Dynamic HARQ Code Block Grouping for 5G Feedback Overhead
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Solution Overview
Problem
The high data rates in 5G and New Radio (NR) networks pose challenges for hybrid automatic repeat request (HARQ) operations, requiring efficient methods to manage and acknowledge code blocks due to increased complexity and resource consumption.
Innovation Solution
Implementing a dynamic code block HARQ mechanism that bundles HARQ-ACK feedback based on transport block size (TBS) thresholds, allowing for adaptive feedback and reducing overhead, with bundle sizes configured through downlink control information (DCI) and radio resource control (RRC) signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high data rates are implemented in 5G and NR networks, then throughput and capacity are improved, but HARQ operation complexity and resource consumption increase
Solution Approach 1:
The patent segments the HARQ feedback process by introducing separate feedback mechanisms for different code block groups. Instead of treating all code blocks uniformly, the system divides them into groups and applies different HARQ-ACK feedback strategies to each group, thereby managing the complexity of HARQ operations at high data rates while maintaining reliable error correction
Solution Approach 2:
The patent implements dynamic HARQ operations where the feedback mechanism adapts based on transport block size thresholds. The system dynamically selects between different feedback modes (e.g., separate HARQ-ACK for small TBS, bundled HARQ-ACK for large TBS) based on real-time conditions, allowing flexible management of HARQ complexity as data rates vary
2Reliability
If detailed HARQ-ACK feedback is provided for each code block, then reliability is improved, but feedback overhead increases
Solution Approach 1:
The patent changes the feedback parameter structure by introducing transport block size thresholds that determine the feedback mode. When TBS exceeds a threshold, the system transitions from providing separate HARQ-ACK for each code block to using bundled HARQ-ACK feedback, thereby reducing feedback overhead while maintaining reliability through adaptive parameter selection
Solution Approach 2:
The patent applies partial feedback action by selectively providing detailed HARQ-ACK feedback only when necessary (for small TBS values), and using condensed bundled feedback for larger TBS values. This partial approach to feedback provides sufficient reliability information without the excessive overhead of always providing complete per-code-block feedback
Data Source
AI summary
Embodiments of a User Equipment (UE), Evolved Node-B (eNB) and methods for communication are generally described herein. The UE may receive downlink control information (DCI) that schedules a transport block (TB) that includes multiple code blocks. The UE may determine a transport block size (TBS) based on the DCI. The UE may attempt to decode the code blocks. The UE may, if the TBS is greater than a predetermined threshold: bundle the code blocks into code block groups for hybrid automatic repeat request (HARQ) acknowledgement; and transmit a HARQ bit per code block group. The UE may, if the TBS is less than or equal to the threshold, transmit a HARQ bit that indicates whether a decode failure has occurred for at least one of the code blocks of the TB.