AP Trigger-Frame Control for MU-to-SU WLAN Channel Access
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Solution Overview
Problem
In wireless LAN systems, switching from multi-user (MU) mode to single-user (SU) mode can lead to inefficient utilization of transmission paths and increased collision probability due to the resetting of contention window (CW) and back-off (BO) parameters, resulting in prolonged waiting periods and disrupted continuous communication.
Innovation Solution
The technology involves controlling channel access operations by an access point (AP) to set and manage access control parameters such as CW and BO for each station (STA) through trigger frames, ensuring optimal parameter settings based on priority, status, and interference considerations, thereby avoiding collisions and reducing waiting times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CW and BO parameters are reset when switching from MU mode to SU mode, then collision avoidance is simplified, but transmission path utilization efficiency deteriorates and waiting periods are prolonged
Solution Approach 1:
The patent applies dynamics by making the CW and BO parameters adjustable based on communication mode. The access point dynamically sets different parameter values for MU mode versus SU mode, allowing the system to adapt to changing communication conditions rather than using fixed reset behavior. This resolves the contradiction by optimizing parameters for each specific mode while maintaining collision avoidance capabilities.
Solution Approach 2:
The patent directly applies parameter changes by modifying CW and BO values based on the communication mode. When switching from MU to SU mode, instead of resetting parameters to default values, the system changes them to optimized values suitable for SU operation. This maintains transmission efficiency while still providing collision avoidance through controlled parameter adjustment.
2Ease of operation
If CW and BO parameters are reset when switching from MU mode to SU mode, then channel access control is simplified, but continuous communication is disrupted and waiting times increase
Solution Approach 1:
The system dynamically adjusts parameter reset behavior based on communication mode transitions. Rather than always resetting parameters when switching modes, the access point intelligently determines whether to maintain or reset parameters based on the specific transition context, reducing unnecessary waiting periods while maintaining operational simplicity through centralized control.
Solution Approach 2:
The access point performs preliminary parameter configuration before mode switching occurs. By pre-setting appropriate CW and BO values for the target mode, the system avoids the need for lengthy reset and reconfiguration periods, thereby reducing waiting time while maintaining simple channel access control through centralized management.
3Productivity
If optimized parameter settings are maintained for each STA, then transmission path utilization improves, but parameter management complexity increases
Solution Approach 1:
The patent merges parameter management functions into the access point, which centrally controls and configures CW and BO parameters for all subordinate stations. This consolidation allows each STA to use optimized parameters without individually managing them, achieving high transmission path utilization while keeping overall system complexity manageable through centralized control.
Solution Approach 2:
The access point automatically performs parameter optimization and configuration for each STA based on observed communication patterns and mode transitions. This self-service approach allows optimized parameter settings to be maintained for each station without requiring complex manual configuration or intervention, balancing productivity improvement with manageable system complexity.
Data Source
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AI summary
To provide a communication apparatus which controls channel access operation under a multi user environment, and a communication method. Channel access operation of each STA after an MU mode is finished is controlled through a trigger frame from an AP to prevent collision immediately after the MU mode is finished. Further, the AP sets a smaller CW upon transmission of the trigger frame than a CW of an STA to preferentially transmit the trigger frame and give priority to communication in the MU mode over communication in an SU mode. Further, by the CW of each STA upon switching of the mode being not reset, a transmission waiting period after the MU mode is finished is shortened.