Contention Window Adjustment via Unlicensed Carrier Feedback
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Solution Overview
Problem
In the LTE-LAA system, adjusting the contention window (CW) for channel detection on the unlicensed carrier is challenging due to the limitations in feedback information transmission, especially when transitioning from LTE-LAA to NR technology which supports multiple networking scenarios.
Innovation Solution
A method and device for adjusting the CW based on feedback information corresponding to the Physical Downlink Shared Channel (PDSCH) on the unlicensed carrier, allowing for dynamic adjustment of CW length to optimize channel detection and coexistence with other communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If feedback information is transmitted only through the licensed carrier in LTE-LAA, then the system supports carrier aggregation scenario, but the system cannot support dual connection and standalone networking scenarios
Solution Approach 1:
The patent makes the unlicensed carrier capable of transmitting feedback information, which was previously only transmitted through the licensed carrier. This multi-functional use of the unlicensed carrier (both for data transmission and feedback transmission) enables support for dual connection and standalone scenarios while maintaining carrier aggregation functionality.
Solution Approach 2:
The patent introduces dynamic selection of feedback transmission carriers based on the networking scenario. The system can dynamically switch between transmitting feedback on the licensed carrier versus the unlicensed carrier depending on whether it's in carrier aggregation, dual connection, or standalone mode, thereby adapting to different operational requirements.
2Productivity
If the contention window length is not adjusted according to unlicensed carrier feedback, then the channel detection efficiency decreases, but the system complexity increases
Solution Approach 1:
The patent establishes a feedback mechanism where the network device receives feedback information from the terminal about unlicensed carrier transmission status, and uses this feedback to dynamically adjust the contention window length. This closed-loop feedback system optimizes channel detection efficiency by adapting CW based on actual channel conditions observed through the feedback.
Solution Approach 2:
The patent changes the contention window parameter dynamically based on feedback information. When feedback indicates poor channel conditions or transmission failures, the system adjusts the CW length parameter to improve channel access success rate, thereby optimizing channel detection efficiency without requiring complex additional mechanisms.
3Adaptability or versatility
If multiple networking scenarios are supported in NR unlicensed carrier, then the system versatility improves, but the feedback information transmission becomes more complex
Solution Approach 1:
The patent implements dynamic carrier selection for feedback transmission based on the active networking scenario. In carrier aggregation mode, feedback is transmitted on the licensed carrier. In dual connection or standalone modes, feedback is transmitted on the unlicensed carrier. This dynamic adaptation allows the system to support multiple scenarios without requiring permanently complex transmission mechanisms.
Data Source
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AI summary
Provided by an embodiment of the present application are a method and device for determining a contention window, the method comprising: according to feedback information sent by a terminal device, a network device determining the length of a contention window (CW) used for channel detection, the feedback information comprising feedback information corresponding to a physical downlink shared channel (PDSCH) sent by the network device on a first carrier wave; according to the length of CW, the network device performing channel detection on the first carrier wave.