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The Value of Cross-LayerThe Value of Cross-Layer
Optimization for 3G NetworksOptimization for 3G Networks
CDG Tech Forum
April 20, 2006
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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
• Transactional – Digital Music, Ringtones
• Rich Media Store and Forward (MMS)
Mobile Workforce
• Mobile Data Connectivity
• Always-on Email
• VPN Access
Product and User Segments
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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
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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
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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
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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
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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
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Frequent Timeouts under Poor RF Frequent Timeouts under Poor RF
And Unpredictable AvailabilityAnd Unpredictable Availability
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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
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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
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Frequent Timeouts under Poor RF Frequent Timeouts under Poor RF
Layered Optimization ElementsLayered Optimization Elements
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Venturi Applies the Cross Layer Concept,
Optimizing Transport and Application Layers
Venturi Applies the Cross Layer Concept,
Optimizing Transport and Application Layers
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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
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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
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Content Delivery Time is Improved
40-60%
Content Delivery Time is Improved
40-60%
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%
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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
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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