Terminal DFT-Spreading Configuration for Spectral Efficiency and PAPR
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Solution Overview
Problem
The DFT-s-OFDM scheme in wireless communication systems faces challenges with low spectral efficiency, high out-of-band leakage, and poor compatibility with future communication frameworks, making it difficult to integrate with evolving systems.
Innovation Solution
A terminal device and method that includes pre-processing and post-processing of DFT spreading, such as zero-padding, data deletion, and spectrum shaping, to enhance DFT-s-OFDM, allowing flexible configuration based on processing configuration, terminal device capability, and key performance indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If DFT-s-OFDM waveform is used to reduce PAPR, then power efficiency is improved, but spectral efficiency deteriorates
Solution Approach 1:
The patent segments the DFT-s-OFDM processing into distinct pre-processing and post-processing stages around the core DFT spreading operation. Pre-processing includes operations like sequence extension and windowing before DFT, while post-processing includes frequency domain filtering and clipping after DFT. This segmentation allows independent optimization of each stage to simultaneously improve power efficiency and spectral efficiency.
Solution Approach 2:
The patent changes key parameters of the DFT-s-OFDM waveform including the DFT size, cyclic prefix length, windowing functions, and frequency domain filtering parameters. By optimizing these parameters, the system achieves lower PAPR (improving power efficiency) while maintaining better spectral containment (improving spectral efficiency) compared to traditional DFT-s-OFDM.
2Productivity
If traditional cyclic prefix is replaced with NCP or UW to reduce out-of-band leakage, then spectral efficiency is improved, but compatibility deteriorates
Solution Approach 1:
The patent creates a universal DFT-s-OFDM processing framework that can accommodate multiple prefix types (traditional cyclic prefix, NCP, UW) through a unified pre-processing stage. The system can select and apply different prefix schemes based on channel conditions and service requirements while maintaining the same core DFT spreading structure, thus achieving both improved spectral efficiency and broad compatibility with different communication scenarios.
Solution Approach 2:
The patent introduces dynamic selection of cyclic prefix types and lengths based on channel characteristics, service type, and interference conditions. The system can adaptively switch between traditional CP, NCP, and UW schemes, and adjust prefix lengths dynamically, providing both spectral efficiency improvements and compatibility with various operational requirements.
3Use of energy by moving object
If FDSS is performed after DFT to reduce PAPR, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts the PAPR reduction function into a dedicated post-processing stage that operates independently on the DFT output. This includes frequency domain clipping, filtering, and selective rescaling operations that are applied only to specific subcarriers with excessive amplitude. By isolating these operations, the system achieves PAPR reduction with minimal additional complexity compared to the core DFT operation.
Solution Approach 2:
The patent employs computationally inexpensive post-processing operations such as simple frequency domain clipping and basic windowing functions that can be applied rapidly with minimal processing overhead. These lightweight operations provide effective PAPR reduction without requiring complex algorithms, thus improving power efficiency while adding minimal device complexity.
4Productivity
If pre-processing and post-processing operations are added to DFT spreading, then spectral efficiency is improved, but processing complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct pre-processing, DFT spreading, and post-processing stages, each with specific functions. Pre-processing includes sequence preparation and windowing, DFT spreading provides the core modulation, and post-processing includes frequency domain filtering and spectral shaping. This segmentation allows each stage to be optimized independently for spectral efficiency while keeping individual stage complexities manageable.
Solution Approach 2:
The patent merges multiple spectral efficiency enhancement techniques (different prefix schemes, windowing functions, frequency domain filtering, and spectral shaping) into a unified DFT-s-OFDM framework. By combining these operations in a coordinated manner around the core DFT spreading, the system achieves cumulative spectral efficiency improvements without the complexity of separate independent systems.
Data Source
AI summary
The present disclosure provides a terminal device and a processing method. The terminal device includes: a receiving unit configured to receive processing configuration information, wherein the processing configuration information indicates at least one of pre-processing and post-processing of Discrete Fourier Transform (DFT) spreading; a processing unit configured to determine at least one of the pre-processing and the post-processing of the DFT spreading according to the processing configuration information.