Broadband Gear Report for March 22, 2007

Feature: Taking All-Digital to the Outer Edge: Converting the Community-Based Analog Channels

By John Hartung, EGT

Since their introduction, community-based channels have helped cable providers differentiate their services from satellite, establish cable's strong foothold as the singular service provider of expanded local TV, and tie the system operator closer to the communities they serve. However, this progress hasn't come without its share of difficulties and as today's operators transition their networks to digital, these local community or "edge" channels present a potential roadblock on the way to an all-digital network.

Traditionally, community or multiple dwelling unit (MDU) local channels have been used mainly for security and convenience, such as lobby or gate cameras. Currently, local analog channel insertion at the edge within closed-communities is done with multiple pieces of equipment and complex cabling. Each channel requires its own onsite analog modulator along with a combining network, and consumes the same amount of bandwidth as 12 digital channels. By converting these local analog channels to digital and inserting them into a multiplexed QAM on the community premise, operators can decrease the bandwidth required per channel and increase the number of channels that can be delivered. This will enable cable operators to realize the full benefit of the all-digital network and offer more programming content or additional services to closed-community subscribers.

Converting cable architectures' last mile to all-digital has many benefits, the most important of which is the decreased cost of deploying digital set-top boxes (STBs). It also opens up new revenue potential. Once a subscriber has been converted to digital, they are more likely to test or purchase additional services such as VOD, high speed Internet and IP telephony. The additional revenue realized from these added services more than offsets the cost of deploying onsite digital conversion equipment.

At the same time, cable operators are keenly aware of the encroaching competition by the telco video providers. Though slow to deploy, telcos' new fiber-to-the-home (FTTH) video networks pose a significant threat to cable systems. With the average number of subscribers per MDU in the hundreds, telcos like Verizon have made their intentions clear on breaking cable's stronghold and they are aggressively targeting community subscribers with FTTH phone, data and now video services. It is up to the cable operators to not only address their existing MDUs, but to grow their business by offering the benefits of all-digital services to new communities as well.

The equipment that is needed to convert the community channels at the very edge of the cable network is the same technology that enables conversion in the cable system headend. Specifically, operators need to employ an encoder, multiplexer, modulator and upconverter. These four key products can be housed in a single device that combines the functionality needed to compress and seamlessly insert these channels at the edge of the network into the digital line-up without any significant cost increase or performance degradation.

To successfully transition analog channels in a closed-community, a service provider must ensure the ongoing, reliable operation of the conversion device in a foreign, uncontrolled environment. Community and MDU environments are typically harsh and exposed, such as basements or closets. Hence, a qualified device must be robust, secure, and operate without concern for varying temperature or dust and debris. From the operator's perspective, it should provide fail safe and fault isolation mechanisms to protect the network from any failure at the community, and ideally offer remote management and monitoring capabilities.

Though there are still many challenges to converting cable's vast video networks to all-digital, transitioning community-based channels at the edge need no longer be an obstacle. Deploying reliable, standalone digital channel insertion devices within communities is a simple, yet elegant solution to rolling out digital community channels.

John Hartung is CTO of EGT.