Physical Link Layer Retransmission for Low Latency

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Solution Overview

Problem

Conventional physical link layer protocols, such as 10 Gigabit Ethernet, face significant latency due to Forward Error Correction (FEC) processing, which can degrade the reliability of data communication systems, particularly in latency-sensitive applications like electronic trading systems.

Innovation Solution

Implementing a method that suppresses administrative control symbols during idle data connections to allow repeated physical layer retransmission of data, using sequence numbers or repeat indicators to distinguish original and repeat frames, thereby reducing the need for time-consuming error correction routines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Forward Error Correction (FEC) is used for reliable data communication, then physical link layer reliability is improved, but data communication latency increases significantly

Engineering Contradiction:

Improvephysical link layer reliabilityVSAvoiddata communication latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent transmits repeat frames in advance during idle periods before they are potentially needed. By proactively retransmitting data frames during connection idle time, the system prepares redundant copies ahead of time, so that when errors occur in original frames, corrected versions are already available at the receiver without waiting for retransmission requests, thus reducing latency while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent keeps the data connection active and productive during idle periods by continuously transmitting repeat frames. Instead of leaving the connection completely idle with control symbols, the system utilizes this time to send redundant data frames, ensuring continuous useful action that improves reliability without requiring additional dedicated bandwidth for retransmission

Inventive Principle:

Principle #20Continuity of useful action

2Reliability

If FEC processing is implemented, then error detection and correction capability is improved, but processing overhead and complexity increase

Engineering Contradiction:

Improveerror detection and correction capabilityVSAvoidprocessing overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates simple binary copies of original data frames and transmits them as repeat frames during idle periods. This copying approach provides redundancy for error correction without requiring complex FEC encoding and decoding processing. The receiver can directly compare and select correct copies based on error detection codes, avoiding the computational complexity of traditional FEC algorithms while maintaining error correction capability

Inventive Principle:

Principle #26Copying

3Stability of the object's composition

If administrative control symbols are transmitted during idle connections, then receiver synchronization is maintained, but available bandwidth for data retransmission is reduced

Engineering Contradiction:

Improvereceiver synchronizationVSAvoiddata retransmission capability

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent transmits repeat frames periodically during idle connection periods instead of continuously transmitting control symbols. By utilizing the periodic idle time between data transmissions to send repeat frames, the system maintains bandwidth availability for retransmission while still providing regular updates that help maintain receiver synchronization, reducing reliance on continuous control symbol transmission

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11303389B2Systems and methods of low latency data communication for physical link layer reliability

Publication Date: 2022.04.12 HYANNIS PORT RESEARCH INC

AI summary

Systems and methods are disclosed herein that provide low latency data communication with improved physical link layer reliability through repeated physical layer retransmission of data over a data connection whenever the connection is idle (i.e., no new data to send). In some embodiments, the transmission of administrative control symbols (e.g., “idles,”“commas”, etc.) can be suppressed or otherwise reduced to allow some of the available connection bandwidth to be used for data redundancy and fault tolerance through the repeated retransmission of data as described in more detail below. Accordingly, instead of executing time-consuming, error correcting routines, a receive node can discard the erroneous data frame and process at least one repeat frame that carries the same data payload. Sequence numbers and/or other repeat indicators can be used to distinguish original frames from repeat frames and/or for identifying which frames carry the same data payload.