Downlink Control Information Alignment for URLLC Reliability
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Solution Overview
Problem
Current communication systems face challenges in achieving reliable downlink control information transmission, particularly in Ultra Reliable Low Latency Communication (URLLC) scenarios, where the limited number of blind decodes per Transmission Time Interval (TTI) and differing DCI sizes complicate the alignment and decoding of control channels, affecting packet transmission reliability.
Innovation Solution
The method involves aligning and coding downlink control information (DCI) sizes by adding a differentiator bit and applying inner channel coding to ensure efficient decoding, sharing blind decodes between standard and URLLC services, and configuring additional coding and CRC attachment to maintain reliability and reduce complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different DCI sizes are used for standard and URLLC services, then service-specific optimization is achieved, but blind decode alignment becomes complex and reliability decreases
Solution Approach 1:
The patent applies homogeneity by padding URLLC DCI with zeros to match the size of standard DCI formats. This ensures that all DCI messages have uniform length, allowing the UE to perform blind decodes without needing to distinguish between different DCI size formats, thereby simplifying the decoding process and improving reliability while maintaining service-specific optimization through differentiated content rather than structure
2Productivity
If the number of blind decodes is limited per TTI, then resource efficiency is improved, but the ability to support both standard and URLLC services simultaneously is reduced
Solution Approach 1:
The patent implements universality by designing a single blind decode mechanism that serves both standard and URLLC services. The UE performs one blind decode operation that can successfully decode both types of DCI messages due to their aligned sizes and structures, allowing the limited number of blind decodes per TTI to be efficiently utilized across multiple service types without requiring separate decode resources for each service
3Device complexity
If DCI sizes are aligned by padding, then decoding complexity is reduced, but transmission overhead increases
Solution Approach 1:
The patent applies this principle by using zero-padding as a disposable, low-cost mechanism to achieve DCI size alignment. The padding bits are simple binary zeros that add minimal overhead compared to the alternative of creating and maintaining multiple DCI format specifications. The padding is a lightweight solution that sacrifices a small amount of transmission efficiency to gain significant reductions in decoding complexity and improve reliability
Data Source
AI summary
For downlink control, a method receives by use of a processor, at User Equipment, a control channel with a first aggregation level in a Transmission Time Interval. The method attempts to decode the control channel. In response to the control channel being successfully decoded, the method determines a first downlink control information (DCI) with a first number of bits based on the received control channel; determines whether to decode the first DCI to determine a second DCI with a second number of bits based on the first DCI; and determines the second DCI with a second number of bits based on the decoded first DCI if determined to decode the first DCI. The method transmits data according to the second DCI if the second DCI is an uplink grant. The method receives data according to the second DCI if the second DCI is a downlink assignment.