iot seminar 2017 - rohde & schwarz€¦ · iot seminar 2017 nanyang polytechnic keck meng ng...

IoT Seminar 2017Nanyang Polytechnic

Keck Meng NgApplication Engineer Rohde & Schwarz Regional Headquarter

Battery Lifetime optimization

The wireless Internet of Things

The low-power design challenge

• Low power architecture• Low power components• Sleep power minimization• Active power optimization• …..

Low-power hardware design• Operating system• Communication protocol• Operational model• Maintenance model (upgrade)• ……

Low-power software design

Low-power wireless communication

LP-PANBluetooth, …

LP-LANWi-Fi Halo, …, ZigBee, Thread, …

LP-WANSigfox, LoRa, …LTE Cat M1/NB1…

Considering/modelling all relevant aspects impacting power consumption

IoT Seminar Day | Nanyang Polytechnic | 9th June 2017 3

Two possible methods to save power: Select the best one and define the optimal parameter!


Is the mobile reacting correctly to the configured timers?

How the power consumption looks like?

Which application bring the device from Idle or PSM to connected state?

How often it happens and which is the impact on the battery life?

How to emulate real user scenarios?

It becomes more complex to optimize the power consumption

Extended DRX(Idle Mode)

UE power classUE category Power saving

mode (PSM)Coverage

enhancement

Conditions

Data exchange architecture

Cat NB1

Cat M1

Cat 0

Cat 1

20 dBm

23 dBm

U-Plane

Non-IP

IP

5.12 s

10.24 s

43.69* min

6 min

12 min

310 h

Level 0

Level 1

Level 2

Design decision Negotiation w/ network

* eDRX timer for eMTC; for NB-IoT up to 175 min


Need for precise power measurements and detailed views on all relevant aspects under reproducible network conditions

IoTapp.

MME

S-GW

SCEF

P-GW

MMECIoTBSDUTPMIC LTE

µP

GPIO1.8 V

3.3 V

2.8 V

• Communication behavior• Timer (eDRX, PSM)• Power modes

VI

• Feature support (PSM,…)• Coverage conditions• Communication modes

• Throughput• Delay, jitter• Loss

• Communication behavior• Device triggering• Maintenance actions

• Power monitoring over long period of time, ideally w/o specific power supply and on multiple channels• Very high dynamic range and high time resolution of I, V and P measurements• Possibility to correlate with signaling/network events


Channel 2

PMIC GPIO

µP

LTE

1.8 V

3.3 V

2.8 V

MinMaxAvgRMS

XCurrent

Voltage

Power V

I Decim

inat

ionA/D

A/D

Channel 1

Device under test (DUT)R&S®CMW500 network emulator R&S®CMW500 network emulator

R&S®RT-ZVC power probe R&S®RT-ZVC power probe

to Ch.#2

R&S®CMWrunR&S®CMWrune.g. LTE-Cat1

Power consumption measurement solution from Rohde & Schwarz

IoTapp.



USB

Up to 50 KSa/s regardless how many channels in use

ZVC04 Probe

Power Adapter

Voltage measurementswith 5 MSa/s each channel

Current measurements with 5 MSa/s each channel

V

I

Analog Frontent

(1..4 power meas. groups)

A/D18 bit

5 MSa/s

A/D18 bit

5 MSa/sA

rithmetic's

(min, m

ax, avg, RM

S)

Xinternalmultiplier

Digital Backend (4 in total)

V

P

I

Decim

ation

5MSa/s(each channel)

Up to 50 KSa/s for current and voltage

R&S RT-ZVCxx Multi-Channel Power ProbeHigh Speed Sampling

VoltmeterGain LSB Scale1/3 114 µV 15 V2/3 57 µV 7.5 V4/3 28 µV 3.75 V8/3 14 µV 1.88 V

AmperemeterShunt Gain = 10 Gain = 100

LSB Scale LSB Scale10K 381 pA* 45 µA 38 pA* 4.5 µA10R 381 nA 45 mA 38 nA 4.5 mA0R01 381 µA 10 A 38 µA 4.5 A

Ext. 3.81 µV 450 mV 381 nV 45 mV

l Digital control of range, amplification/attenuationl Input voltage range: ±15 V to GND (CM + differential), not floatingl Shunt – ampere meter up to 10 Al Variable gain and attenuation in the same signal path

* Lower limit is theoretical, sensitivity is limited by thermal and amplifier noise, see datasheet

