Flexible COT Scheduling for Low-Latency Uplink in Unlicensed Spectrum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current channel occupancy time (COT)/fixed frame period (FFP) scheduling in unlicensed spectrum is inflexible, particularly for ultra-reliable and low latency communication (URLLC), leading to issues like gNB-initiated COT collisions and PUSCH segmentation, which hinder efficient data transmission in latency-critical scenarios.
Innovation Solution
Implement flexible COT behavior allowing both gNB and UE initiation, with signaling mechanisms to enable/disable UE-initiated COT based on RRC or DCI, and handle segmentation and idle periods to optimize transmission in unlicensed spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If gNB-initiated COT is used for channel access in unlicensed spectrum, then channel occupancy is controlled centrally, but transmission delays increase and scheduling flexibility is reduced for latency-critical URLLC traffic
Solution Approach 1:
The patent inverts the traditional gNB-initiated COT approach by enabling UE-initiated COT for uplink transmissions. Instead of the gNB always initiating the COT and the UE waiting for allocation, the UE can now initiate its own COT when it has data to transmit, thereby reducing waiting time and transmission delays for URLLC traffic while maintaining gNB control through configuration and monitoring mechanisms
Solution Approach 2:
The patent introduces dynamic COT initiation capability where the system can adapt between gNB-initiated and UE-initiated COT based on traffic conditions. The gNB configures UEs with COT initiation parameters and can dynamically control whether UE-initiated COT is permitted through RRC signaling and DCI, allowing the system to be flexible and responsive to varying latency requirements
2Productivity
If flexible COT behavior is implemented allowing both gNB and UE initiation, then scheduling efficiency and latency performance improve, but system complexity and signaling overhead increase
Solution Approach 1:
The patent creates a universal COT initiation framework that can operate in multiple modes (gNB-initiated, UE-initiated, and shared COT) within the same system. The gNB and UE both possess COT initiation capabilities depending on configuration, allowing the system to universally handle different traffic types and scenarios with a single flexible mechanism rather than separate systems for each mode
Solution Approach 2:
The patent controls system complexity through parameter-based configuration rather than structural changes. The gNB configures UEs with specific COT initiation parameters including permitted COT initiation indicators, FFP offsets, and duration values. The system dynamically adjusts behavior by changing these parameters through RRC signaling and DCI without requiring complex hardware or protocol modifications
3Loss of time
If UE-initiated COT is enabled for uplink transmissions, then transmission latency is reduced, but channel access conflicts and interference with gNB COT may occur
Solution Approach 1:
The patent applies preliminary action by having the gNB pre-configure UEs with COT initiation parameters before the UE attempts to initiate a COT. The gNB provides FFP offset values, permitted COT initiation indicators, and duration configurations in advance through RRC signaling, allowing the UE to perform LBT and initiate COT at predetermined opportunities without conflicting with gNB transmissions
Solution Approach 2:
The patent implements feedback mechanisms where the gNB monitors UE-initiated COT transmissions and provides acknowledgments or corrections through DCI. The gNB can indicate whether the UE successfully initiated COT, provide feedback on channel conditions, and adjust future COT initiation parameters based on observed performance, thereby maintaining channel access reliability
Data Source
Figure 1
Figure 2
Figure 3
AI summary
According to some embodiments, a method is performed by a wireless device for operation with shared spectrum channel access, wherein a first plurality of fixed frame periods (FFPs) are associated with the wireless device and a second plurality of fixed frame periods (FFPs) are associated with a network node and wherein each FFP comprises an idle period with no transmission and a channel occupancy time (COT) for potential transmission. The method comprises initiating a COT in one of the FFPs of the first plurality of FFPs and upon successful initiation of the COT, transmitting uplink data from the beginning of the COT.