Multicarrier Retransmission Scheduling With Adaptive Code Block Resources
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Solution Overview
Problem
The multicarrier mobile communication system faces inefficiencies in retransmissions due to a constant iteration pattern, leading to suboptimal retransmission efficiency, especially when error rates in code words are low, as the same size of transmission signal is retransmitted regardless of error distribution.
Innovation Solution
The system introduces a dynamic resource allocation mechanism where the receiving unit performs iterative decoding with early termination for code blocks with no errors and requests retransmission of code blocks with errors, allowing for flexible resource assignment based on error detection, thereby optimizing retransmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant iteration pattern is used for retransmission scheduling, then the system maintains simple scheduling logic, but retransmission efficiency deteriorates when error rates are low
Solution Approach 1:
The patent applies dynamics by making the iteration pattern adaptive rather than constant. The base station determines the iteration pattern dynamically based on feedback from the mobile station about decoding status and error rates. This allows the system to switch between different iteration patterns (e.g., incremental redundancy vs. chase combining) depending on channel conditions, thereby improving retransmission efficiency while maintaining manageable scheduling complexity through automated adaptation.
Solution Approach 2:
The patent changes the parameter of iteration pattern based on error rates and decoding success. When error rates are low and decoding succeeds early, the system can use fewer iterations or different redundancy levels. When error rates are high, the system increases iterations or changes to more robust redundancy schemes. This parameter adaptation directly addresses the efficiency problem while keeping the underlying scheduling framework relatively simple.
2Device complexity
If the same size code block is retransmitted regardless of error distribution, then the scheduling process is simplified, but resource allocation efficiency deteriorates
Solution Approach 1:
The patent segments the code block retransmission into variable-sized portions based on error distribution. Instead of retransmitting the entire code block at a fixed size, the system divides the retransmission into segments that target specific error-prone portions. The mobile station provides feedback about which code blocks contain errors, and the base station schedules retransmissions of only those specific segments, thereby improving resource allocation efficiency without significantly increasing scheduling complexity.
Solution Approach 2:
The patent applies local quality by making retransmission size and content specific to the local error conditions of each code block. Rather than applying a uniform retransmission strategy across all code blocks, the system tailors the retransmission size and redundancy level to the specific error distribution observed in each block. This localized approach optimizes resource usage by allocating resources only where needed based on actual error patterns.
3Reliability
If iterative decoding is performed to completion for all code blocks, then decoding reliability is improved, but power consumption and processing time increase
Solution Approach 1:
The patent applies partial action by performing iterative decoding only to the extent necessary for successful recovery. The mobile station monitors decoding progress and provides feedback to the base station about which code blocks have been successfully decoded and which require retransmission. This allows the system to stop iterative decoding early for successfully decoded blocks, avoiding unnecessary power consumption and processing time, while maintaining high reliability by ensuring that all necessary retransmissions are eventually received and decoded.
Solution Approach 2:
The patent uses feedback mechanisms where the mobile station informs the base station about decoding status, error detection results, and iteration completion status. This feedback allows the base station to adjust the iteration pattern and retransmission strategy in real-time, stopping iterative decoding when success is achieved and preventing unnecessary power consumption on already-decoded blocks, thereby maintaining reliability while reducing energy usage.
Data Source
AI summary
A transmitting unit divides a transmit data into a plurality of code blocks, and encodes each of the plurality of code blocks to generate a transmission signal. The transmitting unit transmits the transmission signal, and a receiving unit receives the transmission signal as a reception signal. The receiving unit, when being an error in the reception signal, transmits a retransmission request feedback data which contains a NACK data and a data indicating the first code block group to the transmitting unit. First resources are assigned for each of the plurality of code blocks of the transmission signal. The transmitting unit assigns resources of the first code block group of the plurality of code blocks of the transmission signal to second resources which are fewer than the first resources, based on the retransmission request feedback data, and retransmits the transmission signal to the receiving unit.