Terminal TTI Control for 5G Latency and Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Future radio communication systems, such as those beyond LTE Rel. 13 and 5G, face challenges in providing sufficient communication services when using existing one-ms transmission time intervals (TTIs), especially for high-frequency bands like IoT and MTC applications, where shorter TTIs are required but their control is not effectively managed.
Innovation Solution
A user terminal and radio base station system that employs a control section to manage both normal and shortened TTIs, allowing for flexible configuration of transmission time intervals based on processing capability information, enabling appropriate communication even with shortened TTIs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one-ms transmission time intervals (TTIs) are used in future radio communication systems, then compatibility with existing LTE systems is maintained, but sufficient communication services cannot be provided for high-frequency bands and IoT/MTC applications
Solution Approach 1:
The system dynamically switches between normal TTIs (one-ms) and shortened TTIs based on service requirements and frequency bands. The control section determines whether to use normal or shortened TTIs for each downlink shared channel, allowing adaptive adjustment of TTI length to match communication conditions and service types.
Solution Approach 2:
The invention changes the TTI length parameter from the fixed one-ms value to variable lengths including shortened TTIs. This parameter change enables the system to optimize transmission time intervals for different frequency bands and service types, particularly for high-frequency bands and IoT/MTC applications where shorter TTIs are beneficial.
2Loss of time
If shortened TTIs are used to improve communication services, then processing latency is reduced and more user terminals can be accommodated, but control complexity increases
Solution Approach 1:
The invention segments the TTI control into two distinct modes: normal TTI control for legacy compatibility and shortened TTI control for enhanced performance. The control section selectively applies different control mechanisms depending on the TTI type, managing complexity by dividing the control function rather than creating a completely new control system.
Solution Approach 2:
The control section is designed to handle both normal TTI and shortened TTI operations within a single unified component. This multi-functional control section reduces overall system complexity by consolidating control functions rather than requiring separate control mechanisms for each TTI type.
3Productivity
If shortened TTIs are used, then the number of user terminals accommodated per unit time increases, but timing determination and resource allocation become more difficult
Solution Approach 1:
The control section determines timing advance values in advance based on the TTI type (normal or shortened) before actual transmission occurs. This preliminary determination of timing parameters simplifies subsequent resource allocation and reduces the difficulty of timing management during active communication.
Solution Approach 2:
The system implements timing advance mechanisms where the base station measures uplink timing from user terminals and provides feedback to adjust timing. This feedback loop enables accurate timing determination even with shortened TTIs, allowing the system to accommodate more user terminals by dynamically adjusting timing based on measured conditions.
Data Source
AI summary
A terminal is disclosed including a receiver that receives a physical downlink shared channel (PDSCH); a transmitter that transmits retransmission control information (Hybrid Automatic Repeat reQuest-Acknowledgement: HARQ-ACK) for the PDSCH based on second processing capability; and a processor that, when a number of resource blocks for the PDSCH exceeds a number, controls to provide the HARQ-ACK based on first processing capability that is different from the second processing capability. In other aspects, radio communication method in a terminal is also disclosed.