MAC PDU Channel Access Priority for URLLC in Unlicensed Bands
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Solution Overview
Problem
Existing technologies face challenges in meeting the stringent delay and reliability requirements for Ultra-Reliable Low Latency Communication (URLLC) services in the unlicensed band, particularly due to congestion and channel state issues during PDCP duplication transmissions.
Innovation Solution
The proposed solution involves a method where a wireless communication device determines the channel access priority of a MAC PDU for multiplexing data from multiple logical channels, and performs transmission accordingly. This includes selecting the appropriate channel access priority based on downlink channel information, dynamic or configured grants, and prioritizing URLLC transmissions to ensure low latency and high reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data from multiple logical channels is multiplexed in a MAC PDU for transmission in unlicensed band, then channel utilization efficiency is improved, but delay and reliability requirements for URLLC services cannot be met due to channel congestion and access conflicts
Solution Approach 1:
The patent segments the channel access process by introducing separate channel access procedures for different priority levels. High-priority URLLC data and low-priority data are handled through distinct access mechanisms, allowing URLLC transmissions to occur without being blocked by lower-priority traffic. This segmentation resolves the contradiction by maintaining high channel utilization for general traffic while guaranteeing reliable access for URLLC services.
Solution Approach 2:
The patent applies local quality by assigning different channel access priorities to different logical channels based on their service requirements. URLLC logical channels are configured with higher priority (lower priority class value) while other channels use standard priorities. This localized differentiation ensures that URLLC transmissions receive preferential treatment in channel access, resolving the reliability issue while maintaining overall system efficiency.
2Adaptability or versatility
If channel access priority is determined based on multiple logical channels with different priorities, then transmission flexibility is improved, but determining the appropriate priority class becomes complex
Solution Approach 1:
The patent implements dynamic priority determination where the MAC entity selects the priority class based on the highest priority logical channel included in the MAC PDU. This dynamic selection adapts to the specific composition of each MAC PDU, allowing flexible handling of mixed-priority data while using a simple selection rule (highest priority channel determines PDU priority) that avoids complex decision-making processes.
Solution Approach 2:
The patent uses feedback mechanisms where the network configures priority information for each logical channel, and the UE uses this configured information to determine MAC PDU priority. The network can update priority configurations based on traffic conditions, providing adaptive control without increasing UE complexity. The UE simply follows the configured priority rules when constructing MAC PDUs.
Data Source
AI summary
A system and method for meeting the delay and reliability requirements for signal transmission using URLLC in the unlicensed band. The system and method include determining, by a wireless communication device, a channel access priority of a medium access control (MAC) protocol data unit (PDU), wherein the MAC PDU is to be multiplexed by data from a plurality of logical channels (LCHs); performing, by the wireless communication device, a channel access procedure according to the channel access priority.