optimize ue design for greater battery run-time - keysight · wcdma gsm 1xev-do cdma2000 hspa fm...

© 2012 Agilent Technologies

Wireless Communications

Greater insight. Greater confidence. Accelerate next-generation wireless.

Optimize UE Design for Greater Battery Run-Time




UE Performance Test Challenge

A growing number of complex standards

- operators, UE developers

Long test times

- measured in hours and days

Multiple iterations

- design verification and regression test

Costly to automate in-house

- requires skills, time, adds delay

2



3 © 2012 Agilent Technologies



DUT Applications

•Voice

•Messaging

•eMail

•Internet

•Video streaming

•Music

•Social media

•Navigation

•Gaming

•Camera

Real World

Network

Scenarios

•Cell handovers

•Power level

changes

•Interference

•Fading

•Network loading

•Inter-RAT

handover

•Carrier specific

network settings

Innovative battery drain measurement and analysis techniques

coupled with

Innovative methods for exercising all of the capabilities of a wireless device

5 ms/Div 50 mA/Div

Wake up / idle pedestal

Receive activity/RSSI

Baseband activities

Sleep base

User Network






Agenda:

1. Importance of effectively measuring and analyzing battery drain of

a wireless device while exercising all of it capabilities

2. Shortcomings of traditional techniques & solutions

3. Description of new techniques & solutions

4. Benefits of using new techniques & solutions




Why is it so important now?

Increasingly power hungry devices

• Multiple radio technologies

• Higher data demands

• Larger displays and touch screens

• “Always-connected” applications

• Limited scope for improving

battery capacity

• Complex interaction of

applications/software/hardware

Inadequate design and analysis methods lead to:

•Shorter device run time

•Unanticipated periods of high battery drain

•Additional design cycles to resolve battery drain issues

•Disappointed customers due to short battery life

A-GPS

WCDMA

GSM

1xEV-DO

CDMA2000

HSPA

FM Radio

802.11

Bluetooth

DAB

WiBro

WiMax

LTE

EGPRS

5




Server

Voice

Video

Upload

Download

Messaging

Handover

E-mail

Power changes

DRX

Network User

Fading

UE

Network and user

influences on battery drain

6




Change from circuit-switched

to packet-switched implementation

Developments such as IMS-SIP allow traditional services to be delivered in new ways. For the same use model, the battery profile may vary depending on the underlying implementation.

IP network

VoIP Voice

Video

SMS Hello world!

DUT

8






The Importance of Effectively

Measuring and Analyzing Battery Drain

Optimize battery operating time during HW development:

• Evaluate and optimize overall device and its sub circuits

• Validate and optimize battery power management system

• Identify high peak drain anomalies and their root causes

Validate new code builds In Software Development:

• Run application code regression test suites, impact on battery drain

Quickly run suites of tests in Integration and Validation:

• Current drain for channels & TX power level combinations, & main op modes

• Validate operating time with product’s battery (run-down test)

• Check HW, L1/L2/L3, OS & application interactions on battery drain




Challenges:

• Properly powering the device

• Making accurate, high resolution

current measurements

• Expertise to generate a series of

combinations of simultaneous data-

driven device activities

• Expertise to simulate wireless network

all the way through to the internet

• Massive amounts of data created,

how to best process and manage

• Developing effective visualization

& analysis tools can be difficult

• Software development effort that

yields a flexible & capable system

• Developing takes a large amount of

resources and time

Traditional Solution: Custom RF Stimulus &

Current Drain Logging Setup

Characterizing Battery Drain

under Simulated Network Use

10




.

.

Challenges When Powering

a Mobile Phone

Actual battery response to a GSM

pulse load

Battery voltage drops proportionally

with current

• Battery resistance is 150 mΩ

GP power supply response to a GSM

pulse load

Voltage response and current drain

does not match battery

• Instability & overshoot

• 10% higher drain experienced

11




The Need for Accurate

Current Drain Measurement

50 mA/Div 500 ms/Div

Receive current pulses

sleep current 500 mA/Div

2 ms/Div

Transmit current pulses


idle current

GPRS Smart Phone Battery Drain for Talk… and Standby

Digital wireless devices operate in short bursts of activity to conserve power: •Long periods of sleep or idle between bursts of activity

•Resulting current drain is pulsed; high peak and low average

•Currents span up to 4 decades over range of operation

•Engineers need to observe and measure current drain details to optimize battery life.

Problem: Traditional solutions do not have the dynamic measurement range needed to accurately measure current drain of mobile wireless devices.

