Unequal Phase Interpolation for Low PAPR Waveforms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication standards, such as 5G NR, face challenges in achieving low Peak-to-Average Power Ratio (PAPR) due to the use of waveforms like OFDM, which results in power amplifier inefficiencies and increased inter-symbol interference (ISI).
Innovation Solution
The proposed solution involves generating waveforms with low PAPR by utilizing an unequal phase change method that includes nonlinear phase interpolation. This method adds interpolated symbols between adjacent symbols based on specific phase change conditions, optimizing the trade-off between PAPR and ISI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM is used as the main waveform in 5G NR, then spectral efficiency is improved, but PAPR becomes significantly higher causing power amplifier inefficiencies
Solution Approach 1:
The patent applies parameter changes by modifying the waveform parameters through unequal phase change interpolation. Instead of using standard OFDM with fixed parameters, the system introduces variable phase changes between adjacent symbols based on specific interpolation rules. This changes the signal characteristics to reduce peak power while maintaining spectral efficiency, directly addressing the PAPR-energy efficiency trade-off.
Solution Approach 2:
The patent introduces dynamic phase changes between symbols rather than using static OFDM modulation. The unequal phase change method dynamically adjusts the phase transition characteristics based on the symbol indices and interpolation factor, allowing the waveform to adapt its PAPR characteristics while maintaining spectral efficiency. This dynamic approach resolves the contradiction between spectral efficiency and power amplifier efficiency.
2Loss of energy
If DFT-s-OFDM is used for uplink transmission, then PAPR is reduced compared to OFDM, but PAPR remains too high for future wireless standards
Solution Approach 1:
The patent segments the symbol transmission process by introducing intermediate interpolated symbols between adjacent original symbols. Instead of transmitting symbols directly as in DFT-s-OFDM, the system divides the symbol interval and inserts interpolated symbols at specific positions. This segmentation reduces the peak power of individual symbol transitions while maintaining overall spectral efficiency, achieving lower PAPR without sacrificing productivity.
Solution Approach 2:
The patent introduces interpolated symbols as intermediary elements between adjacent original symbols. These interpolated symbols act as mediators that smooth the transitions and reduce peak power levels. The intermediary symbols are generated through unequal phase change interpolation and are strategically placed to minimize PAPR while preserving spectral characteristics, thus resolving the contradiction between low PAPR and high spectral efficiency.
3Loss of energy
If additional symbols are added in time domain to increase phase continuity, then PAPR is reduced, but ISI increases resulting in poor error performance
Solution Approach 1:
The patent applies local quality by introducing interpolated symbols only at specific locations between adjacent original symbols rather than uniformly throughout the entire signal. The unequal phase change method selectively places interpolated symbols based on the phase change characteristics of adjacent symbol pairs. This localized approach reduces PAPR at critical transition points while minimizing the overall impact on signal length and ISI, thus improving reliability compared to uniform symbol insertion methods.
Solution Approach 2:
The patent employs asymmetry through unequal phase change interpolation where the phase change characteristics are not uniform across all symbol transitions. The interpolation factor and phase change magnitude vary based on the specific symbol indices and their phase relationships. This asymmetric approach optimizes PAPR reduction at critical points while maintaining better error performance than symmetric methods, as it targets PAPR reduction where it matters most without unnecessarily extending the symbol duration.
Data Source
AI summary
In one embodiment, a method includes accessing a modulated symbol sequence comprising multiple symbols, generating interpolated symbols to be added between any two adjacent symbols based on an unequal phase change method, generating an interpolated symbol sequence based on adding the generated interpolated symbols for any two adjacent symbols into the two adjacent symbols, and transmitting a waveform to a wireless endpoint device, wherein the waveform is generated based on the interpolated symbol sequence.