UE Interference Feedback for LBT Link Adaptation
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in efficiently managing interference in unlicensed bands, leading to potential transmission collisions and reduced data transmission reliability.
Innovation Solution
A method where user equipment (UE) performs extended Clear Channel Assessment (eCCA) to determine interference levels on a wireless channel and indicates this information in an acknowledgement message to the base station, allowing the base station to adjust transmission parameters accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station transmits data in unlicensed bands without knowing the actual interference environment at the UE, then transmission speed can be maintained, but transmission reliability deteriorates due to potential collisions and interference
Solution Approach 1:
The UE performs eCCA and provides feedback about the interference environment to the base station through ACK/NACK messages. This feedback mechanism allows the base station to adapt its transmission parameters based on actual channel conditions at the receiver side, improving transmission reliability without requiring complex coordination protocols
Solution Approach 2:
The UE autonomously performs extended Clear Channel Assessment (eCCA) measurements and uses its own measurements to inform the base station about interference conditions. This self-service approach eliminates the need for the base station to perform separate interference measurements, reducing overall system complexity while improving reliability
2Measurement precision
If the base station performs CCA before transmission, then collision avoidance is improved, but the interference environment at the UE cannot be accurately determined
Solution Approach 1:
Instead of having the base station perform interference measurements, the invention inverts the measurement role to the UE, which is positioned to accurately measure the interference environment at the receiver side. The UE then communicates these measurements back to the base station, achieving both accurate measurement and reliable transmission
3Productivity
If the UE transmits ACK messages without eCCA, then communication efficiency is maintained, but transmission collisions increase in high interference environments
Solution Approach 1:
The UE dynamically adjusts its ACK transmission behavior based on real-time interference measurements from eCCA. When interference is high, the UE withholds ACK transmission to avoid collisions; when interference is low, normal ACK transmission resumes. This dynamic adaptation maintains efficiency while improving reliability
Solution Approach 2:
The transmission parameter of ACK messages is changed based on interference conditions. The decision parameter for ACK transmission is modified from a fixed protocol rule to a conditional rule based on eCCA measurement results, allowing the system to adapt to varying interference environments and maintain both efficiency and reliability
Data Source
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Figure 2A~2D
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AI summary
A first apparatus may be implemented as a user equipment (UE) or a component thereof. The first apparatus may be configured to receive a pre-grant message from a base station on a wireless channel. The first apparatus may be further configured to determine an interference level associated with the wireless channel. The first apparatus may then indicate the interference level to the base station in response to the pre-grant message. A second apparatus may be implemented as a base station or a component thereof. The second apparatus may be configured to transmit a pre-grant message to a UE on a wireless channel. The second apparatus may be further configured to detect for an acknowledgement (ACK) message responsive to the pre-grant message from the UE. The second apparatus may then determine an interference level associated with the wireless channel proximate to the UE based on detecting for the ACK message.