EGPRS Transmitting Device Acknowledgment Verification
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Solution Overview
Problem
In enhanced general packet radio service (EGPRS) networks, the fast acknowledged/not acknowledged reporting (FANR) scheme leads to a high probability of undetected errors due to weaker CRC protection, causing 'false positive' acknowledgments, which can result in unnecessary retransmissions, window synchronization issues, and temporary block flow deadlocks.
Innovation Solution
The method involves a transmitting device that differentiates between two types of acknowledgments, using the relative probability of errors to determine the reliability of each, and employs a more reliable acknowledgment type to verify the status of data blocks, allowing for the storage of blocks acknowledged by a weaker CRC and retransmission of blocks marked as positively acknowledged by an unreliable acknowledgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast acknowledged/not acknowledged reporting (FANR) is implemented to increase reporting frequency, then retransmission speed is improved, but error detection reliability deteriorates due to weaker CRC protection
Solution Approach 1:
The patent introduces a verification mechanism using a more reliable acknowledgment type as an intermediary to verify the status of data blocks acknowledged by the weaker CRC acknowledgment. This mediator checks whether the weaker CRC acknowledgment was correct, effectively resolving the contradiction between fast reporting and reliable error detection.
Solution Approach 2:
The patent implements a feedback mechanism where the transmitting device receives two types of acknowledgments and uses the more reliable one to verify the less reliable one. This feedback loop allows the system to detect and correct false positive acknowledgments while maintaining high reporting frequency, thus resolving the contradiction between productivity and reliability.
2Productivity
If weaker CRC protection is used in fast acknowledgment reporting, then reporting frequency is improved, but false positive acknowledgment rate increases
Solution Approach 1:
The patent applies partial verification by using the more reliable acknowledgment type only when needed to verify suspicious acknowledgments from the weaker CRC type. This partial action approach maintains high reporting frequency while correcting accuracy issues only where necessary, resolving the contradiction between reporting frequency and acknowledgment accuracy.
3Reliability
If false positive acknowledgments are corrected by increasing CRC size, then acknowledgment reliability is improved, but bandwidth efficiency deteriorates
Solution Approach 1:
The patent applies local quality by using different CRC sizes for different acknowledgment types - a smaller CRC for frequent fast acknowledgments and a larger CRC for less frequent but more reliable acknowledgments. This localized approach to error protection maintains bandwidth efficiency for frequent transmissions while ensuring reliability when needed, resolving the contradiction between acknowledgment reliability and bandwidth efficiency.
Data Source
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AI summary
A method of transmitting a data block (DB4..DB6) of a type from a transmitting device (for example a transmitting network node) to a receiving device (for example a receiving network node), in particular during a temporary block flow, is disclosed. Furthermore, a transmitting device to perform the inventive method is disclosed. The transmitting device is capable of receiving at least two different types of positive/negative acknowledgements for data blocks of said type from said receiving device and the reaction of the transmitting device to the positive/negative acknowledgements depends on the type of the said received positive/negative acknowledgement.