USB Protocol Adaptation for Low-Delay High-Bandwidth Links
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Solution Overview
Problem
Existing communication technologies face challenges in increasing transmission bandwidth without enlarging connectors and cables, and conventional methods to enhance USB 2.0 data transmission result in increased delay and hardware costs.
Innovation Solution
A communication apparatus and method that performs physical link adaptation on USB 2.0 data to convert it for transmission over higher bandwidth links, eliminating the need for USB physical layers and pins, and using virtual resistors to maintain bus status reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If USB 2.0 electrical signal is converted into signal for common high-speed physical link, then bandwidth utilization is improved, but transmission delay increases greatly
Solution Approach 1:
The patent segments the data transmission path by separating USB protocol layer data from the USB physical layer. USB protocol layer data is directly mapped to high-speed physical link packets without passing through the USB physical layer, dividing the transmission path into protocol adaptation and high-speed transmission segments that operate independently.
Solution Approach 2:
The patent introduces a protocol adaptation layer as an intermediary that converts USB protocol layer data into high-speed physical link packets. This intermediary enables direct transmission on high-speed links while maintaining USB protocol compatibility, avoiding the need for USB physical layer conversion that causes delay.
2Adaptability or versatility
If USB physical layer is added on USB 2.0 data transmission path, then USB 2.0 protocol compatibility is maintained, but chip area and hardware costs increase
Solution Approach 1:
The patent extracts the essential USB 2.0 protocol compatibility function from the complete USB physical layer. Only the protocol adaptation functionality is retained in the USB adapter layer, while the USB physical layer components (pins, physical layer circuitry) are removed, reducing chip area and hardware costs while maintaining protocol compatibility.
Solution Approach 2:
The patent creates a virtual representation of USB protocol layer data that can be directly transmitted on high-speed physical links. Instead of physically implementing USB 2.0 electrical signal conversion, the protocol data structure is copied and adapted to match high-speed link packet formats, achieving compatibility without physical layer hardware.
3Productivity
If quantity of SerDes physical links is increased, then total bandwidth is improved, but sizes of connectors and cables increase
Solution Approach 1:
The patent changes the transmission rate parameter of the SerDes physical link from low-speed (480 Mbps for USB 2.0) to high-speed (10 Gbps or 20 Gbps). By operating the same physical link at higher speeds through protocol adaptation, the system achieves higher total bandwidth without adding more physical links or enlarging connectors and cables.
Data Source
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AI summary
Embodiments of this application provide a communication apparatus and a data transmission method. The communication apparatus includes a universal serial bus USB protocol layer, a USB adapter layer, a transport layer, and a physical layer. The USB protocol layer is configured to send first data to the USB adapter layer. The USB adapter layer is configured to perform physical link adaptation on the first data to obtain second data, and send the second data to the transport layer. The first data is adapted to a first physical link, the second data is adapted to a second physical link, and a bandwidth of the first physical link is lower than a bandwidth of the second physical link. The transport layer and the physical layer are configured to process the second data, and send processed second data to a receive end through the second physical link. According to embodiments of this application, a data transmission delay can be effectively reduced while pin bandwidth utilization of the communication apparatus is increased. In addition, data transmission is not limited by a transmission form of a physical link. Further, compared with the conventional technology, this application can reduce a chip area and hardware costs.