Retransmission Control Using Error Thresholds for Low-Latency Reliability
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Solution Overview
Problem
Existing communication technologies struggle to balance low latency and high reliability in data transmission, particularly in environments with high bit error rates, as conventional ARQ and HARQ methods either fail to meet latency or reliability requirements.
Innovation Solution
A retransmission method that determines the quantity of errors in a signal and compares it to a threshold to decide if the data block should be resent, using error correction and cyclic redundancy check before decoding, thereby improving data transmission efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ARQ technology is used to improve reliability through CRC checking, then data transmission reliability is improved, but data transmission latency increases due to retransmission requests in high bit error rate scenarios
Solution Approach 1:
The patent applies preliminary action by performing FEC encoding on data blocks before transmission. The receiving device decodes and corrects errors proactively before needing to request retransmission. This preliminary error correction capability allows the system to handle certain levels of channel errors without triggering ARQ retransmission, thus reducing latency while maintaining reliability.
Solution Approach 2:
The patent merges FEC and ARQ technologies into a hybrid system. The FEC layer provides initial error correction capability, while the ARQ layer handles residual errors that exceed FEC correction capacity. This combination allows the system to achieve both low latency (through FEC correction) and high reliability (through ARQ fallback), resolving the contradiction between the two requirements.
2Loss of time
If RS (132, 128)+CRC32 FEC solution is used to meet low latency requirements, then data transmission latency is reduced, but error correction capability becomes weak and reliability requirement cannot be met when bit error rate is high
Solution Approach 1:
The patent implements a dynamic error correction strategy where the system first attempts FEC decoding with a relatively weak code (RS 132, 128) to quickly correct common errors. If the error count exceeds the FEC correction capability, the system dynamically switches to requesting ARQ retransmission. This dynamic adaptation allows the system to maintain low latency for typical error conditions while ensuring reliability when error rates are high.
Solution Approach 2:
The patent introduces an intermediary error counting and decision mechanism between the FEC decoder and the ARQ retransmission request. This intermediary component counts the number of errors in the received signal, compares it against a threshold, and decides whether to attempt FEC correction or request retransmission. This intermediary layer enables the system to optimize between latency and reliability based on actual channel conditions.
3Reliability
If RS (544, 514)+CRC32 FEC solution is used to meet high reliability requirements, then error detection capability is strong, but error detection process becomes more complex and latency requirement cannot be met
Solution Approach 1:
The patent applies partial action by using a relatively weak FEC code (RS 132, 128) that can handle a portion of the error correction needs. This partial error correction capability is sufficient for typical channel conditions, avoiding the need to deploy a much stronger (and more complex) code like RS (544, 514) that would be required to handle all possible error scenarios. The system accepts that some extreme error cases will require ARQ retransmission, but this approach maintains low latency for the majority of transmission scenarios.
Data Source
AI summary
This disclosure provides a retransmission method and a communication apparatus, applicable to a wireless or wired communication system. One example method includes: After receiving a signal from a second device, a first device performs first decoding on the signal, then determines whether an error occurs in the signal and a first quantity, and determines, based on a relationship between the first quantity and a first threshold, whether to request the second device to send a first data block, where the first quantity is a quantity of errors that occur in the signal received from the second device, the signal is used to transmit the first data block, and the first threshold is a maximum quantity of errors that can be corrected when the first device decodes the first data block.