User Terminal Frequency Hopping for UL Collision Reduction
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Solution Overview
Problem
In future radio communication systems, the latency due to UL transmission collisions is a significant issue when contention-based UL transmission is employed, as it can lead to failed transmissions and insufficient latency reduction.
Innovation Solution
The implementation of frequency hopping for UL signals in contention-based UL data transmission, where multiple contention-based UL signals are allocated to different frequency fields, reducing the likelihood of collisions and enabling efficient transmission in shortened TTI resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple user terminals transmit UL data in the same time-frequency resource using contention-based UL transmission, then the transmission latency is reduced, but the collision probability increases leading to transmission failures
Solution Approach 1:
The patent applies frequency hopping to distribute UL transmissions across different frequency dimensions. When multiple user terminals transmit in the same time slot, frequency hopping ensures they use different frequency resources, transforming a one-dimensional time conflict into a multi-dimensional resource allocation problem that resolves collisions while maintaining low latency.
2Reliability
If frequency hopping is applied to UL signals in contention-based transmission, then the collision probability is reduced, but the system complexity increases
Solution Approach 1:
The patent changes the frequency parameter dynamically through frequency hopping patterns. By pre-configuring hopping patterns and using simple index-based frequency selection, the system achieves collision avoidance without complex real-time calculations, balancing reliability improvement with manageable device complexity.
3Loss of time
If shortened TTI resources are used for UL transmission, then the communication latency is reduced, but the available time for signal processing is decreased
Solution Approach 1:
The patent performs frequency resource determination and hopping pattern selection in advance, before the actual UL transmission. This preliminary action allows the terminal to prepare transmission parameters quickly, fitting the short processing window of shortened TTIs while maintaining low communication latency.
Data Source
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AI summary
The present invention is designed to reduce the latency due to collisions in UL transmission when contention-based UL data transmission is employed. A user terminal communicates using a second transmission time interval (TTI), having a shorter TTI duration than a first TTI, and this user terminal has a transmission section that transmits multiple UL data without a UL grant from a radio base station, and a control section that controls allocation of the multiple UL data individually, and the control section applies frequency hopping to allocate the multiple UL data to resources of different second TTIs.