12




Most common: Shunt + DAQ

Typical Performance:

~12 to16 bits resolution

~ 50K to 1M samples/sec

~ 0.2 to 1.0% gain error (both shunt and DAQ)

~ 0.05 to 0.2% offset error (mainly DAQ)

Commonly Encountered Challenges:

– Large effort to configure and program

– Peak voltage drop on shunt may be

excessive

– Multiple shunts needed to span wider range

– Greater measurement BW = lower DC

accuracy

– Offset error and noise floor limits

dynamic range of measurement to about

2 decades to assure reasonable accuracy

for minimum (floor) level of a dynamic

signal

Challenges With Traditional

Measurement Solutions

DC source or battery

Shunt

+ +

- - DUT current

Diff Amp MUX Gain Amp ADC

Data Acquisition Equipment Data

out +

-

PC to log long-term data

DUT

13




New Solution for Battery Drain

Characterization

N6705 DC Power Analyzer Mainframe N6781A 2-Quadrant SMU for Battery Drain Analysis

Integrates multiple instrument functions into a single box:

• 1 to 4 advanced power supplies; >22 different models available

• Digital voltmeter and ammeter

• Arbitrary waveform generator

• Oscilloscope

• Long term data logger

• Full functionality from front panel

• Gain insights in minutes, not days!

Specialized DC power supply module for battery drain testing:

• For use in the N6705 mainframe

• Settable battery emulation characteristics

• Fast transient response for pulsed loads

• Zero-burden current measurement and auxiliary DVM for battery run-down testing

• Up to 200 KSa/sec digitizing rate

• Innovation: Seamless ranging spans over 7 decades for accurate measurement of battery drain over wide dynamic range

14




Comparing a Battery to a Battery

Emulator SMU Powering a GSM Handset

Actual battery response to a GSM

pulse load

Battery voltage drops proportionally

with current

• Battery resistance is 150 mΩ

N6781A Battery emulator SMU

response to a GSM pulse load

Voltage response and current

drain comparable to the battery

• SMU set to 150 mΩ

BE-SMU Voltage

BE-SMU Current Battery Current

Battery Voltage

15




N6781A SMU Measurement

Ranging Performance

Range 3 A 100 mA 1 mA 10 µA Measurement

Accuracy ±(0.03% + 250 µA) ±(0.025% + 10µA) ±(0.025% + 100 nA) ±(0.025% + 8 nA)

Seamless measurement between these 3 ranges

Parameter Fixed Range Seamless Improvement

Overall DC accuracy (2.97 mA avg) 8.5% 0.4% 21 X

Sleep base current DC accuracy (1.22 mA avg) 20.5% 0.8% 25.6 X

Measuring DRX Standby Current Drain

50 mA/Div

500 ms/Div Sleep current base (1.22 mA)

Receive current pulses (up to 291 mA)

High digitizing rate, resolution, and DC accuracy are needed for standby operation

• 1.22 mA sleep base current

• Peak pulses up to 291 mA, complex shape

• Low average current of 2.97 mA, determines standby battery life

• High crest factor makes accurate measurement difficult

• N6781A seamless measurement ranging greatly extends dynamic range of accurate measurement, spanning to up to 7 decades

• Improvement depends on signal, shown below for this example

16




N6781A Time Resolution Performance

for Detailed Insights

High level of time resolution provides greater insights details for optimizing run time:

• Able to correlate specific activities to current drain duration and level

• N6781A provides down to 5.12 µsec sample interval in scope mode and down to 20.48 µsec in long-term data log mode to gain greater insight on details

GPRS Smart Phone Battery Drain for DRX Standby

• 1.22 mA sleep current during 1.25 s paging interval

50 mA/Div

500 ms/Div Sleep current base


DRX Burst Current pulse details

• 23 ms pulse: 239 mA peak & 92 mA ave.

5 ms/Div 50 mA/Div

Wake up / idle pedestal

Receive activity / RSSI

Baseband activities

Sleep base

17




N6781A Measure Only Mode: Zero

Burden Ammeter for Battery Run-down

Using actual battery gives most realistic assessment of DUT performance

N6781A regulates zero volts at output while measuring current, acting as a zero burden ammeter, eliminating voltage drop problem of using a shunt

N6781A Aux DVM input simultaneously measures battery voltage

Application note 5990-7370EN provides details on setting up

+ _

0 Volts

A

DUT

battery

Aux in voltage measurement

Zero burden ammeter

Battery current drain

_

+ +

_

N6781A source/measure unit

+

_

Vout + Vout -

DUT

18




Battery Run-down Test

Example Results and Insights

•Results

• Logged min, avg & max volts, amps, & watts

• Markers at start and shutdown determine:

