Access Point Channel Opportunity Allocation for WLAN Synchronization
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Solution Overview
Problem
In wireless local area networks (WLANs) compliant with the orthogonal frequency division multiplexing (OFDM) standard, existing mechanisms for data transmission between stations (STAs) and access points (APs) face challenges in synchronizing the use of different subcarriers for concurrent data transmission, leading to inefficient channel resource usage due to varying wireless channel environments among STAs.
Innovation Solution
An access point sends channel opportunity information, allowing stations to randomly select and concurrently send data using allocated subchannel resources, with the AP allocating channel resources based on received sending request messages and sending acknowledgement messages to ensure synchronized data transmission across multiple subcarriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple STAs simultaneously detect channel idle time and randomly select subchannels to send RTS, then channel resource usage is improved, but synchronization of subcarrier usage cannot be met due to varying wireless channel environments
Solution Approach 1:
The AP performs preliminary actions by sending channel opportunity information and subcarrier allocation information to multiple STAs before they transmit data. This preliminary notification allows STAs to synchronize their subcarrier usage in advance, resolving the synchronization problem while maintaining high channel resource usage through the initial contention-based selection of subchannels.
2Productivity
If multiple STAs concurrently send data on different subchannels after RTS/CTS mechanism, then channel resource usage is improved, but the mechanism complexity increases
Solution Approach 1:
The patent combines the channel request function and subcarrier selection function into a single RTS frame transmission process. Multiple STAs simultaneously send RTS frames that include both channel access requests and subcarrier selection information, merging multiple functions into one mechanism and reducing overall system complexity while improving channel resource usage.
Solution Approach 2:
The AP acts as an intermediary that receives RTS frames from multiple STAs, processes subcarrier allocation information, and sends back CTS frames with confirmed subcarrier assignments. This intermediary mechanism simplifies the coordination process compared to direct STA-to-STA synchronization, reducing mechanism complexity while enabling efficient multi-user concurrent transmission.
Data Source
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AI summary
Embodiments of the present invention provide a data transmission method and apparatus. The method includes: sending, by an access point, channel opportunity information, so that stations that have data to be sent randomly select, after receiving the channel opportunity information, a channel opportunity from the channel opportunity information, and concurrently send a sending request message to the access point; allocating, by the access point according to the received sending request message, to a station that sends the received sending request message, a channel resource that is used for sending uplink data; and sending, by the access point according to the allocated channel resource, a sending acknowledgement message to the station that sends the received sending request message, so that stations that receive the sending acknowledgement message use channel resources to concurrently send uplink data. Therefore, a synchronization requirement that multiple stations use different subcarriers to concurrently send data can be well met.