Breaking new grounds

Mumbai: The first form of communication that evolved in the days of the early man was the sign language. Pretty soon, man learnt to communicate with each other through the spoken word. Here, the limitation of this form of communication was that one could only communicate with another person when they were face to face.

Drawings and the written word followed by means of which mankind has communicated through caves, written texts on leaves and later on, paper. This enabled man to communicate with people living in distant areas and with the latter generations. All this developed up to the late nineteenth century when the telephone and telegraph enabled us to communicate through long distances at a faster pace.

The second half of the twentieth century ushered in another revolution in communications — the Internet, which made it possible for computers to talk to each other at electronic speed. The Internet has changed the way we live, work and play. This form of communication required the constant use of phones as an accessory. The Wi-Fi technology has changed all that. Wi-Fi simply stands for wireless fidelity and under this technology wires are not required to transmit radio waves and the phone costs are less.

The gadgets required for logging on to the Internet are essentially a telephone connection, which receives the radio waves and a modem which converts the analogue signals received in to a digital form and is then transmitted to the computer. Here, the capacity to communicate is limited by two factors — the bandwidth and speed.

Bandwidth can be compared to a highway where depending on the breadth of the highway a limited number of vehicles can ply at the same time without obstructing each other. The telephone supplier, say, Mahanagar Telephone Nigam Ltd (MTNL) supplies you with a band under which signals are transmitted at 0.06 million bits per second (Mbps). Under this band, let us assume that only 5 lakh persons can log on to the Internet at the same time. If more people need to log on at the same time, MTNL''s bandwidth will have to be increased.

Under Wi-Fi technology, the speed of communication is many times faster and the limitation of bandwidth is overcome. With Wi-Fi technology you can communicate under the same band supplied by MTNL at much higher speed than what is available now. This will enable many more than 5 lakh persons to log on to the Internet at the same time.

When we compare bandwidth to a highway, we assume that radio signals like vehicles are physical entities. In reality they are not. We know that two solid matters, say cricket balls, cannot occupy the same space at the same time. In the case of radio signals two or more signals can occupy the same space at the same time and this is what Wi-Fi technology has recognised.

The existing PC modem system exploited the intelligent use of cables while the Wi-Fi system exploits the intelligent use of airwaves. And two technologies have enabled this intelligent use of the airwaves.

First is the spread spectrum technology, which is a method by which transmission is scattered around over many narrow bands. Here even if some of the transmissions are drowned by interference others will get through, as the transmissions are not evenly distributed. Here the receiver knows the sequence of frequencies that the transmissions will be coming in and it can ignore the transmissions it does not want to pick up.

The second is the digital radio, which can break up the transmissions in to the Internet like packages with addresses. A digital radio receivers pay attention only to the packets meant for them, allowing many devices to use the same frequencies. To this is added the error correction mechanism, which has the ability to re-send any part of the transmission that is lost. Thus you have a system which can cut through the most crowded environments and share airwaves with hundreds of near by transmitters.

The gadgets required here are a walkman-sized device called the access point or port, which is plugged into a phone socket. This device sends transmissions wirelessly in a certain area to other PCs, laptops and personal digital assistants like the digital dairy, which at their end have a small card, which receives the signals. The cost of the port is very affordable and the cards are much cheaper than having a phone connection.

So how does one gain from Wi-Fi? Imagine a housing society comprising 50 households. Today if each of these households need to have Net access, they will require need 50 phone connections. With Wi-Fi, all you need is one phone connection, one common access point and 50 cheap receiving cards and the 50 households can merrily access the net. And yes, the Net can also be accessed from the kitchen, the garden and the swimming pool.

Though it is early days, Wi-Fi has caught the fancy of consumers in the US. The technology has also come to India in a small way. The Taj group and the Oberois have Wi-Fi installed in some of their hotels. It is only a matter of time that other hotels, airports, coffee shops, university campuses and companies will go for this system. Companies are a bit shy of adapting this system for security reasons. Infosys and a few companies, however, have already installed Wi-Fi in their campuses.

The real benefits of this breakthrough technology goes far beyond just multiple Net access at a cheaper cost. Necessity, as they say, is the mother of invention. This technology came about with the need for accessing airwaves, which were not licensed. In other words, accessing the airwaves controlled by MTNL and other suppliers meant that licensing fees had to be paid to them. Now the Internet can be accessed without these intermediaries. That will bring about a drastic change in telecom and regulatory policies.

In the US the clamour for the change in telecom regulatory policies, which require payment of huge licensing fees, has already begun.