By Dr. Robert L. Howald, Vice President of Network Architecture, Comcast
While it may seem like a distant memory, and in retrospect seems hard to fathom, High-Definition (HD) video got off to a very slow and inauspicious start. The adoption cycle was quite long. Obviously display technology, costs at every stage of the content cycle from creation to display, and a very recent massive digital video revolution played a role in the adoption rate. Once the conditions were in place, however, HD took hold and there was no going back. Fast forward to today, where HD is mature, deployed in scale, and impossible to live without. While an important and profitable component of the operator’s business model, there is a resource price to be paid in term of the capacity HD consumes compared to Standard Definition (SD) TV. Operators are regularly adjusting their service mix and introducing technology to increase capacity and make better use of existing capacity to support service evolution. Today’s HD falls into this latter category. High Def’s maturity, and MPEG-4 encoding’s capability present in fielded STBs allows operators to deploy HD content more efficiently.
An HD channel typically has an SD brother in the channel lineup – it’s a simulcast. This is not very efficient, but also not terribly penalizing given the relative bandwidth that SD consumes. Now, along comes….4kHD. It’s not quite really here, and there will be clear limitations at first. But, it is quite reasonable to expect that 4kHD scales into a mass service within a decade. However, a simulcast approach for current HD channels to be made available in 4kHD would be difficult. The likely option to prepare for 4kHD, in addition to HEVC encoding, is transitioning to an all-IP architecture. Already part of most operator’s future plans, 4kHD may be additional inspiration to drive forward with a methodical transition strategy. This paper will take the reader through an all-IP transition scenario that considers key aspects that an operator must coordinate in phases. Access architecture, bandwidth, encoders, CPE, home architecture, and multicast services represent major balls to be juggled in the transition of services. We will walk through a hypothetical case study based on a typical existing system serving as the Day 0 scenario. We will quantify the CPE situation and migration plans for STB and HSD solutions. We will describe a spectrum management plan with a sensible pace that balances legacy box retirement with capacity demand. And, we will consider how services and capacity tie to network evolution. An all-IP nirvana has been a future vision for quite some time. With enhanced video and continued HSD speed demand, the future has arrived