Logical Channel Prioritization for Pre-Emption in Wireless Devices
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Solution Overview
Problem
Current 3GPP NR-IoT systems lack a comprehensive framework for managing overlapping dynamic and configured uplink grants, leading to inefficiencies in prioritizing and pre-empting ongoing transmissions, particularly in scenarios with multiple periodic URLLC and eMBB traffic types, where existing guidelines focusing on logical channel prioritization are insufficient.
Innovation Solution
A wireless device implements a method to determine whether to pre-empt an ongoing transmission based on comparing prioritization information of overlapping grants, allowing for correct prioritization and multiplexing of logical channel data, even if a MAC PDU has already been constructed, ensuring that higher priority data is transmitted without discarding the pre-empted data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE follows existing LCP guidelines to prioritize URLLC traffic, then URLLC transmission reliability is improved, but the framework cannot handle overlapping dynamic and configured grants efficiently
Solution Approach 1:
The patent segments the grant management process into distinct phases: identifying overlapping grants, determining priority relationships, and executing pre-emption decisions. This segmentation allows the UE to handle complex overlapping grant scenarios systematically while maintaining URLLC reliability through structured decision-making procedures.
Solution Approach 2:
The patent introduces dynamic pre-emption mechanisms that allow the UE to adaptively adjust transmission priorities based on real-time grant overlap conditions. The system dynamically evaluates priority relationships between dynamic and configured grants and adjusts transmission behavior accordingly, enabling efficient handling of varying traffic patterns while maintaining reliability.
2Productivity
If the UE pre-empts an ongoing transmission to accommodate higher priority data, then data priority handling is improved, but radio resources may be wasted if pre-emption is not properly managed
Solution Approach 1:
The patent implements feedback mechanisms where the UE continuously monitors grant priorities and transmission status. When a higher priority grant is identified, the system provides feedback to trigger pre-emption decisions. This feedback loop ensures that pre-emption occurs only when necessary, preventing radio resource wastage while maintaining high data transmission efficiency for urgent traffic.
Solution Approach 2:
The patent changes the priority parameter dynamically based on grant type and traffic requirements. By adjusting priority parameters in real-time, the system can determine when pre-emption is appropriate versus when to maintain ongoing transmissions, thereby optimizing the balance between transmission efficiency and resource conservation.
3Speed
If the UE constructs MAC PDU based on first grant before receiving second grant, then transmission timing is maintained, but the UE cannot accommodate higher priority data that arrives later
Solution Approach 1:
The patent applies preliminary action by constructing the MAC PDU based on the first grant in advance, maintaining transmission timing. However, it also prepares the system to evaluate and potentially pre-empt this preliminary construction when a higher priority second grant arrives. This approach maintains speed while preserving adaptability through the pre-emption mechanism.
Solution Approach 2:
The patent introduces dynamic re-evaluation of the constructed MAC PDU when overlapping grants are detected. The system can dynamically adjust the transmission plan by pre-empting the initially constructed MAC PDU if a higher priority grant requires the resources, thus maintaining both timing efficiency and priority adaptability.
4Ease of operation
If the UE discards pre-empted data to clear resources for higher priority transmission, then priority handling is simplified, but data loss occurs
Solution Approach 1:
The patent implements a discard and recover mechanism where pre-empted data is temporarily set aside rather than immediately discarded. The system evaluates whether the pre-empted data can be recovered and transmitted later, possibly in remaining resources or subsequent opportunities. This approach maintains simple priority handling while preventing permanent data loss through recovery procedures.
Data Source
AI summary
A method performed by a wireless device includes receiving a first grant of resources from a network node. The first grant of resources is associated with first prioritization information. The wireless device constructs a Medium Access Control Protocol Data Unit, MAC PDU, based on the first grant. A second grant of resources that overlaps with the first grant of resources is received from the network node, and the second grant of resources is associated with second prioritization information. The wireless device determines whether to pre-empt transmission of the constructed MAC PDU based on comparing the first prioritization information and second prioritization information and pre-empts the transmission of the constructed MAC PDU if the second prioritization information indicates a higher priority than indicated by the first prioritization information.