10 Steps to Determine 3G/4G IP Data Wireless Product Planning - - PowerPoint PPT Presentation

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10 Steps to Determine 3G/4G IP Data Wireless Product Planning - - PowerPoint PPT Presentation

Sep 24, 2022 226 likes •671 views

Michael Lawton 10 Steps to Determine 3G/4G IP Data Wireless Product Planning Engineer Throughput Marv Wagner Wireless Applications Engineer Slide 1 Agenda Introduction 10 Steps to Data Throughput Testing building up complexity

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SLIDE 1

10 Steps to Determine 3G/4G IP Data Throughput

Michael Lawton Wireless Product Planning Engineer Marv Wagner Wireless Applications Engineer

Slide 1

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SLIDE 2

Agenda

  • Introduction
  • 10 Steps to Data Throughput Testing – building up

complexity

  • Case studies – “peeling back the onion”
  • Summary

Slide 2

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SLIDE 3

Technology Drivers for Wireless Networks

  • Higher speed,
  • Lower latency
  • All IP
  • Convergence (Radio Access and Core Networks)

–LTE and IMS

  • Interworking

E2E IP Throughput Testing is a key performance test which aligns with these technology drivers

20 40 60 80 100 120 100 200 300 400 500 600 700 800

Mbps ms

Slide 3

Voice Data

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SLIDE 4
  • Mobile penetration continues to grow: > 5

billion subscribers worldwide – more than 70% penetration*

  • Mobile data traffic is growing exponentially -

caused by growing number of mobile devices such as tablets and smartphones accessing high-bandwidth applications.

  • More spectrum is being made available
  • In addition to subscriber growth, there is

parallel growth in cellular peak data rates

It’s All About More Data, Faster!

Source: LTE World Summit presentation 2011

384 kbps 14 Mbps 21-168 Mbps 150-300 Mbps HSPA+ LTE LTE-Advanced W-CDMA HSPA 1 Gbps

Growth in cellular peak data rates (theoretical) showing more than 2500 times higher data rate over a period of 10 years

* Note some users have multiple subscriptions

42 Mbps

VoLTE

Slide 4

= 1 exabyte!

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SLIDE 5

IP Multimedia System (IMS) Convergence

Voice Chat Video File Share Find Me

Contacts/ Presence

Now

Multiple vertical solutions

2013 and on … All IMS/IP

Multiple Access Networks Multiple Access Networks Multiple Access Networks Multiple Access Networks Core Networks Core Networks Core Networks Core Networks

Voice SMS IP

Legacy

Multiple Access Networks IP/ IMS arch. Multiple Access Networks Multiple Access Networks Multiple Access Networks

Applications Applications Applications Applications

IMS RCSe IMS VoLTE

Slide 5

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SLIDE 6

Traditional Data Channel Testing Methods

Physical layer testing

– Benefits: Verifies coding and basic performance of L1 – Issues: Does not include higher layers, signaling, or apps

Standards-based testing

– Benefits: Industry standard, repeatable, required for conformance – Issues: Does not include apps, limited configs tested, ideal conditions Often does not match real user experience

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SLIDE 7

Traditional Data Channel Testing Methods

Field testing

– Benefits: Real world conditions, can include apps – Issues: Not repeatable, often requires travel, difficult to troubleshoot and time consuming

Proprietary test systems

– Benefits: Repeatable test scenarios, in house 24x7 access – Issues: Requires large investment $$ and time plus dedicated staff

Slide 7

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SLIDE 8

E2E IP as a Measurement

  • Benefits

– A simple measurement to make yielding quick results – Tests a key performance parameter vs a headline theoretical limit – Is a stress test that tests the complete phone – Excellent at finding if you have a problem

  • Issues

– Not so good at isolating what your problem is! – Sometimes finds problems with the test and not the phone

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SLIDE 9

Agenda

  • Introduction
  • 10 Steps to Data Throughput Testing – building up

complexity

  • Case studies – “peeling back the onion”
  • Summary

Slide 9

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SLIDE 10

E2E IP … 10 Step Plan, building up complexity

1. Will my device connect? 2. Do I have a good quality transmitter? 3. Do I have a good quality receiver? 4. Can I achieve max E2E tput under ideal conditions with UDP 5. What about with TCP and simultaneous UL/DL? 6. What happens if I try real application? 7. What happens under non-ideal conditions? 8. Is it robust? 9. Does it work closed loop?

