Phase Rotation Optimization for 320 MHz WLAN PAPR
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Solution Overview
Problem
Current wireless LAN systems face challenges in optimizing the phase rotation value for high-throughput communications, particularly in the 80 MHz band, which affects the PAPR of L-STF and L-LTF fields, leading to suboptimal subcarrier efficiency and throughput.
Innovation Solution
A method and apparatus that set a phase rotation value for the legacy preamble to optimize PAPR in the L-STF and L-LTF fields, using a combination of phase rotation values defined for 160 MHz and 80 MHz bands, applied in a 320 MHz or 160+160 MHz broadband transmission, ensuring optimal PAPR across all fields in the PPDU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a phase rotation value defined for 160 MHz band is repeated for 320 MHz band transmission, then the implementation complexity is reduced, but the PAPR optimization for L-STF and L-LTF fields becomes suboptimal
Solution Approach 1:
The 320 MHz band is segmented into multiple 80 MHz sub-bands, and a specific phase rotation value is applied to each segment. This allows the patent to optimize PAPR for L-STF and L-LTF fields in each segment while maintaining manageable implementation complexity through systematic segmentation of the broadband transmission.
Solution Approach 2:
Different phase rotation values are applied to different frequency segments within the 320 MHz band. The patent uses a phase rotation value of -3π/8 for the primary 80 MHz band and -π/8 for secondary 80 MHz bands, creating local optimization rather than uniform application across the entire bandwidth.
2Productivity
If bandwidth is increased to 320 MHz or 160+160 MHz for high throughput, then data transmission capacity is improved, but subcarrier efficiency deteriorates due to non-optimized PAPR
Solution Approach 1:
The patent changes the phase rotation parameter from the conventional -π/4 used in 160 MHz systems to specific values (-3π/8 and -π/8) optimized for 320 MHz broadband transmission. This parameter change optimizes PAPR for L-STF and L-LTF fields, thereby improving subcarrier efficiency while maintaining high bandwidth utilization.
3Manufacturing precision
If phase rotation value is optimized for L-STF and L-LTF fields in 320 MHz band, then subcarrier efficiency is improved, but compatibility with legacy 802.11ax systems may be affected
Solution Approach 1:
The patent segments the 320 MHz band into primary and secondary 80 MHz bands, applying different phase rotation values to each segment. This segmentation allows the system to optimize performance for new EHT devices while the structured approach maintains a level of compatibility with legacy 802.11ax systems that operate in narrower bands.
Solution Approach 2:
By applying local optimization with specific phase rotation values to different frequency segments rather than a uniform approach, the patent achieves subcarrier efficiency improvement while the localized nature of the change preserves backward compatibility for devices operating in standard bandwidths.
Data Source
AI summary
Proposed are a method and 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 broadband is a 320 MHz band or a 160+160 MHz band. The PPDU includes a first field and a second field. The first field includes an L-LTF. The first field is generated on the basis of a first or second phase rotation value. The first phase rotation value is generated on the basis of a third phase rotation value and a fourth phase rotation value. The third phase rotation value is a phase rotation value obtained by repeating a phase rotation value for an 80 MHz band defined in an 802.11be wireless LAN system.