Power Headroom Reporting Across One- and Two-Symbol sTTIs
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Solution Overview
Problem
Current wireless communication standards face challenges in implementing one-symbol shortened transmission time intervals (sTTIs) due to the complexity of modifying existing 2-symbol sTTI configurations, which are necessary for supporting Ultra-Reliable and Low-Latency Communications (URLLC) without significant design changes and increased scheduler and receiver complexity.
Innovation Solution
The proposed solution involves modifying the 2-symbol sTTI design to enable 1-symbol sTTI operation with minimal changes to the current configuration, utilizing a hybrid approach that leverages existing 2-symbol sTTI frameworks to support one-symbol sTTIs, thereby meeting the design and performance goals for low-latency communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 2-symbol sTTI configuration is modified to support 1-symbol sTTI, then latency is reduced and reliability is improved, but device complexity and scheduler complexity increase
Solution Approach 1:
The patent implements dynamic TTI length adaptation where the system can switch between 1-symbol and 2-symbol sTTI configurations based on traffic requirements. The 1-symbol sTTI is activated only when low-latency high-reliability communication is needed, while 2-symbol sTTI is used for normal operations, allowing the system to adapt its structure dynamically rather than maintaining fixed complex configuration always
Solution Approach 2:
The patent changes the TTI duration parameter from fixed 2-symbol to variable length (1 or 2 symbols) based on service requirements. By modifying this key parameter conditionally, the system achieves improved reliability for urgent communications without permanently increasing the complexity of the scheduler and receiver designs
2Loss of time
If 2-symbol sTTI configuration is modified to support 1-symbol sTTI, then latency is reduced, but implementation complexity increases
Solution Approach 1:
The patent segments the sTTI structure into configurable units where the first symbol can be independently utilized as a standalone 1-symbol sTTI when needed, while maintaining the option to combine with the second symbol for 2-symbol sTTI operation. This segmentation allows the receiver to process 1-symbol transmissions without requiring complete redesign of the 2-symbol processing architecture
Solution Approach 2:
The system dynamically adjusts the active TTI length based on traffic conditions, activating 1-symbol mode only when low-latency communication is required. This dynamic approach reduces average latency for critical transmissions while keeping the receiver complexity manageable by using the existing 2-symbol framework as the base configuration
3Ease of manufacture
If existing 2-symbol sTTI framework is used to support 1-symbol sTTI, then design changes are minimized, but flexibility for optimal performance is reduced
Solution Approach 1:
The patent makes the 2-symbol sTTI framework universal by enabling it to serve multiple functions: it can operate as a complete 2-symbol TTI for normal traffic, or the first symbol can be independently activated as a 1-symbol sTTI for low-latency requirements. This multi-functionality allows the system to maintain implementation simplicity while gaining the flexibility to adapt to different performance requirements
Solution Approach 2:
The system prepares the 2-symbol sTTI framework in advance to support both operational modes, configuring the physical layer and MAC layer to recognize and process both 1-symbol and 2-symbol transmissions. This preliminary configuration enables seamless switching between modes without requiring significant design changes, balancing implementation ease with operational flexibility
Data Source
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AI summary
Certain aspects of the present disclosure relate to methods and apparatus for PHR reporting by UEs that support both normal and shortened Transmission Time Interval (sTTI) configurations.