Multi-Link Channel Access with Adaptive Backoff Under Self-Interference
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Solution Overview
Problem
Multi-link devices experience self-interference and cannot perform simultaneous transmit and receive (STR) on multiple links, leading to inefficient channel contention when one link is busy, limiting transmission to a single link.
Innovation Solution
The multi-link device performs channel contention again on a link after backing off to 0 without transmission, adjusting the contention window value to balance backoff time and collision probability by keeping it unchanged or setting it to the minimum value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-link device performs parallel communication on multiple links to increase transmission rate, then transmission rate is improved, but self-interference occurs between links causing channel access inefficiency
Solution Approach 1:
The patent segments the channel access process into independent per-link operations. Each link maintains its own backoff counter and contention window, allowing links to be managed independently. When one link's backoff counter reaches 0, the device can immediately transmit on that link without waiting for other links, thus resolving the self-interference issue while maintaining high transmission rates through parallel communication.
Solution Approach 2:
The patent implements dynamic channel access where the backoff counter is decremented independently for each link based on its own channel conditions. The contention window size is dynamically adjusted per link based on transmission success or failure. This dynamic approach allows the device to adapt to changing channel conditions on each link independently, eliminating the need to wait for all links to complete channel contention before transmitting.
2Reliability
If the device waits for channel contention on another link after backoff counter becomes 0 on one link, then interference between links is eliminated, but channel access efficiency deteriorates
Solution Approach 1:
The patent applies preliminary action by having each link independently complete its channel contention and backoff process before transmission. The backoff counter for each link is decremented in advance based on channel conditions, and when it reaches 0, the link is ready for immediate transmission without requiring other links to also complete their contention. This preliminary independent preparation eliminates the need to wait for other links while maintaining reliable interference avoidance.
3Productivity
If the device performs channel contention again on a link after backoff counter becomes 0 without transmission, then channel access efficiency is improved, but contention collision probability increases
Solution Approach 1:
The patent changes the parameter of contention window size dynamically. When a link's backoff counter reaches 0 but transmission is delayed, the device can perform channel contention again with an adjusted contention window. The contention window size is modified based on the current channel conditions and transmission history, allowing the device to balance between accessing the channel efficiently and minimizing collision probability through adaptive parameter adjustment.
Data Source
AI summary
Example channel access methods and apparatus are described. One example method includes performing first channel contention by a multi-link device on a first link, where an initial value of a backoff counter in the first channel contention is determined based on a first value of a contention window. The multi-link device may perform second channel contention on the first link when a value of the backoff counter becomes 0 in the first channel contention and when the multi-link device does not perform transmission on the first link. An initial value of the backoff counter in the second channel contention is determined based on a second value of the contention window, and the second value is equal to the first value or a minimum value of the contention window.