Station RTS Synchronization via Triggered OFDMA Access
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Solution Overview
Problem
Existing uplink multiuser data transmission methods in 802.11 specifications face issues such as 'triggering without response,' interference diffusion due to parallel access by geographically dispersed stations, and synchronization problems, leading to reduced access efficiency.
Innovation Solution
A station (STA) in a basic service set (BSS) initiates a multiuser parallel access scheme by sending a request to send (RTS) frame after obtaining channel resources, where surrounding STAs with buffer data and sufficient signal strength within the same BSS can access the channel, reducing interference and improving synchronization through orthogonal frequency division multiple access (OFDMA) or uplink multi-user multiple-input multiple-output (UL MU-MIMO) technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all STAs perform independent channel listening and backoff to contend for access, then channel access flexibility is improved, but RTS sending synchronization deteriorates causing mutual interference
Solution Approach 1:
The patent segments the uplink transmission opportunities by dividing the channel into multiple sub-channels and assigning them to different STAs through AP scheduling. This segmentation allows multiple STAs to transmit simultaneously on different sub-channels without interfering with each other, thus maintaining synchronization while preserving access flexibility.
Solution Approach 2:
The AP performs preliminary scheduling by sending trigger frames to STAs before the actual uplink transmission. This preliminary action includes allocating specific sub-channels to specific STAs based on their buffer status and channel conditions, ensuring that RTS sending is synchronized and interference is avoided before it occurs.
2Productivity
If AP triggers multiple users before knowing which users have uplink data, then scheduling efficiency is improved, but triggering without response problems occur
Solution Approach 1:
The patent implements a feedback mechanism where STAs send buffer status reports to the AP before the triggering phase. The AP uses this feedback information to identify which STAs actually have uplink data, and only triggers those specific STAs. This ensures that triggering responses are reliably received while maintaining high scheduling efficiency.
3Productivity
If multiple STAs distributed broadly perform parallel access, then channel utilization is improved, but interference diffusion increases
Solution Approach 1:
The patent applies local quality by making the triggering and transmission conditions location-dependent. The AP considers the geographic distribution of STAs and their channel conditions when allocating sub-channels. STAs that are geographically close or have similar channel characteristics are assigned to different sub-channels, ensuring that parallel access occurs only when it will not cause harmful interference, thus controlling interference diffusion while maintaining channel utilization.
Data Source
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AI summary
Embodiments of the present invention provide an access point AP, a station STA, a communications system, and a data transmission method. The data transmission method includes: sending, by a master station obtaining at least one channel by means of contention, a request to send to an access point in a same basic service set as the master station, where the basic service set includes the access point and multiple stations, and the master station is a station that is the first to obtain a channel by means of contention in the multiple stations; instructing a surrounding station to determine, according to conditions, whether to follow the master station to send a request to send, where a station following the master station to send a request to send satisfies conditions as follows: the station has buffer data to be transmitted; the station is in the same basic service set BSS as the master station; and a power of a signal received from the master station is greater than a preset threshold; and receiving response information sent by the AP, to transmit uplink data on a specified sub-channel. The data transmission method of the present invention can avoid triggering without response and reduce an interference range.