I avg = 233 mA

V avg voltage = 3.82 V

Charge = 843 mA-h

Energy = 3.19 W-h

Run time = 3 hr 38 min

V shutdown = 3.44 V

Insights:

• Delivered charge (843 mA-h) less than spec’d (1000 mA-h)

• V shutdown high (target 3V)

• Often energy (unspec’d) is more related to actual run-time than Charge (spec’d)

Voltage

Current

Power

24 min/div

N6781A SMU and 14585A Software Measuring

Battery Run-down on a GSM/GPRS Mobile Phone

20




DUT

Battery In RF

N6705B DC Power Analyzer

with N6781A SMU emulates

the DUT battery

PXT Wireless

Communications Test Set

PC running 14585A

Battery Drain

Analysis software

Analyzing & Optimizing LTE DRX,

Example System Setup

DRX (Discontinuous Receive) power savings mode

High speed digitizing measurement system captures DUT current drain

Base station emulation, maintains standby with DUT for DRX-off and DRX-on modes

21






Effects of DRX on Battery Drain

LTE example

The UE may use Discontinuous Reception (DRX) in idle or connected mode

in order to reduce power consumption.

No DRX – High constant current drain in either Idle or Connected Mode

Idle DRX – dramatically reduce current drain, but lengthen re-action times

• 4 DRX settings, 320, 640, 1280, 2560 sub-frames

Connected DRX – multiple settings

• If only long cycle configured, UE could be “asleep” in Connected mode for

more than 2 seconds, dramatically changing current drain, but leaving a

very slow reaction time.

• If both long and short cycles are used, UE may be able to react a little

faster, current drain will be slightly higher than if only long cycle used.

System settings such as DRX can have a significant effect on battery drain.




Analyzing & Optimizing

LTE DRX Power Savings

LTE Data Modem

Idle DRX rate set to 320 sub-frames

Highest level of activity for standby

Found average current was 180mA and peak was 466mA

23






LTE Data Modem


High level of activity for standby


24






LTE Data Modem


Lower level of activity for standby


25






LTE Data Modem


Lowest level of activity for standby


26






LTE Long and Short Cycle DRX 36.321, 36.331

Page 27

drx-InactivityTimer

onDurationTimer

longDRX-Cycle

drx-InactivityTimer

longDRX-Cycle

onDurationTimer

drxStartOffset

SF0

drxStartOffset

SF0

drxShortCycleTimer

(number of short cycles)

shortDRX-Cycle

If both short and long cycles are configured, the UE will (if no activity during

the drx-inactivityTimer), drop to the short cycle. This will allow the UE to be

more reactive to data reception. After the number short cycles defined in the

drxShortCycleTimer, if there remains no activity, the UE reverts to the long

cycle.






Battery Drain Influences

LTE examples






Battery Drain Influences

LTE examples

What influences LTE Current Drain Tx Power has VERY high influence in LTE Tx Allocations (number of RB’s), Rx much less so Connected Mode DRX settings Paging Cycle setting MIMO Many applications which use SatNAV / Location services do not switch off Touch Screen use, constant backlighting What does not influence LTE Current Drain significantly BSE Tx level – causing adjustments in UE Rx, gain etc. BUT open loop Tx will be influenced Some strange effects with non-contiguous DL allocations. Unacknowledged Vs Acknowledged mode RLC Ciphering What MIGHT influent LTE Current Drain – untested SPS and TTI Bundling Voice Vs Data




Challenge:

Easily Exercise UE Capabilities

Requirements

• Exercise All Applications (Voice, Video, Messaging, e-Mail, Download, Upload etc)

• Exercise All Network Conditions (Handovers, Power Level Changes, DRX)

• Flexibility to quickly setup, change, and re-run tests

Traditional Solutions

• Custom software for application

• Use a general purpose graphical test executive program environment

• Test mode operation of device

Specialized Approach

• Simultaneous and multi-threaded exercising of device under defined network conditions

Challenges

• Custom software is a huge programming effort

• Learning curve for test implementation and measurement methods

• Tests a limited subset of UE features

35






N5972A

Interactive Functional Test Software

• Multiple radio access technologies

• LTE using PXT and associated protocol logging

• UMTS and CDMA with 8960 and associated protocol logging

• Voice, video, messaging with IMS-SIP emulator (E6966A)

• Battery drain test with DC power source, modules and analysis software

(66319B/D or 66321B/D DC source with 14565B device characterization

s/w & now supporting N6705B DC power analyzer, N6781A source and

14585A s/w)




Protocol Log

Simultaneous and Multi-threaded Exercising of Devices

Simultaneous activities (SMS/MMS, FTP, battery profile etc.)

