1. Mobile VoIP over Wireless Wide-Area Networks Presented by: Chris Whiteley, Director of Business Development xG Technology, Inc. Jan. 20, 2010 QoS Requirements for Mass-Scale Mobile VoIP

2. What’s at Stake In-spite of the growing rate of data services, voice services remain the major revenue earner for the service providers. There are approximately 4.3 billion wireless users in the world, of which roughly 90 percent are voice-only users ABI Research forecasts annual mobile voice revenues to reach $580 billion in 2010. Total mobile data services should generate $169 billion in 2009. Supporting voice over IP has many challenges. Real-time applications like VoIP require minimum service guarantees that go beyond the structure of today’s data-centric mobile IP networks. – Current 3G technologies have poor quality of service(QoS) and support mobile VoIP with inconsistent quality and a low number of simultaneous calls – QoS in the wireless access network is the key to mass-scale mobile VoIP

3. WiMax Standard calls for QoS capable of supporting mobile VoIP – “System SHOULD support 25 simultaneous VoIP calls per MHz” WiMax Forum © Mobile Profile System Specification Release 1.5 Standard specifies different QoS mechanisms, but does not define an end- to-end system. e.g no details of scheduling and reservation management Performance results of point to multipoint (PTMP) performance of mobile VoIP over WiMax are not publically available. – “WiMAX equipment may be seriously underperforming when having to deal with large numbers of small and frequently arriving packets” WiMAX Evolution: Emerging Technologies and Applications Edited by Tsutomu Ishikawa© 2009 John Wiley & Sons Kicking the can down the road with 802.16m?

4. LTE Most of the standardization work has focused on the data aspects of LTE and voice has been somewhat neglected. Top approaches for VoIP over LTE appear to focus on ensuring 2G fallback. – Circuit Switch Fallback: While making or receiving a voice call the LTE terminal suspends the data connection with the LTE network and sets up the voice connection via 2G. – IMS-based VoIP: While the initial voice call is established over the LTE network, if the user goes out of the LTE coverage area, then the call is handed off to the legacy CS core network via the IMS core. – Voice over LTE via Generic Access (VoLGA): Introduces a new network element that interlocks LTE and the legacy CS core network. Interesting ramifications for OTT, third party VoIP providers

5. xMax Optimized for the delivery of mass-scale mobile VoIP and broadband Internet services – A scalable SIP-centric MAC protocol for high QoS mobile VoIP – No greater than 30ms latency from the handset to the basestation. – End-to-end system optimization with enhanced SIP and RTP protocols capable of operating robustly over mobile wireless links. Rapid Detect and Avoid (DAA) algorithm capable of outmaneuvering the interference found in the 902-928 MHz band – Spectrum covers 924 million people Network operating in densely populated, interference-rich environment Opportunistic and low-cost spectrum access – Path to White Space spectrum

6. New Set of Requirements While voice doesn't require much bandwidth, it requires error-free delivery – The number one killer of voice traffic is network latency and jitter WiMAX and LTE must implement scalable QoS to support simultaneous mobile VoIP sessions. – “4G systems that integrate quality of service and VoIP over WWAN aren’t expected to mature before 2015” Phil Redmond, Gartner QoS limitations in the mobile IP access networks could be the last line of defense to prevent third-party VoIP providers from siphoning off of voice revenues before carriers can transition to data-centric revenues.