Streaming Multicast Error Correction with Early Check Packets
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Solution Overview
Problem
Existing forward error correction techniques are ineffective for streaming media multicasts due to the accumulation of errors in tree-based network topologies, where check packets often arrive too late to be useful for decoding missing packets in streaming media transmission.
Innovation Solution
Implementing forward error correction by generating and transmitting check packets in a tree-based network to downstream nodes before missing streaming media packets are needed, using a combination of XOR operations and pseudo-random number generators to create an arbitrarily large number of check packets, and adjusting transmission rates based on network conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If forward error correction check packets are transmitted in traditional multicast networks, then packet loss can be recovered, but check packets arrive too late to be useful for decoding missing streaming media packets
Solution Approach 1:
The patent applies preliminary action by generating and transmitting check packets before the actual missing data packets are needed. The system predicts which packets might be lost and prepares check packets in advance using XOR operations on current and future packets, so that when a packet is lost, the check packet is already available at the receiver for immediate reconstruction.
Solution Approach 2:
The patent segments the error correction process into multiple independent check packets, each protecting against specific packet losses. Instead of waiting to generate a single check packet after loss detection, the system creates multiple check packets from different combinations of data packets, allowing selective use of appropriate check packets for different loss scenarios.
2Adaptability or versatility
If multiple levels of nodes are added to expand network coverage, then more recipients can receive streaming content, but error rates accumulate and increase
Solution Approach 1:
The patent applies preliminary action by having intermediate nodes generate and forward check packets in advance, before errors actually occur. Each node in the multicast tree prepares check packets using XOR operations on packets it receives, so that downstream nodes have error protection available before they experience packet losses, preventing error accumulation across multiple levels.
Solution Approach 2:
The patent uses intermediate nodes as mediators that actively generate and forward check packets through the network. These intermediary nodes perform XOR operations locally and inject check packets into the multicast stream, providing distributed error protection that scales with network depth and prevents error accumulation across multiple forwarding levels.
3Reliability
If check packets are generated using XOR operations on message packets, then missing packets can be reconstructed, but the system requires precise timing to ensure check packets are available before missing packets are needed
Solution Approach 1:
The patent applies preliminary action by generating check packets with advance timing, incorporating future data packets into the check packet creation process. This allows the system to prepare error correction data before actual packet losses occur, eliminating the need for complex real-time synchronization and retransmission protocols.
Data Source
AI summary
Forward error correction may be implemented in a network having first, second and third nodes. The second node receives streaming media message packets and one or more check packets from an upstream first node. The second node transmits the message packets and check packets to a downstream third node. The second node uses the check packets to decode missing message packets and transmits the decoded missing packets to the third node before the missing message packets are to be presented by the third node. The third node may receive message packets and a first set of check packets from the second node and a second set of check packets from the first node. The third node may use check packets from both sets to decode missing message packets.