We present forward error correction systems based on soft-decision low-density parity check (LDPC) codes for applications in 100-400-Gbps optical transport networks. These systems are based on the low-complexity "adaptive degeneration" decoding algorithm, which we introduce in this paper, along with randomly-structured LDPC codes with block lengths from 30 000 to 60 000 bits and overhead (OH) from 6.7% to 33%. We also construct a 3600-bit prototype LDPC code with 20% overhead, and experimentally show that it has no error floor above a bit error rate (BER) of 10 −15 using a field-programmable gate array (FPGA)-based hardware emulator. The projected net coding gain at a BER of 10 −15 ranges from 9.6 dB at 6.7% OH to 11.2 dB at 33% OH. We also present application-specific integrated circuit synthesis results for these decoders in 28 nm fully depleted silicon on insulator technology, which show that they are capable of 400-Gbps operation with energy consumption of under 3 pJ per information bit. Index Terms-Application-specific integrated circuit (ASIC) synthesis, forward error correction (FEC), low-density parity-check (LDPC) codes, low power.
Abstract-In this brief, we introduce a new iterative decoder implementation called pulsewidth-modulated min-sum (PWM-MS), in which messages are exchanged in a pulsewidth-encoded format. The advantages of this method are low switching activity, very low complexity check nodes, low routing congestion, and excellent energy efficiency. We implement a fully parallel PWM offset MS decoder for a (660, 484) regular (4, 15) low-density parity-check code with 4-bit quantization in 0.13-µm CMOS, with a core area of 5.76 mm 2 (4.24-mm 2 cell area or 556K equivalent AND gates). In postlayout simulations, this decoder achieves an average information throughput of 5.71 Gb/s and an energy consumption of 65.8 pJ per information bit at a signal-to-noise ratio of 5.5 dB. Our results show a 21% reduction in area, a 0.6-dB improvement in coding gain, and an energy efficiency improvement of 19% over the comparable bit-serial MS decoder architecture. We also demonstrate 3-bit implementations, in which the coding gain is traded off for further improvements in throughput, area, and energy efficiency.Index Terms-Low-density parity-check (LDPC) codes, low power, low switching activity, min-sum (MS) iterative decoding, pulsewidth modulation (PWM).
We present a low-density parity check (LDPC) decoder using the adaptive degeneration (AD) algorithm with a (3600, 3000) LDPC code, integrated in 1.85 mm 2 in 28 nm FD-SOI. With early termination and variable latency decoding, this decoder achieves an optimal energy efficiency of 0.16 pJ/bit and information throughput of 13.6 Gbps with a core supply voltage of 0.4 V. At a core supply voltage of 1.0 V, it achieves 0.58 pJ/bit energy efficiency and 181 Gbps throughput. With constant latency equal to the maximum number of iterations, it achieves optimal energy efficiency of 0.52 pJ/bit and information throughput of 7.2 Gbps at a supply voltage of 0.55 V, and 1.9 pJ/bit energy and 24 Gbps throughput at 1.0 V. The net coding gain at a bit error rate of 10 −12 is 8.7 dB.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.