Configured Grant Uplink Collision Handling in NR-U
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Solution Overview
Problem
In unlicensed spectrum scenarios, configured uplink transmissions in NR-U face issues due to shared channels being busy or occupied, leading to challenges in prioritizing and managing data transmissions using configured grants.
Innovation Solution
A method for user equipment to determine channel availability, prioritize data based on logical channels, service types, quality of service requirements, and queuing time, and utilize hybrid ARQ buffers to manage data transmission opportunities, including storing data in separate HARQ buffers and selectively reordering them for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If configured grant transmissions are used in unlicensed spectrum, then uplink transmission efficiency is improved, but channel collision and interference increase due to shared spectrum access
Solution Approach 1:
The patent applies preliminary action by performing Listen-Before-Talk (LBT) procedures before configured grant transmissions. The UE checks channel availability in advance and prepares transmission opportunities only when the channel is determined to be free, preventing collisions before they occur. This is implemented through periodic LBT checks and configuration of transmission opportunities based on channel status.
Solution Approach 2:
The patent implements dynamics by making configured grant transmissions adaptive to real-time channel conditions. The UE dynamically adjusts transmission behavior based on LBT outcomes, channel busy indicators, and competing transmission detections. Transmission parameters such as power levels and timing are modified according to detected channel occupancy and interference conditions.
2Adaptability or versatility
If multiple data types are transmitted using configured grants, then service versatility is improved, but data prioritization and QoS management become more complex
Solution Approach 1:
The patent applies segmentation by dividing data into separate logical channels with distinct QoS requirements. Each logical channel is assigned specific priority levels and handling rules. The UE maintains separate buffers for different logical channels and applies channel-specific prioritization rules, simplifying the management of diverse data types while maintaining service versatility.
Solution Approach 2:
The patent implements local quality by assigning different priority levels and QoS parameters to different logical channels based on their specific service requirements. Each logical channel receives customized handling rules, such as different prioritization weights, buffer management policies, and transmission timing rules, allowing tailored QoS management for each service type rather than uniform treatment.
3Reliability
If channel availability checking is performed before each transmission opportunity, then transmission reliability is improved, but time loss increases due to repeated LBT procedures
Solution Approach 1:
The patent applies periodic action by scheduling LBT procedures and transmission opportunities at regular intervals defined by configured grant parameters. Instead of continuous channel monitoring, the UE performs LBT checks at predetermined periodic moments, reducing time loss while maintaining reliable transmission opportunities. This periodic structure allows efficient use of configured grant resources.
Solution Approach 2:
The patent implements preliminary action by performing channel availability checks in advance of actual data transmission. The UE determines channel status beforehand and prepares transmission buffers accordingly, allowing reliable transmission decisions to be made early. This preliminary checking enables the system to plan transmissions ahead, reducing last-minute delays and time loss.
4Reliability
If HARQ buffers are used to store pending data, then data transmission reliability is improved, but buffer management complexity increases when handling multiple data types
Solution Approach 1:
The patent applies segmentation by dividing HARQ buffers into separate logical channel buffers. Each logical channel has its own dedicated buffer space, preventing mixing of different data types. This segmentation simplifies buffer management by allowing independent handling of each logical channel's data, reducing the complexity of managing multiple data types while maintaining transmission reliability through HARQ mechanisms.
Data Source
AI summary
Embodiments include methods, performed by a user equipment (UE), for uplink (UL) transmission on a shared channel in a cell of a radio access network (RAN). Such methods include determining that the shared channel is unavailable for UL transmission of pending data during a first transmission opportunity. This determination can be based on performing a listen-before-talk (LBT) procedure on the shared channel. Such methods include determining that further data for UL transmission is available before a second transmission opportunity that is after the first transmission opportunity, and determining whether the pending data or the further data should be prioritized for UL transmission during the second transmission opportunity. This prioritization determination can be based on various factors. Such methods can also include transmitting the pending data or the further data, during the second transmission opportunity, based on the prioritization determination. Other embodiments include UEs configured to perform such methods.