HE-STF Sequence Design for Multi-Band Wireless LAN
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Solution Overview
Problem
Next-generation wireless LAN systems face challenges in improving spectrum efficiency and area throughput, especially in dense environments with multiple access points and stations, and in outdoor settings, where existing solutions struggle to enhance performance amidst interference and high user loads.
Innovation Solution
The proposed method involves generating a sequence for a short training field (STF) that can be used across multiple bands, optimizing the HE-STF sequence to support diverse frequency bandwidths by repeating a binary M sequence, and applying coefficients to optimize Peak to Average Power Ratio (PAPR), allowing for efficient communication in both uplink and downlink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed STF sequence is used for 20 MHz bandwidth, then the sequence design is simple, but it cannot be directly applied to 40 MHz and 80 MHz bands requiring separate sequence designs
Solution Approach 1:
The patent creates a universal STF sequence generation method that works across 20 MHz, 40 MHz, and 80 MHz bands by using band selection fields and configurable repetition patterns. A single base sequence can be adapted to different bandwidths through controlled repetition and phase rotation, eliminating the need for separate sequence designs for each band.
Solution Approach 2:
The patent segments the STF sequence into repeating units that can be independently controlled. By dividing the sequence into configurable segments with specific repetition factors and phase rotation patterns, the system can adapt the same base sequence to different bandwidth requirements through systematic segmentation and recombination.
2Reliability
If conventional STF sequences are used, then implementation is straightforward, but PAPR remains high causing signal distortion and reduced transmission efficiency
Solution Approach 1:
The patent systematically changes key parameters of the STF sequence including repetition factors, phase rotation angles, and time-domain positioning. By optimizing these parameters, the invention reduces PAPR while maintaining sequence effectiveness for training and synchronization, thereby improving transmission reliability and reducing power loss.
Solution Approach 2:
The patent introduces dynamic elements to the STF sequence design through configurable repetition patterns and phase rotations that can be adjusted based on channel conditions and bandwidth requirements. This dynamic approach allows the sequence to adapt to different transmission scenarios, optimizing performance and reducing PAPR compared to static conventional sequences.
3Measurement precision
If separate STF sequences are designed for each frequency band (20 MHz, 40 MHz, 80 MHz), then each sequence can be optimized for its specific band, but the overall system complexity increases
Solution Approach 1:
The patent establishes a universal sequence generation framework that produces band-appropriate STF sequences through a single standardized process. By using band selection fields and configurable repetition patterns, the same base sequence can be adapted to 20 MHz, 40 MHz, or 80 MHz bands, maintaining channel estimation accuracy while eliminating the need to manage separate sequence designs for each band.
4Productivity
If existing STF sequences are used in dense environments with multiple APs and STAs, then implementation is simple, but spectrum efficiency and area throughput cannot be improved
Solution Approach 1:
The patent employs periodic repetition patterns in the STF sequence design, where base sequences are repeated at configurable intervals with controlled phase rotations. This periodic structure improves spectral efficiency by enabling better signal detection and channel estimation in dense environments, while the systematic nature of the repetition patterns keeps the generation process manageable.
Data Source
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AI summary
Disclosed are a method and receiving apparatus in a wireless LAN system for receiving, by the receiving apparatus, a short training field, STF, signal for a 80+80MHz band from a transmitting apparatus, wherein the STF signal for the 80+80MHz band is included in a physical protocol data unit, PPDU, wherein the STF signal for the 80+80MHz band is generated based on a first sequence, wherein the first sequence is defined as [HES HES1], wherein HES is a STF sequence for lower 80MHz band and defined as {M, 1, -M, 0, -M, 1, - M}*(1+j)/sqrt(2), wherein HES1 is a STF sequence for upper 80MHz band and defined as {-M, -1, M, 0, -M, 1, -M} *(1l+j)*sqrt(1/2), wherein the sqrt() represents square root, and wherein M is a preset sequence having 15 elements and is defined as {-1, -1, -1, 1, 1, 1, -1, 1, 1,1,-1,1,1,-1,1}.