Trigger-Based Uplink Resource Unit Adaptation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication protocols in WLANs, such as IEEE 802.11ax, face inefficiencies in trigger-based multi-user uplink transmissions due to the lack of clear channel assessment (CCA) status awareness by access points, leading to degraded spectrum usage when subchannels are busy, preventing stations from transmitting even if one subchannel is occupied.
Innovation Solution
Implementing schemes that allow stations to transmit using downsized resource units or aggregate resource units based on CCA status reports, enabling medium access control layer and physical layer adaptations like subcarrier puncturing and power control, along with explicit signaling or auto-detection methods to optimize resource allocation and usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a STA performs CCA per-20MHz subchannel before responding to a trigger frame, then channel access reliability is improved, but spectrum usage efficiency deteriorates when subchannels are busy
Solution Approach 1:
The patent segments the 996-tone RU into multiple 20MHz subchannels and allows the STA to perform CCA independently on each subchannel. When only some subchannels are busy, the STA can still transmit on the clear subchannels using downsized RUs, rather than abandoning the entire transmission. This segmentation enables partial transmission and improves spectrum efficiency while maintaining reliable channel access assessment.
Solution Approach 2:
The patent changes the RU size parameter dynamically based on CCA results. When some subchannels are busy, the STA adjusts the RU allocation from the full 996-tone RU to smaller downsized RUs that fit only the clear subchannels. This parameter adaptation allows the system to maintain reliable channel assessment while improving spectrum utilization by transmitting on available frequencies.
2Speed
If a STA transmits using the full assigned RU, then data transmission rate is improved, but transmission reliability deteriorates when CCA indicates busy subchannels
Solution Approach 1:
The patent introduces dynamic RU allocation where the STA can adjust its transmission bandwidth based on real-time CCA conditions. Instead of using a fixed full-bandwidth RU, the system dynamically determines the appropriate RU size after channel assessment, allowing the STA to transmit at the highest possible rate on clear subchannels while avoiding busy ones, thus balancing speed and reliability.
3Productivity
If the AP allocates a large RU to a STA, then resource allocation efficiency is improved, but flexibility deteriorates when subchannel CCA status varies
Solution Approach 1:
The patent segments the large allocated RU into multiple 20MHz subchannels that can be independently assessed and transmitted upon. This segmentation allows the system to maintain efficient resource allocation by assigning large RUs while simultaneously gaining the flexibility to adapt to varying CCA conditions by selectively transmitting on clear subchannels using downsized RUs.
Solution Approach 2:
The patent enables parameter changes in RU allocation by allowing the STA to modify the effective RU size based on CCA results. The AP can allocate large RUs for efficiency, and the STA can adaptively change the transmission parameters to use smaller RUs when some subchannels are busy, thus achieving both efficiency and flexibility.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Various examples pertaining to efficient trigger-based, TB, multi-user, MU, uplink, UL, transmissions in wireless local area networks, WLANs, are described. A station, STA, receives a trigger frame from an access point, AP, with the trigger frame assigning one or more resource units, RUs, (1210) corresponding to one or more subchannels of a plurality of subchannels. The STA then performs a transmission using the assigned one or more RUs responsive to receiving the trigger frame (1220). In an event that at least one subchannel of the plurality of subchannels is detected as being busy, the one or more subchannels may include a subset, e.g., some but not all, of the plurality of subchannels.