LTE sPDCCH Scheduling With Short TTI for Lower Uplink Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LTE networks experience high latency in applications such as alarm systems, automotive safety, and real-time communications, which can be improved by reducing scheduling grant acquisition time, transmission time interval, and hybrid-ARQ round-trip time.
Innovation Solution
Implementing short transmission time intervals (sTTIs) with enhanced PUCCH and PUSCH designs, including sPUCCH and sPUSCH configurations, to optimize channel utilization and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a WTRU sends multiple transmissions that overlap in time, then spectral efficiency and throughput are improved, but the risk of exceeding maximum power or energy level increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting power levels and energy distribution across overlapping transmissions. The WTRU modifies transmission parameters (power, energy, timing) to ensure that concurrent transmissions do not exceed maximum power or energy levels, thereby maintaining reliability while achieving spectral efficiency improvements through overlapping transmissions.
2Loss of time
If short TTI (sTTI) time resources are utilized for control or data transmissions, then latency is reduced, but the complexity of resource allocation and power headroom reporting increases
Solution Approach 1:
The patent applies segmentation by dividing the transmission time into short TTI (sTTI) segments, allowing independent control and optimization of each time resource. This segmentation enables reduced latency for time-sensitive transmissions while managing complexity through structured resource allocation across multiple sTTI units, with power headroom reporting adapted to the segmented time framework.
Solution Approach 2:
The patent implements dynamics by enabling flexible and adaptive allocation of sTTI time resources based on traffic requirements and channel conditions. The system dynamically adjusts which sTTI resources are used for control versus data transmissions, and adapts power headroom reporting timing and content to match the dynamic sTTI structure, thereby reducing latency while managing complexity through intelligent adaptability.
3Loss of time
If power headroom (PH) reporting utilizes short TTI (sTTI), then reporting timeliness is improved, but the processing overhead and signaling complexity increase
Solution Approach 1:
The patent applies periodic action by establishing regular intervals for power headroom reporting within the sTTI framework. Instead of continuous or ad-hoc reporting, the system uses periodic reporting triggered at defined sTTI boundaries or intervals, which reduces processing overhead and signaling complexity while maintaining timely reporting for latency-sensitive applications.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A wireless transmit receive unit (WTRU) may monitor downlink short transmission time intervals (sTTIs) for a sTTI physical downlink control channel (sPDCCH) region. The WTRU may determine the sPDCCH region from a set of candidate sPDCCH regions for an uplink grant. The sPDCCH may be determined based on a WTRU-specific parameter.