Uplink Feedback Transmission via LBT Detection
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Solution Overview
Problem
In communication systems like LTE and NR, ensuring reliable uplink information transmission on grant-free spectrum is challenging due to uncertainty in channel availability and fairness in channel occupation time, which affects data transmission reliability.
Innovation Solution
A method where a terminal device determines N uplink resources and transmits corresponding uplink feedback information to indicate data transmission conditions for N sets of downlink resources, with available uplink resources identified through LBT detection to improve channel occupancy and transmission reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the terminal device transmits uplink feedback information on grant-free spectrum, then the transmission flexibility is improved, but the reliability of uplink information transmission deteriorates due to channel availability uncertainty
Solution Approach 1:
The terminal device performs LBT detection before transmitting uplink feedback information to determine channel availability in advance. This preliminary action ensures that the device only transmits when the channel is available, thereby maintaining reliability while operating on grant-free spectrum.
Solution Approach 2:
The terminal device transmits uplink feedback information (such as HARQ-ACK) to provide feedback about downlink data reception status. This feedback mechanism enables the network device to adjust transmissions and ensures reliable communication even on grant-free spectrum where traditional scheduling is not used.
2Productivity
If the terminal device determines available uplink resources through LBT detection, then the channel occupancy probability is improved, but the complexity of resource management increases
Solution Approach 1:
The uplink resources are divided into multiple candidate resources, and the terminal device performs LBT detection on each candidate resource independently to determine availability. This segmentation approach simplifies the detection process by breaking it down into discrete, manageable checks rather than managing resources as a single complex entity.
Solution Approach 2:
The terminal device autonomously performs LBT detection and selects available uplink resources without requiring network scheduling or coordination. This self-service mechanism increases channel occupancy probability while the standardized LBT procedure keeps the implementation complexity manageable.
3Reliability
If multiple uplink resources are allocated for feedback information, then the reliability of data transmission is improved, but the loss of uplink resources increases when channels are unavailable
Solution Approach 1:
The terminal device is allocated multiple candidate uplink resources (excessive allocation) but only activates and transmits on the subset of resources that pass LBT detection (partial usage). This approach ensures reliability through multiple opportunities while minimizing resource loss by not wasting resources on unavailable channels.
Solution Approach 2:
The system changes the state of uplink resources from a static allocation to a dynamic selection process where resources are evaluated based on channel conditions. By changing parameters such as channel availability status and resource selection based on LBT outcomes, the system optimizes both reliability and resource efficiency.
Data Source
AI summary
The present disclosure relates to an information transmission method, a terminal device, and a network device. The method includes determining N uplink resources used to carry N sets of uplink feedback information. The N sets of uplink feedback information is used to feed back data transmission conditions in N sets of downlink resources. The i-th set of uplink feedback information corresponding to the i-th uplink resource is used to feed back the data transmission condition in the i-th set of downlink resources, when i is greater than 1. The i-th set of downlink resources include some or all of the (i−1)-th set of downlink resources, where N is a positive integer greater than 1, and i=1, 2, 3, . . . , N. The method also includes determining M available uplink resources in the N uplink resources, where M is a positive integer less than or equal to N. The method further includes using the M available uplink resources to send, to the network device, M sets of uplink feedback information corresponding to the M available uplink resources.