Krishna Yarlagadda
Monday, October 3, 2011
Consumers and Enterprise users are both eagerly waiting for the high resolution, good quality, 2-way, video and voice-chat for years now. This is all the more important for Silicon India Parivaar, who has their folks, eight thousand miles away. Their dream got close to reality, with Apple launching the Facetime, and multiple Video and VoIP applications on Android devices. But these have their own limitations--migrating between the networks and compensating for packet losses in the real-time environment. Apart from the client issues, the media quality was un-acceptable on 3G networks, due to bandwidth limitations and limited coverage of 4G WiMax Networks. This article provides an overview of some of the challenges for implementing a V.VoIP, in a real-time environment and possible improvements on 4G LTE networks.

V.VoIP, over the fixed broadband (both Cable & DSL), has been around for quite some time, has been deployed and very well-accepted globally. The primary factors that contributed to its success were the guaranteed QoS, low latency, high capacity, and hence acceptable user-experience. Second and Third generation wireless-technologies, have not be able to cater to the user requirements to offer reliable V.VoIP service. While the fourth generation WiMax network was a teaser, the LTE network guarantees all the primary requirements mentioned above--bringing revolution to the world of mobile V.VoIP. LTE is now rapidly gaining momentum, with large mobile operators like AT&T, Verizon, MetroPCS, Vodafone, China Mobile, DoCoMo, showing a sense of urgency to deploy the LTE networks in short order. This is first time ever that the operators are committed to using the Mobile broadband pipe for Voice communication. Many have already announced their plans to launch the Voice, over LTE (VoLTE) service in near future, with some launching as early as the first quarter of next year. While there were attempts made in the past to bring the voice over IP networks in a Mobile perspective, they have not been as successful due to the lack of support from the network infrastructure and operators. There was increased pressure on the operators to adopt the superior quality Video and VoIP over the mobile broadband networks, since the evolution of Smartphones.

SmartPhone penetration is expected to flourish many folds over the next few years. About 65 percent of the U.S. population, or over 200 million people, will have a smartphone and/or tablet in 2015, according to the research firm In-Stat. Most of the Smartphones shipping today have multiple GHz processors, integrated with high-end graphics and video hardware; thus enabling superior quality V.VoIP user experience. Today’s SmartPhones, invariably have large screens; thus further improving the end-users viewing experience.

User expectations for a rich multi-media experience have exponentially increased, with the rapid growth of LTE and Smartphones. Key factors that determine the success of V.VoIP technology are as follows:

1. Improved User Experience

Unlike the other wireless technologies, LTE guarantees QoS and low latencies that are pre-requisite for an intelligent 2-way conversation. In addition, higher capacity in a LTE environment enables an improved, 2-way video experience. Thus, LTE has all the ingredients to provide superior quality V.VoIP and increased user adoption.

2. Seamless Roaming

As LTE is just starting to get rolling, continuous coverage is an issue; hence it is mandatory to switch to the legacy circuit-switched, where LTE is not available. During the early deployment stages, it is very important to implement a very efficient Voice Call Continuity (VCC) algorithm, to provide a seamless voice-experience, when moving between the circuit-switched and packet-switched networks. This can be further extended to, between packet-switched networks, such as WiFi and/or 3G networks.

3. Increased Battery Life

LTE technology inherently, is lower power than its predecessors, such as WiMax. This can be further improved, by implementing an optimized V.VoIP application on a handset. Some of the techniques include -

*Optimizing the voice algorithms, for the targeted processor, to run at a reduced speed; thus lowering the power consumption and increasing the battery life.

*Making use of the hardware accelerators, such as the hardware Video engine.

*Shutting down the sub-systems when not in operation.

4. Extensive Interoperability

Some of the early V.VoIP implementations, though very attractive, failed miserably, as they could not communicate with other equally attractive devices and networks. For adoption across wide-range of the users, the ecosystem of Operators, Infrastructure vendors, and Client vendors have to work together very closely, to ensure that they deliver a standard-based solution that can communicate with any device, at any location, and at any time.

5. Reduced Time to Market

While VoLTE does require implementation of some additional RFCs and features, it mostly uses the legacy VoIP and IMS-based standards, where many of the client vendors have invested heavily to make them work on low bandwidth 3G and earlier generation wireless networks. This has also given the client vendors, extended learning curve, to understand the complexities of wireless environment and address any consequences.

Some of the legacy standards and protocols that 3GPP based VoLTE uses include –

*Session Initiation Protocol (SIP) signaling, Real- time Transport Protocol (RTP), Real-Time Transport Control Protocol (RTCP), and Session Description Protocol (SDP)

* IP Multimedia Subsystem (IMS)

* Voice Call Continuity (VCC)

*Supplementary enterprise call features, like 3-way conferencing, call waiting, call transfer, call hold/resume

*Voice and Video Media engine, including Video and Speech Codecs, Acoustic Echo Canceller (AEC), Voice Activity Detection (VAD), Comfort Noise Generation(CNG), and other media modules

*Since there was no QoS on the infrastructure side, on third generation and earlier wireless technologies; it was mandatory, to handle the inefficiencies in the network, on the client side. The very robust Packet Loss Concealment (PLC) and Adaptive Jitter Buffer (AJB) algorithms were developed to cater to the packet losses in the network.

To summarize, LTE ecosystem, is very much committed to provide a rich multi-media experience to the users over the mobile broadband.

The author is Founder, President & CEO of HelloSoft

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