Delta CQI/MCS Feedback for Accurate NR Link Adaptation
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Solution Overview
Problem
Current NR channel state information (CSI) reporting frameworks lack efficient mechanisms for delta-channel quality indicator (CQI)/modulation and coding scheme (MCS) feedback, particularly for ultra-reliable low-latency communication (URLLC) scenarios, leading to suboptimal link adaptation and scheduling decisions.
Innovation Solution
Implementing delta-CQI/MCS feedback systems that report the difference between the actual and recommended MCS for PDSCH transmissions, allowing gNB to adjust scheduling and link adaptation more accurately, with methods for determining applicable PDSCHs, multiplexing with HARQ-ACK feedback, and configuring reporting resources and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CSI reporting frameworks are used, then system complexity is reduced, but link adaptation accuracy and scheduling decision quality deteriorate
Solution Approach 1:
The patent segments the MCS feedback into two distinct components: absolute MCS recommendations and delta-CQI/MCS adjustments. This segmentation allows the system to maintain separate reporting mechanisms for different types of feedback information, improving link adaptation accuracy by providing more granular and specific feedback for each component while managing overall system complexity through structured organization.
Solution Approach 2:
The patent implements dynamic feedback mechanisms where delta-CQI/MCS values are adjusted based on actual transmission outcomes (ACK/NACK). The feedback system adapts its behavior dynamically, selecting between reporting absolute MCS values or delta adjustments depending on channel conditions and transmission results, thereby improving link adaptation accuracy while maintaining flexibility to manage complexity.
2Productivity
If detailed delta-CQI/MCS feedback is reported for all PDSCH transmissions, then scheduling decision accuracy is improved, but feedback overhead and processing time increase
Solution Approach 1:
The patent extracts only the essential feedback information needed for scheduling decisions by reporting delta-CQI/MCS values rather than complete MCS tables. This extraction approach reduces feedback overhead by transmitting only the differential adjustments needed, while still providing sufficient information for accurate scheduling decisions. The system takes out only the critical delta values rather than transmitting full MCS recommendations for every PDSCH.
Solution Approach 2:
The patent applies partial action by reporting delta-CQI/MCS feedback selectively rather than for all PDSCH transmissions. The system determines whether to report feedback based on specific conditions, such as transmission outcomes or channel variations, providing feedback only when necessary to maintain scheduling accuracy while minimizing overall feedback overhead and processing requirements.
3Reliability
If feedback reporting is delayed, then processing load is reduced, but latency in URLLC scenarios increases
Solution Approach 1:
The patent implements preliminary action by preparing and transmitting delta-CQI/MCS feedback as soon as transmission outcomes are determined, rather than waiting for scheduled reporting opportunities. The system proactively reports feedback information immediately when available, reducing processing delays and ensuring timely updates for URLLC transmissions, thereby improving reliability without significant latency penalty.
Solution Approach 2:
The patent establishes a tight feedback loop where delta-CQI/MCS information is rapidly reported based on transmission outcomes and immediately utilized for subsequent scheduling decisions. This continuous feedback mechanism ensures that the system quickly adapts to channel conditions and transmission results, maintaining high URLLC performance by minimizing the time between transmission and actionable feedback while managing processing load through efficient feedback generation.
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for reporting of delta channel quality indicator (CQI)/modulation and coding scheme (MCS) feedback are provided.