HARQ-ACK Feedback Bitmap for CBG Uplink Contention Window Control
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting and receiving hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback, particularly in unlicensed bands, which affects the reliability and efficiency of data transmission and retransmission processes.
Innovation Solution
A method and apparatus for a terminal to receive configuration information for code block group (CBG)-based uplink transmission and downlink feedback information (DFI) bitmap configuration, enabling efficient determination of a contention window value based on feedback information, thereby enhancing HARQ-ACK feedback in wireless communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK feedback is transmitted in unlicensed bands using existing methods, then data transmission can occur, but the reliability and efficiency of feedback transmission deteriorates due to channel contention and interference
Solution Approach 1:
The feedback mechanism is segmented into two distinct parts: DFI (Downlink Feedback Information) transmitted on PDCCH for HARQ-ACK feedback, and DFI determination-related information transmitted on PDSCH for contention window value determination. This segmentation allows separate optimization of each feedback component, improving overall reliability by isolating critical HARQ-ACK feedback from potential interference affecting other data channels.
Solution Approach 2:
The patent implements a feedback mechanism where the terminal determines contention window values based on DFI determination-related information received from the base station. This feedback loop allows the system to adaptively adjust contention window sizes based on channel conditions and feedback quality, thereby improving reliability by dynamically responding to harmful factors like interference and contention.
2Productivity
If configuration information for CBG-based transmission and DFI bitmap is implemented, then HARQ-ACK feedback efficiency improves, but device complexity increases due to additional processing requirements
Solution Approach 1:
The base station pre-configures the terminal with DFI determination-related information on PDSCH before HARQ-ACK feedback transmission. This preliminary action includes providing bitmap configurations and contention window value mappings in advance, so the terminal can efficiently determine feedback parameters without complex real-time calculations, thereby improving feedback efficiency while managing device complexity through pre-computed configurations.
Solution Approach 2:
The patent changes key parameters from fixed to configurable: DFI bitmap configurations, contention window value mappings, and resource allocations are all made configurable through higher-layer signaling. This allows the system to optimize feedback efficiency for different scenarios while managing terminal complexity by providing flexible parameter sets that can be selected based on channel conditions and service requirements.
3Reliability
If DFI determination-related information is transmitted on PDSCH, then feedback information delivery is improved, but transmission time and resource overhead increase
Solution Approach 1:
The DFI determination-related information is transmitted periodically or event-triggered on PDSCH rather than continuously. This periodic action allows the system to balance reliability of feedback delivery with time efficiency by updating contention window configurations only when necessary, reducing unnecessary transmission overhead while ensuring feedback information is delivered reliably when channel conditions warrant updates.
Data Source
AI summary
Provided is a terminal for performing transmission and reception of data in a wireless communication system, wherein the terminal receives, from a base station, first configuration information for code block group (CBG)-based uplink transmission, and second configuration information including a downlink feedback information (DFI) bitmap configuration method, transmits a CBG-based uplink signal to the base station, based on the first configuration information, receives, from the base station, DFI including feedback information about the CBG-based uplink signal, based on the second configuration information, and determines a contention window value of the terminal, based on the feedback information included in the received DFI, wherein the DFI bitmap configuration method indicates whether the feedback information is for feedback in units of transport blocks (TBs) or for feedback for one or more CBGs.