  • 10. How good is my battery life?

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SLIDE 11

Step 1: Will my device connect?

SIB info provides capability info

UE/eNB exchange RRC connection Request/Setup messages

Obtain IP address Establish Default bearer AAA exchanges with MME

UE/eNB exchange RRC connection Reconfig/Complete messages

Attach complete

UE sends PRACH using Zadoff Chu Sequence If no response UE re- transmits with higher power BS responds addressing MS with the preamble identifier and providing an RA-RNTI BS sends timing alignment BS provides UL grant allocation using TC- RNTI

UL Power ranging & Random Access

Power on Scan for downlink channels

Synchronize with Downlink of serving BS

Decode PBCH Decode PDCCH/PDSCH to get SIB data

Sync to DL and decode broadcast info

Security, bearer establishment, and IP

Slide 11

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  • 1. Will my device connect?

Protocol test

PDCP RLC MAC PHY

RF UE

IP RRC PDCP RLC MAC PHY IP RRC RRC

  • Is the UE able to sync to the DL?
  • Can I get through the connection set-up
  • Can I ping my UE?
  • If not take a log and de-bug message exchange
  • Make edits as required with Message editor

NAS NAS NAS

Protocol Logging and Analysis Software (N6061A) DL UL Message Editor Software (N6062A) Script Layer 3 RRC/NAS scenarios

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SLIDE 13
  • 2. Do I have a good quality Transmitter?

RF test

UE DL UL

  • High data throughput testing relies on good quality UL

transmissions

  • Look for the following:-

– Ensure you have appropriate power and attenuation settings – High EVM for high order modulation schemes – High EVM at the band edge – Spurs both in band and out of band – Linearity issues/ spectral growth – Switching transients, LO settling time – Repeat tests with any “other” radio’s active

Slide 13

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SLIDE 14

3GPP Tx Measurements

Test case Number

3GPP 36.521 Test Case Description

6.2.2 UE Maximum Output Power 6.2.3 Maximum Power Reduction (MPR) 6.2.4 Additional Maximum Power Reduction (A-MPR) 6.2.5 Configured UE transmitted Output Power 6.3.2 Minimum Output Power 6.3.3 Transmit OFF Power (Covered by 6.3.4.1) 6.3.4.1 General ON/OFF time mask 6.3.4.2.1 PRACH time mask 6.3.4.2.2 SRS time mask 6.3.5.1 Power Control Absolute power tolerance 6.3.5.2 Power Control Relative power tolerance 6.3.5.3 Aggregate power control tolerance 6.5.1 Frequency error 6.5.2.1 Error Vector Magnitude (EVM) 6.5.2.1 A PUSCH-EVM with exclusion period 6.5.2.2 Carrier leakage 6.5.2.3 In-band emissions for non allocated RB 6.5.2.4 EVM Equalizer spectrum flatness 6.6.1 Occupied bandwidth 6.6.2.1 Spectrum Emission Mask 6.6.2.2 Additional Spectrum Emission Mask 6.6.2.3 Adjacent Channel Leakage power Ratio 6.6.3.1 Transmitter Spurious emissions 6.6.3.2 Spurious emission band UE co-existence 6.6.3.3 Additional spurious emissions 6.7 Transmit intermodulation Slide 14

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SLIDE 15

UL RF Measurements

Constellation Channel Power Sub-carrier flatness SEM ACLR EVM vs symbol

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  • 3. Do I have a good quality receiver?
  • High Data throughput testing

relies on good a quality receiver

  • Look for the following:-

– sensitivity for different modulation schemes – Max input level performance – susceptibility to interference (simultaneous UL/DL, other radios, spurs from digital board, …)

Slide 16

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SLIDE 17
  • 3. Do I have a good quality receiver?

