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Page 1
Push-to-Talk over 1xEV-DO
Vedat EyubogluCTO, Airvana
CDG Technology Forum on PTTJune 30, 2004
Page 2
Evolution of 1xEV-DO
All-IP Multimedia
DataOptimized
Rev A
V2oIP P2TStreaming Internet
Page 3
P2T over 1xEV-DO — Basic Network Diagram
Internet
IP
IP
P2TServer
1xEV1xEV--DO DO RNCRNC
1xEV1xEV--DO DO RNRN
PDSN
PDSN
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Why P2T over 1xEV-DO?
• Superior performance– Very fast call setup, low mouth-to-ear latency
• Higher capacity– Significantly higher than CDMA2000 1X
• Frees the switch (MSC) from P2T traffic– Operator can use the switch capacity for circuit voice
• Frees CDMA2000 1X capacity to serve growing circuit voice traffic
• Supports advanced push-to-media services with QoS• Enables integration with future VoIP services• Can be implemented on existing 1xEV-DO networks
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P2T over 1xEV-DO vs. P2T over CDMA2000 1X
Power-controlledFixed-rate (9.6)Dedicated TCH
Circuit-like
Rate-controlledAdaptive modulation
Hybrid ARQQoS & Packet scheduling
Packet-based
CDMA2000 1X
1xEV-DO
Superior
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1xEV-DO P2T Phases
Phase 1
MSM65xx
CSM5500
MSM6800
CSM5500
1xEV-DORAN
CSM5500
1xEV-DORAN
CSM6800
PDSN PDSNQoS
MSM7500
QoS
Rev A SW Rev A SW/HW
Phase 2
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P2T 1xEV-DO Performance Summary
48 Erlangs27 ErlangsAirlink Capacity
≈ 0.5 s≈ 0.5 sMouth-to-Ear Delay
< 1 s≈ 1.0 sCall Setup (Qchat)
< 2 s≈ 2.5 sCall Setup (SIP)
Phase 2Phase 1
Assumptions: ½ Rate EVRC, Bundling: 6, No HC
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Fast Call Setup Time in 1xEV-DO
• Fast low-overhead traffic channel setup• No MSC interaction• Variable paging cycle• Faster transmission speed → Low transmission delay
– Low-latency RL transmission with HARQ*
• Efficient data over signaling protocol*– To send SIP Invite over common channels– Enhanced with faster access channel
* Phase 2 Features
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1xEV-DO QoS in Rev A
• 1xEV-DO Rev A allows the RAN to apply different treatment to different flows; e.g., P2T bearer
• Allows subscribers to use applications with different QoS requirements simultaneously– Push-to-media– Integrated MMS & VoIP– Audio and video conferencing
1xEV-DORAN
RLP NAK: Enable, DARQ: Disable, Scheduler: BE
RLP NAK: Disable, DARQ: Enable, Scheduler: EF
Best Effort Flow
High-Priority Flow
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Forward Link Scheduling
• Scheduler prioritizes P2T traffic
P2T BE
User # 1 User # 3User # 2 User # 4 User # 5 User # 6
P2T BE P2T BE P2T BE P2T BE P2T BE
UserQueues
Scheduler RF Channel Info (DRC)
Recent T’put (for BE)
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QoS Signaling for P2T over 1xEV-DO
1xEV-DO RANHandset
P2T (Bearer) Packet Filter
P2T QoS Request
Multi-Flow RLP Setup
P2T QoS Accept
P2T QoS Setup Complete
PDSNPDSN
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Seamless CDMA2000 1X Interoperability
CDMA2000 1X Region 1xEV-DO Region
CDMA20001X P2TPhone
1xEV-DO P2T Phone
Same P2T application for CDMA2000 1X and 1xEV-DO
P2TServer
CDMA20001X Network
1xEV-DO Network
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Fast Inter-system Handoffs
CDMA2000 1X Region 1xEV-DO Region
CDMA20001X Network
1xEV-DO Network
Dual-mode 1xEV-DO P2T Phone
1xEV-DO Handset constantly monitors both pilot strengths
P2TServer
PDSN A10
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Fast 1xEV-DO-to-1X Handoffs
CDMA2000 1X Region 1xEV-DO Region
CDMA20001X Network
1xEV-DO Network
Dual-mode 1xEV-DO P2T Phone
When outside of 1xEV-DO coverage, handset establishes a TCH on CDMA2000 1X
P2TServer
PDSNA10
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IP Voice Services over 1xEV-DO
CellularGrade VoIP
InternetGrade VoIP
Push-to-Talk
MouthMouth--toto--Ear DelayEar Delay
Cap
acit
y
300 ms 600 ms
Page 16
Thank You
