Bidirectional USB Data Transmission Over MHL A/V Channels
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Solution Overview
Problem
Existing technologies face challenges in simultaneously transmitting high-resolution HDMI or MHL videos and USB data over USB links due to differing bandwidth and latency requirements, with current methods being susceptible to data corruption from electromagnetic interference.
Innovation Solution
Implementing a bidirectional data transmission system using time division multiplexing (TDM) over a multimedia link, where USB data is buffered and transmitted alongside A/V data, with synchronization signals to align data packets and separate channels for control data, allowing for efficient and interference-resistant communication between source and sink devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If USB data is transmitted alongside A/V data over the same link, then bandwidth utilization is improved, but data corruption from electromagnetic interference increases
Solution Approach 1:
The patent divides the transmission medium into two distinct physical channels: a first physical channel for A/V data transmission and a second physical channel for USB control data transmission. This segmentation isolates the high-speed A/V data from lower-speed USB data, preventing electromagnetic interference between the two data types while maintaining efficient bandwidth utilization of the overall link.
2Manufacturing precision
If high resolution HDMI or MHL videos are transmitted over USB links, then video quality is improved, but latency constraints are violated
Solution Approach 1:
The patent implements periodic transmission of synchronization signals at predetermined intervals within the data stream. These synchronization signals enable the receiving device to continuously realign and resynchronize with the incoming high-resolution video data, maintaining video quality while accommodating the time constraints of USB transmission through periodic resetting of the synchronization state.
3Adaptability or versatility
If bidirectional USB data exchange is implemented, then communication versatility is improved, but synchronous mechanisms are lacking
Solution Approach 1:
The patent introduces a dedicated second physical channel that serves as an intermediary for USB control data transmission. This separate channel carries USB protocol data packets in both directions between source and sink devices, providing the necessary synchronous mechanisms for bidirectional communication without complicating the primary A/V data transmission path.
4Device complexity
If A/V and USB data are transmitted over an auxiliary bus, then device complexity is reduced, but transmission speed requirements are not met
Solution Approach 1:
The patent segments the transmission requirements by allocating the high-speed A/V data to a dedicated first physical channel optimized for multimedia transmission, while USB control data is transmitted over a separate second physical channel. This segmentation allows each channel to be optimized for its specific data type, ensuring that A/V transmission speed requirements are met without the interference and speed limitations that would result from sharing an auxiliary bus.
Data Source
AI summary
Embodiments relate to half-duplex bidirectional transmission of data compliant with a first standard (e.g., Universal Serial Bus (USB) standard) over a physical channel of a multimedia link for transmitting audio/video (“A/V”) data compliant with a second standard (e.g., Mobile High-Definition Link (MHL) standard) between a source device and a sink device using time division multiplexing (TDM). The source device sends units of data including A/V data and forward data compliant with the first standard at first times whereas the sink device sends units of data including backward data compliant with the first standard at second times between transmissions from the source device. The first times do not overlap with the second times. Synchronization signals may be added to the first and second units of data to align character symbols embedded in the first and second units of data.