated by means of integrating the drain current between the start of the measurement (with a fully charged

battery) till the moment where the end of life voltage is reached:

Current Consumption and Battery Lifetime

For estimation of the to be expected battery lifetime t, the measured and over time averaged current Imeasured

is used together with the measured battery capacity Cas described in chapter 19 of the specication [2]:

Anritsu Test Solution

Anritsus solution (Figure 2) supports the GSMA Test case dened in Table 3. Due to the automation software,

SSM Anritsu covers a substantial part of the specication. All measurements of the fast changing current and

an appropriate averaging over time are performed automatically by the automation software.

Table 3. Anritsu Battery Testing automation test cases following GSMA TS09 recommendation.


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Anritsus solution is also exible and allows an easy customization and integration of different technologies

such as WLAN or GPS in the automation system.

Measure Current During:

Call Processing

Messaging

File Transfer

Web Browsing

Video Streaming

VoLTE/RCS/IMS

WLAN Ofoad

Positioning

Camera


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Conclusion

Whether you are a business traveler in an airport needing to keep in constant communication with the ofce

or you are a teenager sharing the latest sele with a BFF, nothing is as frustrating as running out of

battery power on your smartphone. Phone manufacturers and carriers understand how important battery life

is in their customers choices for equipment and service and promote battery life performance to differentiate

themselves from the competition.

Anritsu leverages its unique SmartStudio Manager (SSM) environment to implement its Battery Life Test

Package. This test package automatically congures the MD8475A Signaling Testers network simulator,

controls the power supply data collection and generates detailed test results that can be converted into a

spreadsheet for reporting purposes.

Battery Life Test Packages are available for the AT&T Ecosystem (2G, 3G, LTE) and Verizon Wireless

Ecosystem (LTE). There are also Basic Battery Life Test Packages available according to GSMA as

standard-installed in SSM.

With its portfolio of network simulator tester combined with the automation software, Anritsu allows

to easily create custom scenarios and provides a set of battery consumption tests based on GSMA

specications which are recommended by GCF since March 2012.

References

[1] Moore, Gordon E. (1969). Cramming more components onto integrated circuits (PDF).

Electronics Magazine. p. 4

[2] GSMA TS.09 Battery Life Measurement and Current Consumption Technique


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Anritsu Company 2015 Document Number: Anritsu AOC AppNote _v1 Printed February 15

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Understanding Battery Life Testing