Polyphase filtered OFDM transmission system

A polyphase filtered orthogonal frequency division multiplexing (PF-OFDM) technique is presented. The proposed structure uses a modified discrete Fourier transform transmultiplexer to achieve greater spectral efficiency than an OFDM system, while preserving backward compatibility with it. The prototype PF-OFDM filter has excellent time and frequency localisation properties, which make it possible to eliminate a guard interval and easily suppress interchannel interference.