USB Type-C VDM Packet Segmentation for Large Data Transmission
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Solution Overview
Problem
The USB Type-C standard's vendor-defined message (VDM) is limited to 24 bytes, restricting the transmission of control signals and encrypted authentication data, which cannot distinguish between various external devices from the same manufacturer and are limited in size due to encryption, leading to inefficiencies in device authentication and control.
Innovation Solution
An electronic device with a USB Type-C connector and a processor that transmits and receives packets including a message header, a VDM header, and a second VDM header with a product identifier and data type, allowing for the use of multiple VDMs to transmit large capacity data or encrypted authentication information, enabling proper device identification and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the standard VDM size of 24 bytes is used for transmission, then the transmission protocol is simple and compatible, but the data capacity is limited and cannot accommodate large capacity data or encrypted authentication information
Solution Approach 1:
The patent divides the data transmission into multiple VDM packets, where each packet contains a portion of the total data along with identification information. This segmentation allows large capacity data to be transmitted through the limited 24-byte VDM channel by breaking it into manageable chunks that can be sequentially transmitted and reassembled.
Solution Approach 2:
The patent implements a nested packet structure where identification information (first VDM header) is embedded within the data packet structure. This nesting allows the receiver to identify and process different types of data packets correctly, enabling both simple identification and complex data transmission within the same protocol framework.
2Loss of information
If only manufacturer identifier is transmitted in VDM, then the transmission is simple, but various external devices from the same manufacturer cannot be distinguished
Solution Approach 1:
The device identification information is segmented into different fields within the packet structure, including a first identification field in the header and a second identification field in the data portion. This segmentation allows comprehensive device identification while maintaining compatibility with the standard VDM format.
Solution Approach 2:
The patent adds a new dimension to device identification by incorporating product-specific identification information alongside the manufacturer identifier. This multi-dimensional identification approach enables distinction between various devices from the same manufacturer without significantly increasing the overall data transmission burden.
3Reliability
If encrypted authentication data is transmitted, then device security is improved, but the data size exceeds the VDM limit due to encryption overhead
Solution Approach 1:
The encrypted authentication data is divided into multiple segments that fit within the 24-byte VDM limit. Each segment is transmitted as a separate packet with appropriate identification information, allowing secure authentication data to be transmitted in chunks that comply with the protocol size constraints.
Solution Approach 2:
The patent changes the transmission parameters by using multiple smaller packets instead of one large encrypted data block. This parameter change allows the authentication process to maintain security through encryption while adapting to the size constraints of the VDM protocol through iterative transmission.
Data Source
AI summary
In an electronic device and a method for operating the electronic device according to various embodiments, the electronic device may comprise a housing, a USB Type-C connector configured to be connected to the housing or exposed through the housing and to include at least one configuration channel (CC) pin, a circuit configured to be disposed in the housing and connected electrically to the connector, and a processor configured to be disposed in the housing and connected electrically to the circuit. The circuit may be configured to transmit and receive a packet through the CC pin. The packet may sequentially comprise a message header, a first vendor defined message (VDM) header, and a second VDM header including a product identifier and a data type. Further, various other embodiments can be implemented according to the present disclosure.