WLAN Station OBSS Frame Detection and Virtual Carrier Sensing
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Solution Overview
Problem
In wireless local area networks (WLANs), especially in overlapping basic service set (OBSS) environments, communication entities often lose transmission opportunities due to frames transmitted by other entities, leading to inefficient channel utilization and reduced throughput.
Innovation Solution
A method and apparatus for a WLAN station to determine whether a received frame is from its own basic service set (BSS) or an overlapping BSS (OBSS) based on signal strength and information within the frame's preamble, adjusting virtual carrier sensing and transmission opportunities accordingly to optimize channel usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a station performs virtual carrier sensing using information from all received frames, then channel access reliability is improved, but transmission opportunities are lost due to OBSS frames
Solution Approach 1:
The patent applies local quality by differentiating the treatment of received frames based on their BSS origin. Frames from the same BSS (MY_BSS) trigger virtual carrier sensing, while frames from overlapping BSS (OBSS) do not. This selective approach allows the station to maintain reliable channel access for its own BSS while seizing transmission opportunities in OBSS environments, resolving the contradiction between reliability and productivity.
2Measurement precision
If a station uses a low CCA threshold to detect OBSS frames, then channel sensing accuracy is improved, but transmission opportunities are reduced
Solution Approach 1:
The patent implements local quality by setting different CCA thresholds based on the BSS origin of received frames. A first (higher) threshold is used for OBSS frames to allow transmission opportunities, while a second (lower) threshold is used for MY_BSS frames to ensure accurate channel sensing. This resolves the contradiction between measurement precision and productivity by applying appropriate sensitivity levels to different frame sources.
3Reliability
If a station sets virtual carrier sensing for all received frames, then collision avoidance is improved, but channel utilization is reduced
Solution Approach 1:
The patent applies local quality by selectively setting virtual carrier sensing based on BSS identification. Virtual carrier sensing is activated only for frames from the same BSS (MY_BSS), while frames from OBSS are ignored for virtual carrier sensing purposes. This allows the station to avoid collisions within its own BSS while maximizing channel utilization in OBSS environments, resolving the contradiction between collision avoidance and channel utilization.
Data Source
AI summary
Disclosed are methods and apparatuses for transmitting and receiving a frame in a WLAN. A method for transmitting a frame, performed in a first station, may comprise receiving a first PPDU; determining whether a BSS of the first PPDU is a BSS to which the first station belongs or a BSS to which the first station does not belong; when the BSS of the first PPDU is the BSS to which the first station does not belong and a received signal strength of the first PPDU is higher than a first threshold, setting a virtual carrier sensing by using information included in a preamble of the first PPDU. Therefore, performance of the WLAN can be enhanced.