It is defined by a mathematical technique for generation and demodulation of radio waves. It may be transmitted by AM, FM or QAM (quadrature AM).

OFDMA distributes data over a large no of carrier that are spaced apart at precise frequencies. This spacing provides “orthogonality” thus preventing demodulation from seeing frequencies other than their own.

It is used not just for mobile communication but also in digital audio broadcast (DAB) and digital video broadcast (DVB).

It is multicarrier transmission technique provides high rate communications.

Advantages:

• Spectral efficiency
• Simple channel equalisation
• Suppression of inter symbol interference