USB Link Transition Using RS-FEC and Dual-Transmitter Sync
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Solution Overview
Problem
The USB4 specification lacks detailed implementation steps for transitioning to a symmetric link, which is necessary for optimal data transfer and link management.
Innovation Solution
A method and device implementation for link transition in USB devices, involving the transmission of RS-FEC blocks, training sequences, and specific pattern sequences by multiple transmitters, with a controller managing the lane adapter state machine to coordinate the transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the USB4 specification follows the basic transition steps for symmetric link, then the link transition can be completed, but the implementation lacks detailed guidance and is difficult to execute
Solution Approach 1:
The patent applies preliminary action by having the first transmitter send RS-FEC blocks before the second transmitter is fully activated. This preparatory data transmission establishes a foundation for the transition process, allowing the system to maintain operational continuity while the second transmitter is being brought online through training sequences and pattern transmission.
Solution Approach 2:
The transition process is segmented into distinct phases: initial RS-FEC block transmission by the first transmitter, UNBOND set detection, second transmitter activation through LASM, training sequence transmission, pattern sequence transmission, and final synchronized dual-transmitter operation. This segmentation makes the complex transition manageable and implementable.
2Productivity
If multiple transmitters are activated simultaneously, then the data transfer speed increases, but the coordination and synchronization between transmitters becomes complex
Solution Approach 1:
The patent implements feedback mechanisms where the receiver detects UNBOND sets from transmitters and sends appropriate responses. The lane adapter state machine (LASM) monitors the status of both transmitters and coordinates their operation based on received signals. This feedback loop ensures that the second transmitter is properly activated and synchronized before full dual-transmitter operation begins, managing the complexity through continuous status monitoring and adaptive control.
Solution Approach 2:
The lane adapter state machine (LASM) acts as an intermediary between the two transmitters and the receiver. It manages the activation process of the second transmitter, coordinates the training sequence transmission, and ensures proper synchronization. The UNBOND set serves as an intermediary signal that triggers the transition from single-transmitter to dual-transmitter operation, simplifying the coordination complexity through a dedicated control mechanism.
Data Source
AI summary
A method for link transition in a USB device includes transmitting a plurality of first RS-FEC blocks by a first transmitter, receiving an UNBOND set by a receiver, waking up a second transmitter by a LASM when the receiver receives the UNBOND set, transmitting a training sequence by the second transmitter, transmitting a specific pattern sequence by the second transmitter after finishing transmitting the training sequence, determining whether a current RS-FEC block to be transmitted by the first transmitter is a DESKEW block, stopping transmitting the specific pattern sequence if the current RS-FEC block is determined to be the DESKEW block, and transmitting a plurality of second RS-FEC blocks by the first transmitter and the second transmitter.