Wireless CWS Adjustment via HARQ-ACK Feedback
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently adjusting contention window sizes (CWS) based on the success or failure of hybrid automatic repeat request-acknowledgment (HARQ-ACK) feedback, which affects communication reliability and capacity, especially in scenarios involving multiple cells and unlicensed bands.
Innovation Solution
A method and apparatus for adjusting the contention window size (CWS) in a wireless communication system by considering the downlink signal, the identity of cells, and the successful reception of HARQ-ACK by the base station, allowing for dynamic adjustments based on specific conditions such as the inclusion of downlink control information and the type of physical channels used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contention window size (CWS) is adjusted based on HARQ-ACK feedback in multi-cell scenarios, then communication reliability is improved, but the complexity of CWS adjustment logic increases
Solution Approach 1:
The patent applies local quality by differentiating CWS adjustment rules based on specific local conditions: whether the first cell and second cell are identical, the type of downlink signal (DCI or PDSCH), and HARQ-ACK reception status. Each condition combination has its own adjustment rule, allowing the system to optimize reliability for each specific scenario without requiring a single complex universal rule.
Solution Approach 2:
The patent implements dynamic CWS adjustment where the contention window size is not fixed but adaptively changed based on real-time HARQ-ACK feedback and cell configuration. The CWS can be maintained, reset, or increased dynamically depending on the specific condition, enabling the system to respond flexibly to changing communication states.
2Reliability
If dynamic CWS adjustment is implemented based on multiple conditions (downlink signal type, cell identity, HARQ-ACK status), then transmission success rate is enhanced, but the processing overhead increases
Solution Approach 1:
The patent applies preliminary action by pre-defining adjustment rules for each possible condition combination before actual transmission occurs. The UE and BS have predetermined knowledge of what CWS adjustment to apply based on the current state, eliminating the need for complex real-time calculations and reducing processing overhead during actual operation.
Solution Approach 2:
The patent implements feedback mechanisms where HARQ-ACK information is used to inform CWS adjustments. The reception status of HARQ-ACK feedback provides direct information about transmission success, which is fed back into the CWS adjustment decision process, creating a closed-loop system that improves transmission success rate while keeping processing efficient.
3Productivity
If CWS is maintained for identical cells with successful HARQ-ACK reception, then communication efficiency is improved, but the adaptability to different scenarios decreases
Solution Approach 1:
The patent applies local quality by creating specific adjustment rules for specific local conditions. For identical cells with successful HARQ-ACK reception, the CWS is maintained to improve efficiency. For different cell scenarios or failed receptions, different rules apply (reset or increase). This localized approach allows the system to be highly adaptive to different scenarios while maintaining efficiency in each specific case.
Data Source
AI summary
In the present disclosure, in a wireless communication system: a base station transmits, to a terminal, a downlink signal in a first cell; the terminal receives the signal and executes a channel access procedure (CAP); on the basis of the CAP, the terminal transmits, to the base station, a hybrid automatic repeat and request acknowledgement (HARQ-ACK) in a second cell included in an unlicensed band; the base station receives the signal; and the terminal and the base station are able to adjust a CWS.