Voice over LTE via Generic Access

1. Voice over LTE via Generic Access Jyothi Nandikonda Supervisor: Olav Tirkkonen

2. Agenda • Study and Objectives • Thesis scope • Problem being studied and addressed • Methodology used • What is LTE? • LTE migration path • What LTE brings to Operators / End-users • Voice over LTE – Challenges • Lack of Standards • The problem of voice in LTE • Solution for the problem • Alternative Solutions • CSFB • VoLGA • IMS • Other • VoLGA • What is VoLGA and How it works? • Why VoLGA ? • Conclusions

3. Objectives & Scope • To study and elaborate on the problem of bringing the Voice solution into LTE networks • To study the various alternatives available for the operators to implement the Voice in LTE networks • As an intermediate alternative, to study in detail the VoLGA solution and compare the against various other implementation choices

4. Long Term Evolution (LTE) • LTE is a new radio access technology, next generation mobile broadband standard, and obvious successor to the 3G UMTS technologies • Known as 3.9G, a way forward to 4G • LTE brings improved spectral efficiency at lower latency and offers high peak data rates • Almost 100 times imrovement • A key aspect of LTE is it’s simplified, flat-network architecture based on all IP networks • Anywhere, anytime and always-on • Ideal for delivering Real-time services which require high speed data and high efficient radio • Multimedia, Streaming, IPTV, VoD

5. Long Term Evolution (LTE) • Operator benefits • Low CAPEX and OPEX + Highly efficient • Maximize Return on Investment • Low cost structure for all mobile services • Support of exisiting / profitable business models • Smooth migration path • LTE is an Investment safe technology • End-user Benefits • Reasonable costs with high data speeds • Seemless user experiance with always ON • Full interoperability support and international roaming support • PSTN is the largest comms network ever created • >4 billion active mobile connections at end-2008; >6 billion by 2014 • By 2014, 77% of revenue globally is voice & SMS (vs. 86% in 2009)

6. Voice over LTE - Challenges • Lack of Standards • Clarity in standards missing to support the delivery of voice in LTE • The Real Problem • No Native Voice and SMS in LTE • IMS Telephony outside planning timeline • SMS is an essential for LTE data only deployments • Solution • Re-use existing Core Network Systems and mechanisms • Bring the primary revenue services (Voice/SMS) to LTE • Enable Long-Term Service evolution • Counter over the top VoIP Competetion

7. Alternative Solutions • CSFB – Circuit Switched Fallback • VoLGA – Voice over LTE via Generic Access • IMS – IP Multimedia Subsystem • Other • One Voice Initiative • Over the top VoIP

8. Circuit Switched Fallback • CS Fallback • LTE handsets reverts or ‘fallback’ to a 3G or 2G radio network whenever voice service are required • Costly and Complex • Must require MSC Upgrades • Increased signalling due to network switching (LTE->3G/2G) • Poor user experiance • Call setup times are high; > 1.5sec • Increased potential for call /network drops • No Parallel voice and data if legacy network is 2G • A Step away from IMS • No support for IMS RCS • No support for LTE Femtocells

9. Tel SMS VMS EPC VANC BSC RNC MSC Voice over LTE via Generic Access 1 Circuit Services Packet Services • A technological approach for delivering Voice and SMS services over LTE access networks • Leverages a mobile operators existing core voice networks and investments • Build upon fully 3GPP compliant Rel-8 LTE/EPC network • Derived from the existing 3GPP GAN Standard • Supported by industry consortium known as VoLGA Forum GERAN UTRAN LTE

10. IP Multimedia Subsystem • IP Multimedia Subsystem • It’s not a technology, rather an architecture framework based on set of open standards developed by 3GPP • Enables the convergence of data, speech and mobile network technology over IP-based infrastructure • One of Key enabler for IMS is SIP protocol, which is used for establishing, managing and terminating sessions on IP networks • IMS is Costly and Complex • Solution availability and stability not feasible in time • Solution would consists of IMS platform, various application servers and requires major upgrade/changes to MSC servers • No eco-system in place yet for IMS Voice/SMS roaming and interconnect

11. Tel SMS VMS EPC VANC BSC RNC MSC What is VoLGA? 1 Circuit Services Packet Services • VoLGAdoesn’t fallback to 2G /3G network for Voice/SMS • Voice services are packetized and delivered natively over LTE • Excellent User Experiance • Same or faster call setup times as 3G • Full support of extended voice services • E.g: E911, prepaid • Minimal cost/complexity • No MSC upgrades • Introduces VANC (VoLGA access network controller) • A better path to IMS • Supports IMS RCS and Combinational Voice/Data services today • Supports LTE Femtocells GERAN UTRAN LTE

12. How VoLGA Works? • The concept is to connect the already existing MSC to LTE Network via gateway known as VANC • VANC responsible for connecting the Packet Switched LTE network to Circuit Switched Core Network • UE registers with MME over LTE access network • UE establishes a connection with VANC via PDN Gateway over SGi interface • UE registers to the MSC through the Secure tunnel and the VANC. • VANC connects to GSM/UMTS MSC via A/Iu-cs interface respectively • All signalling and data traffic (UE-VANC) is transported via SGi interface • In case of handover, E-UTRAN initiates HO, and informs to UE • VANC triggers intra/inter MSC-Handover

13. Why VoLGA? • VoLGA is Fastest , Low Cost and Low risk approach • Avoids MSC upgrades/changes • Provides IMS RCS services and Combinational of voice and data services • Provides long-term investment protection • Full service transparency with proven service core • For devices, VoLGA is the lowest impact design • Minimizes the impact on UE, especially User Interface • Supported by all major handset manufacturers • VoLGA delivers SMS over LTE • SMS is essential for early LTE data-only deployments • SMS is required for Subscriber Management/EU Roaming • SMS is a key for LTE dongles, datacards and netbooks • VoLGA is very robust and efficient • Based on 3GPP GAN Standard • Relies on many of same underlying technology as IMS for Voice • Uses RFC4867 for VoIP and Robust Header Compression -RoHC (like in IMS)

14. Conclusion • For many operators, the target architecture for voice over LTE is IMS • Sooner or later, operators move to IMS for their initial deployment • However, it is clear that there will be an interim period for other operators, who are not yet invested in IMS for voice, for those an interim solution is needed • VoLGA today • offers a less-intrusive, low cost and low risk approach • provides higher quality user experiance than CSFB • offers a better path towards IMS voice networks • supports IMS RCS and combinational voice / data services • provides long-term investment protection as well as short-term service acceleration designed to deliver profitable voice services • offers by far the best combination of simplicity and functionality

15. Questions?