Forward error correction with turbo/non-turbo switching

Simple SummaryContent extracted from patent full text and abstract with AI.

This patent describes a method and system for improving the reliability of data transmission over noisy or unstable communication channels (such as optical fiber) by using a forward error correction (FEC) decoder that can switch between two decoding modes: a turbo mode, where a differential decoder and a FEC decoder exchange information iteratively, and a non-turbo mode, where only the FEC decoder is active. By switching between these modes based on the condition of the signal (for example, depending on the detection of problematic errors called cycle slips), the system can achieve superior error correction and a lower error floor, improving data integrity even under challenging channel conditions.

Use CasesContent extracted from patent full text and abstract with AI.

• High-speed optical communication networks, such as those used in data centers or long-haul fiber optic links.
• Satellite communication systems where channel noise and phase slips are common.
• Wireless communication systems employing complex modulation schemes susceptible to phase ambiguities and cycle slips.
• Next-generation telecommunication infrastructure requiring robust, high-integrity data transmission.
• Any digital communication scenario involving differential encoding and the need for resilient error correction.

BenefitsContent extracted from patent full text and abstract with AI.

• Significantly reduces the error floor caused by cycle slips in differentially encoded systems, resulting in improved data reliability.
• Maintains the strong performance of turbo decoding in environments dominated by additive white Gaussian noise (AWGN), while mitigating its shortcomings in the presence of cycle slips.
• Allows for dynamic or static adaptation to current channel conditions, optimizing performance without manual intervention.
• Flexibility to operate with various error correction codes (like LDPC), making it applicable to a wide array of communication systems.
• Can deactivate parts of the decoder in suitable conditions, potentially saving power and reducing computational load.
• Achieves a better trade-off between signal-to-noise ratio (SNR) performance and robustness to rare but severe errors, compared to traditional decoders.

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Patent Abstract

A forward error correction and differentially encoded signal (40) obtained via a communication channel is supplied to a soft-input soft-output (SISO) differential decoder (50) that is bi-directionally coupled to a SISO forward error correction decoder (52). Over a first portion of a plurality of decoding iterations of the differentially encoded signal, the SISO differential decoder and the SISO forward error correction decoder are operated in a turbo decoding mode in which decoded messages generated by the SISO differential decoder are supplied to the SISO forward error correction decoder and forward error correction messages are supplied to the differential decoder. Over a second portion of the plurality of decoding iterations of the differentially encoded signal, the SISO forward error correction decoder is operated in a non-turbo decoding mode without any messages passing to and from the SISO differential decoder. Decoder output is obtained from the SISO forward error correction decoder.