Backoff Timer Logic for Wireless Collision Avoidance
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Solution Overview
Problem
In wireless communication systems, particularly those adhering to the IEEE 802.11 standard, there is a need for improved collision avoidance protocols to prevent collisions during Awake Windows in Peer Power Save Mode, where multiple stations may attempt to transmit frames simultaneously, leading to inefficiencies and potential penalties for stations.
Innovation Solution
The implementation of an enhanced distributed channel access function that includes a backoff timer and procedure, where the system determines the start of an Awake Window and invokes a backoff procedure only if the backoff timer has been zero for at least one backoff slot, ensuring that transmissions are delayed until a safe time, thereby avoiding collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stations transmit frames at the start of Awake Window, then data transmission efficiency is improved, but collision risk increases
Solution Approach 1:
The patent applies preliminary action by implementing a backoff procedure that checks the backoff timer value before allowing transmission at the start of the Awake Window. The system performs a preliminary check to determine if the backoff timer has been zero for at least one backoff slot, and only then permits frame transmission. This preliminary verification prevents collisions by ensuring the channel is clear before stations attempt to transmit, thus resolving the contradiction between maintaining high transmission efficiency and avoiding collisions.
2Reliability
If backoff procedure is always invoked at Awake Window start, then collision avoidance is improved, but transmission delay increases
Solution Approach 1:
The patent applies parameter changes by making the backoff procedure conditional rather than mandatory. The system changes the parameter of backoff invocation from a fixed rule to a conditional check based on the backoff timer value. Specifically, the backoff procedure is only invoked when the backoff timer has been zero for at least one backoff slot, otherwise transmission proceeds immediately. This dynamic parameter adjustment resolves the contradiction by avoiding unnecessary delays while maintaining collision avoidance when needed.
Data Source
AI summary
A method and apparatus for avoiding collisions is provided. The method may include determining a start of an awake window, determining whether at the start of the awake window a backoff timer has had a zero value for at least one backoff slot. Additionally, the method may include invoking a backoff procedure upon a determination that the backoff timer has had a zero value for at least one backoff slot.