Coordinated Spatial Reuse TXOP Segmentation for WLAN
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in channel usage due to high collision probabilities and unpredictable channel access in high-load scenarios, particularly in unlicensed bands, which affects the performance of wireless local area networks (WLANs) and Quality of Service (QoS) applications.
Innovation Solution
Implementing coordinated spatial reuse (CSR) of TXOPs (Transmit Opportunity) between access points (APs) to share radio resources for multiple PPDUs (Physical Protocol Data Units) while coordinating acknowledgment information transmissions to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple APs share a TXOP using coordinated spatial reuse, then channel utilization and throughput are improved, but interference between data transmissions and acknowledgment transmissions occurs
Solution Approach 1:
The patent segments the shared TXOP into multiple sub-TXOPs, where each sub-TXOP is dedicated to a specific AP for transmitting either data or acknowledgments. This segmentation prevents interference by ensuring that data transmissions and acknowledgment transmissions occur in separate time intervals within the shared TXOP, thus resolving the contradiction between improving channel utilization and maintaining transmission reliability.
2Productivity
If multiple APs transmit multiple PPDUs simultaneously in a shared TXOP, then spatial reuse is enhanced, but collision probability increases
Solution Approach 1:
The patent divides the shared TXOP into multiple sub-TXOPs with different spatial reuse configurations. Some sub-TXOPs allow simultaneous transmissions from multiple APs to different STAs, while other sub-TXOPs are dedicated to acknowledgment transmissions. This segmented approach enables spatial reuse to be enhanced in data transmission phases while preventing collisions during acknowledgment phases, thus resolving the contradiction between spatial reuse and collision probability.
3Reliability
If acknowledgment transmissions are coordinated across multiple APs, then interference is reduced, but system complexity increases
Solution Approach 1:
The patent implements preliminary action by having the coordinating AP allocate specific sub-TXOPs for acknowledgment transmissions to other APs before the actual data transmissions begin. This advance allocation of acknowledgment resources simplifies the coordination process by establishing a predetermined schedule, reducing the complexity of real-time coordination while ensuring interference reduction through proper timing separation.
4Stability of the object's composition
If a single AP reserves a long TXOP, then channel access predictability is improved, but spatial reuse opportunities are reduced
Solution Approach 1:
The patent segments the long reserved TXOP into multiple sub-TXOPs that can be shared with other APs through coordinated spatial reuse. The coordinating AP maintains control over the overall TXOP structure and timing, ensuring channel access predictability, while simultaneously enabling other APs to transmit data in designated sub-TXOPs, thus creating spatial reuse opportunities without sacrificing the stability and predictability of the channel access framework.
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
An access point (10) of a wireless communication system contends for access to a medium. In response to gaining access to the medium, the access point (10) reserves a transmission opportunity, TXOP, on the medium. The access point (10) cooperates with one or more further access points (10) of the wireless communication system by sharing the TXOP based on spatial reuse of at least some radio resources of the TXOP for transmission of multiple physical protocol data units, PPDUs, by each of the access points (10). Further, the access point (10) coordinates transmissions of acknowledgment information for each of the multiple PPDUs within the TXOP.