User Terminal Repetition Control for UL Grant-Free Transmission
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Solution Overview
Problem
Future radio communication systems face challenges in improving the performance and reliability of UL grant-free repeated transmissions due to resource contention and uncoordinated repetition control, leading to potential interruptions and reduced communication efficiency.
Innovation Solution
A user terminal and radio communication method that controls UL grant-free repeated transmissions by counting the number of repetitions based on the type of allocated radio resources, distinguishing between types where the base station and user terminal have the same or different recognition of resource usage, to prevent misalignment and enhance communication reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If UL grant-free repeated transmission is performed without coordination, then transmission speed increases, but communication reliability deteriorates due to resource contention and misalignment between base station and user terminal
Solution Approach 1:
The invention implements feedback mechanisms where the base station provides downlink control information to the user terminal regarding resource allocation and repetition configuration. The user terminal feeds back acknowledgment information about received repetitions, enabling coordinated control between base station and terminal to maintain reliability while performing grant-free repeated transmission
Solution Approach 2:
The base station performs preliminary configuration of repetition parameters, resource allocation, and stopping conditions before the user terminal executes repeated transmission. This preliminary coordination ensures that both parties have aligned understanding of resource usage, preventing misalignment and interference during actual transmission
2Reliability
If the number of repeated transmissions is increased, then communication reliability improves, but resource efficiency deteriorates due to uninterrupted repetition counting
Solution Approach 1:
The invention makes the repetition counting process dynamic by allowing the user terminal to suspend counting under specific conditions (such as when receiving downlink control information indicating resource reallocation) and resume later. This dynamic adjustment optimizes resource usage while maintaining the ability to achieve required reliability through sufficient repetitions when conditions permit
3Adaptability or versatility
If resource allocation is made flexible for grant-free transmission, then adaptability improves, but measurement precision deteriorates due to difficulty in determining resource usage status
Solution Approach 1:
The invention uses distinct downlink control information formats and resource indication methods to clearly signal different resource allocation states to the user terminal. These signaling mechanisms act as 'color codes' that enable the terminal to accurately determine whether resources are allocated for repetition, new transmission, or other purposes, maintaining measurement precision despite flexible resource usage
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A user terminal according to one aspect includes: a transmission section that transmits UL data without a UL transmission indication from a radio base station; and a control section that repeatedly transmits the UL data based on a number of times of repeated transmission, and the control section controls whether or not to count the number of times of repeated transmission based on a radio resource type allocated to the repeated transmission. According to this one aspect, it is possible to appropriately perform UL grant-free repeated transmission, and improve performance and reliability of radio communication.