HARQ-ACK Channel Access in Unlicensed Bands With Mixed CBG UEs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge of efficiently transmitting signals in cellular wireless communication systems, particularly in unlicensed frequency bands, is exacerbated by the difficulty in ensuring communication quality and minimizing interference with existing wireless communication devices, necessitating a robust coexistence mechanism for LTE and NR technologies.
Innovation Solution
A method and device for downlink and uplink transmissions in user equipment (UE) and base stations that utilize HARQ-ACK feedback to determine contention window sizes based on HARQ-ACK values, adjusting backoff counters, and employing CBG-based HARQ-ACK bit sequences for efficient channel access, especially in mixed environments with CBG-configured and non-CBG-configured UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If channel access is performed in unlicensed bands using conventional methods, then spectral efficiency is improved, but interference with existing wireless communication devices increases and communication quality deteriorates
Solution Approach 1:
The base station performs preliminary channel sensing and determines channel accessibility before transmitting downlink data. The base station adjusts the backoff counter based on HARQ-ACK feedback from previous transmissions, performing preliminary actions to ensure channel availability and reduce interference before actual data transmission occurs.
Solution Approach 2:
The system implements a feedback mechanism where the base station receives HARQ-ACK feedback from user equipment and uses this feedback to adjust the contention window size and backoff counter for subsequent channel access attempts. This feedback loop enables adaptive channel access that responds to actual channel conditions and transmission outcomes.
2Productivity
If contention window size is adjusted based on HARQ-ACK feedback, then channel access efficiency is improved, but system complexity increases due to mixed CBG-configured and non-CBG-configured UE
Solution Approach 1:
The system segments the handling of HARQ-ACK feedback by distinguishing between CBG-configured and non-CBG-configured user equipment. The base station determines whether received HARQ-ACK feedback corresponds to CBG-based or non-CBG-based transmission and applies appropriate processing rules for each segment, enabling efficient channel access while managing complexity through structured segmentation.
3Object-affected harmful factors
If backoff counter adjustment is performed based on HARQ-ACK feedback, then interference reduction is achieved, but transmission latency increases due to additional sensing and adjustment steps
Solution Approach 1:
The backoff counter adjustment mechanism is made dynamic, allowing the base station to adapt the contention window size and backoff behavior based on real-time HARQ-ACK feedback and channel conditions. This dynamic adjustment enables the system to balance interference reduction with latency considerations by modifying channel access parameters according to actual transmission outcomes and traffic patterns.
Data Source
AI summary
Disclosed are a wireless communication device of a wireless communication system and a wireless communication method using same. More specifically, disclosed are a wireless communication device and a wireless communication method using same, wherein the wireless communication device determines a contention window size on the basis of HARQ-ACK values determined according to HARQ-ACK information bits for each transmission block of HARQ-ACK feedback, performs a backoff on the basis of the selected backoff counter value within the contention window size, and determines one HARQ-ACK value on the basis of N bits of HARQ-ACK information of a CBG-based HARQ-ACK bit sequence.