eTV - Models
MODELS of ENHANCED TV
In order to implement enhanced TV certain components must be in place:
Methods of Propagation – Because metadata can be packaged within the VBI, one-way, interactive enhanced content can be delivered to the viewer in digital or analog form through cable, terrestrial on-air broadcast, the Internet and satellite. The return channel can use any form of Internet connectivity including cable, DSL, telephone service, and even satellite uplinking.
Operational models of common types of enhanced TV systems:
Terrestrial - Broadcasters in the US are upgrading to DTV transmission, allowing for increased resolution, HDTV, and expanded data transmission content.
DTV's lacks a direct return channel. While this doesn’t affect one-way enhanced analog or digital broadcasts, it presents an impediment to two-way interactivity.
Return channel options:
Satellite- In the mid 1990s, satellite digital broadcast systems (DBS) first became available to the public. By December 2002, DirecTV and DISH Network had nearly 20 million installed systems.
DBS provides one-way digital interactivity and two way interactivity employed through land-based return channels. If a customer orders a PPV through DISH Network, the STB uses the telephone line to bill the user’s account.
Broadband 2-Way Satellite Service: Hughes Network Systems developed a system allowing users to download data from a satellite and upload over a telephone modem. Their newer development, DirecPC is a two-way system allowing downloading and uploading from a satellite. Starband is another company offering bi-directional satellite networking.
Cable – The Cable Act of 1984 helped deregulate the industry and boosted cable growth. The 1990s saw many cable companies upgrading their systems to two-way digital networks, capable of supporting a wide range of services.
In 2001 digital cable service and cable modems were available to more than 65 million homes. (NCTA)
Digital cable households can receive standard cable, digital cable, telecommunications services, and high-speed Internet access. Internet users tired of slow dialup connections have increasingly turned to digital cable for its “always on” broadband Internet service. The scope of two-way interactivity varies with the cable distributor as well as the geographic location.
Telco/IP Systems – In addition to terrestrial, cable and satellite, IP systems are viable means to bring television into a household and providing users a means to receive interactive content.
Telephone companies have a long history of providing Internet connectivity through dial-up connections, and have recently began to offer broadband service at rates comparable to cable.
IP television providers across the globe have been experimenting with delivering programs and other full motion video.
Pros/Cons - Broadband IP networks have been designed to support two-way communication and potentially offer a higher degree of interactivity.
This two-way communications can pose a problem in the flow of communication over such networks. When demand is high, the whole network can slow down.