Find your voice Define the experience - RTC Conferencertc-conference.com/.../gravity_forms/.../ELKIN-VoLTE-is-here-Now-Wh… · The Impact of DTX and DRX on VoLTE and Skype Voice

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Find your voice

Define the experience

VoLTE IS HERE. NOW WHAT?

Ed Elkin

IP Platforms September 30th, 2014

2


WHAT’S NEXT?

WHY DID IT TAKE SO LONG?

IS IT WORTH

IT?

2


VoLTE HAS TAKEN SOME TIME

3


VoLTE HELPS ENABLE BUSINESS RESULTS

IMPROVED MOBILE

EXPERIENCE

Reduce churn

• Faster broadband

• Better voice

• Video, IP Messaging

MOVE TELCO TO THE

DATA-CENTRIC ECOSYSTEM

Sell more mobile data

• Data-centric pricing plans

• More LTE spectrum

• Multitask, video,

content-sharing

PLATFORM FOR NEW

SERVICES & MARKETS

• Wired for all-IP

• APIs & WebRTC

• NFV: Lean & Agile

CaaF in apps & web,

M2P/IoT comms,

Mobile enterprise, etc.

IS IT

WORTH IT?

NFV: Network Functions Virtualization

CaaF: Communications as a Feature in apps & websites

M2P: Machine to Person (machine initiated messages & conversations)

4


FIRST THINGS FIRST

DELIVERING MORE MOBILE DATA, FASTER

WHY DID IT

TAKE SO

LONG?

LTE is now broadly available

and rapidly growing

Huge growth in mobile data

Had to deploy new networks

LTE is a trademark of ETSI

5


IT’S WORTH DOING IT RIGHT

Clearer voice,

less noise

Minimize network

resource utilization

VoLTE’s distinguishing characteristic:

INTEGRATION WITH DEVICE & E2E NETWORK

IMS RAN EPC

Mobile

Backhaul

Devices

WHY DID IT

TAKE SO

LONG?

6


MARKET-FIRST PERFORMANCE ANALYSIS:

1. INDEPENDENT ANALYST

2. REAL WORLD CONDITIONS

3. COMPARES VoLTE, 3G UMTS, and SKYPE

AT&T LIVE COMMERCIAL SERVICE

ALCATEL-LUCENT IS THE INFRASTRUCTURE

SUPPLIER IN THE ANALYZED MARKET

Pages of facts, tests, charts,

analysis, results

67

7


TEST ENVIRONMENT

TEST EQUIPMENT ITEM

Spirent’s Nomad User Experience Analytics System MOS, Call setup time, Call reliability

Spirent’s Quantum Battery Life Measurement System Power consumption, Current drain, Implied battery life

Qualcomm’s QXDM Resource utilization, and capture RF parameters (Layer 1 measurements & PPP messages)

Accuver XCAP software and Xceed Technologies’ Windcatcher software Post-processing & analysis of the QXDM logs

4G LTE

3G UMTS

SGSN GGSN

GPRS packet core

PCRF

PGW SGW

MME

Evolved Packet Core

S6a

Rx

SGi

3G voice core

MSC MGW

Cx, Sh

Sv

IMS

HSS

Mw

S1-U

S1-MME

IuCS

IuPS

8


GENERAL OBSERVATIONS

MOS: Mean Opinion Score

TTI: Transmission Time Interval

PDCCH: Physical Downlink Control Channel

VOICE QUALITY

Drive Tests: VoLTE MOS (~3.8) was

• Significantly higher than 3G CS voice (~2.2 UL, ~2.8 DL)

• Measurably higher than Skype (~3.0)

• VoLTE MOS steady; Variable for 3G CS & Skype

Network loading or concurrent data transactions

on the test phone

• Brought Skype to its knees

• Had no impact on VoLTE

VoLTE versus SKYPE: RESOURCE UTILIZATION

• 10x less bandwidth

• 7x fewer Resource Blocks

• 5x fewer Transmission Time Intervals (TTI)

• 6x fewer PDCCH Grants

• Transmitted 4x less often

• Required 2.3dB less power from UE to Tower

BATTERY LIFETIME

With VoLTE, the battery life was

• 56-94% longer than Skype

• 11-17% less than 3G UMTS

CALL SETUP TIME

CALL RELIABILITY

• VoLTE faster than 3G Circuit Switched Fallback

• VoLTE comparable to 3G Circuit Switched Fallback

9


ENABLING TECHNOLOGY

QCI: QoS Class Indicator

RoHC: Robust Header Compression

DTX/DRX: Discontinuous Transmission & Reception

VOICE QUALITY

• VoLTE integrated into Smartphone & Network

• AMR-WB codec

• QCI=1 bearer invoked by voice service

• QCI=1: Guaranteed bit rate, Lower latency,

Higher priority, Larger packet error loss rate

• AT&T 3G UMTS uses AMR; VoLTE uses AMR-WB and Skype uses OPUS

BATTERY LIFETIME

• Smartphone: natively integrated VoLTE

client leverages HW resources

• Radio: RoHC, DTX / DRX, silence

indicator frames drive reduced

throughput, fewer resource blocks &

TTI, less time spent transmitting &

receiving, reduced transmit power, etc.

