Retransmission Control via ACK/NACK Probability Estimation
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Solution Overview
Problem
In mobile communication systems, existing retransmission control methods often lead to inefficient data retransmissions due to incorrect determination of acknowledgement (ACK) or negative acknowledgement (NACK) responses, resulting in poor network quality and unnecessary data delays.
Innovation Solution
A retransmission control method and device that determine the normality of control data, estimate response data as ACK or NACK, and selectively retransmit packetized data based on probability estimation techniques, such as temporal proximity, number of transmissions, amount of data, and data type, to minimize unnecessary retransmissions and improve reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitting device always retransmits packetized data when control data cannot be correctly received, then data transmission reliability is improved, but unnecessary retransmissions increase causing network quality deterioration
Solution Approach 1:
The transmitting device uses feedback from the receiving device (ACK/NACK responses) to determine whether retransmission is necessary. By correctly interpreting the receiving device's response even when control data reception is imperfect, the system avoids unnecessary retransmissions while maintaining reliable data transmission.
Solution Approach 2:
The system changes the parameter of retransmission decision-making from binary (always retransmit or never retransmit) to probabilistic (estimate likelihood of ACK/NACK). This allows optimization of both reliability and network quality by making informed decisions based on estimated response probabilities.
2Reliability
If the transmitting device increases retransmission attempts to ensure data delivery, then reception probability is improved, but transmission delays increase
Solution Approach 1:
The transmitting device performs preliminary estimation of the receiving device's response (ACK or NACK) before deciding whether to retransmit. This preliminary action allows the system to avoid unnecessary retransmissions and their associated delays while still ensuring reliable data delivery when actually needed.
3Device complexity
If the transmitting device uses simple retransmission control, then device complexity is reduced, but retransmission accuracy deteriorates
Solution Approach 1:
The system introduces an intermediary estimation process that interprets the receiving device's response when control data cannot be correctly received. This intermediary layer uses probability estimation based on temporal proximity and transmission conditions to accurately determine whether ACK or NACK was intended, improving determination accuracy without significantly increasing overall system complexity.
Data Source
AI summary
It is determined whether control data that a receiving device (2) has transmitted to a transmitting device (1) in response to reception of packetized data from the transmitting device (2) is normal data. If it is determined that the control data is not normal data, it is estimated whether response data included in the control data is acknowledgement response data (ACK) or negative acknowledgement response data (NACK). If it is determined that the control data is normal data and the response data included in the control data is NACK, or if it cannot be estimated that the response data included in the control data is ACK, the packetized data is retransmitted.