Reference Clock Acquisition in MMT Broadcasting Frames

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Solution Overview

Problem

In broadcasting systems using the MMT scheme, the conventional method of transmitting reference clock information is inefficient, requiring multiple software processes and leading to longer acquisition times and potential jitter, as it involves extracting the information from multiple packet layers, which complicates the acquisition of high-precision clock information.

Innovation Solution

The proposed method involves transmitting reference clock information in IP packets using a different data structure than MMT packets, with the object IP packet positioned at the head of each frame and omitting header compression, allowing for simplified and faster acquisition by the reception apparatus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If reference clock information is transmitted using conventional MMT packet structure, then the information can be transmitted through standardized protocol, but the reception apparatus requires multiple software processes and longer time to extract the information from multiple packet layers

Engineering Contradiction:

Improveprecision of reference clock information acquisitionVSAvoidtime required to acquire reference clock information

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts the reference clock information from the complex MMT packet structure and places it directly into the IP packet header. This extraction eliminates the need for multiple software processes to traverse nested packet layers, allowing the reception apparatus to acquire the reference clock information directly and quickly from the IP packet header without time-consuming extraction operations.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the reference clock information transmission by placing it in a dedicated field within the IP packet header, separate from the MMT packet structure. This segmentation allows the reception apparatus to access the reference clock information independently without processing the entire MMT packet hierarchy, reducing acquisition time and improving precision.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If header compression processing is applied to IP packets containing reference clock information, then bandwidth efficiency is improved, but the reception apparatus cannot easily identify and extract the uncompressed reference clock information

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidease of extracting reference clock information

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The patent applies local quality by making the IP packet containing reference clock information distinct through the absence of header compression. This creates a locally identifiable characteristic (uncompressed header) that allows the reception apparatus to easily recognize and extract the reference clock information without needing to decompress or complexly process the packet, while other packets may still use compression for bandwidth efficiency.

Inventive Principle:

Principle #3Local quality

3Reliability

If reference clock information is embedded within MMT packet structure, then standardized protocol compliance is maintained, but the acquisition process becomes complex requiring multiple software processes

Engineering Contradiction:

Improveprotocol complianceVSAvoidcomplexity of acquisition process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the IP packet header as an intermediary carrier for the reference clock information. Instead of embedding the information deep within the MMT packet structure, the IP packet header serves as an intermediate layer that delivers the reference clock information directly to the reception apparatus, simplifying the acquisition process while maintaining protocol compliance through proper IP packet formatting.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11523191B2Transmission method, reception method, transmission apparatus, and reception apparatus

Publication Date: 2022.12.06 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

A transmission method includes generating one or more frames for content transfer using IP (Internet Protocol) packets, and transmitting the one or more generated frames by broadcast. Each of the one or more frames contains a plurality of second transfer units, each of the plurality of second transfer units contains one or more first transfer units, and each of the one or more first transfer units contains at least one of the IP packets. An object IP packet of the IP packets which is stored in a first transfer unit positioned at a head in the one or more frames contains reference clock information that indicates time for reproduction of the content in data structure different from data structure of an MMT (MPEG Media Transport) packet, and header compression processing on the object IP packet is omitted.