Slide 17

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Rx Measurements

Section 7 Receiver Characteristics

Requires SS Requires SA

7.3 Reference sensitivity level

Supported Yes Yes

7.4 Maximum input level

Supported Yes Yes

7.5 Adjacent Channel Selectivity (ACS)

Supported Yes Yes Y

7.6.1 In-band blocking

Supported Yes Yes Y

7.6.2 Out-of-band blocking

Supported Yes Yes Y

7.6.3 Narrow band blocking

Supported Yes Yes Y

7.7 Spurious response

Supported Yes Yes Y

7.8.1 Wideband intermodulation

Supported Yes Yes Y x 2

7.9 Spurious emissions

Supported Yes Yes Y

Slide 18

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SLIDE 19

E6621A PXT DL UL

  • iperf used to provide UDP data stream and measure received throughput
  • No IP level ACKs required
  • Measure results vs modulation/coding scheme
  • Fluctuating BLER may indicate RF issues
  • Sudden loss of data may indicate memory loss issues

DL data tput controlled by iperf Received DL data tput for radio link No Acks reqd at IP layer

Tput/BLER

Slide 19

  • 4. Can I achieve max E2E Tput under ideal

conditions with UDP?

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SLIDE 20

DL Data Throughput for TD LTE

(20MHz channel, 2x2 MIMO, UL/DL config 5, special subframe config 6)

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20 40 60 80 100 120 5 10 15 20 25 27

Theory MAC meas E2E IP meas

MCS Mbps

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Measurement Technique: UDP vs FTP (TCP)

+ Unacknowledged + removes flow control complexity + removes higher layer acks + Less susceptible latency

FTP

+Simulates real-world file transfers +Transferred files can be viewed and/or compared

UDP

  • Not the full story for file transfers
  • Not suitable for used in shared

networks

  • Adds flow control complexity
  • Add higher layer acks and re-

transmissions

  • TCP Control algorithms sensitive

to multiple parameters

  • Test system configuration can

affect results

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SLIDE 22

E6621A PXT DL UL

  • TCP adds higher layer support for error detection, re-transmissions, congestion control and

flow control

  • TCP flow control algorithms interpret “lost” packets as congestion
  • Careful consideration of parameters such as window size, number of parallel process,

segment size etc. need to be considered

DL data tput controlled by TCP flow control Received DL data tput for radio link Acks reqd at IP layer

Tput/BLER

Slide 22

  • 5. Can I achieve max E2E tput under ideal conditions with

TCP?

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SLIDE 23

TCP “Flapping”

The same file FTP’d 10 times. 9 times rate is flat and consistent. 1 time there is a TCP slow-start as the flow control algorithm responds to an error – this is known as a TCP “flap”

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SLIDE 24
  • 6. What happens if I try a real application? …

(Voice, video, ftp …)

VIDEO VOICE

E6621A PXT DL UL Received DL data tput for radio link

Tput/BLER

  • This should not add too much complexity
  • Most IP applications will typically use UDP
  • r TCP

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  • 7. What happens under non-ideal conditions?
  • Typically fade the DL and use

robust UL

  • Perform test mode and E2E

testing

  • Measure MAC (BLER & Tput) and

IP layer throughput

  • Use TCP with care!

AWGN CHANNEL EMULATOR OCNG

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  • 8. Is it robust? …
  • E2E IP tests PHY, MAC, PDCP, and IP layers all working together at full rate
  • Check processor can handle multiple real time activities – add SMS and voice

calls during E2E IP

  • Check there are no memory overflow/leakage issues

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  • 9. Does it work closed loop?
  • BLER/Tput Testing
  • Supports Test Mode and E2E Testing

CQI PMI RI 1 RI

AUTO

2

QPSK MCS 0-9

16QAM MCS 10-16

64QAM MCS 17-25

DL MCS

AUTO

CHANNEL EMULATOR

PMI

AUTO

1 3 2

Slide 27

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SLIDE 28
  • 10. How good is my battery life?

Client:

  • Interactive Functional Test (IFT)
  • Wireless Protocol Advisor
  • License Keys
  • Modem drivers

Server:

  • FTP server
  • UDP Server
  • Apache HTTP server
  • MMS/SMS server

PSU:

  • Current monitoring

8960:

  • 2G/3G BS emulation

Slide 28

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SLIDE 29

Agenda

  • Introduction
  • 10 Steps to Data Throughput Testing – building up

complexity

  • Case studies – “peeling back the onion”
  • Summary

Slide 29

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Automated Measurements Give Repeatable 21Mbps Results!

