Remote Tuning and Clock Synchronization for IP Video
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Solution Overview
Problem
Multi-dwelling establishments face challenges in providing digital video services due to high bandwidth requirements and clock jitter issues, which degrade video quality and reliability in network set-top box systems.
Innovation Solution
A system for remote tuning and clock synchronization that includes a device for receiving user requests, filtering signals, and computing adjusted timestamps to synchronize the network clock, reducing bandwidth usage and eliminating clock jitter by transferring satellite tuning functions to a Mini-Headend unit and using a precision local clock to apply accurate time stamps to IP data packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital broadcast signals are distributed over wires/networks to provide video services in multi-dwelling establishments, then video service quality and reliability are improved, but bandwidth requirements increase significantly leading to high costs
Solution Approach 1:
The patent extracts the satellite tuning and signal processing functions from individual set-top boxes and concentrates them in a headend unit. This allows multiple users to share the same satellite receiver and processing resources, significantly reducing the total bandwidth required in the network while maintaining service quality for each user.
Solution Approach 2:
The headend unit acts as an intermediary between the satellite broadcast signal and the network distribution system. It receives, processes, and conditioners the signal before distributing it to multiple set-top boxes, enabling efficient bandwidth utilization through centralized signal management and conditional access control.
2Adaptability or versatility
If A/V data signal is converted into IP packets for network transmission, then flexibility and scalability are improved, but clock jitter is introduced degrading video quality
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors packet arrival times and dynamically adjusts buffering and timing parameters. This feedback loop compensates for jitter introduced during IP packetization, maintaining synchronized video playback without sacrificing network flexibility.
Solution Approach 2:
The system performs preliminary timing synchronization and buffer management before video playback. By pre-processing packets to establish proper timing relationships and allocating buffer space in advance, the system eliminates jitter effects during actual playback while maintaining IP network adaptability.
3Device complexity
If conventional clock recovery methods are used in network set-top box systems, then implementation simplicity is maintained, but clock synchronization fails due to jitter from IP packetization
Solution Approach 1:
The headend unit serves as a timing intermediary that generates and distributes synchronized timing signals to all set-top boxes. This centralized timing source eliminates the need for complex distributed clock recovery algorithms in each box, maintaining simplicity while ensuring reliable synchronization despite IP network jitter.
Data Source
AI summary
The disclosed embodiments relate to a system for providing remote tuning and clock synchronization in a network. The system includes a device that receives a signal that includes a plurality of channels, a device that receives a user request indicative of a desire to view at least one of the plurality of channels, and a filter that filters the received signal and transmits a user signal corresponding to the at least one of the plurality of channels to the user. An alternative embodiment of the system includes a device that receives a signal that includes a plurality of packets, at least a portion of the plurality of packets comprising an embedded time stamp, a device that detects the at least a portion of the plurality of packets containing the embedded time stamp, and a device that computes an adjusted time stamp based on the embedded timestamp and a precision local clock and incorporates the adjusted timestamp into the at least a portion of the plurality of packets containing the embedded timestamp prior to transmitting the at least a portion of the plurality of packets to the network.