Partial Subframe Uplink Transmission in Unlicensed Bands
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Solution Overview
Problem
The challenge in wireless communication systems, particularly in cellular networks, is to efficiently transmit signals in unlicensed frequency bands while maintaining communication quality and avoiding interference with conventional wireless communication devices.
Innovation Solution
The proposed solution involves a user equipment (UE) that performs uplink transmission in a partial subframe with a duration shorter than a standard subframe, adjusted based on channel access results and indications from the base station. This includes adjusting the contention window for channel access and determining reference subframes for successful transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE technology is deployed in unlicensed band, then spectrum utilization is improved, but interference with conventional wireless communication devices occurs
Solution Approach 1:
The base station performs channel access procedures and listens to the channel before initiating uplink transmission. This preliminary action ensures the channel is clear before LTE devices transmit, preventing interference with conventional wireless communication devices while maintaining efficient spectrum utilization
2Productivity
If uplink transmission is performed in partial subframe, then transmission efficiency is improved, but transmission reliability deteriorates
Solution Approach 1:
The base station dynamically adjusts the uplink transmission format based on channel access results. When channel conditions permit, it uses partial subframe for efficient transmission; when reliability is Concerned, it can extend to full subframe duration. This dynamic adaptation resolves the contradiction between transmission efficiency and reliability
3Productivity
If contention window is adjusted dynamically, then channel access efficiency is improved, but system complexity increases
Solution Approach 1:
The base station adjusts the contention window size based on feedback from channel access outcomes. Successful transmissions trigger window reduction, while failures trigger window expansion. This feedback-driven adaptation improves channel access efficiency without requiring complex centralized control, as each base station autonomously adjusts based on its own transmission results
Data Source
AI summary
A user equipment of a wireless communication system is disclosed. The user equipment includes a communication module, and a processor. The processor is configured to transmit a radio frame divided into a plurality of subframes through the communication module, and perform a UL transmission in a partial subframe having a duration shorter than one subframe duration to the base station based on at least one of an indication of a base station and a result of a channel access of the wireless communication system.