Trigger-Based PPDU Transmission via CCA on Idle Subbands
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Solution Overview
Problem
In wireless local area networks (WLANs), existing technologies face challenges in efficiently transmitting trigger-based physical protocol data units (PPDUs) due to resource allocation issues and the difficulty in decoding PPDUs when some resources are not idle.
Innovation Solution
The proposed method involves a transmitting device in a WLAN system that receives a trigger frame from an access point (AP), performs clear channel assessment (CCA) on allocated resources, and transmits a trigger-based PPDU on the allocated resource, including information about the CCA result in the physical layer signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trigger-based PPDU is transmitted on resources allocated by an AP, then the transmission follows resource allocation rules, but it becomes difficult to decode the PPDU when some allocated resources are not idle
Solution Approach 1:
The patent extracts and transmits CCA result information separately in the PHY layer signal, allowing the AP to identify which subbands are idle versus busy. This separation enables the AP to decode the PPDU by focusing only on the idle subbands, resolving the contradiction between following resource allocation rules and handling non-idle resources.
Solution Approach 2:
The patent segments the frequency band into multiple subbands and performs CCA assessment on each subband individually. The PPDU can then be transmitted on idle subbands while avoiding busy subbands, allowing partial transmission rather than complete transmission failure. This segmentation resolves the contradiction by enabling flexible resource usage within the allocated resources.
2Reliability
If transmission is performed only when all allocated resources are idle, then decoding reliability is maintained, but transmission efficiency decreases when some resources are busy
Solution Approach 1:
The patent applies partial action by transmitting the PPDU on only the idle subbands rather than requiring all allocated subbands to be idle. The CCA result information in the PHY layer signal enables the AP to decode the partial transmission successfully. This resolves the contradiction by allowing transmission to proceed with reduced scope rather than being completely blocked.
Solution Approach 2:
The patent implements feedback by including CCA result information in the PHY layer signal, providing the AP with real-time information about which subbands are idle. This feedback mechanism enables the AP to adjust its decoding process accordingly, maintaining reliability even when transmission occurs on only a portion of the allocated resources.
3Measurement precision
If CCA is performed on the entire allocated bandwidth, then accurate channel assessment is achieved, but transmission flexibility is reduced when some bands are busy
Solution Approach 1:
The patent segments the bandwidth into multiple subbands for CCA assessment, maintaining accurate channel knowledge for each segment while enabling flexible transmission decisions. The PPDU can be transmitted on idle subbands while avoiding busy subbands, achieving both measurement precision and transmission adaptability simultaneously.
Solution Approach 2:
The patent applies local quality by allowing different transmission decisions for different subbands based on their individual CCA results. Idle subbands are used for transmission while busy subbands are avoided, enabling the system to adapt locally to channel conditions rather than applying a uniform decision across the entire bandwidth.
Data Source
AI summary
In a wireless local area network (WLAN) system, an STA performs CCA on resources allocated thereto via a trigger frame from an AP and can transmit a TB PPDU via an idle channel among the allocated resources on the basis of the result of the CCA, wherein the PHY of the TB PPDU may include information about the result of the CCA.