Multi-User Sounding Sub-Channel Allocation for WLAN Interference
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Solution Overview
Problem
Existing wireless local area network (WLAN) systems face challenges in efficiently managing peer-to-peer traffic and optimizing channel utilization, particularly in multi-user scenarios where frequency selectivity and interference can impact performance.
Innovation Solution
The implementation of a multi-user sounding procedure that allows multiple stations to simultaneously transmit sounding signals across the entire frequency band or sub-channels, using techniques such as time and frequency domain separation, and interleaved sounding to improve channel estimation and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple stations transmit sounding signals simultaneously across the entire frequency band, then channel estimation accuracy is improved, but interference between signals increases
Solution Approach 1:
The frequency band is divided into multiple sub-channels, and stations transmit sounding signals on different sub-channels simultaneously. This segmentation allows parallel channel sounding while reducing interference between stations by assigning orthogonal frequency resources to each station.
Solution Approach 2:
The patent introduces time-domain separation by transmitting sounding signals at different times for different stations. This adds a time dimension to the channel sounding process, allowing complete channel estimation for each station without mutual interference, thereby resolving the contradiction between simultaneous measurement and interference avoidance.
2Object-generated harmful factors
If traditional sequential channel sounding is used, then interference is minimized, but overhead and time consumption increase
Solution Approach 1:
The frequency band is segmented into sub-channels that can be sounded in parallel. Multiple stations transmit their sounding signals simultaneously on different sub-channels, reducing the total time required for channel sounding while maintaining low interference through orthogonal frequency division.
Solution Approach 2:
The patent combines frequency-domain parallel transmission with time-domain scheduling to enable multiple stations to sound their respective channels simultaneously. This merging of approaches allows significant reduction in sounding time while maintaining interference-free operation through proper resource allocation.
3Loss of information
If the entire frequency band is used for sounding, then channel information completeness is improved, but spectral efficiency during data transmission decreases
Solution Approach 1:
The frequency band is divided into sub-channels for sounding purposes. This segmentation allows the system to obtain complete channel information across the entire band while identifying which specific sub-channels have good channel conditions for data transmission, thereby enabling efficient spectral utilization.
Solution Approach 2:
The patent applies local quality by selecting specific sub-channels for data transmission based on their channel conditions. Instead of using the entire frequency band for all transmissions, the system identifies and utilizes only the sub-channels with favorable channel characteristics, optimizing spectral efficiency while maintaining complete channel awareness.
Data Source
AI summary
A STA may comprise a receiver configured to receive, from an AP, a first polling frame addressed to a broadcast address and sent to a plurality of STAs. The first polling frame may indicate a plurality of sub-channels. The STA may further comprise a transmitter configured to transmit, to the AP, a first PPDU indicating SNR information, on one or more sub-channels of the plurality of sub-channels, a SIFS after the first polling frame is received. The transmitter may be configured to transmit the first PPDU while a second PPDU is transmitted to the AP by another STA of the plurality of STAs, wherein the second PPDU is transmitted on one or more other sub-channels of the plurality of sub-channels.