India's Homegrown System for "Fixed Wireless" Has Legs

A novel way of providing plain old connected telephone service wirelessly is concocted in Chennai (Madras)

3 min read

1 July 2003—No copper? No problem. Systems for connecting customers to the telephone system wirelessly rather than by means of the tried-and-true copper loop can be an attractive option in areas that have yet to set up a copper infrastructure. One such system, developed at the Indian Institute of Technology (IIT)�Madras (Chennai), is being extensively deployed in rural parts of India and has already attracted serious interest in a dozen other countries, including South Africa, Brazil, Russia, Egypt, and Iran.

Methods of providing local telephone service via radio connections to the home or office are generally referred to as ”fixed wireless” in the United States, or ”wireless in local loop” in India. The IIT system, called corDECT, was developed by a telecommunications and computer networking group under Ashok Jhunjhunwala, a professor of electrical engineering.

”At about [US] $200 per subscriber unit, corDECT is much cheaper than the $500 per fixed line connection [it costs] basic operators [to provide service], especially in suburban and rural areas,” claims Jhunjhunwala.

CorDECT derives its name from the Digital Enhanced Cordless Telecommunications standard (DECT) of the European Telecommunications Standards Institute (ETSI, Sophia-Antipolis, France). ETSI defines the air interface for users in the1880�1900 MHz range. It purports to be the world’s only fixed wireless technology offering simultaneous voice and Internet data.

There are four basic elements of the system. At the subscriber’s end is a terminal or wall set that links the subscriber wirelessly to a relay base station up to 10 km away. The wall set in the subscriber’s home is an intelligent device that searches for access to the strongest base station among many, and latches on to the quietest channel through a dynamic channel selection procedure. It can be connected to any standard telephone, modem, or fax machine.

The relay base station then transmits the signal as far as another 25 km to a so-called compact base station, a wall-mounted unit capable of serving 30-70 subscribers and connecting to a DECT interface unit. In effect, each DECT unit is a kind of super base station, linking a maximum of 20 compact base stations to the voice and data infrastructure.

A delayed takeoff

India’s communications authorities initially were slow to recognize the merits of the country’s homegrown fixed-wireless technology, in part perhaps because of an ill-conceived notion that rural India needed only standard telephony and no Internet capability. The Department of Telecommunications (Delhi) ignored corDECT, while the state-owned telecom owner placed large orders for imported products with arguably less impressive features.

The emergence of Reliance Infocomm Ltd. (Mumbai) with a bold plan to make corDECT the basis of a ”limited mobility” cellular network, in addition to a ”wireless in local loop” system, has done much to change the dynamics [see ”Indian company stretches fixed wireless phone technology to make cellular network,” IEEE Spectrum, July 2003, pp. 16-17]. Reliance is installing 1.5 million lines in 1450 sites in the country.

Meanwhile, the Indian government has commissioned about a million corDECT lines and their accompanying infrastructure. It is also being deployed in the country under various programs for rural connectivity, including the Rural Access to Services through Internet (RASI) program, a joint effort of the Massachusetts Institute of Technology, the Center for International Development at Harvard University (both in Cambridge), the I-Gyan Foundation (Boston), and IIT�Madras.

One of the notable examples of corDECT being used for local needs is the effort by a spinoff of IIT-Madras, n-Logue Communications Private Ltd. (Chennai). This venture-funded start-up has connected 500 villages in its first year of operation and is aiming to connect another 15 000 villages with 50 million people in its second year.

According to n-Logue chief executive officer P.G. Ponnapa, the system already is being used for everything ”from providing expert advice about diseases affecting crops to providing e-mail connections to relatives living abroad or in cities.” Among other things, n-Logue has combined with a private bank to bring rural, low-cost automatic teller machines to villagers.

Based on what n-Logue has accomplished, Jhunjhunwala says, just ”give us $32 million annually for three years and we’ll wire up all of rural India.”

About the Author

Seema Singh writes about science, technology, and business, from Bangalore, India.

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