WLAN Link Adaptation via Preamble MU-BAR Feedback
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Solution Overview
Problem
Current WLAN link adaptation methods are inadequate for ultra-high reliability (UHR) wireless communications, particularly in environments with interference from devices like Bluetooth, cellular, and Ultra-wideband, as they fail to provide sufficient feedback for accurate transmission parameter adjustment, leading to suboptimal communication quality.
Innovation Solution
The implementation of a fast feedback system that includes a feedback sequence number (FBSN) and feedback data within the preamble of a physical layer protocol data unit (PPDU), allowing receiving devices to provide immediate feedback on link adaptation parameters, such as modulation and coding scheme (MCS) and number of spatial streams (NSS), to the transmitting device for adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current WLAN link adaptation methods are used, then device complexity is reduced, but reliability deteriorates due to insufficient feedback for accurate transmission parameter adjustment
Solution Approach 1:
The patent applies preliminary action by embedding the MU-BAR frame in the preamble of the MU-PPDU before data transmission. This allows receiving devices to be pre-informed about the requirement to provide feedback, enabling them to prepare and send accurate link adaptation feedback (including MCS and NSS recommendations) without requiring complex post-transmission negotiation, thus improving reliability while maintaining simplicity.
Solution Approach 2:
The patent implements a structured feedback mechanism where receiving devices send block acknowledgments containing link adaptation feedback in response to the embedded MU-BAR frame. This feedback includes specific parameters like MCS (modulation and coding scheme) and NSS (number of spatial streams) recommendations, enabling the transmitting device to adjust transmission parameters accurately, thereby improving communication reliability in interference-prone environments.
2Adaptability or versatility
If immediate feedback is implemented, then adaptability is improved, but loss of time is reduced due to faster parameter adjustment
Solution Approach 1:
The patent merges the block acknowledgment frame with link adaptation feedback by embedding the MU-BAR frame in the preamble. This combination allows receiving devices to send both acknowledgment and link adaptation feedback (MCS, NSS parameters) in a single transmission opportunity, improving adaptability while minimizing the time loss associated with separate feedback exchanges.
Solution Approach 2:
By embedding the MU-BAR frame in the preamble before data transmission, the patent enables receiving devices to prepare their feedback responses in advance. This preliminary action reduces the processing time required after data reception, allowing immediate feedback transmission and thus reducing overall loss of time while enhancing link adaptation capability.
3Measurement precision
If feedback data is included in the preamble, then measurement precision is improved, but device complexity increases due to preamble structure modifications
Solution Approach 1:
The patent segments the feedback information by placing the MU-BAR frame with link adaptation measurement data in a dedicated location within the preamble structure. This segmentation allows receiving devices to extract and process feedback parameters (MCS, NSS recommendations) independently from other preamble fields, improving measurement precision while managing device complexity through structured, modular processing.
Data Source
AI summary
Some aspects of this disclosure include an apparatus, method, and computer program product for wireless local area network (WLAN) link adaptation for multi-user transmission. For example, a receiving device can receive a multi-user-physical layer (PHY) protocol data unit (MU-PPDU) including a preamble and a plurality of data portions. The preamble can include a PHY multi-user-block acknowledgement request (MU-BAR) frame indicating a frequency band for transmitting a trigger-based (TB)-PPDU. The receiving device can decode at least a portion of a first data portion of the and transmit the TB-PPDU including feedback (FB) data corresponding to the first data portion in the frequency band. Even if the decoding of the first data portion fails, the receiving device can use information in the PHY MU-BAR frame to transmit a TB-PPDU to the transmitting device that includes a negative acknowledgment (NACK) frame and a FB sequence number of the MU-PPDU.