Multi-channel power probe designed for large range measurements

R&S®RT-ZVC

9IoT Seminar Day | Nanyang Polytechnic | 9th June 2017

Burden Voltage


l Circuit in the DUT PCB need to be opened such that the current can be flow into the instrument probe and back to the circuit again

l In ideal case, the instrument should appear like a short circuit (zero resistance) to the current flow

l In reality, the instrument’s internal fuse, switches and external testing cables and leads have finite resistance

l This lead to voltage drop across the instrument which is known as Burden Voltagel If not properly control, Burden Voltage can lead to additional voltage drop across the

DUT and in turn may affect DUT operational behavior and measurement instabilityl To mitigate the effect of Burden Voltage, a shunt resistor can be inserted across the

instrument probe

Burden Voltage


Without burden voltage (figure a), the calculated current is:Iactual = 1.5 V / 5 ΩIactual = 0.3 A

With burden voltage (figure b), the current in this circuit equals:Imeasured = (1.5 V-0.5 V ) / (5 Ω)Imeasured = 0.2 A

In this case, the error caused by the burden voltage is 33%

Convenient use of the ampere meter:its internal shunt eliminates the need to modify the DUT

DUT

Ix

Probe channel #x

Im

Ix = Im

V15A

Shielded twisted pair cable

Exte

rnal

sou

rce

Build-in high precision shunt

Internal selectable shunts10 mΩ 1000 mW10 Ω 125 mW10 kΩ 250 mW

Internal selectable shunts10 mΩ 1000 mW10 Ω 125 mW10 kΩ 250 mW

Shunt included in the calibration procedure

Ready to go setup

Im

R&S®RT-ZVC


High impedance voltmeter: current measurements with external shunt

DUT

Ix

Probe channel #x

Im

V15A

Shielded twisted pair cable

Exte

rnal

sou

rce

Ix >> ImIdeal for measurements at board level

No need to open the circuit

External shunt can be easily adapted acc. to the current to be measuredReady-to go setup

Im

External shunt

R&S®RT-ZVC


Connecting current probe to Device Under Test


The headers soldered to the DUT Printed Circuit Board, provide firm contact with the test point during the whole measurements.

The signal lead is plugged onto soldered-in headers on the DUT

Current Test Points Voltage Test Points



Current Test Points

Voltage Test Points

The PCB cables provide a flexible connection to the DUT. They are soldered onto the DUT and connected with the signal lead.



Shunt Resistor

To reduce burden voltage, use the external shunt for measurements of higher current drains. The figure shows the soldered-in connection of external shunt.

Current Test Points

Precise metal strip resistors are recommended, such as Vishay CSM series. The smallest shunt available in this series is 1 mΩ

R&S®RT-ZVC measurements with more than one channel

Channel 4

^ MinMaxAvgRMS

XCurrent

Voltage

Power V

I Deci

min

atio

nA/D

A/D

Channel 3Channel 2

Channel 1

Model RT-ZVC044 current and 4 voltage channels

Model RT-ZVC022 current and 2 voltage channels


LTE Power Saving Mode (PSM) Optimization: Power vs. Delay

IoT Seminar Day | Nanyang Polytechnic | 9th June 2017

R&S®CMW500 R&S®RT-ZVC

R&S®CMWrun

20

Test sequencertool

Test sequencertool

Power consumption monitor


Voltage

Power

CurrentUL Power: 0 dBm

UL Power: 10 dBm

UL Power: 23 dBm

Event Marker

R&S®CMWrun: power consumption monitor with signaling events


IP ThroughputMonitor

IP ThroughputMonitor



Downlink Uplink

TAU

Idle

PSM

I-DRX

RRC Connected

Open TCP FTP


Detailed power analysis using power probe and scope


LTE Burst

Current

600 MHz .. 6 GHz models

R&S®RT-ZVC

R&S®RTO/RTE

23

Application ExamplePower Consumption of a Bluetooth Low Energy Device


Supply Voltage

Current shows peaks up to 12 mA

Current zoom window shows uA quiescentcurrents

Math channel showsinstantaneous power consumption

Area measurement shows how much energy this device activity consumed

Bluetooth Low Energy Device MeasurementLong-Term Measurement / Multi Domain Measurement


Long-term measurement with zoom where BLE is active

Multi-domain measurement:BLE current consumption /

wireless transmission

R&S RT-ZVCxx Multi-Channel Power Probe


Amperemeter

Voltmeter

LTE device

LAN for CMW remote control

USB based control

plug and play

R&S®CMW500 / radio comm. tester

RF

USB A/C Adapter

Demonstration

Your Partner in testing the Internet of Things


Thanks for your attention.

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iot seminar 2017 - rohde & schwarz€¦ · iot seminar 2017 nanyang polytechnic keck meng ng...

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