WLAN AP Slot-Based Channel Access for Low-Collision PIFS Traffic
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Solution Overview
Problem
Contention and collisions in channel access processes of wireless local area networks (WLANs) affect the quality of service for latency-sensitive traffic, such as real-time online gaming and industrial wireless applications, due to the IEEE 802.11 research group's defined latency requirements of 1 ms to 100 ms.
Innovation Solution
A channel access method that allocates different slots to multiple access points (APs) using priority interframe space (PIFS) and provides indication information for accurate contention access, including slot intervals, durations, and start moments, ensuring time synchronization and collision avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a device listens to a channel for a long period before transmitting, then collision probability is reduced, but channel access delay increases
Solution Approach 1:
The device dynamically adjusts the listening period duration based on channel conditions and traffic requirements. Instead of using a fixed listening period, the system can adaptively select from multiple contention window sizes or adjust the backoff counter range, allowing optimization between collision probability and access delay based on current network conditions.
Solution Approach 2:
The invention changes the parameter of listening period duration by introducing variable contention window sizes and adjustable backoff counter ranges. By modifying these parameters dynamically, the system can reduce collision probability when needed while maintaining acceptable channel access delay, resolving the contradiction between reliability and time loss.
2Loss of time
If a device transmits data immediately after sensing the channel, then channel access delay is reduced, but collision probability increases
Solution Approach 1:
The system dynamically adjusts the backoff period based on channel occupancy detection results. When the channel is detected to be occupied for an extended period, the device extends its backoff period before transmitting, reducing collision probability while still allowing relatively quick access when the channel is free.
Solution Approach 2:
The invention changes the transmission timing parameter by introducing variable backoff periods based on detected channel occupancy duration. This parameter adjustment allows the device to transmit sooner when the channel is briefly occupied (reducing delay) while extending the backoff when occupancy is prolonged (reducing collision probability).
3Reliability
If the listening period is extended to detect channel occupancy, then collision probability is reduced, but power consumption increases
Solution Approach 1:
The invention changes the listening period duration parameter based on detected channel conditions. Instead of continuously listening for fixed periods, the device adjusts the listening duration according to traffic patterns and channel occupancy, reducing power consumption while maintaining collision avoidance effectiveness.
Solution Approach 2:
The system dynamically adjusts listening behavior based on channel conditions and traffic requirements. When traffic is light or channel is consistently free, the listening period is shortened to save power. When congestion is detected, listening periods are extended to reduce collisions, optimizing the balance between reliability and energy consumption.
Data Source
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AI summary
Embodiments of this application disclose a channel access method and apparatus. The method includes: A first device determines a first frame, where the first frame includes first indication information, the first indication information indicates a first AP in at least one access point AP to perform contention access for a first traffic in a first slot, and the first traffic includes a traffic for which channel access is performed by using a priority interframe space PIFS; and the first device sends the first frame to the first AP. According to embodiments of this application, contention and a collision with another AP in a channel access process are avoided, to improve quality of service of a traffic.