Uplink Scheduling Gaps for Timely URLLC Feedback
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently allocating feedback resources to meet stringent quality of service (QoS) targets, particularly in environments requiring ultra-reliable low latency communications (URLLC) with strict latency, jitter, and reliability requirements, such as industrial Internet of Things (I-IoT) and factory automation deployments.
Innovation Solution
The system allocates uplink resources with gaps for UEs to transmit feedback information, using downlink control information (DCI) or reserved symbols, allowing timely retransmissions within specified time limits by indicating starting transmission symbols and length indicators, and employing joint mapping of resource indicators to optimize scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink resources are allocated continuously without gaps, then resource utilization efficiency is improved, but feedback transmission timing cannot meet stringent QoS targets for URLLC
Solution Approach 1:
The uplink resource allocation is segmented into multiple parts with gaps inserted at specific positions. The DCI message includes a first SLIV for resources before the gap and a second SLIV for resources after the gap, allowing feedback to be transmitted in the gap while maintaining overall resource utilization
Solution Approach 2:
The gap for feedback transmission is preliminarily arranged in the uplink resource allocation before data transmission begins. This predetermined gap ensures that feedback can be transmitted timely without delaying the retransmission deadline
2Adaptability or versatility
If multiple SLIV indicators are provided for uplink resource allocation, then flexible scheduling is improved, but DCI message overhead increases
Solution Approach 1:
Multiple SLIV values are merged into a single DCI message through the resource indicator field. The first SLIV and second SLIV are both contained within the same DCI structure, reducing the number of separate messages needed while maintaining scheduling flexibility
Solution Approach 2:
The resource indicator field in DCI is designed to serve multiple functions: it can indicate a single continuous resource allocation or multiple segmented resource allocations with gaps. This multi-functionality allows the same field structure to handle different scheduling scenarios without increasing overhead
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described for efficient allocation of feedback resources and transmission of feedback for low latency communications. A first user equipment (UE) may be allocated uplink resources for uplink transmissions having one or more gaps during which a second UE may transmit feedback information to initiate a retransmission within specified time limits to achieve desired quality of service (QoS) targets. The one or more gaps may be provided through a downlink control information message that indicates uplink resources to the first UE based on a first starting transmission symbol and a first length indicator, and a second starting transmission symbol and a second length indicator. The one or more gaps may be additionally or alternatively provided through one or more reserved symbols, and the first UE may skip uplink transmissions in one or more reserved symbols.