Packet Erasure Coding with Interspersed Redundancy for Low Delay
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Solution Overview
Problem
Conventional forward error correction methods in data communication networks result in significant delay due to the placement of redundant coded packets at the end of blocks, which requires buffering of subsequent packets until lost packets can be reconstructed, making it difficult to ensure low delay in-order delivery across lossy communication links.
Innovation Solution
Interspersing redundant coded packets amongst information packets based on packet loss rate and other factors, allowing for earlier reconstruction of lost packets and reducing in-order delivery delay, as opposed to the traditional block code approach where coded packets are transmitted after all information packets in a block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coded packets are placed at the end of a block to maximize throughput capacity, then network throughput efficiency is improved, but packet delivery delay increases proportionally to block size
Solution Approach 1:
The invention divides the traditional block code structure into smaller sub-blocks or segments, where coded packets are distributed across multiple smaller groups rather than concentrated at the end of one large block. This segmentation allows receivers to reconstruct lost packets from smaller subsets, reducing the waiting time proportional to smaller block sizes while maintaining overall throughput efficiency through systematic distribution of redundancy.
Solution Approach 2:
The invention transmits coded packets in advance within the block structure rather than waiting until the end. By placing coded packets at intermediate positions within blocks, the system performs error correction preparation earlier, allowing receivers to have recovery capability available before all information packets are received, thus reducing delay without sacrificing throughput capacity.
2Productivity
If block size is increased to maximize use of available network capacity, then throughput optimality is improved, but delay for error correction increases
Solution Approach 1:
The patent segments large blocks into smaller sub-blocks with intermediate coded packets. This allows the system to utilize large overall block sizes for throughput optimization while creating smaller effective reconstruction units that reduce error correction delay. The segmentation enables parallel processing and earlier recovery points without reducing the total amount of data transmitted in large batches.
Solution Approach 2:
The invention dynamically adjusts the placement and density of coded packets within blocks based on network conditions and loss patterns. Rather than using fixed block structures, the system can adaptively position coded packets to optimize both throughput and delay performance, making the block structure flexible rather than rigid to balance capacity utilization with latency requirements.
3Reliability
If coded packets are transmitted after all information packets in a block, then each coded packet can protect all information packets in the block, but recovery cannot occur until all NR information packets are transmitted and received
Solution Approach 1:
The patent segments the error correction coverage into multiple smaller coverage areas corresponding to sub-blocks. Instead of one coded packet protecting all N packets in a large block, coded packets are distributed to protect smaller subsets. This segmentation enables earlier recovery points where receivers can reconstruct lost packets from smaller groups, reducing delay while maintaining comprehensive error correction coverage through the distributed arrangement.
Solution Approach 2:
The invention introduces intermediate coded packets within the block structure that act as mediators between information packets and final reconstruction. These intermediate coded packets provide partial recovery capability at multiple points within the transmission sequence, allowing receivers to begin reconstruction earlier while the full block is still being received, thus reducing delay without compromising the ability to correct errors across the entire block.
Data Source
AI summary
Provided is a method for correcting errors in a data transmission network, comprising: transmitting a plurality of uncoded information packets across a network path; transmitting a plurality of coded packets for recovering information packets lost in transmission across said network path, the coded packets being temporally interspersed among said uncoded information packets, wherein the coded packets are encoded based on information packets transmitted prior to a previously transmitted coded packet; and determining the interspersion of the coded packets according to a packet loss rate.