Mobile communication in spectrum

How does mobiles communicate in a spectrum?

You must have seen the term “3G spectrum or 3G auctions” in any leading newspaper or TV channel. To understand the basics, you must know a little bit of Electro Magnetic Spectrum. In mobile phones our speech signal i.e. voice is first converted to electrical pulses for processing. Since electrical signals cannot travel through air, so after processing they are converted into Radio waves (a part of EM spectrum).

What are Electromagnetic waves?

Electro-Magnetic waves are invisible waves that can pass through any solid medium. They have longer range and can travel long distance (kilometers) with the help of antennas and repeaters. These radio waves are not only used for mobile communication but are also used in wide range of applications like radio broadcasting, satellite and military communication, radars, navigators like GPS etc.

Need of spectrum management

In today’s digital world most wireless activities occurs simultaneously, so there must be a monitoring body present to look after these frequency bands and check whether these bands are overlapping with each other or not. “So several non-colliding frequency bands make up a spectrum.” For example if we do not have separate frequency bands for radio broadcasting and mobile communication then there will be overlapping of frequencies resulting in a distorted output. In order to prevent this, radio and mobiles are given different frequency bands. In India we have frequency band of radio is 87 MHz to 108 MHz and 900/1800 MHz for mobile. Similarly, for satellite communication we have 30 to 300 GHz of high frequency range.

Auction Body and role of TRAI

In India spectrum auction is done by TRAI (Telecom Regularity Authority of India). It is a part of government’s body that spends considerable amount of time allocating particular services so that they do not interfere with each other. These services are bounded by rules which are agreed and accepted internationally. Thus in order to buy any particular frequency band telecom operators has to provide a certain sum of money to the government. Some of the Telco’s that participated in the recent 3g auction were Vodafone, Bharti Airtel, Reliance, Tata etc.

Therefore the main purpose of splitting the spectrum is to provide different services with different non colliding frequency bands.