Rei Brockett, vice president of marketing and product management at GoBackTV, Inc, reports.

IPTV is so much more than broadcast television delivered in IP packets. It’s more than the ubiquitous ‘what you want, when you want’ slogans. IPTV is all about taking advantage of the implicit existence of a two-way network to deliver the services an operator needs at the various points within his network in a flexible, scalable manner that suits that operator’s unique set of circumstances. With the proper implementation, ‘IPTV’ means that the operator is freed to add, expand, change, and combine the services, vendors, equipment, and transport mechanisms that best meet his current and future needs. GoBackTV was founded with the idea that IP could revolutionise television in the same way that the Internet revolutionised data networking, making personal TV economically feasible. No single company is big enough to be best-in-breed in every aspect of delivering television to the viewer; forging partnerships between ecosystem components, and integrating with existing services, is critical to IPTV. GoBackTV’s RetroVue System focuses on providing modular components that work standalone or in combination to deliver real-time and time-shifted video services over cable (both IPTV and RF), copper, and fiber.

IPTV ecosystem and RetroVue

Figure 1: Digital television ecosystem

The IPTV ecosystem is a confederation of products and services that can be mixed and matched as needed. GoBackTV’s RetroVue products deliver storage, middleware, and transport functionality, and were designed to support high volumes of time-shifted (unicast) video with a distributed or tiered architecture. Because of this, RetroVue solutions scale from 50-room hotels up to more typical metropolitan deployments.
•StreamCache - a high ingestion rate video server for VoD, network DVR, television time shifting, and startover.
•RetroVue Application Server - resource management, service management, and MyRV portal HTML-based middleware.
• GigaQAM - a smart edgeQAM, capable of dynamic multiplexing, DVB-CSA scrambling, traditional RF transport, and cable IPTV downstream transport.
• GigaQAM IP - a DOCSIS-based CMTS core for cable IPTV modem control and upstream channel support.
•IP Streamer - ASI-to-Gigabit Ethernet protocol converter, with MPTS-to-SPTS demultiplexer.
The thorniest technological aspects of IPTV are ‘Will the ecosystem interoperate?’ and ‘Will it scale gracefully?’. In order to create a solution for which the answers are ‘Yes!’, the operator should feel comfortable with both his current needs and his most likely future directions.

Multicast and unicast services
An IPTV system should be chosen or enhanced with an understanding of how design choices will affect future options. ‘Current needs’ typically revolve around multicast video delivered to a television set, and design questions encompass decisions like:

• MPEG2, MPEG4, or something else.
• standard definition or high definition.
• switched multicast or fixed multicast.
• thin-client or thick-client middleware.
• how many channels.

Future growth includes ever-increasing amounts of unicast traffic. The most common unicast video application is Video on Demand, but content rights issues have advanced to the point that many other unicast applications are now possible:

• network-based DVR (nDVR).
• multi-room DVR.
• time-shifted television (pause, rewind, fast forward).
• startover (one-button return to start of programme).
• lookback (archival access to television programming).
• customised advertising.
• over the top (OTT) content.
• applets and middleware applications.

Increased unicast traffic will lead to segmented networks with distributed resources in order to provide the necessary subscriber bandwidth and processing without creating a centralised bottleneck. Time-shifted television will generate higher unicast stream requirements than the 10% VoD rule-of-thumb. In-home Digital Video Recorders (DVRs) create higher peak multicast demands on the last-mile network, while nDVR has the potential to increase the sustained unicast load. In addition, the unicast infrastructure needs to cope with variable bit rate (VBR) television, rather than the traditional constant bit rate (CBR) VoD content. Customised advertising and middleware applications also have the potential to add unicast bandwidth to every multicast stream.

Planning for growth and innovation in the home - home networking and multiple screens
Another aspect of growth is that television content will increasingly need to reach more devices within the home, as well as different types of devices. Multiple HD set top boxes will not only require broadband access to the home, but also require a robust home networking solution: direct drop, powerline (HomePlug AV), wireless (802.11 b/g/n), MOCA, and others compete in this space. Subscribers are also starting to untether their viewing habits from the television. According to eMarketer (‘The Digital Home: Emerging Trends in TV/PC Viewership’, Nov 2009), most video is still watched on a television set (98.5% of watched hours), but alternate screen hours are growing by 50-90% year on year, primarily on computers and mobile devices.

Convergence across multiple transport media
As the types of end-devices proliferate, operators will want to support a variety of transport media, as well. With the proper design, an IPTV system can use a common ecosystem to deliver unified IPTV services over fibre, Ethernet, xDSL, wireless, and cable. By using a hybrid cable/IP set top box, some vendors can also support traditional digital cable with the same backend IPTV platform and features. There are many innovative and dedicated vendors within the IPTV ecosystem, whose specialties can be combined to build solutions covering a broad spectrum of requirements and visions. By understanding the tradeoffs, the system will have the resiliency and versatility to meet future demands for many years to come. GoBackTV's products and ecosystem partnerships provide an affordable yet open turnkey IPTV platform for television service operators to succeed and grow.  Our deployments have validated our architectural decisions, and our field experience can benefit small and large operators alike.  
www.gobacktv.com

Figure 2: Accommodating growth with GoBackTV’s RetroVue System