Grant-Free Uplink LBT Priority Configuration for Unlicensed Spectrum
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Solution Overview
Problem
In 5G NR mobile communication systems, the unlicensed spectrum resources are inefficiently utilized due to transmission collisions among UEs sharing the same uplink resources, leading to resource wastage and reliability issues in grant-free uplink transmission.
Innovation Solution
The method involves determining grant-free uplink transmission configuration information for UEs, including LBT detection configuration to differentiate their priorities, allowing them to perform LBT detection at designated times and resource allocation, thereby avoiding collisions and optimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple UEs are scheduled for grant-free uplink transmission to share unlicensed spectrum resources, then the system can utilize unlicensed spectrum for uplink communication, but massive uplink resources are reserved and UEs that are scheduled do not always have uplink service information to be transmitted all the time, resulting in waste of resources
Solution Approach 1:
The base station determines in advance which UEs will share the periodic uplink transmission resources and configures LBT detection priorities before the actual transmission occurs. This preliminary configuration allows UEs to know their priority levels ahead of time, enabling efficient resource allocation without wasting reserved resources on UEs that may not have data to transmit.
2Reliability
If multiple UEs perform LBT detection simultaneously for channel collision avoidance, then transmission collisions can be avoided, but transmission collisions still occur when multiple UEs succeed in LBT detection at the same time
Solution Approach 1:
Different LBT detection priorities are configured for different UEs based on their specific needs and service types. This local differentiation ensures that UEs with higher priorities (such as those with urgent data or higher service requirements) have an advantage in LBT detection, while UEs with lower priorities wait for subsequent opportunities, thereby reducing collisions without completely blocking lower-priority access.
Solution Approach 2:
The base station dynamically adjusts LBT detection parameters including detection starting times and detection windows for different UEs. By changing these temporal parameters, the system creates staggered detection opportunities that reduce simultaneous detection conflicts while maintaining fair access for all scheduled UEs.
3Extent of automation
If the base station schedules periodic uplink transmission resources for UEs without individual scheduling, then the system implements grant-free uplink transmission, but the base station cannot control which UE transmits when multiple UEs are scheduled
Solution Approach 1:
The base station performs preliminary scheduling decisions to determine which UEs will share the periodic resources and configures their specific LBT detection priorities in advance. This preliminary action maintains the automation benefits of grant-free transmission while establishing control mechanisms through pre-configured priority levels that guide UE transmission behavior.
Data Source
AI summary
An information transmission method includes: determining grant-free uplink transmission configuration information of at least two target UEs, the grant-free uplink transmission configuration information at least comprising LBT detection configuration information of each of the at least two target UEs, the LBT detection configuration information configured to distinguish respective LBT detection priorities of the at least two target UEs for channel collision avoidance, wherein the at least two target UEs share periodic uplink transmission resources in an unlicensed spectrum; and transmitting, to each of the at least two target UEs, the grant-free uplink transmission configuration information, so that any one of the at least two target UEs performs an LBT detection according to the grant-free uplink transmission configuration information, transmits uplink service data through a currently shared uplink transmission resource after the LBT detection succeeds.