The union cabinet has finally ap- proved direct-to-home (DTH) TV broadcasting, about three years after enthusiastic Indian TV viewers were tantalised by the prospect of access to hundreds of global channels.
DTH is a concept whereby high-density TV signals in the Ku band from the satellite are beamed directly to the home of the viewer, obviating the need of a cable operator. Using 30cm to 46cm diameter small dish antennae and TV set-top boxes, subscribers are able to decode channels and view a plethora of programmes. Users are provided with channel cards that are essentially prepaid debit cards.
The price of set-top box and antenna varies from Rs 10,000 to Rs 25,000. However, the actual cost to a subscriber can be lower. In the countries where DTH is legal, satellite channels sell the system at a subsidised price to the consumers. Service providers recover their costs through the subscription fee that accrues to them from the sales of channel cards. The DTH operator offers a bouquet of channels, once the subscriber purchases the SIM card.
The elite class in the metropolitan cities is on the upbeat mode. Their kids would now be able to watch more Cartoon and Discovery type channels in English. Foreign diplomats, businessmen, and MNCs can watch channels of their choice in their own language. Users will have direct access to high-quality programmes on pay channels such as Star Movies. People in far flung areas,where cable operators are yet to provide the service, can use dish antennae for receiving channels. DTH can also provide satellite-based radio services.
Regulatory issues
The government has allowed DTH with certain safeguards. DTH players will have to beam from the home soil through earth stations within the country and adhere to the laid down programme and advertisement codes. The CEO and a majority of directors of DTH companies would have to be resident Indians. To obviate creation of monopolies, existing broadcasting companies and cable network owners are restricted to 20 per cent share in DTH ventures.The companies will have to furnish an initial deposit of Rs 100 million and Rs 400 million as bank guarantee for the 10-year licence period. At least 10 per cent of the revenue generated will have to be shared with the government. There is a 49 per cent limit on foreign equity. Of this, up to 20 per cent is to be foreign direct investment (FDI) and the balance from institutional investors, overseas corporates, and NRI investments.
DTH operators are allowed to set up the satellite earth station only on Indian soil. The earth station will act as the nerve centre for receiving and distributing signals from the satellites. It will enable government agencies to monitor the programme content to ensure that it conforms to the country’s parameters of security and decency. “No porn channels or tobacco/liquor ads” is the first rule of DTH in India.
Content will have to pass through the common encryption and conditional access system located within the earth station. DTH operators will provide access to all facilities, including equipment, records, and systems, to government agencies. They will provide access to all content providers and channels on a non-discriminatory basis, but shall not carry prohibited channels.
The DTH is barred from being used for other means of communication, such as voice, fax, and data. In other words, DTH operators will not be able to provide the Internet and voice communication services, as of now. They are bound to carry all channels of Prasar Bharti on the most favoured financial terms extended to other channels.
Pros and cons
Many cable subscribers are unhappy with the erratic cable TV services that keep on shifting the channels, at the expense of other channels, without any prior notification. Archiac hardware, cable wires, poor-quality reception, electrical disturbances, etc are irritating. DTH obviates the requirement of cable-wallahs altogether and enables viewers to access error-free programmes with better picture- and audio-quality. It allows the broadcasters to tap homes in rural and remote uncabled areas. One can choose from as many as 300 to 800 channels.
Pay channels will have direct and better control over revenues. Broadcasters, particularly of pay channels, feel that cable operators misrepresent the number of actual subscribers, resulting in revenue leaks. Pay channels can now monitor how many homes are watching their channels, and collect their revenue accordingly. DTH enables people with niche interests to view channels that are normally not available with the cable operators.
Because of the high investment of Rs 10,000 to Rs 25,000 for pizza-sized satellite-dish and digital decoder, along with monthly fee of about Rs 1,000, this service may not be affordable for most of the existing cable homes. But, if one pays the premium, one is the recipient of better picture quality with a wider choice.
DTH also promises to benefit hardware manufacturers as increase in subscriber base would lead to increase in demand and supply of DTH components.
Cable operators claim that they can also provide the Internet, interactive facilities on TV, and video-on-demand. But subscribers cannot call up the DTH providers and ask them to repeat their favourite Bollywood blockbusters on TV.
Technically, the only drawback to DTH is the effect caused by the various modes of interference like rain, sun, adjacent satellites, and terrestrial interference. Moisture blocks signals and also absorbs some of them. Sun spots, the magnetic storm on the sun’s surface, can directly affect satellites placed outside the ionsphere. Users need a clear and unobstructed view of the satellite, and the dish must be aligned accurately.
Commercial viability and the tremendous expense involved for both service providers as well as subscribers are the other major deterrents to DTH.
Enabling innovations
The idea to launch satellites for direct diffusion of TV programmes to ordinary people appeared economically realisable at the beginning of the 1970s. WARC (World Administration Radiocomm-unication Conference) defined the frequency bands, transponder power, and polarisation to be used, and allocated orbital positions, channels, and EIRP contours to each of the participating countries. The attributed frequency band (11.700 to 12.500 GHz), known as the direct broadcast satellite (DBS) band, was chosen, since it allows well delimited service areas with relatively small transmission antennae of less than 3m diameter on the satellite and does not suffer too much from meteorological conditions.
The specifications of DTH TV satellites have evolved considerably since then. The reception heads, the LNBs (low-noise boosters), have made enormous progress, with average noise factors in the range of 1.5 to 1.8 dB in 1990 and 0.8 to 1.1 dB in 1998, compared to 3 to 5 dB in 1977. This ensures the same service area with much smaller transmission power (50 to 100W instead of 200W) at identical or smaller antenna dimensions.
