In-Band File Transport via Hash-Based PID Assignment
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Solution Overview
Problem
Existing electronic information distribution systems face challenges in efficiently transporting and managing large numbers of files over digital television networks, particularly due to data rate limitations in Out of Band (OOB) communications links, which can lead to issues with directory information transmission and file availability.
Innovation Solution
The system employs a transform method that generates a unique Packet Identifier (PID), Payload Identifier (PIF), and Multicast Identifier (MCI) for each file, allowing for deterministic PID assignment and reducing the likelihood of collisions, thereby enabling efficient file transport without relying on OOB links by using In-Band communication for directory information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Out of Band (OOB) communications links are used for directory information transmission, then file transport can be established, but data rate limitations cause delays in detecting file-not-found conditions and reduce efficiency
Solution Approach 1:
The patent merges the directory information transmission with the existing in-band video/audio data stream by embedding directory information in unused portions of the transport stream. This eliminates the separate OOB communication path and utilizes the already-established high-bandwidth in-band connection, thereby achieving both reliable file availability detection and high transmission speed simultaneously.
2Reliability
If traditional PID assignment methods are used, then file transport is possible, but PID collisions occur leading to data corruption and reduced reliability
Solution Approach 1:
The patent introduces a hash function as an intermediary mechanism that transforms file identifiers into unique PID values. This hash-based assignment method serves as a mediator between the file identification system and the PID allocation system, ensuring that each file receives a unique PID without manual assignment or complex management, thereby maintaining data transport accuracy while simplifying the overall system complexity.
3Adaptability or versatility
If more files are transported over the network, then service versatility improves, but bandwidth consumption increases and system resources are depleted
Solution Approach 1:
The patent segments the directory information into fixed-size blocks and assigns each block a unique PID for separate transport. This segmentation allows the receiver to process and assemble directory information incrementally as blocks arrive, rather than requiring the entire directory to be transmitted simultaneously. This approach enables support for a larger number of files while optimizing bandwidth utilization through parallel transmission of multiple small blocks rather than one large data structure.
Data Source
AI summary
A system and method for transmitting files from a sender to a receiver in a television distribution system, for example, a cable television distribution network, is provided. The files are transmitted without the need for transmitting a directory over an out of band communications link. In an exemplary embodiment, a filename corresponding to a file to be transmitted is provided to a transform. The transform calculates a PID based on the filename. The calculated PID is incorporated into the MPEG2 data stream carrying the corresponding file contents. When an application program running in the receiver requests a file, the filename of the requested file is provided to a transform operating in the receiver. The transmitter and receiver transforms are identical. The transform provides a corresponding PID at its output. The PID is used to tune a PID filter on the receiver end such that the requested file is selected from the incoming MPEG bit stream for processing by the processor.