Compact DCI Formats for PDCCH Reliability in 5G URLLC
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Solution Overview
Problem
Current 5G New Radio (NR) systems face challenges in achieving ultra-reliable and low-latency communications due to limitations in the physical downlink control channel (PDCCH) reliability and coverage, particularly in mmWave bands, where path loss and channel conditions are severe, and existing control information formats are not optimized for these requirements.
Innovation Solution
The introduction of new compact or size-matched downlink control information (DCI) formats, such as DCI formats 0_2 and 1_2, which reduce the DCI payload size, optimize existing fields, and introduce new fields to enhance reliability and link performance for ultra-reliable low-latency communications (URLLC) applications, enabling better support for URLLC features and link adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DCI payload size is reduced using compact DCI formats, then the SNR and PDCCH reliability are improved, but the information transmission capacity is reduced
Solution Approach 1:
The DCI format is segmented into essential control fields only, separating critical scheduling information from optional parameters. This segmentation allows the payload size to be reduced while maintaining the most important control functions, thereby improving reliability without completely sacrificing information capacity.
Solution Approach 2:
Non-essential fields and parameters are extracted or removed from the DCI format, keeping only the minimum necessary information for reliable control channel operation. This extraction reduces payload size and improves SNR while the removed fields represent the sacrificed information capacity.
2Reliability
If new fields are introduced to enhance reliability and link performance, then the URLLC support is improved, but the DCI payload size increases
Solution Approach 1:
New fields are introduced locally only where needed to enhance specific URLLC functions, rather than uniformly expanding the entire DCI structure. This localized addition minimizes the overall payload size increase while providing targeted reliability improvements for ultra-reliable low-latency communication requirements.
Solution Approach 2:
Only the necessary portion of new fields required for URLLC enhancement are added, avoiding excessive expansion. The payload size increases partially, just enough to provide the needed reliability and link performance improvements without unnecessary bloat.
3Productivity
If existing DCI fields are optimized, then the resource allocation efficiency is improved, but the compatibility with legacy systems may be reduced
Solution Approach 1:
The DCI fields are made dynamic and configurable, allowing the system to adapt between optimized modes for improved resource allocation and legacy modes for compatibility. This dynamic structure enables the same DCI format to serve both efficiency improvement and backward compatibility requirements under different operating conditions.
Solution Approach 2:
The optimized DCI fields are designed to serve multiple functions - they can operate in an optimized configuration for improved resource allocation efficiency while maintaining the ability to function in a legacy-compatible mode, making the format universal across different system requirements.
Data Source
AI summary
Embodiments of the present disclosure describe methods, apparatuses, storage media, and systems for determining a capability of a UE to support a first downlink control information (DCI) format for Physical Downlink Shared Channel (PDSCH) reception in a downlink (DL) bandwidth part (BWP) and a second DCI format for scheduling uplink (UL) grants for physical uplink shared channel (PUSCH) transmission in a UL bandwidth part (BWP), where the first DCI format is different from DCI formats 1_0 or 1_1, and the second DCI format is different from DCI formats 0_0 or 0_1. Furthermore, a base station may determine search spaces for monitoring physical downlink control channel (PDCCH) candidates to obtain DCI formats indicated by the base station. Other embodiments may be described and claimed.