2. LTE: An IP Packet Only Network. ▫ LTE: Long Term Evolution. • Wireless
network beyond 3G. • Enhanced UTRAN (E-UTRAN). • System Architecture
Evolution ...
Voice over LTE Overview James Ni 03/17/2010
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LTE: An IP Packet Only Network
LTE: Long Term Evolution • Wireless network beyond 3G • Enhanced UTRAN (E-UTRAN) • System Architecture Evolution (SAE)
E-UTRAN
SAE EPC 2
LTE: Interoperability with 2G and 3G
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LTE: Voice and Interoperability with 3G
LTE: No native voice and SMS Three solutions • All VoIP Solution -- IP only signaling and bearer – VoIP LTE – VoIP UMTS – Both IMS oriented
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VoIP in LTE and SRVCC in UMTS – SRVCC CS voice and PS signaling Compatible with UMTS/GPRS/GSM
– VoLGA – Voice over LTE via Generic Access CS core and PS access GAN access: GSM + WiFi + … VoLGA Access Network Controller (VANC) connect MSC and LTE core In LTE: VANC = external IP node In GSM/UMTS VANC = BSC / RNC
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Circuit Switched Fallback (CSFB) – No VoIP – Only CS voice – Fallback to 2G or 3G for voice services
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LTE Voice: IMS based all IP Voice Service
IP Signaling (SIP, H.248, Diameter etc.) IP Bearer IMS to control the services delivery IMS to interwork with 2G / 3G CS AS to provide services and features Circuit Circuit Switch Switch Network Network
IMS
E-UTRAN E-UTRAN E-UTRAN E-UTRAN
EPC EPC
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GSM GSM/ / UMTS UMTS
LTE Voice: VoLGA
Voice Over LTE via Generic Access • Access gateway (VANC) to bridge 2G/3G with LTE – To LTE, VANC is an external IP node – To GSM / UMTS, VANC is an BSC / RNC
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UE registration: – – – –
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UE register with MME MME retrieve subscriber information from HLR/HSS Establish security tunnel between UE and VANC over LTE UE register with MSC through security tunnel and VANC
Voice calls are established using 2G / 3G procedures via security tunnel – VANC does TDM/ATM IP translation for bearer traffic
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Handoff – MME initiates the handoff – VANC executes the handoff – Invokes standard GSM/UMTS handoff procedure – SRVCC assists (?)
VoLGA Architecture 6
LTE Voice: Circuit Switched Fallback (CSFB)
CSFB • No VoIP • Pure CS voice services • Registration – UE register with MSC via MME
• Calls – Originates MO calls via 2G / 3G CS network – Pages UE via MME/eNB for MT calls, calls are setup via 2G /3G CS network
