Unlicensed Band Channel Access with Sequential Fixed Durations
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Solution Overview
Problem
The challenge of using unlicensed frequency bands in wireless communication systems is the difficulty in ensuring communication quality due to potential interference with existing devices and the need for a robust coexistence mechanism to avoid affecting these devices.
Innovation Solution
A channel access method involving fixed duration-based channel access attempts, where a first fixed duration-based access is attempted when the channel is sensed to be idle for a specific duration, and a second fixed duration-based access is attempted if the first fails, with the first duration being shorter than the second, to facilitate transmission in unlicensed bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed duration-based channel access is used in unlicensed bands, then channel access efficiency is improved, but interference with existing devices increases
Solution Approach 1:
The channel access process is segmented into multiple fixed duration-based access attempts (first fixed duration-based channel access, second fixed duration-based channel access). Each attempt has a specific duration and can be independently evaluated, allowing the system to balance access efficiency with interference avoidance by stopping after a predetermined number of attempts.
Solution Approach 2:
The system performs channel sensing before each access attempt to determine whether the channel is idle. This preliminary action allows the system to avoid accessing the channel when it would cause interference to existing devices, while still maintaining efficient access when the channel is available.
2Reliability
If multiple channel access attempts are made, then transmission reliability is improved, but time consumption increases
Solution Approach 1:
The access process is divided into discrete fixed duration segments (first fixed duration, second fixed duration). Each segment represents a complete access attempt with a predetermined time limit. This segmentation allows the system to achieve reliable transmission through multiple attempts while bounding the total time consumption by preventing indefinite waiting.
Solution Approach 2:
The system dynamically adjusts the channel access strategy based on the results of previous attempts. If the first fixed duration-based channel access fails, the system proceeds to the second fixed duration-based channel access. This dynamic adaptation improves reliability by trying alternative access times while controlling time consumption through the predetermined structure of the attempts.
Data Source
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AI summary
A base station of a wireless communication system is disclosed. The base station of wireless communication includes a communication module and a processor. The processor is configured to receive a grant for scheduling a plurality of uplink transmissions from the base station, and when the UE attempts to a first fixed duration-based channel access for a first transmission which is one of the plurality of uplink transmission and fails in the first fixed duration-based channel access, attempt to a second fixed duration-based channel access for a second transmission which is a transmission following the first transmission.