Code Block Aware Slot Preemption in 5G URLLC
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Solution Overview
Problem
In wireless communications, particularly in 5G New Radio systems, the stringent latency requirements of ultra-reliable low-latency communication (URLLC) lead to challenges in slot transmission preemption, where puncturing or preemption of slot data transmissions by mini-slot transmissions increases the probability of partially punctured code blocks being unrecoverable, resulting in higher retransmission rates and reduced throughput.
Innovation Solution
A method and system for code block aware slot transmission preemption, where a wireless transmitter determines a resource allocation for high-priority transmissions to preempt lower-priority transmissions by calculating the fraction of bits to be punctured, using a threshold to decide whether to spread puncturing over multiple code blocks or confine it to fewer blocks, thereby minimizing retransmissions and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mini-slot transmission preempts slot transmission resources to meet stringent latency requirements, then transmission speed and latency are improved, but the reliability of slot data transmission deteriorates due to increased puncturing
Solution Approach 1:
The patent segments the slot transmission into multiple code blocks and introduces the concept of code block groups (CBGs). By dividing the transmission into smaller manageable units, the system can selectively retransmit only the affected CBGs rather than the entire slot, thereby maintaining reliability while enabling fast preemptive transmission of mini-slots.
Solution Approach 2:
The patent changes the parameter of transmission granularity by introducing CBGs as an intermediate unit between the entire slot and individual code blocks. This parameter change allows the system to adjust the scope of retransmission dynamically, improving reliability without sacrificing the speed benefits of mini-slot preemption.
2Loss of time
If puncturing is applied to slot transmissions to accommodate high-priority mini-slot transmissions, then latency is reduced, but the number of unrecoverable code blocks increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring code block groups and establishing their mapping to physical resources before transmission. When preemption occurs, the system can quickly identify which CBGs are affected and initiate targeted retransmission without needing to analyze the entire slot structure, thus reducing latency while minimizing information loss.
Solution Approach 2:
The patent applies local quality by treating different code block groups differently based on their puncturing status. Instead of uniformly handling all code blocks, the system identifies specifically which CBGs are affected by the mini-slot preemption and applies retransmission only to those local regions, thereby reducing the overall loss of information.
3Device complexity
If conventional slot preemption is used without code block awareness, then resource allocation is simplified, but retransmission rates increase
Solution Approach 1:
The patent segments the slot into code block groups with distinct identifiers, allowing the system to track and manage each CBG independently. This segmentation enables the receiver to identify exactly which CBGs were punctured and request retransmission only for those specific groups, significantly reducing retransmission rates while maintaining manageable complexity through standardized CBG signaling.
Data Source
AI summary
According to certain embodiments a method is provided for use in a wireless transmitter that includes receiving an indication to schedule a high-priority transmission to preempt a lower-priority transmission that comprises one or more code blocks. A first resource allocation is determined for the high-priority transmission. A fraction of bits in the one or more code blocks of the lower-priority transmission that will be punctured by the first resource allocation is determined. When the fraction of bits in the one or more code blocks of the lower-priority transmission that will be punctured is less than a threshold, the first resource allocation is used for the high-priority transmission. Otherwise, a second allocation for the high-priority transmission is determined and used to minimize a number of the one or more code blocks that will be punctured.