HE-PPDU Preamble Structure for WLAN Throughput
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The next-generation wireless LAN system, IEEE 802.11ax, requires efficient methods for configuring signal frames and training fields, particularly with the introduction of increased FFT sizes and OFDMA transmission, to enhance throughput and robustness in outdoor environments and dense user scenarios.
Innovation Solution
A station device in the WLAN system generates a high-efficiency physical protocol data unit (PPDU) with a physical preamble that includes a legacy preamble and a high-efficiency preamble, where the legacy preamble is extended with a repeated L-SIG field and the HE preamble includes repeated HE-SIG-A and HE-SIG-B fields, allowing for faster signal identification and improved data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the FFT size is increased and OFDMA transmission is introduced to enhance throughput and robustness, then system performance in outdoor environments and dense user scenarios is improved, but the complexity of signal frame configuration and processing increases
Solution Approach 1:
The signal frame is segmented into distinct fields including legacy preamble fields (L-STF, L-LTF, L-SIG) and HE-specific fields (HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF). This segmentation allows legacy receivers to process only the legacy portion while HE receivers can access both legacy and HE-specific information, thereby managing complexity through modular frame结构设计
Solution Approach 2:
The patent introduces a new dimension to the signal frame by adding HE-specific fields alongside the legacy preamble structure. This dimensional extension enables OFDMA and increased FFT sizes without disrupting existing legacy frame processing, allowing new functionality to coexist with legacy systems
2Speed
If new HE preamble fields are added for faster signal identification, then signal processing speed is improved, but the frame structure becomes more complex
Solution Approach 1:
The HE-SIG-A field is positioned immediately after the legacy L-SIG field in the preamble, allowing receivers to identify HE signal characteristics early in the processing sequence. This preliminary placement of identification information enables faster signal classification before full frame processing begins
Solution Approach 2:
The legacy L-SIG field serves dual purposes: it provides information for legacy receivers while also serving as a foundation for HE signal identification. The HE-SIG-A field extends this universality by carrying both compatibility information and new HE-specific parameters, reducing the need for separate identification mechanisms
3Adaptability or versatility
If the L-SIG field is repeated for legacy receiver compatibility, then backward compatibility is improved, but the frame length and transmission time increase
Solution Approach 1:
The L-SIG field is copied and repeated within the HE preamble structure to ensure legacy receivers can correctly interpret the signal. This copying mechanism allows legacy devices to process the repeated L-SIG information while HE receivers utilize the original L-SIG followed by HE-specific fields, achieving compatibility without requiring entirely new frame structures
Solution Approach 2:
Rather than repeating the entire frame structure, only the critical L-SIG field is repeated within the preamble portion. This partial repetition provides sufficient compatibility information for legacy receivers without duplicating the entire data payload, thereby minimizing the increase in frame transmission time while maintaining backward compatibility
Data Source
AI summary
Disclosed herein is a station (STA) device of a wireless LAN (WLAN) system. The STA device includes a radio frequency (RF) unit transmitting and receiving a radio signal; and a processor controlling the RF unit. The processor may generate a high efficiency (HE) physical protocol data unit (PPDU) including a physical preamble and a data field and transmit the PPDU using the RF unit.