Low-Latency WLAN Traffic Indication for Collision-Aware Access
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Solution Overview
Problem
Existing WLAN systems face challenges in managing low latency traffic to meet maximum delay and jitter requirements, necessitating improved latency management features.
Innovation Solution
Implementing methods and apparatuses for stations (STAs) to transmit high priority traffic with specific parameters, perform backoff checks, and defer transmissions if collisions occur, along with AP solicitation and reception of high priority traffic indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard WLAN backoff procedure is used for all traffic, then channel access is simple and fair, but low latency traffic cannot meet maximum delay requirements
Solution Approach 1:
The patent applies local quality by differentiating traffic handling based on traffic type. High priority traffic (video, voice, gaming) receives specialized treatment with reduced backoff and collision avoidance mechanisms, while best effort traffic uses standard procedures. This localized differentiation enables low latency guarantees for specific traffic streams without affecting overall system simplicity.
Solution Approach 2:
The patent segments traffic into high priority and best effort categories at the STA level. Each segment is handled according to its specific requirements, with high priority traffic receiving dedicated resources and reduced backoff periods. This segmentation allows independent optimization of latency-sensitive flows while maintaining simplicity for bulk traffic.
2Loss of time
If high priority traffic transmits without backoff, then latency is reduced, but transmission collisions increase
Solution Approach 1:
The patent implements preliminary action by having high priority STAs perform a simplified backoff procedure before transmission. Instead of complete random backoff, high priority STAs use a reduced backoff mechanism that still provides collision avoidance but with shorter duration. This preliminary action reduces overall transmission delay while maintaining sufficient collision prevention through the simplified backoff check.
Solution Approach 2:
The patent applies partial action by implementing a partial backoff mechanism for high priority traffic. Rather than full backoff, high priority STAs perform a limited backoff period followed by immediate transmission opportunity. This partial backoff provides enough collision avoidance for reliability while significantly reducing the time loss compared to standard backoff procedures.
3Reliability
If STA continuously monitors channel for transmissions during backoff, then collision detection is improved, but processing complexity and time consumption increase
Solution Approach 1:
The patent applies partial monitoring by having STAs perform channel sensing only during the simplified backoff period rather than continuous monitoring. The STA monitors the channel during its backoff countdown and immediately upon completion, providing sufficient collision detection for the reduced backoff scenario without the continuous processing overhead of full monitoring.
Solution Approach 2:
The patent changes the monitoring parameter from continuous to intermittent/channel-state-dependent monitoring. During the simplified backoff period, the STA performs monitoring only at specific intervals or when channel state changes, rather than continuous monitoring. This parameter change maintains collision detection accuracy for the reduced backoff duration while significantly lowering processing complexity.
Data Source
AI summary
Methods and apparatuses are disclosed for a station (STA) in a Wireless Local Area Network (WLAN) to indicate its intent to transmit high priority traffic, such as low latency traffic, over a shared wireless medium. Multiple embodiments for the transmission by a STA of a signal referred to as a Low Latency Traffic Indication (LLTI) as well as low latency traffic are disclosed. An Access Point (AP) manages the conditions subject to which STAs may transmit the LLTI and contend for the wireless medium for the purpose of transmitting low latency traffic, and may solicit the LLTI and low latency traffic from the STAs. Multiple embodiments of methods and apparatuses are disclosed.