Telephone company to add video on hybrid fiber plant
mitch shapiro
A telephone-company-built hybrid fiber/coaxial-cable (HFC) network has received the green light from Connecticut state regulators to compete with cable-TV operators. A draft decision issued recently by Connecticut`s Department of Public Utility Control (dpuc) would give snet Personal Vision (SPV) an 11-year, statewide cable-TV franchise. SPV`s sister company, Southern New England Telephone (snet), is building the HFC network, which it also plans to use for voice services.
The network, dubbed i-snet, is expected to eventually consist of approximately 19,800 miles of HFC plant and will serve roughly 1.2 million households in snet`s service territory. The company has estimated the cost of the statewide upgrade at $4.5 billion, a figure that also includes modernization of its switching fabric and its network and operations systems.
SPV`s cable-TV launch is expected to follow the schedule of snet`s installation of i-snet. According to documents filed with the dpuc, SPV proposes to pass approximately 22% of Connecticut`s homes by the end of 1997 and roughly 36% by year-end 1998. By the year 2000, 60% of the state will have a choice of cable operators, rising to 88% by 2005.
At the time of the dpuc draft decision, snet was running a 200-home pilot of its HFC network in Stamford, CT. Among the towns expected to see commercial service first are Darien, Farmington, Westport, New Britain and parts of Fairfield, West Hartford, Hartford, Stamford and Norwalk.
Connecticut is currently divided into 24 cable-TV franchise territories served by 12 cable-TV operators. Some of these operators are moving quickly to counter snet`s video offensive by launching HFC-based telephone services.
Two cable operators, Cablevision Systems and Tele-Communications Inc., have already received dpuc approval for such services. The latter plans to launch telephone, Internet access and digital video services "on a controlled scale" by year-end, says Matt Fleury, director of communication and government affairs at TCI Connecticut.
TCI currently serves about 180,000 subscribers in Hartford and 21 surrounding towns. It is in the process of deploying a 750-MH¥HFC plant and expects to be serving nearly 90% of its customers via this new network by year-end 1996. The remaining 23,000 subscribers will be connected to the 750-MH¥plant next year. According to Fleury, the return path on the TCI network will be activated as two-way services, such as telephony and data, are introduced.
Even as they race to deploy competing full-service HFC networks, Connecticut`s cable-TV and telephone companies continue to wage war over how regulators should implement the Telecommunications Act of 1996.
The state`s cable-TV operators fiercely challenged SPV`s statewide franchise application and have attacked the dpuc`s draft decision as opening the door to "cream-skimming" and anticompetitive cross-subsidies. Echoing the views of other cable-TV operators, TCI`s Fleury contends the dpuc decision "dismisses [the state`s] level playing field statute."
For its part, snet has joined with GTE to challenge the FCC`s recent interconnection order, which establishes rules for the introduction of local competition. The joint motion, filed in late August, asked the FCC to suspend implementation of its ruling until the companies can obtain federal court review of the agency`s decision.
This action by snet and GTE is just the first wave of legal challenges to the FCC`s order, says Allan Tumolillo, chief operating officer of Probe Research, a NJ-based research firm specializing in newly competitive telecommunications markets. He predicts similar challenges will be launched soon by the Bell operating companies, a view shared by other industry watchers.
According to Ron Serrano, president of snet`s retail group, "The order discourages telecommunications competition rather than encouraging it, by requiring local companies to subsidize their competitors` entrance, . . . giving some of the country`s biggest corporations a free ride into local markets."
Three-tiered architecture
SPV is deploying a three-tiered architecture to support its video services (see figure). At the highest level, says Hoshang Mulla, i-snet vice president in charge of network planning, are two master headends. These, he explains, receive and assemble satellite, off-air and local-origination programming and are linked to each other and to seven remote hubs in a ring served by ADC Telecommunications` 2.4-Gbit/sec DV-6000 digital transport product.
The remote hubs, which are collocated in central office locations, customize program lineups based on local demand, public access and "must carry" requirements. They also support local ad-insertion functions. On average, each remote hub serves roughly 130,000 homes. The hubs convert the digital video signals to analog signals, which are delivered to end-office locations via AM optical supertrunks, explains Mulla. Including the master headend and remote hub locations, these end offices number more than 140, he says.
From the end offices, video and telephony signals are delivered on separate fibers to electro-optical nodes that serve an average of 200 homes. Equipment for this portion of the i-snet HFC network is being supplied by Lucent Technologies and ADC Telecommunications. It includes central- office-based host digital terminals equipped with a TR-303 switch interface, which integrate broadband and narrowband services that are delivered via fiber to the electro- optical nodes.
Mulla says each node can be served by a different vendor`s equipment. He adds, however, that the company`s current plan calls for AT&T and ADC equipment to be used exclusively within a given wire center.
Typically, the output of an end-office-based distributed feedback laser carrying video signals is split among several nodes. For telephony signals, this part of the network is fully redundant, with "hot" standby transmitters and receivers in place. Mulla says nearly 90% of snet`s plant is aerial.
From the nodes, coaxial cable delivers both narrowband and broadband signals to pole-mounted network access units. In most areas, each unit serves four homes. Most of the coaxial cable runs, says Mulla, will have no more than two RF amplifiers between the node and subscribers` homes.
The network access units contain the telephony line interface cards and common equipment to communicate with the central office switch. They also handle multiplexing and demultiplexing chores. In terms of video signals, the device serves as a tap that supports remote service activations and terminations. It is also equipped with filters to minimize signal ingress problems.
Extending from the network access unit are composite drops that include two to five twisted pairs for voice services, plus coaxial drop wire used for video and high-speed data. At the side of the home, a passive network interface device connects the drop cables to the customer`s inside wiring.
Although its critics say HFC architectures cannot cost-effectively support large amounts of high-bandwidth interactive services and will face serious ingress problems, Mulla says that snet, after looking at data and doing its own testing, has confidence in HFC. With well-built plant and proper filters, he says, ingress "is not a real issue."
Snet serves 200 homes
With regard to long-term capacity, Mulla points out that snet is deploying nodes that serve only 200 homes, compared to 500 to 2000 homes for the typical cable-TV operator. And, he adds, if demand for interactive services grows beyond expectations, "there are other levers to pull to get capacity," such as splitting nodes so that each serves as few as 50 homes, and frequency stacking to load more return-path traffic on upstream lasers.
Mulla also points to substantial operating cost savings expected from the switch to an HFC platform. These savings, he says, are expected to average roughly $75 annually per line. He says a minimum of six fibers will be deployed to each node, with extras included in high-growth areas or those likely to generate demand from large businesses or other point-to-point applications.
Like other operators deploying fiber-rich networks that must support lifeline phone service, snet has faced the thorny question of how to power the network. After considering a range of options, the company developed a unique approach for which it has applied for a patent.
Instead of deploying distributed power systems at each node, snet is installing special cables that surround the fiber cables with metallic conductors that transport central office power. The cables are currently being supplied by Okonite, a NJ-based manufacturer. When asked whether its new cable design will be available to potential competitors, Mulla would say only that the company is "open to discussions" regarding licensing and is "talking to a number of players."
While HFC will be the predominant architecture deployed by snet, Mulla says the company may find that some areas with high concentrations of large-business customers will be better served by next-generation fiber-based digital loop carrier technology. He suggests that this would be deployed side-by-side with the HFC network, which would still be used for video. q
Mitch Shapiro writes from Encinitas, CA.