Preamble Phase Rotation for PAPR Optimization in Punctured WLAN
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Solution Overview
Problem
Next-generation WLAN systems face challenges in optimizing spectrum efficiency and throughput, particularly in dense environments with multiple access points and stations, where existing technologies struggle to minimize Peak to Average Power Ratio (PAPR) in wideband transmissions.
Innovation Solution
The proposed method involves setting phase rotation values for legacy preambles in a WLAN system, specifically for 80, 160, 240, or 320 MHz bands, using optimized phase rotation values defined for 80 MHz bands and applying them in units of 20 MHz bands, to achieve optimized PAPR during preamble puncturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wideband transmission (80, 160, 240, or 320 MHz) is performed in next-generation WLAN systems, then spectrum efficiency and area throughput are improved, but Peak to Average Power Ratio (PAPR) increases causing transmission performance degradation
Solution Approach 1:
The patent applies different phase rotation values to different subcarriers within the wideband transmission. Specifically, it uses first phase rotation values for subcarriers in first frequency subbands and second phase rotation values for subcarriers in second frequency subbands. This local differentiation optimizes PAPR performance in each subband while maintaining overall spectrum efficiency across the wideband.
Solution Approach 2:
The patent changes the phase rotation parameter across different frequency subbands to optimize PAPR. By applying different phase rotation values (first phase rotation values and second phase rotation values) to different subbands, the system dynamically adjusts the signal characteristics to minimize peak power while maintaining average power efficiency, thus resolving the contradiction between spectrum efficiency and transmission performance.
2Adaptability or versatility
If preamble puncturing is performed in wideband transmission, then flexibility in resource allocation is improved, but PAPR optimization becomes more difficult
Solution Approach 1:
The patent segments the wideband frequency spectrum into multiple frequency subbands (first frequency subbands and second frequency subbands) and applies different phase rotation values to each segment. This segmentation allows independent optimization of PAPR in each subband while accommodating preamble puncturing patterns, thus managing the complexity of PAPR optimization in punctured wideband transmissions.
Solution Approach 2:
The patent applies local phase rotation optimization by using different phase rotation values for different frequency subbands affected by preamble puncturing. This localized approach allows the system to maintain PAPR optimization in non-punctured subbands while adapting to puncturing patterns in specific subbands, balancing resource allocation flexibility with PAPR management.
Data Source
AI summary
A method and apparatus for transmitting PPDU in a wireless LAN system are proposed. Specifically, a transmitter generates the PPDU, and transmits the PPDU to a receiver through a 320 MHz band in which some bands are punctured. The PPDU includes a legacy preamble and an EHT field. The legacy preamble includes L-STF and L-LTF. The legacy preamble is generated by applying a first phase rotation value or a second phase rotation value. The first phase rotation value is obtained 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 having repeated a phase rotation value defined for an 80 MHz band in an 802.11ax system. The fourth phase rotation value is a phase rotation value defined in units of the 80 MHz band in the 320 MHZ band on the basis of an optimal PAPR of the L-LTF.