DFT-s-OFDM Waveform Generation with Lookup Table Precoding

The patent segments the uplink transmission into different waveform types (OFDM for data, DFT-s-OFDM for control and reference signals) optimized for their specific requirements. This segmentation allows each signal type to use the most appropriate waveform, enabling control and reference signals to achieve low PAPR and full power transmission while data signals maintain high throughput capability.

The patent applies spectrum shaping as a preliminary action during the waveform generation process, specifically during the DFT spreading stage. By incorporating the spectrum shaping filter in the frequency domain before IDFT, the low PAPR property is achieved inherently during signal generation rather than requiring complex post-processing or specialized hardware modifications at the power amplifier stage.

The patent changes the key parameter of PAPR from high to low through the use of DFT-s-OFDM waveform and spectrum shaping. This parameter change enables the power amplifier to operate in its highly efficient saturation region without introducing significant nonlinear distortions, as the low PAPR signal has reduced peak excursions that would otherwise cause amplifier saturation and signal degradation.

The patent applies local quality by assigning different waveform characteristics to different signal types based on their specific requirements. Control and reference signals use DFT-s-OFDM with spectrum shaping optimized for low PAPR and reliable detection, while data signals can use standard OFDM optimized for throughput. This localized optimization ensures each signal type has the appropriate transmission characteristics for its function.