Predictably or randomly changing over short or long periods of time

– Enables user-experience testing scenarios

– Stresses phones and finds issues earlier, vs. sequential testing

38

FTP

SMS

Cell

Power

Failure caused

by unique

combination of

Activities

Failure due to

SMS buffer

limitations in

DUT

Failure




DUT

DC Supply RF

Control interface

N6705B DC Power Analyzer

with N6781A SMU in

battery emulation mode

PXT Wireless

Communications Test Set DUT

PC running N5972A

Interactive Functional

Test (IFT) SW, and

14585A Battery Drain

Analysis SW

Optional PC or internet

connection for running

server applications

LAN

Example System Setup For

Automated Operation

39




Remote or Local Server Interfaces

Device Automation Tools

• Parallel activity

execution.

• Creates more

realistic user

experience

Function Test

Activities • Current drain

• SMS (MO, MT)

• MMS(MO,MT)

• ftp,http,UDP

• Call processing

• Network impairments

Current Drain vs. Simultaneous

FTP, SMS, and Power Changes

Current Drain Monitoring

40




Controls with blue arrow Icons can be “drag & dropped” into the scripting interface, It basically writes the code for you.

• VB.Net “Based” Programming environment (Scripter) allows custom automation of Interactive Activities.

• What ever you create in Interactive mode can easily be programmed and modified in the Scripting Mode.

41






N5972A Interactive Functional

Test Operating Modes

Interactive mode

– User manually sets up and executes activities through easy to use controls

– Use for troubleshooting design issues

– Setup and define test processes that can be saved in the script interface

Script development mode

– Once test process has been defined through the interactive mode, easily save the setup as a script

– Enhance and modify the scripts to include other user defined tasks

Stress test mode

– Setup an automated test plan that runs created scripts

– Combine multiple scripts into a single test plan

– TCP/IP API interface can control test plan execution through other programs

– E-mail notification of test plan status and results






N5974A IFT automation for

AT&T compliance test plan

N5974A-9FP IFT scripts for battery performance test

– example test conditions (UMTS / LTE modes)

• AMR Call

• SMS & MMS

• Idle mode

• FDP

• UDP

• Video streaming

• CSFB

Speaker Note:

Additional details of

this product are

behind this note and

are available only to

companies approved

by AT&T




Benefits: Bring smaller, longer running, more competitive products to market

Faster time-to-market and at lower expense by reducing development time

In Development, optimize battery

operating time:

• Evaluate and optimize overall device and its

sub circuits

• Validate and optimize battery power

management system

• Identify high peak drain anomalies and their

root causes

In Software Development, validate

new code builds:

• Run application code regression test suites,

impact on battery drain

In Design Integration and Validation:

run suites of benchmark tests:

• Current drain for channels & power level

combinations, & main op modes

• Validate operating time with product’s battery

(run-down test)

• Check impact of HW, L1/L2/L3, OS &

application interactions on battery drain

Summary: A Growing Need for

Real World Tests

46




Some Examples:

In Design Validation:

• Test suite of current drain vs. transmit (TX)

power levels & channels

In Software Development:

• Validate against current drain with

regression test suites

• Timestamp current drain behavior

synchronized to specific DUT activity

In Integration and Verification:

• Stress testing designs to find issues early in

the design cycle

• Perform realistic network testing before

network drive tests

• Ensure Product’s meet published

specifications & industry benchmarks

• Ensure Product’s meet Service provider

sourcing requirement specification

Network Operator compliance plans:

• Focus on testing without having to create

complex code or program test equipment

Why Automate Current

Drain Measurements?

Benefits: Reduce Time-to-market - Get product out more quickly and with less resources

Test early and more thoroughly - Perform tests previously not practical to do

47




48

The Benefits of Using New Techniques

Bring hardware, protocol and software together, check that it works

Performance verification & regression test of components and integrated devices

More expansive testing of UEs for interoperability and performance against expected use models

Use on real networks

Design Integration

Validation Testing

Operator Deployment

Develop a BETTER product

Achieve test EFFICIENCY

Efficiently and accurately complete necessary iterations of design and verification cycles

Get to market FASTER






Additional Resources

Interactive functional test software

www.agilent.com/find/N5972A

IFT automation for AT&T compliance test plan

www.agilent.com/find/N5974A

DC Power Analyzer

www.agilent.com/find/N6705B

http://www.agilent.com/find/N5972A

http://www.agilent.com/find/N5974A

http://www.agilent.com/find/n6705B

optimize ue design for greater battery run-time - keysight · wcdma gsm 1xev-do cdma2000 hspa fm...

Documents