USB 3.0 Isochronous Packet Transfer Without Header Retry
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Solution Overview
Problem
In isochronous data transfers, such as audio and video transmissions over USB 3.0, existing methods require re-transmission of packets with incorrect headers, leading to unnecessary delays and synchronization issues due to retry signals, which decrease transfer efficiency and cause discontinuous conditions.
Innovation Solution
A method where the receiving end ignores packets with incorrect headers and does not send retry signals, allowing the transmitting end to skip re-transmitting faulty packets, instead setting the header sequence number for the next packet to maintain sequence integrity and enable quicker transmission of subsequent packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiving end sends a retry signal when the header is incorrect, then the header error is handled, but the transmission delay increases and synchronization is deteriorated
Solution Approach 1:
The patent extracts the retry signal sending action from the receiving end's error handling process. When a header error is detected in an isochronous packet, the receiving end simply discards the packet without sending a retry signal, thereby eliminating the time loss associated with retry mechanisms while maintaining error handling capability
Solution Approach 2:
The patent inverts the conventional error handling approach by having the transmitting end maintain sequence continuity instead of re-transmitting. The receiving end detects errors and the transmitting end compensates by adjusting the sequence number of subsequent packets, reversing the traditional sender-initiated retry mechanism
2Reliability
If the transmitting end re-transmits the packet, then the header error is corrected, but the transfer efficiency decreases
Solution Approach 1:
The patent applies the skipping principle by having the transmitting end bypass re-transmission of erroneous packets. Instead of repeating the failed transmission, the system moves forward with the next packet in sequence, rushing through the error condition to maintain overall transfer efficiency
Solution Approach 2:
The patent changes the sequence number parameter of subsequent packets to account for discarded packets. The transmitting end adjusts the header sequence number to maintain continuity, allowing the receiving end to reconstruct the correct packet sequence without actual re-transmission
3Measurement precision
If the receiving end sends retry signals for incorrect packets, then error detection is performed, but the synchronization between ends is un-synchronized
Solution Approach 1:
The patent implements feedback at the transmitting end rather than through retry signals. The receiving end's packet discarding action provides implicit feedback, and the transmitting end responds by adjusting sequence numbers of subsequent packets to maintain synchronization without disrupting the real-time flow
Solution Approach 2:
The patent applies preliminary action by pre-adjusting the sequence number of the next packet in anticipation of a discarded packet. The transmitting end prepares the corrected sequence number in advance, ensuring synchronization is maintained before the receiving end even processes the error
Data Source
AI summary
A method for increasing the efficiency of transferring packets of isochronous transfer type in USB 3.0 includes ignoring a packet of isochronous transfer type with an incorrect header. When the receiving end receives a packet of isochronous transfer type with an incorrect header, the receiving end does not send a retry signal to the transmitting end. Therefore, the transmitting end can more quickly transmit the following packets of isochronous transfer type.