The recent commissioning of the Ku Band-based NICNET National Info Highway has opened the doors for a wide variety of informatics services which could propel the Country to the very frontiers of Information Technology. And for the first time in India, NIC is now on the verge of launching the Satellite Data Broadcast Facility.

The Technology

Data Broadcast is similar to conventional radio and television broadcast except that digital data, instead of audio or video signals, are carried by the satellite RF signal. Special digital transmission and reception techniques are employed to enhance coverage and provide error-free delivery of the transmitted information.

The receiving equipment is a low-cost Receive-Only Very Small Aperture Terminal (ROV). The information transmitted in Data Broadcasting can be in the form of plain text, pictures or even multimedia presentations. While the plain text is displayed on normal VDU, multimedia presentations are possible in multimedia workstations.

With Data Broadcast Facility, linking remote sites to Delhi for one-way data transmission can now be done at one-third the annual cost of multiple point-to-point terrestrial links. Satellite transmission is reliable, the data is error-free, and the receiving equipment can be installed within an hour.

The ROV

The ROV, which is the distinguishing feature of data broadcast technology, basically consists of the following components:

  • A small dish antenna, typically 60/90 cm in diameter. The small size of the antenna makes it window or even desktop mountable, wherever there is a clear view up into the southern sky, at an elevation of 45 degrees.
  • An LNB (Low Noise Block) Converter of the TVRO type, that receives the satellite signals and downconverts them.
  • An IDU (Indoor Unit) box weighing 3 kgs, which is placed within 60 metres of LNB and antenna. This demodulates the signal, corrects errors in the incoming data, separates (demultiplexes) the various data streams and forwards each to an RS 232 port for output. Each IDU has 1-4 ports which can be configured to receive any particular stream and can work at 50 bps to 64 kbps. At the receiving end, the User typically connects a PC with application-specific database and display software.

Applications

Any information that is required simultaneously at many sites over a wide geographical area is suitable for data broadcasting. The information can be provided directly by independent information agencies who are interested in real time and/or selective dissemination of information. Typical applications include:

  • Distribution of Financial Information on share prices and exchange rates to brokerage houses, banks and financial institutions
  • News Agency Transmission
  • Fax Broadcasting
  • Remote database updating from a central location in bibliographic services, credit card verification etc.
  • Weather and Agriculture Information distribution
  • Head office-to-branch office transmission of real-time status information and circulars
  • Backbone relay for all-India paging, teletext and radio data broadcast networks

Interface for Broadcast

In data broadcasting, the National Informatics Centre will act as the relaying agent between the Information Providers on one hand and the Information Subscribers on the other. Potential information providers will extend their data feed to the uplinking hub station at NIC Headquarters in Delhi. This can be done using the two-way NICNET National Info Highway or via telephone lines. The hub can accept up to 32 such independent streams at individually configurable rates of 50 bps to 64 kbps. The data received from multiple sources is multiplexed into one composite stream, encoded and upconverted into Ku-band.

Block Diagram of Data Broadcast Hub

Subscriber Management

The Information Provider will have full control over who can receive the data stream. Using the Network Management System, NIC will enable only those receivers specifically authorized by the Information Provider. Individual receiving stations can be enabled for up to any four data streams which can also be separately disabled on instructions from the Information Provider.

Getting your ROV

NIC places no restrictions on the procurement method for ROVs. These can be imported from manufacturers, leased from IESL, Bangalore, or in some cases, obtained from the Information Provider. In special cases, these can be obtained from NIC. No formal frequency or sighting clearance is required for installation of these stations, but prospective Users should first check with NIC for the correct dish size.

For further information, please contact

TDPP Group, NIC, A-Block, CGO Complex, Lodhi Road, New Delhi - 110 003.

Tlx: 031-61274 NICS IN, Ph: 4360788, 4362628

Fax: 91-11-4362489, 4362628

Email: sumitro.sarkar @X400.nicgw.nic.in