Subcarrier-Specific Phase Rotation for 320 MHz WLAN PAPR Reduction
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Solution Overview
Problem
Current wireless local area network (WLAN) systems face challenges in efficiently transmitting Physical Protocol Data Units (PPDUs) due to high Peak-to-Average Power Ratio (PAPR) in Legacy-Short Training Fields (L-SIG), which limits transmission range and overall performance, especially in broadband communications.
Innovation Solution
A method and apparatus that apply phase rotation values to each subcarrier in a WLAN system, specifically optimizing phase rotation for a 320 MHz band by using a combination of per-20 MHz and per-subcarrier phase rotations to reduce PAPR, thereby enhancing PPDU transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phase rotation is applied to L-SIG in broadband WLAN, then transmission can be performed, but PAPR remains high which limits transmission range and performance
Solution Approach 1:
The patent changes the phase rotation parameters by introducing subcarrier-specific phase rotation values (e.g., alternating +1 and -1 patterns across different subcarrier groups) instead of uniform phase rotation. This parameter modification redistributes the signal amplitude across subcarriers, effectively reducing PAPR while maintaining transmission reliability and extending transmission range in broadband WLAN systems.
Solution Approach 2:
The patent applies different phase rotation values to different subcarrier groups within the broadband spectrum. By making the phase rotation property local to each subcarrier group rather than uniform across all subcarriers, the system optimizes PAPR reduction in specific frequency regions while maintaining overall signal integrity and transmission performance.
2Productivity
If increased bandwidth is used for broadband communication, then data rate is improved, but PAPR increases which reduces transmission efficiency
Solution Approach 1:
The patent introduces subcarrier-specific phase rotation parameters that vary across the broadband spectrum. This parameter change allows the system to maintain high data rates over increased bandwidth while controlling PAPR by distributing signal energy more evenly across subcarriers, thereby improving transmission efficiency in broadband WLAN communications.
Solution Approach 2:
The patent segments the broadband spectrum into multiple subcarrier groups and applies different phase rotation values to each segment. This segmentation approach allows independent optimization of PAPR in each frequency segment while maintaining the overall high data rate capability of the broadband system, resolving the contradiction between bandwidth utilization and power efficiency.
Data Source
AI summary
Proposed are a method and a device for receiving a PPDU in a wireless LAN system. Specifically, a reception STA receives a PPDU from a transmission STA through a broadband and decodes the PPDU. The PPDU includes a legacy preamble and a first and a second signal field. The legacy preamble and the first and second signal fields are generated on the basis of a first and a second phase rotation value. When the broadband corresponds to a 320 MHz band, the first phase rotation value is [1 −1 −1 −1 1 −1 −1 −1 −1 1 1 1 −1 1 1 1]. An element of the first phase rotation value is applied to each 20 MHz band of the 320 MHz band. An element of the second phase rotation value is applied to each subcarrier of the 320 MHz band.