User Terminal Dynamic UL/DL Ratio Control
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Solution Overview
Problem
Existing TDD-based LTE systems face limitations in scalability and flexibility due to strict timing control for UL/DL configurations, leading to high delay and reduced spectral efficiency, particularly in HARQ-based retransmission control.
Innovation Solution
A user terminal and radio base station that dynamically control the UL/DL ratio within a radio frame using self-contained subframes, allowing for flexible scheduling of uplink data transmission and HARQ feedback based on real-time acknowledgment information, enabling improved spectral efficiency and reduced delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the predetermined period before delivery acknowledgment information is transmitted is shortened to reduce delay, then the communication delay is reduced, but the frequency of transmitting delivery acknowledgment information increases, resulting in decreased spectral efficiency
Solution Approach 1:
The patent applies dynamics by making the feedback timing flexible rather than fixed. The base station dynamically determines the timing of delivery acknowledgment information transmission based on buffer status and traffic conditions. This allows the system to adapt the feedback period length according to actual needs, resolving the contradiction between reducing delay and maintaining spectral efficiency by using short feedback periods only when necessary.
Solution Approach 2:
The patent changes the parameter of feedback timing from a fixed predetermined period to a variable parameter that can be adjusted based on system conditions. The base station controls the timing parameter dynamically, changing it according to buffer status indicators and traffic patterns, thereby optimizing both delay performance and spectral efficiency under different operating conditions.
2Reliability
If strict timing control based on UL/DL configurations is implemented in TDD-based LTE, then the system maintains synchronization and proper timing, but the scalability and flexibility of data transmission scheduling are limited
Solution Approach 1:
The patent segments the feedback transmission into two parts: buffer status indicators (BSIs) that maintain timing synchronization with the network, and delivery acknowledgment information that can be transmitted flexibly. This segmentation allows the system to preserve reliable timing control for synchronization purposes while enabling flexible scheduling for data transmission and acknowledgment feedback.
Solution Approach 2:
The patent introduces dynamic control of feedback timing where the base station can adjust when delivery acknowledgment information is transmitted based on buffer status. This dynamic approach maintains the reliability of timing-synchronized elements (BSIs) while adding flexibility to the acknowledgment feedback timing, allowing adaptation to varying traffic conditions and scheduling needs.
Data Source
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AI summary
The present invention is designed so that it is possible to achieve both improved spectral efficiency and reduced delay in communication. According to one aspect of the present invention, a terminal comprises a receiving section configured to, when the terminal is configured to transmit uplink data in continuous transmission time intervals, receive information to restrict allocation of the uplink data in the continuous transmission time intervals; and a control section configured to determine a period not to transmit the uplink data in the continuous transmission time intervals based on the information.