Base Station Automatic Retransmission Scheduling Method
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Solution Overview
Problem
In TDD systems using carrier aggregation technology, the bundling or multiplexing of HARQ ACK/NACK feedback leads to compression of true HARQ information, resulting in unnecessary retransmissions and waste of radio resources due to the inability to differentiate between correctly and incorrectly received transport blocks.
Innovation Solution
A base station (BS) and automatic retransmission scheduling method where the status report of a first retransmission mechanism assists in scheduling the second retransmission mechanism by comparing the retransmission serial number of the second layer PDU with the ACK serial number from the first protocol layer, determining whether to disable retransmissions and thereby reducing unnecessary retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If HARQ bundling or multiplexing is used to compress ACK/NACK feedback in TDD systems, then the feedback quantity is reduced and can be transmitted in limited uplink subframes, but the true HARQ information is lost and unnecessary retransmissions occur
Solution Approach 1:
The invention segments the feedback information by introducing a separate indication field that identifies which specific transport blocks (TBs) within a codeblock group (CBG) were successfully received. This segmentation allows the system to maintain compressed feedback structure while preserving granular information about individual TB reception status, thereby resolving the contradiction between feedback compression and information loss.
Solution Approach 2:
The invention adds a new dimension to the feedback structure by introducing an indication field that operates alongside the traditional ACK/NACK bits. This additional dimension provides supplementary information about the reception status of specific TBs without increasing the time-frequency resources allocated for feedback transmission, thus maintaining compression while reducing information loss.
2Quantity of substance
If spatial bundling operation is performed to compress the quantity of HARQ ACKs/NACKs in carrier aggregation systems, then the feedback can be transmitted using existing PUCCH formats, but unnecessary retransmissions occur due to loss of true HARQ information
Solution Approach 1:
The invention segments the codeblock group into individual transport blocks and introduces an indication field that specifies which TBs were successfully received. This segmentation enables the system to maintain the compressed feedback structure required for PUCCH format compatibility while providing sufficient information to avoid unnecessary retransmissions, thereby improving transmission efficiency.
Solution Approach 2:
The invention enhances the feedback mechanism by adding an indication field that provides detailed reception status information. This improved feedback allows the base station to make more accurate retransmission decisions, reducing unnecessary retransmissions and improving overall transmission efficiency while maintaining compatibility with existing PUCCH formats.
3Device complexity
If multiple transport blocks are compressed into one ACK/NACK for feedback, then the feedback transmission is simplified and resource-efficient, but retransmission of correctly received blocks occurs causing waste of radio resources
Solution Approach 1:
The invention segments the feedback information by introducing an indication field that identifies which specific transport blocks within the codeblock group were successfully received. This segmentation maintains the simplified feedback transmission structure while providing sufficient information to prevent unnecessary retransmissions, thereby reducing radio resource waste without increasing feedback complexity.
Solution Approach 2:
The invention changes the parameter structure of the feedback by adding an indication field that provides additional information about TB reception status. This parameter change enables the system to maintain simple feedback transmission while improving the accuracy of retransmission decisions, thus reducing unnecessary retransmissions and radio resource waste.
Data Source
AI summary
The invention provides a base station and an automatic retransmission scheduling method thereof. The automatic retransmission scheduling method includes the following steps: when at least one first layer of protocol data unit of a first protocol layer constitutes a second layer PDU of a second protocol layer, assigning a retransmission serial number of the second layer PDU according to a serial number of the first layer PDU; sending the second layer PDU to a user equipment; receiving a status report of a first retransmission mechanism of the first protocol layer, and an acknowledgement serial number indicates that receiving of multiple PDUs of the first protocol layer by the UE is acknowledged; comparing the retransmission serial number of the second layer PDU with the ACK serial number, and determining whether to disable retransmission of the second layer PDU based on a second retransmission mechanism.