The US cable operator Citizens Cablevision has introduced IP transport into its regions, giving itself the option to convert IP into QAM for last mile coax networks or run IP video right to the home on fibre. Report by Steve Hawley

Much is being reported and written about telcos “making the jump to lightspeed,” by implementing IPTV services over switched digital video networks. But at the same time, and somewhat under the radar in many cases, there is an emerging trend of cable operators making upgrades to fibre access networks, giving them the opportunity to move to IPTV themselves. Here is the story of one of them: Citizens Cablevision. Citizens Cable Communications is a wholly-owned subsidiary of Citizens Telephone of Mammoth, Pennsylvania, a multi-service operator with 5,500 telephone access lines. In 1995 the company built a cable television system using hybrid-fibre coax (HFC) access, passing about 2,500 homes and having about 2,000 subscribers. Initially, Citizens Cablevision offered 64 TV channels: a combination of network programming delivered to its headend via satellite, plus local programming. In addition, Citizens operates an ISP service and offers broadband Internet access to residential subscribers via cable modem.

Digital migration

According to Dennis Cutrell, general manager, several motivating factors contributed toward Citizens’ decision to evolve from analogue to digital. First was the fact that its cable service coverage area did not coincide with its telephone coverage. By unifying the delivery of telephone and cable services into one network, it could double its potential TV customer base and provide like services to all existing telephone and cable subscribers. In turn, the decision presented the opportunity to modernise its network by deploying fibre-to-the-home, which not only solved the coverage issue but also dramatically increased the bandwidth available to each subscriber.

Deploying fibre also provided Citizens with a foundation to expand beyond its original channel line-up and to offer the triple-play over an all-digital distribution network, without interrupting TV service to existing cable subscribers in the short-term. During the planning process, Citizens Cablevision engineers collaborated with headend vendor Tut Systems to design a headend and help them decide upon a network architecture that could serve basic TV channels to existing cable customers via analogue using QAM modulation, later add a simulcast digital tier, then finally migrate the entire channel line-up to digital over IP transport, as it replaces the remaining HFC access with fibre.

The Citizens Cablevision headend was designed to deliver each channel as an IP-encapsulated Single Programme Transport Stream (SPTS). The network then distributes them to all customer areas via digital transport. One result is to enable Citizens to use either FTTH or HFC as a delivery option in the last mile. For neighbourhoods served by fibre access, the programme streams remain digital all the way to the home. For those still served by HFC, programme streams can be sent via IP to fieldbased QAM modulators that would convert the programming to analogue only for those subscribers.

IP to QAM

Citizens is evaluating a chassis from Copper Mountain Networks, a Tut Systems company, that can convert IP to QAM and encrypt it within a single chassis. This element would fit well into the overall network, given the need to convert IP-distributed streams back to QAM for distribution to those subscribers with HFC access. Although Citizens’ traditional cable customers are still served over the HFC access network, the groundwork has been laid for conversion to fibre over time. Some adjacent telephone companies - one with about 5,000 subscribers and another with more than 1,000 of its own - have expressed an interest in re-transmission from Citizens’ IPTV headend to speed their time to market without shouldering the expense of building headends of their own. Supporting those neighbouring systems would also result in an additional revenue stream to Citizens. In the final analysis, Citizens has become a strong believer in IP as a common protocol and transport mechanism that enables the smooth transition from analogue to digital, placing it in a position to simultaneously modernise its network, offer more programming options to subscribers, accommodate HDTV and serve nearby communities with a master headend; a multiple-win situation for the operator and one that may provide an example for other small cable companies.

Citizens Cablevision service offer

Citizens offers ten channels of HDTV programming, 130 channels of SD and an additional 47 channels of digital music. So far, digital penetration is at about 10 per cent but this uptake is expected to increase and accelerate as the company educates its community. Because it carries HD Net, which includes The Discovery Channel and ESPN, Citizens representatives find it easy to demonstrate the service. Mr Cutrell notes that some of his subscribers have moved to Citizens from the DISH Network. The Citizens deployment is still a work in progress: the operator has yet to make its middleware and set-top box selections. The vendor consolidation currently underway in the IPTV infrastructure space has not gone unnoticed. Cutrell recognises that Cisco’s purchase of Scientific-Atlanta is a strategic move to capture and penetrate the digital home, and this fact may inform Citizens’ Customer Premise Equipment decision.

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