MDDI Packet Structure for Flexible Sub-Frame Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Mobile Display Digital Interface (MDDI) systems have limitations due to fixed sub-frame lengths, which lead to bandwidth wastage and increased latency when transmitting large packets, and repetitive retransmission of unchanged video packet data, necessitating improvements for more efficient data transfer.
Innovation Solution
The implementation of a flexible sub-frame length system, windowless video stream packets, and an enhanced reverse link encapsulation packet that combines round trip delay and reverse encapsulation packets, along with the ability to specify present fields in video stream packets and a link freeze feature to manage data transmission efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed sub-frame length is used, then timing intervals are regular and simple, but large packets must be delayed until the next sub-frame to be transmitted, wasting bandwidth and increasing latency
Solution Approach 1:
The patent implements dynamic sub-frame length adjustment where the sub-frame length is no longer fixed but can be varied based on packet size requirements. The sub-frame length is determined by the receiver based on the actual packet data length, allowing flexible adaptation to different transmission needs and eliminating the delay of large packets until the next fixed sub-frame boundary.
Solution Approach 2:
The patent changes the parameter of sub-frame length from a fixed value to a variable parameter that can be adjusted according to transmission requirements. This allows the system to optimize bandwidth utilization by matching the sub-frame length to the actual packet size, thereby resolving the contradiction between regular timing and efficient bandwidth usage.
2Loss of time
If fixed sub-frame length is used, then the system operates at a fixed rate, but this prevents packets from spanning from one sub-frame to the next, increasing latency
Solution Approach 1:
The patent enables dynamic packet transmission control where packets can span multiple sub-frames based on their size and the available bandwidth. The receiver dynamically determines the sub-frame length based on the packet data length, allowing packets to be transmitted efficiently without unnecessary delays and reducing overall latency.
3Reliability
If sub-frame header packet is transmitted frequently, then synchronization is maintained, but bandwidth is wasted when link is stable
Solution Approach 1:
The patent implements a feedback mechanism where the receiver sends back the actual packet data length information to the transmitter. This feedback allows the transmitter to adjust the sub-frame length accordingly, transmitting sub-frame header packets only when necessary for synchronization rather than at fixed intervals, thereby reducing bandwidth waste while maintaining synchronization stability.
4Reliability
If video packet data is retransmitted repeatedly when parameters are unchanged, then data reliability is ensured, but bandwidth is wasted
Solution Approach 1:
The patent uses feedback mechanisms where the receiver acknowledges received packets and indicates when parameters have not changed. This allows the transmitter to avoid redundant retransmissions of unchanged video packet data, maintaining data reliability while significantly improving bandwidth efficiency by only transmitting necessary changes.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In a device using a mobile display digital interface (MDDI), a link freeze is used to halt a transmission of a data stream at any point in the transmission and resume the transmission by a host. The link freeze involves halting a transmission of a data stream by the host, maintaining current output bits of both data and strobe signals for a period of time greater than a bit time of one transmission bit, retaining a value of output levels as part of a last transmitted bit of the data and strobe signals, and resuming the transmission of the data stream by the host.