NR-U Logical Channel Prioritization for URLLC Grant Collisions
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Solution Overview
Problem
Existing wireless communication systems face challenges in harmonizing uplink configured-grant enhancements for ultra-reliable and low latency communications (URLLC) in unlicensed spectrum, particularly in handling collisions between overlapping grants and prioritizing transmissions based on logical channel priorities.
Innovation Solution
A wireless communication method and user equipment (UE) that prioritizes autonomous transmission of pending medium access control (MAC) protocol data units (PDUs) based on logical channel (LCH) priorities, using parameters such as lch-based Prioritization, autonomous transmission indicator (autonomousTX), and configured grant retransmission timer (cg-RetransmissionTimer) to resolve collisions and enhance transmission efficiency in unlicensed bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If autonomous transmission of pending MAC PDU is prioritized over new data transmission, then transmission reliability for URLLC is improved, but transmission latency for high-priority new data increases
Solution Approach 1:
The patent introduces lch-based Prioritization as a configurable parameter that dynamically changes the prioritization behavior between autonomous transmission and new data transmission. When lch-based Prioritization is enabled, the system transitions from always prioritizing autonomous transmission to comparing logical channel priorities and making decisions based on the highest priority, thus resolving the contradiction by making the prioritization behavior adaptable rather than fixed
Solution Approach 2:
The patent makes the transmission prioritization dynamic by introducing the lch-based Prioritization mechanism that allows the system to adapt its behavior based on current logical channel priorities. The MAC entity dynamically compares the priority of pending MAC PDU with new data MAC PDU and selects the transmission based on real-time priority conditions, enabling flexible response to different traffic requirements
2Productivity
If logical channel based prioritization is implemented to resolve grant collisions, then transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the MAC entity to autonomously perform logical channel priority comparison and transmission selection without external intervention. The UE automatically detects grant collisions, compares lch priorities of pending and new data MAC PDUs, and makes transmission decisions based on the comparison result, reducing the need for complex external scheduling while improving transmission efficiency
Solution Approach 2:
The patent uses lch-based Prioritization as a configurable parameter that simplifies the collision resolution mechanism. Instead of implementing complex collision detection and resolution algorithms, the system changes the prioritization parameter to enable simple logical channel priority comparison, thereby improving transmission efficiency while keeping device complexity manageable
Data Source
AI summary
A user equipment (UE) executes a wireless communication method to harmonize features for NR-based access to unlicensed spectrum (NR-U) and Ultra-reliable low-latency communications (URLLC). The UE comprises a medium access control (MAC) entity. The MAC entity prioritizes autonomous transmission of a pending MAC protocol data unit (PDU) through a first UL grant over transmission of the MAC PDU indicated as new data through a second UL grant when a logical channel (LCH) priority associated with the MAC PDU indicated as new data is not higher than an LCH priority associated with the pending MAC PDU. The MAC entity prioritizes transmission of the MAC PDU indicated as new data through the second UL grant over autonomous transmission of the pending MAC PDU when the LCH priority associated with the MAC PDU indicated as new data is higher than the LCH priority associated with the pending MAC PDU.