Anti-Shadow Stream for Wireless Media Streaming
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Solution Overview
Problem
Wireless networks experience unstable signal conditions, leading to data loss and service interruptions due to temporary blockages, which existing error correction methods like Forward Error Correction and jitter buffers cannot effectively address, especially in broadcast or multicast scenarios.
Innovation Solution
A streaming process that includes an anti-shadow stream as a backup copy of the main media stream, sent ahead of the output media stream with a time offset, allowing for seamless recovery from signal blockages and reducing start latency by using separate or simultaneous logical channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Forward Error Correction is used to correct data errors, then data corruption caused by bit errors is addressed, but it cannot correct total signal blockage or loss of consecutive frames
Solution Approach 1:
The patent segments the media stream into multiple independent frames, each with its own timestamp and sequence number. This segmentation allows the receiver to identify and handle lost frames individually, enabling the system to recover from signal blockages by requesting retransmission of specific lost frames rather than requiring complete error correction codes for the entire stream.
Solution Approach 2:
The patent implements preliminary action by having the receiver buffer incoming frames and maintain a timeline of expected frames before playback. This allows the system to detect missing frames in advance and request their retransmission before the playback timeline is affected, preventing service interruptions rather than merely correcting errors after they occur.
2Reliability
If jitter buffers are used to combat temporal jitters, then packet arrival time variations are handled, but large delays cannot be compensated and data loss cannot be recovered
Solution Approach 1:
The patent implements a dynamic buffer management system where the receiver adjusts its buffering strategy based on real-time network conditions and playback requirements. The system dynamically determines which frames to buffer, which to play immediately, and which to request for retransmission, allowing it to handle temporal jitters adaptively without forcing a fixed start latency waiting period.
Solution Approach 2:
The patent introduces feedback mechanisms where the receiver monitors frame arrival times, detects jitter and data loss, and sends requests for retransmission of lost frames. This feedback loop allows the system to continuously adjust its buffering and playback strategy, resolving temporal jitters in real-time without requiring the receiver to wait for a fixed buffer fill period before starting playback.
3Reliability
If retransmission is used to compensate for data loss, then data loss is recovered, but end-to-end synchronization complexity increases and feedback mechanisms are required
Solution Approach 1:
The patent segments the media stream into independently addressable frames with sequence numbers and timestamps. This segmentation simplifies retransmission by allowing the receiver to request specific lost frames by their sequence numbers rather than managing complex synchronization of entire data blocks, reducing the feedback and synchronization overhead compared to traditional retransmission protocols.
4Reliability
If the receiver waits for the jitter buffer to be filled, then temporal jitters are combated, but service start latency increases
Solution Approach 1:
The patent applies partial buffering by filling only enough of the buffer to handle expected temporal jitters without requiring a complete buffer fill before playback starts. The receiver begins playback once sufficient frames are available to cover the anticipated jitter period, then continues to buffer frames in the background, allowing service to start quickly while still providing jitter protection.
Data Source
AI summary
In the present technique of streaming a main media stream that has been requested, an anti-shadow stream (36) that represents a backup copy of the main media stream (24) is sent along with an output media stream (34) that represents an output copy of the main media stream. The content of the anti-shadow stream (36) is preferably forward-shifted in time from the output media stream (34) so as to provide replacement of loss data of the output stream. Put differently, sequenced data frames of the output stream (34) are delayed by order compared to that of the anti-shadow stream (36).