Variable-Rate VLSI Architecture for 400-Gb/s Hard-Decision Product Decoder
Journal article, 2021

Variable-rate transceivers, which adapt to the conditions, will be central to energy-efficient communication. However, fiber-optic communication systems with high bit-rate requirements make design of flexible transceivers challenging, since additional circuits needed to orchestrate the flexibility will increase area and degrade speed. We propose a variable-rate VLSI architecture of a forward error correction (FEC) decoder based on hard-decision product codes. Variable shortening of component codes provides a mechanism by which code rate can be varied, the number of iterations offers a knob to control the coding gain, while a key-equation solver module that can swap between error-locator polynomial coefficients provides a means to change error correction capability. Our evaluations based on 28-nm netlists show that a variable-rate decoder implementation can offer a net coding gain (NCG) range of 9.96-10.38 dB at a post-FEC bit-error rate of 10^-15. The decoder achieves throughputs in excess of 400 Gb/s, latencies below 53 ns, and energy efficiencies of 1.14 pJ/bit or less. While the area of the variable-rate decoder is 31% larger than a decoder with a fixed rate, the power dissipation is a mere 5% higher. The variable error correction capability feature increases the NCG range further, to above 10.5 dB, but at a significant area cost.

Optical communication

variable rate transceivers

high throughput

energy efficiency

forward error correction

product codes

very large scale integration (VLSI)


Vikram Jain

KU Leuven

Christoffer Fougstedt

Chalmers, Computer Science and Engineering (Chalmers), Computer Engineering (Chalmers), Electronics Systems

Per Larsson-Edefors

Chalmers, Computer Science and Engineering (Chalmers), Computer Engineering (Chalmers), Electronics Systems

IEEE Transactions on Circuits and Systems I: Regular Papers

1549-8328 (ISSN)

Vol. 68 1 25-34

Areas of Advance

Information and Communication Technology

Driving Forces

Sustainable development

Subject Categories

Communication Systems

Embedded Systems



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Latest update

2/3/2021 9