Dynamic Code Block Group Size Adjustment for HARQ Interference Mitigation
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Solution Overview
Problem
In communication systems, the inefficiency of Automatic Repeat Request (ARQ) protocols due to discarding erroneous data and the need for asynchronous Hybrid ARQ (HARQ) for both uplink and downlink to manage interference from sources like RADAR systems, which affects the size and efficiency of code block groups (CBGs) in cellular networks.
Innovation Solution
A method where a wireless transmit/receive unit (WTRU) and base station dynamically adjust the size of code block groups (CBGs) based on interference patterns, using feedback mechanisms and signaling through master information block (MIB), radio resource control (RRC), and downlink control information (DCI) to optimize retransmissions and reduce unnecessary data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed-size code block groups (CBGs) are used for HARQ retransmissions, then the system structure is simple and easy to implement, but unnecessary retransmissions occur when interference affects only specific code blocks, reducing throughput
Solution Approach 1:
The patent implements dynamic CBG size adjustment where the base station and WTRU adaptively change the number of code blocks per CBG based on detected interference patterns. During interference periods, the CBG size is reduced to isolate affected blocks, while during normal periods, the size is increased to improve throughput. This dynamic adaptation resolves the contradiction by allowing the system to optimize productivity without permanent complexity.
Solution Approach 2:
The patent changes the parameter of CBG size (number of code blocks per group) based on interference conditions. The base station detects interference patterns and signals the WTRU to adjust the CBG configuration parameter accordingly. This parameter change allows the system to maintain simple fixed-size structures during normal operation while adapting to interference conditions, thereby improving throughput without permanently increasing complexity.
2Reliability
If smaller CBG sizes are used to isolate interference impact, then retransmission efficiency improves by limiting retransmissions to only affected blocks, but the overhead of managing multiple smaller CBGs increases system complexity
Solution Approach 1:
The patent segments the transport block into multiple code blocks that can be grouped into different-sized CBGs based on interference patterns. When interference is detected affecting specific code blocks, the system creates smaller CBGs that isolate only the affected blocks, allowing selective retransmission. This segmentation improves retransmission efficiency by avoiding unnecessary retransmission of unaffected blocks while managing complexity through structured segmentation rules.
3Adaptability or versatility
If asynchronous HARQ is implemented for dynamic TDD and unlicensed spectrum operation, then system flexibility and adaptability improve, but interference management becomes more challenging affecting HARQ performance
Solution Approach 1:
The patent implements a feedback mechanism where the WTRU detects interference patterns in received transmissions and reports them to the base station. The base station uses this feedback to adjust CBG sizes and configure retransmissions appropriately. This feedback loop allows asynchronous HARQ to maintain its flexibility and adaptability while actively managing interference impact, as the system continuously adapts based on real-time interference conditions reported by the WTRU.
Data Source
AI summary
A method performed by a base station may compromise: detecting an interference pattern; determining that the interference pattern impacts one or more code blocks (CBs) within one or more code block groups (CBGs); adjusting a size of the one or more CBGs; and transmitting, to a wireless transmit/receive unit (WTRU), information associated with the adjusting of the size of the one or more CBGs. The interference pattern may be caused by a radio detection and ranging (RADAR) system. The adjusting of the size of the one or more CBGs may compromise increasing or decreasing the number of CBs within the one or more CBGs. The transmitting of the information relating to the adjusting of the size of the one or more CBGs may be performed via master information block (MIB) signaling, radio resource control (RRC) signaling, or downlink control information (DCI) signaling.