OFDM in a nutshell
Principle of the OFDM transmission - usage in cellular systems

An elementary principle for increasing throughput by a factor of n is to transmit several information items in parallel on n channels.

This is what OFDM (Orthogonal Frequency Division Multiplexing) achieves, with n values of up to a few thousand, which was impossible for radio transmissions with analog technologies because it required n transmitters and n receivers. This required, for example, n oscillators, each tuned to a particular frequency, and coupling elements to avoid multiplying antennas (figure 1 ). With the advent of digital technologies, simultaneous transmission over a large number of frequencies can be achieved...