HEW PPDU Phase Rotation for PAPR Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in increasing transmission efficiency and reducing Peak-to-Average Power Ratio (PAPR) while maintaining compatibility with legacy systems and supporting higher throughput in congested environments.
Innovation Solution
The proposed method involves an High Efficiency WLAN (HEW) system that uses a modified Physical Layer Protocol Data Unit (PPDU) format with increased OFDM subcarriers per unit frequency, achieved by increasing FFT sizes, and phase rotation techniques to decrease PAPR, while ensuring backward compatibility with legacy systems through dual FFT size transmission and phase rotation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FFT size is increased to increase the number of OFDM subcarriers per unit frequency, then transmission efficiency and data transmission capacity are improved, but Peak-to-Average Power Ratio (PAPR) of the transmitter increases
Solution Approach 1:
The patent applies parameter changes by modifying the phase rotation pattern parameters in the frequency domain. Specifically, it changes the phase rotation values applied to different subcarriers to achieve a more uniform power distribution across the transmitted signal, thereby reducing PAPR while maintaining the increased FFT size and subcarrier count for high transmission efficiency.
2Productivity
If modified PPDU format with increased FFT sizes is used to enhance transmission capacity, then throughput is improved, but compatibility with legacy systems deteriorates
Solution Approach 1:
The patent segments the PPDU format into distinct parts: a legacy-compatible preamble portion that legacy systems can recognize and process, and a data portion that utilizes the extended FFT size and increased subcarriers for high throughput. This segmentation allows legacy and HEW systems to coexist in the same network environment.
Solution Approach 2:
The patent applies local quality by maintaining traditional PPDU format characteristics in specific portions (preamble) that require legacy compatibility, while introducing modified characteristics (increased FFT size, phase rotation patterns) in other portions (data section) where performance enhancement is the priority. This allows different parts of the same signal to serve different functional requirements.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for transmitting a data unit and a device suing the same is provided. The device generates a physical layer protocol data unit (PPDU) that includes a first part and a second part. The first and second part are generated with different fast Fourier transform (FFT) size. A phase rotation of the second part is different from a phase rotation of the first part.