Fragmented Packet Retransmission With Transferable Retry Credit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for retransmitting fragmented packets are sensitive to errors in the propagation channel and provide unequal error protection across fragments, leading to inefficient packet transmission and high untransmitted packet rates.
Innovation Solution
Assigning a persistence value to each fragmented packet, allowing for dynamic reallocation of transmission credits based on acknowledgement receipt, and incorporating error-detecting codes to manage retransmissions effectively, ensuring each fragment receives the necessary retransmissions to achieve a desired error probability distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an overall retransmission credit is assigned to all fragments of an IP packet, then the transmission cost is controlled, but the first fragment transmitted exhibits a much lower probability of error than subsequent fragments
Solution Approach 1:
The patent applies local quality by assigning different persistence values to different fragments of the same IP packet. Instead of uniform error protection, each fragment receives a tailored persistence value based on its position and importance, creating unequal error protection (UEP) that optimizes overall packet transmission reliability while controlling retransmission costs.
Solution Approach 2:
The patent changes the parameter of retransmission persistence from a uniform value to variable values across fragments. By dynamically adjusting persistence values for each fragment based on channel conditions and fragment characteristics, the system optimizes the balance between error protection and transmission efficiency.
2Device complexity
If the retransmission scheme is based on correct receipt of acknowledgements, then the protocol is simple, but it is highly sensitive to errors related to channel fluctuations in the return pathway
Solution Approach 1:
The patent prepares for potential acknowledgement errors by incorporating error-detecting codes (such as CRC) in the acknowledgement messages. This beforehand cushioning allows the system to detect and handle corrupted acknowledgements without requiring complex retransmission protocols, maintaining simplicity while improving robustness against channel fluctuations.
3Reliability
If unequal error protection is provided for fragments, then the first fragment has lower error probability, but this is not always desired and reduces flexibility
Solution Approach 1:
The patent introduces dynamics by making the error protection level for each fragment configurable rather than fixed. The persistence values can be adjusted dynamically based on application requirements, channel conditions, and fragment importance, allowing the system to adapt between equal and unequal error protection strategies as needed.
Data Source
AI summary
A method is provided for retransmitting fragmented packets for which a transference of retransmission credit is performed from one fragment onto the next. The method makes it possible to do away with the drawbacks of the methods existing by appreciably improving performance in terms of untransmitted packet rate and by making it possible to configure the distribution of the error probabilities for the fragments of an IP packet.