VoLTE versus SKYPE: RESOURCE UTILIZATION

• Smartphone’s VoLTE interface to LTE RAN

• Robust Header Compression (RoHC)

• Discontinuous Reception / Transmission (DRX/DTX)

• Semi-Persistent Scheduling (SPS)

• TTI-Bundling

• etc.

CALL SETUP TIME

CALL RELIABILITY

• VoIP/LTE (avoids retuning radios & paging)

• VoLTE’s signaling uses QCI=5

• Integration into E2E network

• Includes eSRVCC for VoLTE to 2G/3G handover

TTI: Transmission Time Intervals

eSRVCC: enhanced Single Radio Voice Call Continuity

10


NETWORK RESOURCE UTILIZATION: throughput



SPS: Semi-Persistent Scheduling

PROCEDURES:

• Used Qualcomm QXDM to capture

chipset diagnostic information during

drive test

OBSERVATIONS:

• ~13x higher throughput on Skype

• No evidence of voice activity pattern

during Skype call

• VoLTE supports RoHC and DTX/DRX

• Skype also supports DTX / DRX, but

takes less advantage of it

• Increases data capacity & battery life

Increases battery life

Increases data capacity

VoLTE Drive Test Downlink MAC Layer Throughput versus Time

Skype Voice over LTE Drive Test Downlink MAC Layer Throughput versus Time

11


NETWORK RESOURCE UTILIZATION:

resource blocks and transmission time intervals (TTI)

OBSERVATIONS:

• LTE uses Resource Blocks and TTI to

transport data

• VoLTE uses substantially less network

resources than Skype for the same voice

activity patterns

• Increases data capacity & battery life

Increases battery life

Increases data capacity

DL: Downlink

UL: Uplink

RB: Resource Blocks

TTI: Transmission Time Intervals

Summary of Resource Block Requirements – VoLTE versus Skype Voice over LTE

9.4x

6.1x

Summary of TTI Requirements – VoLTE versus Skype Voice over LTE

12


NETWORK RESOURCE UTILIZATION: DTX/DRX, RoHC and PDCCH Grants

OBSERVATIONS:

VoLTE transmits less often

VoIP signaling headers are relatively large compared to relatively small payloads … VoLTE’s RoHC shrinks the signaling header

VoLTE requires fewer PDCCH signaling grants

Increases data capacity and battery life




4.9x

The Impact of VoLTE and Skype Voice over LTE on PDCCH

Signaling Messages without SPS

The Impact of RoHC on VoLTE and Skype Voice over LTE The Impact of DTX and DRX on VoLTE and Skype Voice

3.3x 3.0x

QCI: QoS Class Indicator

SPS: Semi-Persistent Scheduling

13


VoLTE TECHNOLOGY DIVIDEND

VoLTE uses less LTE bandwidth, and fewer

PDCCH Grants, Resource Blocks and

Transmission Time Intervals.

REDUCE VoIP/LTE’s

RESOURCE UTILIZATION MORE VOICE CAPACITY / MHz

• Codec’s lower throughput

• Robust Header Compression (RoHC)

• Semi-Persistent Scheduling (SPS)

• DRX/DTX (take more advantage)

• Better link budget (TTI-Bundling, RLC Segmentation)

• 2G GSM (AMR 5.9) ~33 users / 5 MHz

• 3G UMTS (AMR 12.2) ~60

• 4G LTE-FDD (AMR-WB 12.65) ~200

• Unoptimized VoIP/LTE Unpredictable

VoLTE enables economically refarming

attractive 2G/3G spectrum to 4G LTE.

MORE CAPACITY FOR LTE’s FASTER DATA

TTI: Transmission Time Interval

RLC: Radio Link Control


14


WHAT’S

NEXT?

Efficient

re-wiring

of mobile

to all-IP

Mass

Market

VoLTE

App

Providers

Execute Innovate

• Explore art of possible

• Learn new things

• Unbounded to Internet’s

breadth

• Explore Telco market

using IP, APIs, WebRTC

• Things are shifting

(Foundries, Innovation

Centers, hackathons,

sandboxes, etc.)

Create

• Migrate subscribers

• Sell new bundles

• Interconnection &

Roaming

15


• Enterprise keeping pace with changing productivity habits

• Huge growth (VoLTE and WebRTC). What to interoperate and how?

• Voice’s ripple effect: Narrowband Wideband Super Wideband

• Operator and App Provider: business + technology deals that help both

SOME

CHALLENGES

Documents

Find your voice Define the experience - RTC Conferencertc-conference.com/.../gravity_forms/.../ELKIN-VoLTE-is-here-Now-Wh… · The Impact of DTX and DRX on VoLTE and Skype Voice