6G • Spectrum
Faster-Than-Nyquist (FTN) Signaling
Non-Orthogonal Time and Frequency Pulse Packing for 6G
Transmission technique transmitting pulses faster than the classical Nyquist rate to boost spectral efficiency by 25-40% at the expense of intentional ISI.
Technical Explanation
In 1928, Harry Nyquist proved that transmitting pulses faster than symbol period T = 1/(2B) introduces inter-symbol interference (ISI). Faster-Than-Nyquist (FTN) deliberately transmits pulses at a rate accelerated by a factor of tau < 1 (e.g. tau = 0.75). Although this introduces deterministic inter-symbol interference, modern 6G deep learning Viterbi and sphere decoders can cleanly untangle the known interference, yielding a free 25% to 40% throughput increase without requiring additional spectrum bandwidth.
Key Functions
- Packs pulse symbols closer in time and frequency than the classical Nyquist limit
- Delivers 25% to 40% higher data throughput over identical spectrum bandwidth
- Utilizes deep neural network sequence decoders to untangle intentional ISI
- Maximizes channel capacity in band-limited sub-THz and optical wireless links
Specifications
IEEE Trans. Information Theory, 3GPP Rel-19 Non-Orthogonal PHY Studies
Interfaces
FTN Pulse ShaperNeural Sequence Equalizer
Related 6G Concepts
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