Dynamic Backoff Window Adjustment for LAA Wi-Fi Coexistence
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Solution Overview
Problem
In the LTE system, the LAA system faces challenges in coexisting fairly with Wi-Fi systems when using unlicensed spectrum resources, as the existing LBT mechanisms lead to a higher probability of channel preemption, resulting in reduced access probability for Wi-Fi systems and unfair coexistence.
Innovation Solution
A backoff window adjustment method is introduced, where the LAA system and Wi-Fi system adjust their respective backoff windows based on feedback information, such as response and collision data, to ensure fair contention for channel resources, considering the differences in protocol architecture, interference immunity, and scheduling mechanisms between the two systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LAA system uses a fixed backoff window value as specified by regulations, then the system meets the regulatory requirements for unlicensed spectrum access, but the system experiences higher channel preemption probability and reduced fair coexistence with Wi-Fi systems
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed backoff window value to a dynamically adjustable backoff window. The base station determines the backoff window size based on channel occupancy time and collision detection results, allowing the LAA system to adapt its channel access behavior to actual channel conditions while maintaining regulatory compliance and improving fair coexistence with Wi-Fi systems.
2Productivity
If the LAA system uses a larger backoff window to reduce channel collisions, then the fair coexistence with Wi-Fi is improved, but the channel access efficiency and network capacity are reduced
Solution Approach 1:
The patent implements dynamic adjustment of the backoff window size based on real-time channel conditions. When channel occupancy time is high or collisions are detected, the backoff window is increased to improve fair coexistence with Wi-Fi. When channel conditions are good, the backoff window is reduced to maintain high channel access efficiency, thus avoiding the trade-off between fairness and efficiency.
Solution Approach 2:
The patent changes the backoff window parameter dynamically based on channel occupancy time and collision detection results. This parameter adjustment allows the system to optimize channel access probability and fair coexistence with Wi-Fi while maintaining efficient resource utilization, resolving the contradiction between increasing backoff window for fairness and maintaining access efficiency.
3Productivity
If the LAA system increases channel access probability to improve network capacity, then the operator's demand for communication speed is met, but the channel preemption increases and reduces Wi-Fi system access probability
Solution Approach 1:
The patent implements a feedback mechanism where the base station detects channel occupancy time and collision events, then adjusts the backoff window size accordingly. This feedback loop allows the LAA system to increase channel access probability and network capacity when appropriate, while automatically reducing preemption behavior when Wi-Fi systems are affected, thus resolving the contradiction between network capacity and fair coexistence.
Data Source
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AI summary
Embodiments of the present invention provide a backoff window adjustment method, and an apparatus. In downlink transmission, a base station obtains a trigger condition for adjusting a length of a backoff window on a first channel, and adjusts the length of the backoff window of the base station on the first channel according to the obtained trigger condition for adjusting the length of the backoff window on the first channel. In uplink transmission, UE obtains a trigger condition for adjusting a length of a backoff window on a first channel, and adjusts the length of the backoff window of the UE on the first channel according to the obtained trigger condition for adjusting the length of the backoff window on the first channel. When an LAA system and a WIFI system coexist, the LAA system and the WIFI system both adjust respective backoff windows, so that the WIFI system and LAA system can fairly contend for a channel resource after channel collision.