Phase Rotation Optimization for EHT PPDU PAPR in 320 MHz WLAN
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Solution Overview
Problem
Current IEEE 802.11/Wi-Fi networks experience varying worst-case latency, affecting performance and reliability for real-time applications, particularly in environments with traffic congestion, and require improvements in MAC and PHY layers to support predictable and low latency, as well as enhanced reliability.
Innovation Solution
The method involves optimizing phase rotation values for Physical Protocol Data Units (PPDUs) in WLAN systems to minimize Peak to Average Power Ratio (PAPR) across different RF transmission bandwidths, enabling efficient transmission in 80/160/240/320 MHz bands, and applying these values to legacy and EHT fields within the PPDU structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phase rotation values are optimized for minimum PAPR in broadband transmissions, then subcarrier efficiency and throughput are improved, but the system must accommodate wireless devices with different maximum transmission bandwidths of RF, increasing system complexity
Solution Approach 1:
The patent applies different phase rotation values to different subcarrier groups within the broadband transmission. Specifically, the broadband signal is divided into multiple subbands, and each subband is assigned optimized phase rotation values tailored to its characteristics and the RF capabilities of receiving devices. This local optimization approach improves overall throughput while managing system complexity by treating different portions of the spectrum differently rather than applying a single global configuration.
Solution Approach 2:
The broadband transmission is segmented into multiple subbands or frequency groups, each with its own phase rotation optimization. The patent divides the wide bandwidth into smaller manageable segments that can be independently configured based on RF device capabilities. This segmentation allows the system to optimize PAPR for each segment while maintaining compatibility across devices with different maximum transmission bandwidths.
2Productivity
If phase rotation is optimized for minimum PAPR across the entire broadband, then transmission efficiency is improved, but devices with different RF bandwidth capabilities cannot be properly supported, reducing adaptability
Solution Approach 1:
Different phase rotation values are applied to different frequency subbands based on the RF capabilities of receiving devices. The system identifies the maximum transmission bandwidth capability of each device and applies appropriate phase rotation optimization only to the subbands that device can receive, leaving other subbands with default or alternative configurations. This ensures both transmission efficiency for capable devices and compatibility for devices with limited bandwidth.
Solution Approach 2:
The phase rotation configuration is made dynamic and adaptive to the specific RF capabilities of receiving devices. The system can adjust which phase rotation values are applied based on real-time device capability information, allowing the same broadband transmission to be efficiently received by devices with different maximum bandwidths. This dynamic adaptation maintains both transmission efficiency and device compatibility.
3Productivity
If wide bandwidth transmissions are used to increase throughput, then data rate is improved, but worst-case latency becomes less predictable, affecting real-time application performance
Solution Approach 1:
The patent optimizes the PAPR parameter through carefully selected phase rotation values, which directly impacts the power amplifier efficiency and transmission reliability. By minimizing PAPR through optimized phase rotation, the system achieves more consistent signal quality across the wide bandwidth, reducing variations in transmission performance that would otherwise cause unpredictable latency. This parameter optimization allows wide bandwidth transmissions to maintain both high data rates and predictable latency characteristics.
Data Source
AI summary
Proposed are a method and device for transmitting an EHT PPDU in a wireless LAN system. Specifically, a transmission device generates an EHT PPDU and transmits the EHT PPDU to a receiving device through a 320 MHz RF band. A legacy preamble includes an L-STF and an L-LTF. The legacy preamble is generated by applying a first phase rotation value. The first phase rotation value is determined on the basis of a first technique and a second technique. The first technique acquires an optimal PAPR in the L-STF and the L-LTF. The second technique acquires an optimal PAPR on the basis of the maximum transmission bandwidth supported by the RF. The first phase rotation value is acquired on the basis of a second phase rotation value and a third phase rotation value. The second phase rotation value is obtained by repeating a phase rotation value defined for an 80 MHz band in an 802.11ax system. The third phase rotation value is defined in 80 MHz band units in a 320 MHz band.