Uplink Channel Occupancy Sharing With Gap-Based Downlink Access
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Solution Overview
Problem
The challenge of ensuring robust coexistence of LTE and NR technologies in unlicensed frequency bands, particularly in unlicensed bands, where interference with existing wireless communication devices is a concern, and efficient channel sharing is required to maintain communication quality.
Innovation Solution
A method for uplink transmission in a wireless communication system involving configured grant (CG) and scheduled uplink transmissions using Listen Before Talk (LBT) bandwidth subsets, with conditions for dropping symbols if LBT bandwidth subsets are not satisfied, ensuring continuous resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If user equipment performs uplink transmission in unlicensed bands, then channel occupancy is established, but interference with existing devices and coexistence with LTE/NR technologies becomes challenging
Solution Approach 1:
The base station performs channel sensing before downlink transmission to detect whether the channel is occupied by user equipment or other devices. This preliminary action prevents interference by identifying occupied channels in advance, allowing the system to coexist harmoniously with LTE and NR technologies while maintaining efficient channel utilization in unlicensed bands
Solution Approach 2:
A gap period is introduced as an intermediary time interval between uplink transmission by user equipment and subsequent downlink transmission by the base station. This gap serves as a mediator that allows the base station to perform channel sensing and detect ongoing transmissions, thereby preventing interference while maintaining efficient channel access
2Productivity
If downlink transmission is performed immediately after uplink transmission, then transmission efficiency is improved, but channel sensing cannot be performed leading to potential interference
Solution Approach 1:
The base station performs channel sensing in the gap period before initiating downlink transmission. This preliminary detection ensures that the channel is clear of ongoing uplink transmissions or other interferers, making channel access reliable while the gap itself is minimized to maintain overall transmission efficiency
Solution Approach 2:
The system maintains continuous channel access by minimizing the gap period to the essential minimum time required for channel sensing. The useful action of data transmission continues as smoothly as possible, with only the necessary brief interruption for channel detection, thereby maintaining high transmission efficiency while ensuring reliable channel access
Data Source
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AI summary
A method for receiving downlink transmission by a terminal comprises the steps of: performing uplink transmission, which is related to channel occupancy shared between a base station and the terminal, to the base station; and receiving, from the base station, downlink transmission performed after a gap from a time point at which the base station has received the uplink transmission, wherein the downlink transmission is performed on the basis of channel access performed by the base station, the channel access is performed on the basis of the gap, and information included in the downlink transmission and a resource through which the downlink transmission is performed are determined on the basis of whether the base station has configured, for the terminal, a threshold value of energy detection for the channel occupancy.