The increase in useful load of the satellite-launching rockets allowed an important increase in the total electrical power available, which, coupled with the satellite transponder power reduction, allowed the number of transponders per satellite to be increased by a factor of four. These satellites now have sufficient electrical autonomy to ensure an uninterrupted and normal service during equinox solar eclipses. The lifetime of satellites has doubled, approximately to 15 years, partly due to the better accuracy of the launches, which strongly influences the quantity of remaining propellent necessary for position control of the satellite.
Circular polarisation is preferred over the linear polarisation used by telecommunication satellites. This is because, for circular polarisation, the orientation of the reception head (LNB) around the propogation axis is unimportant, and therefore does not require any precise adjustment. This point is especially important for motorised antennae which, with linear polarisation, require a polarisation adjustment for each different satellite.
In the early 1980s, the home satellite systems started sprouting up all over the US. Japan became the first country to launch a DTH service in 1984. Subsequent innovative developments over the years started modernising and changing the lifestyles of people. DTH transmission has been operational in most Western countries since 1986.
Although the US had a long history of DTH satellite reception on large ‘TV receive only’ (TVRO) satellite antennae, it was not until the launch of theHughes DBS-I satellite in December 1993, and subsequent availability of diminutive satellite dishes with digital receivers, that the services started developing. The year 1994 brought a breakthrough in the debut of the first DBS service. In June 1994, consumers in Jackson, Mississipi, USA became the first Amercians to purchase the 45.7cm satellite dish and digital satellite receiver, enabling DBS reception.
By the end of 1994, over one million homes had subscribed to DBS multichannel services. Hughes developed DirectTV, a high-power DBS, to supply digitally compressed TV to the home. Contracts were issued to Thomson Consumer Electronics for the supply of antennae, home receiving equipment, and digital compression hardware. Individual antenna reception of TV was used in most homes in nine out of sixteen European countries, including the UK, France, Italy, and Spain—containing 70 million TV homes and 55 per cent of all Europe. These homes formed the target for DTH satellite broadcasting. The number of individual satellite receiving antennae and receivers increased dramatically in the UK and Germany, and higher power transmitted by satellites were receivable by antennae as small as 30 cm in diameter.
Functioning
A DTH network includes a broadcasting centre, one or more high-power satellites, and DTH receivers. Broadcasting centre, the hub of the network, is a complex production/playback studio with satellite uplink facility, subscriber management/access control system, and access network management system in the case of interactive and data services. Analogue or digital video programmes are received through satellite contribution links, fibre-optics, or microwave terrestrial connections. Audio-video(AV) programmes are also available through tape library or CD/DAT media. In case data or the Internet services are offered, connections to servers are used via cable or satellite links.
AV programmes are edited at the edit suite and final control centre (FCC). The final control centre consists of a mixing desk in which video, audio, and data programme scheduling and management are performed, with the insertion of commercials and promotionals, as required.
A typical DTH service provider leases Ku-band transponders from the satellite, accommodating the TV channels using compression techniques, after he has negotiated with different broadcasters (A1, A2, A3, A4) for these channels. The source of analogue signals from these channels could be camera, tape, or disk. Video, audio, data, or text signals are converted into digital format by encoder and mixed in multiplexer. Different programmes from various channels are mixed on a DTH platform. Subscriber management system manages various requests for different channels from the users.
Each decoder with the subscriber can be controlled individually at the multiplxer. A modulator superimposes the information on an RF carrier for transmission to the earth station. The earth station uplinks the signals to the satellite transponder for subsequent downlinking to individual households, apartments, hotels, and cable head-ends. Small-diameter antannae on the rooftops (or flats’ outer walls) transmit the signals to the integrated receiver decoder (IRD). A smart card inserted into the IRD completes the conditional access progress, enabling the system to descramble the encrypted signals. The IRD is connected to the TV set.
DTH vs Cable
| Installation cost | Rs 10,000 for 30cm Rs antenna + Rs 10,000 to 15,000 for decoder | 150 for wiring |
| Monthly charges | Rs 500-1,000 | Rs 100-200 |
| Number of channels | More than 200 | 50-100 |
| Reception quality | Excellent | Average to good |
| Other services | Fax, Internet, teleshopping time | Not available for being |
Digital TV decoder/receiver
Signal frequencies ranging from 10.7 to 12.75 GHz received from the satellite are amplified and down-converted into the 950MHz to 2,150MHz range by the LNB. The tuner selects the required RF channel in this range and converts it into a 480MHz IF. This signal is then
amplified and demodulated. The analogue signals are converted by A-to-D converter and error correction is realised by forward error correction (FEC) block.
Selection and descrambling of the packets for the required programme are performed by the descrambler under the control of the conditional access device that includes smart card readers. The demultiplxer selects the packets corresponding to the programme selected by the user, using programmable filters. The audio and video outputs of the demultiplexer are applied to the MPEG block that combines MPEG AV and graphic-control functions for the electronic programme guide. MPEG decoding generally requires at least 16 Mbps of DRAM and SDRAM. Video signals reconstructed by the MPEG decoder are then applied to digital video recorder for conversion and subsequent display on a TV set. A 32-bit microprocessor controls the circuitry, interprets user commands from the remote control, and manages the smart card readers and the communications interfaces. Software is located in a Flash-EPROM.
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