Dynamic TTI Scheduling for Low-Latency Radio Communication
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Solution Overview
Problem
In existing LTE systems, the rigid scheduling of downlink and uplink data transmission and reception limits the flexibility of the flexible duplex scheme, leading to increased latency and reduced frequency usage efficiency, making it difficult to achieve low-latency communication.
Innovation Solution
A user terminal and radio base station configuration that allows for dynamic control of downlink and uplink communication within the same time interval (TTI), enabling simultaneous data transmission, reception, and HARQ (Hybrid Automatic Repeat Request) acknowledgement, with flexible allocation of radio resources to optimize communication timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid scheduling is used to secure future radio resources at early timing, then resource allocation stability is improved, but communication latency increases and flexible duplex potential is not fully realized
Solution Approach 1:
The patent applies dynamics by transitioning from rigid, pre-configured scheduling to dynamic, real-time scheduling. The base station can now dynamically allocate downlink and uplink resources within the same TTI based on current channel conditions and traffic demands, rather than being constrained by fixed future scheduling. This dynamic approach reduces latency while maintaining stability through controlled scheduling mechanisms.
Solution Approach 2:
The patent changes the scheduling parameter from fixed future timing to flexible same-TTI allocation. By allowing downlink and uplink transmissions to occur within the same TTI rather than requiring separate future slots, the system achieves lower latency while maintaining resource allocation stability through controlled parameter adjustments.
2Productivity
If flexible duplex scheme is implemented with dynamic subframe allocation, then frequency spectrum utilization is improved, but scheduling complexity increases and latency control becomes difficult
Solution Approach 1:
The patent segments the TTI into distinct downlink and uplink portions, allowing independent control and allocation of each segment. This segmentation enables the system to achieve high frequency spectrum utilization through flexible duplex while managing scheduling complexity by handling each segment separately with well-defined allocation rules.
Solution Approach 2:
The base station performs preliminary scheduling decisions within the same TTI before data transmission occurs. By preparing and allocating resources in advance within the same TTI framework, the system achieves efficient frequency utilization while controlling scheduling complexity through proactive rather than reactive allocation.
3Loss of time
If same-TTI data transmission and HARQ acknowledgement are enabled, then communication latency is reduced, but transmission time interval configuration complexity increases
Solution Approach 1:
The patent merges data transmission and HARQ acknowledgement within the same TTI, combining what were previously separate time intervals into a single integrated transmission window. This merging reduces communication latency significantly while managing configuration complexity by treating the combined TTI as a unified structure with defined allocation rules for both data and acknowledgement channels.
Data Source
AI summary
According to the present invention, low-latency communication in a next-generation mobile communication system can be achieved. A user terminal includes a receiving section configured to receive at least one piece of downlink control information out of first downlink control information that schedules reception of downlink data and second downlink control information that schedules transmission of uplink data; and a control section configured to perform a control to carry out communication using a transmission time interval (TTI) configuration, including an allocation section for receiving the downlink control information, a data section for carrying out reception of downlink data corresponding to the received downlink control information and/or transmission of uplink data, and a delivery acknowledgement section for carrying out reception and/or transmission of delivery acknowledgement information corresponding to predetermined data.