DL UDP UL UDP Simul UL/DL UDP DL FTP UL FTP Simul UL/DL FTP

Consistent UL UDP Over-flood issues Occasional TCP “flapping” (2 of 23)

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Device Performance: MIPS Matter!

This comparison was made with a very early Cat 8 HSDPA phone. When the MAC-d block size is smaller, the device doesn’t have the MIPS to sustain the high rate.

MAC-d PDU Size Comparison with UDP

PDU = 336 bits, Average = 497 kBytes/s (3.98 Mbps) PDU = 656 bits, Average = 792 kBytes/s (6.34 Mbps) UDP UDP FTP FTP 656 bit PDU 336 bit PDU

Slide 31

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Cat14 (21Mbps) Devices – Better the second time around

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Dual-Carrier HSDPA (42Mbps) – Diversity Matters!

Throughput for Rx Power = -20dBm to -85dBm 2nd RF Connector terminated (or connected via a splitter) Same device with 2nd RF connector left “floating”

Slide 33

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SLIDE 34

Dual-Carrier HSDPA (42Mbps) – Diversity Matters!

Slide 34

Throughput for Rx Power = -20dBm to -85dBm Same device with 2nd RF connector left “floating” Device with only 1 RF connector available

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SLIDE 35

Not All HSDPA Cat 6 Devices Have the Same Throughput

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TCP Flap

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SLIDE 36

Slide 36

It’s really hard to tell when individual FTP transfers start and stop (there are 10 on this screen capture). You can see the “clean” FTP is the high data rate

  • n the Ch 10677 trace.

Not All HSDPA Cat 6 Devices Have the Same Throughput

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SLIDE 37

Slide 37

Not All HSDPA Cat 6 Devices Have the Same Throughput

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SLIDE 38

Data Throughput Across Input Power Level

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2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00

  • 100
  • 90
  • 80
  • 70
  • 60
  • 50
  • 40

Data Throughput (Mbps) Received Power (dBm)

Data Throughput vs RF Input Level

Ch 10637

Classic digital modulation

  • performance. Consistent

performance up to sensitivity threshold with very quick rolloff at power levels below threshold.

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SLIDE 39

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2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00

  • 100
  • 90
  • 80
  • 70
  • 60
  • 50
  • 40

Data Throughput (Mbps) Received Power (dBm)

Data Throughput vs RF Input Level

Ch 10637 Ch 10562

Data throughput roll off at high input, low band edge

Data Throughput Across Input Power Level

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SLIDE 40

Data Throughput Across Channels and RF Input Levels

Slide 40

Data Throughput vs Channel and RF Input Level - Phone A

2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00

  • 100
  • 90
  • 80
  • 70
  • 60
  • 50
  • 40

Received Power (dBm) Data Throughput (Mbps)

Ch 10562 Ch 10587 Ch 10612 Ch 10637 Ch 10662 Ch 10687 Ch 10712 Ch 10737 Ch 10762 Ch 10787 Ch 10812 Ch 10837

Very consistent sensitivity across all RF Channels.

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SLIDE 41

Slide 41

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

  • 100
  • 90
  • 80
  • 70
  • 60
  • 50
  • 40

Data Throughput (Mbps) Received Power (dBm)

Data Throughput vs Channel and RF Input Level - Phone B

Ch 10562 Ch 10585 Ch 10608 Ch 10631 Ch 10654 Ch 10677 Ch 10700 Ch 10723 Ch 10746 Ch 10769 Ch 10792 Ch 10815 Ch 10838

Sensitivity Issue at high band edge (approx 10dB)

Data Throughput Across Channels and RF Input Levels

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SLIDE 42

Agenda

  • Introduction
  • 10 Steps to Data Throughput Testing – building up

complexity

  • Case studies – “peeling back the onion”
  • Summary

Slide 42

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SLIDE 43

Summary

  • E2E IP Data throughput is a very useful measurement

which stress tests the device against a key specification

  • The measurement is good for finding problems
  • Troubleshooting the problem requires you to peel back the
  • nion
  • We have looked at examples of E2E IP issues found

testing 3G/4G commercial UEs

Slide 43