Short TTI Uplink Signal Allocation in LTE Systems
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Solution Overview
Problem
Future radio communication systems, such as those in 5G, require short transmission time intervals (TTIs) to support high-frequency bands and applications like IoT and V2V, but existing LTE systems with 1 ms TTIs may not provide sufficient communication services, particularly for Device-to-Device and Vehicular-to-Vehicular communications, which demand short delay communications, and face challenges in arranging UL transmission signals and channels.
Innovation Solution
The implementation of short TTIs, configured in units of symbols within existing systems, allows for efficient allocation of UL signals and channels, using frequency hopping to achieve equal symbol allocation across different frequency ranges, maintaining compatibility with existing systems by establishing short TTIs within existing radio frame structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If short TTIs are used to reduce transmission delay, then communication speed and responsiveness are improved, but the complexity of arranging UL transmission signals and channels increases
Solution Approach 1:
The patent segments the uplink transmission resources by dividing them into different types (PUCCH, PUSCH, PRACH) and organizing them within the short TTI structure. This segmentation allows for systematic management of multiple signals and channels, reducing the complexity of arrangement while maintaining low latency transmission.
Solution Approach 2:
The patent introduces dynamic resource allocation mechanisms that adapt to different TTI lengths and traffic conditions. The system can dynamically adjust the arrangement of UL transmission signals and channels based on the specific short TTI configuration, making the system flexible and reducing operational complexity.
2Productivity
If short TTIs are implemented to support high-frequency bands and low-latency applications, then communication performance is improved, but compatibility with existing LTE systems deteriorates
Solution Approach 1:
The patent designs the short TTI structure to serve multiple functions: it can operate in both new high-frequency band scenarios and legacy LTE environments. The framework supports different TTI lengths and configurations, allowing the system to maintain compatibility with existing LTE systems while enabling advanced short TTI-based communications for high-frequency bands and low-latency applications.
Solution Approach 2:
The patent introduces a new dimension of TTI length configuration that extends beyond the traditional 1ms TTI. By adding this temporal dimension flexibility, the system can accommodate both legacy LTE operations and new short TTI requirements without fundamentally altering the existing framework, thus maintaining compatibility while improving performance.
3Productivity
If frequency hopping is used to allocate UL signals across different frequency ranges, then resource utilization is improved, but the complexity of signal arrangement increases
Solution Approach 1:
The patent employs periodic frequency hopping patterns for UL signal allocation across different frequency ranges. This periodic structure provides regularity and predictability to the resource allocation process, improving resource utilization while reducing the complexity of signal arrangement through standardized, repeating patterns rather than arbitrary allocations.
Data Source
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AI summary
The invention aims to perform UL transmission in an appropriate manner even when using short transmission time intervals (TTIs). A user terminal includes a transmission section that performs the UL transmission using at least one of a plurality of TTIs contained in one subframe of existing systems, and a control section that controls allocation of an UL signal and/or an UL channel. The TTI is constituted of an even number of symbols of the existing system. The control section allocates an uplink control channel on the basis of the TTI.