1

The Value of Cross-LayerThe Value of Cross-Layer

Optimization for 3G NetworksOptimization for 3G Networks

CDG Tech Forum

April 20, 2006

2

3G Mobile Data – Multiple Revenue

Stream Opportunities

3G Mobile Data – Multiple Revenue

Stream Opportunities

Infotainment Services

• VoD and Video Streaming

• High Quality Audio Streaming

• Networked Gaming

• Entertainment

• Location Based Services

Wireline BroadbandAlternative

• 3G, 802.16x Broadband Services

• 3G to Wi-Fi gateway

• Narrowband made “Broadband”

• Rural or emerging markets with

low Internet penetration

Basic Data Services

• Instant Messenger

• Email

• Transactional – Digital Music, Ringtones

• Rich Media Store and Forward (MMS)

Mobile Workforce

• Mobile Data Connectivity

• Always-on Email

• VPN Access

Product and User Segments

3

3G Mobile Data Adoption3G Mobile Data Adoption

High Expectations from Users

– Shaped by previous experiences with Wi-Fi, DSL, Cable

– Cost of not meeting expectations: low adoption, high churn,

high customer care costs

Mobile E-Commerce Requires Consistency

– Session connectivity critical for mobile e-commerce

– Higher level of user frustration/time lost vs. voice calls

New 3G Services Assumes Consistency

– Consumers assume video/audio content to behave like

TV/radio

– Long buffering and interruptions kill the user experience

4

Effective Spectrum Efficiency –

Important in a Growing User Base

Effective Spectrum Efficiency –

Important in a Growing User Base

Maximize subs/Hz

Lower CAPEX per sub –

infrastructure costs

Lower OPEX per sub –

customer care and

backhaul

Growin

g Subscrib

ers and T

raffi

c

Efficient Utilizationof Assets Become

More Critical

More Traffic

More Users

5

Combining IP and Radio Network

Stacks - Challenges

Combining IP and Radio Network

Stacks - Challenges

Goals

Robust point to pointdata delivery

Congestion control

Technology Evolution

IP Network Radio Network

Goals

Spectrum efficiency

Optimized for voicetraffic

Technology Evolution

Tradeoffs between application robustness andspectrum efficiency

UDP for streaming

TCP for transaction-based applications

Scheduling algorithms

Link adaptationtechniques

Hybrid ARQ techniques

Frequency hopping

Diversity antenna

6

Radio Link Variances Impact Overall

Network Performance

Radio Link Variances Impact Overall

Network Performance

Signal Strength Interference Fading Network Load

RF Quality Metrics Affected: RSSI, SINR , BER/FER

Loss (p)

Pro

po

rtio

n o

f s

uc

ces

sfu

l p

ac

kets

7

Leading to Inconsistent ThroughputLeading to Inconsistent Throughput

Good RF conditions Poor RF conditions

Throughput Can Degrade 80% in Poor RF AreasThroughput Can Degrade 80% in Poor RF Areas

0

20

40

60

80

100

Average RF conditions

Av

era

ge

Me

dia

n T

ime

to

Do

wn

load

(secs

)

Degraded Signal

Interference

Fading

High Load

Service Unusable

8

Frequent Timeouts under Poor RF Frequent Timeouts under Poor RF

And Unpredictable AvailabilityAnd Unpredictable Availability

9

TCP Does Not Efficiently Utilize the

Wireless Network Efficiently

TCP Does Not Efficiently Utilize the

Wireless Network Efficiently

Bandwidth efficiency swings due to radio link variances

Retransmission and prolonged wait for ACKs force applicationprotocols to timeout

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Impact on Subscriber Adoption and LoyaltyImpact on Subscriber Adoption and Loyalty

Why does it take so

long to download this

email?

Why is this media

freezing so

often?

Why can’t this

submit request

go through?

Was I supposed to

make the right turn

at the last signal?

Lower service uptake

Higher customer support costs

Higher cancellation rate

Brand is impacted

Examples

RESULT

11

Cross Layer OptimizationCross Layer Optimization

Optimization of the applicationlayer (IP network) and theradio link layer

Inter-layer exchange acrossthe protocol stack

Cross Layer Optimization addresses the challenges of IP over

the wireless environment

12

Frequent Timeouts under Poor RF Frequent Timeouts under Poor RF

Layered Optimization ElementsLayered Optimization Elements

13

Venturi Applies the Cross Layer Concept,

Optimizing Transport and Application Layers

Venturi Applies the Cross Layer Concept,

Optimizing Transport and Application Layers

14

Cross Layer Optimization Even More

Relevant for Handset

Cross Layer Optimization Even More

Relevant for Handset

QoS scheduling is mostefficient at the chip level

Phoneware driver can feedradio parameters back intotransport layer

Better traffic throttling controlthrough control planeinteraction

15

Adaptive Airlink OptimizationTM

Patented Venturi Transport Protocol (VTP)

Adaptive Airlink OptimizationTM

Patented Venturi Transport Protocol (VTP)

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The Venturi ImpactThe Venturi Impact

Improved Data Throughput Improved Data Throughput Improved Data Throughput

Service Consistency Service Consistency Service Consistency

Increased Network EfficiencyIncreased Network EfficiencyIncreased Network Efficiency

Lowered Cost per Sub Up to 50% reduction in network CAPEX

together with lower OPEX

Improved Capacity Utilization More subscribers on existing infrastructure

and spectrum

Greater Reliability Reduced drops and connection time-outs Fewer interruptions during streaming

Enhanced CoverageConsistent data speeds throughout the cell

Accelerated Data Speeds 2-9X faster data throughput

2-3X faster video/audio downloads Shorter buffering time and improved imagequality for streaming media

17

Content Delivery Time is Improved

40-60%

Content Delivery Time is Improved

40-60%

E-Mail

Games/

Ringtones

Web/Info

Audio/Video

Streaming,

Program Streaming

& Downloads

50% Reduction

39% Reduction

62% Reduction

55% Reduction

With VenturiWithout Venturi

Delivery Time

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More Available CapacityMore Available Capacity

Traffic Flow DiagramTraffic Flow Diagram

Faster Transaction Delivery Time with Venturi

= More Available Capacity

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Reliable Access and Stable

Connections

Reliable Access and Stable

Connections

without Venturi with Venturi

93%

Download Success Rate (Poor RF)Download Success Rate (Poor RF)

Notes: RSSI= -106 dB; Tests performed on EV-DO network in Las Vegas, NV (12/16/04)

53%

20

The User Experience is Consistent

Across the Network

The User Experience is Consistent

Across the Network

Poor RF Poor RFGood RFGood RF

87 secs17 secs19 secs 12 secs8 secs7 secs

Performance Degrades 5X Performance Stays Consistent

21

Venturi Enhances Multimedia

Performance

Venturi Enhances Multimedia

Performance

Buffering time: 30 sec

Frame rate: 15 frames per second

25% of frames dropped

Player auto-adjusts to 100 kbps

without Venturi with Venturi

Typical performance w/o Venturi

Buffering time: 10 sec

Frame rate: 30 frames per second

Zero dropped frames

Player auto-adjusts to 450 kbps

Typical performance with Venturi

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ConclusionsConclusions

Consistent user experience necessary to drive adoption

– User expectations must be met

Subscriber efficiency becomes critical as the market for3G services grows

Cross layer optimization addresses radio link challenges,improving the user experience and subscriber efficiency

Venturi optimization delivers

– Better capacity utilization

– 2X – 7X improved throughput

– Overall increased reliability and coverage