Article
Engineering, Electrical & Electronic
Peng-Wei Zhang, Francis C. M. Lau, Chiu-Wing Sham
Summary: This paper proposes a new type of codes called SC-PLDPCH-CCs, which approach the ultimate Shannon limit. An efficient decoding algorithm combining pipeline decoding and layered scheduling is developed for SC-PLDPCH-CCs. The decoding thresholds of SC-PLDPCH-CCs are estimated using a layered PEXIT algorithm. The results show that SC-PLDPCH-CCs outperform block codes and other low-rate codes in terms of error performance.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Sima Naseri, Amir H. Banihashemi
Summary: In this paper, a design technique is proposed for constructing variable-regular time-invariant spatially-coupled low-density parity-check (SC-LDPC) codes with small constraint length and low error floor. The proposed technique reduces the error floor by imposing simple constraints on the short cycles in the code's Tanner graph, leading to the elimination of the most dominant trapping sets of the code. The designed codes outperform the state-of-the-art in terms of error floor performance and/or decoding complexity and latency.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Qianfan Wang, Suihua Cai, Wenchao Lin, Shancheng Zhao, Li Chen, Xiao Ma
Summary: This paper introduces a new class of spatially coupled codes, BMST-LDPC codes, which are constructed by sending codewords of LDPC-BC in a BMST manner. The proposed codes offer lower error floors and decoding latency, and introduce partial superposition to alleviate decoding error propagation. By integrating BMST-LDPC scheme with HARQ over block fading channel, the throughput performance is improved with potential up to 10% improvement over conventional HARQ scheme.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Salman Habib, David G. M. Mitchell, Jorg Kliewer
Summary: Nested array-based spatially coupled low-density parity-check (SC-LDPC) codes are studied in this article, with an optimization scheme proposed to minimize the number of dominant absorbing sets. The overlapping parity-check matrices of different nested sub-codes impose constraints on optimization, requiring a multi-step and sequential optimization process. The order of optimization significantly impacts the number of dominant absorbing sets, showing a trade-off between nested code performance and optimization sequence.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2021)
Article
Mechanics
Dan Yao, Yong-chuan Duan, Mu-yu Li, Ying-ping Guan
Summary: A hybrid identification method based on BP neural network and GA is proposed to calibrate the parameters of a coupled viscoplastic-damage constitutive model, which shows higher accuracy compared to traditional inverse calibration methods.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Physics, Multidisciplinary
Yang Liu, Sha Sun, Yuzhi Zhang, Bin Wang
Summary: A general and efficient finite-length analysis method is proposed for evaluating the performance of SC-LDPC codes, based on the base matrix. The expression for the error probability is derived by analyzing the evolution of residual graphs during the decoding process. The analysis results show that the predicted error probabilities match the simulated error probabilities, verifying the effectiveness of the proposed method.
Article
Engineering, Electrical & Electronic
Minwei Shi, Jianguo Li, Xiaozheng Gao, Kai Yang, Dusit Niyato, Zhu Han
Summary: In this correspondence, we investigate the impact of spatial coupling between base stations (BSs) and users on the cell load in cellular networks. By modeling the locations of BSs as a homogeneous Poisson point process (PPP) and the locations of users as a spatially coupled Poisson cluster process (PCP), we derive the probability generating function of intra-cluster load and propose a closed-form approximation for the distribution of typical cell load. Additionally, we analyze the load disparity in cell center and cell edge and provide insights into the mean loads and user-perceived rate coverage probabilities in these regions.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Mona Nasseri, Xin Xiao, Bane Vasic, Shu Lin
Summary: This paper introduces two types of concatenated LDPC coding schemes, one of which combines finite geometry LDPC codes and finite field LDPC codes for global coupling, while the other designs both local and global coupling codes as finite field LDPC codes. These two schemes differ in decoding methods and construction, but both demonstrate flexibility and feasibility in practical implementation.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Shancheng Zhao, Chaojie Yang, Jinming Wen
Summary: This letter presents a new construction of spatially coupled serially concatenated codes, showing that a performance gain of about 0.25 dB can be achieved by properly selecting component codes and re-encoding ratio.
ELECTRONICS LETTERS
(2021)
Article
Computer Science, Information Systems
Ruiqi Yang, Suixiang Gao, Lu Han, Gaidi Li, Zhongrui Zhao
Summary: This paper discusses the optimization problem of maximizing the sum of suBmodular and suPermodular functions under a streaming fashion. It proposes a threshold-based streaming algorithm that achieves an approximation of ((1 - kappa)/(2 - kappa) - O(epsilon)) for BP maximization. The paper also considers a more general model with fair constraints and presents a greedy-based algorithm that obtains the same approximation.
TSINGHUA SCIENCE AND TECHNOLOGY
(2023)
Article
Telecommunications
Yihuan Liao, Min Qiu, Jinhong Yuan
Summary: This letter investigates the design of self-connected spatially coupled low-density parity-check (SC-LDPC) codes. First, a termination method is proposed to reduce rate loss. We introduce a single-side open SC-LDPC ensemble to halve the rate loss of conventional terminated SC-LDPC codes by reducing the number of check nodes. Moreover, a self-connection method is proposed to improve the decoding threshold by allowing reliable information propagation from multiple directions. The proposed codes exhibit better trade-off, threshold saturation behavior, and superior error performance compared to existing protograph SC-LDPC codes.
IEEE COMMUNICATIONS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Chaojie Yang, Shancheng Zhao
Summary: This paper investigates the performance of spatially coupled serially concatenated codes over AWGN channel and introduces a new class of concatenated codes RS-SC-SCC, which outperforms SC-SCC in both the error floor region and the waterfall region.
DIGITAL SIGNAL PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Matthias Herrmann, Norbert Wehn
Summary: This article presents an in-depth investigation on the implementation of SC-LDPC decoders for throughputs beyond 100 Gbit/s, exploring various design trade-offs and complementing it with virtual silicon implementation.
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING
(2022)
Article
Chemistry, Analytical
Huan Deng, Dan Song, Zhiping Xu, Yanglong Sun, Lin Wang
Summary: This paper proposes a belief propagation algorithm based on the duality principle for lossy compression in the Internet of Things. By optimizing the algorithm, the impact of trapping sets on compression performance is weakened.
Proceedings Paper
Engineering, Electrical & Electronic
Mojtaba Mahdavi, Muhammad Umar Farooq, Liang Liu, Ove Edfors, Viktor Owall, Michael Lentmaier
Summary: Spatially coupled serially concatenated codes (SC-SCCs) are explored in this paper for their near-capacity performance and low error floor. The impact of various design aspects on performance, complexity, and latency is investigated, leading to proposed design guidelines for flexible exchange of block length and coupling memory. Results show that performance can be improved without increasing latency and complexity by using higher coupling memory with smaller blocks, achieving enhanced performance compared to uncoupled ensembles for fixed latency and complexity.
2021 IEEE 93RD VEHICULAR TECHNOLOGY CONFERENCE (VTC2021-SPRING)
(2021)
Article
Engineering, Electrical & Electronic
Yohei Sobu, Guoxiu Huang, Shinsuke Tanaka, Yu Tanaka, Yuichi Akiyama, Takeshi Hoshida
Summary: A study on an all-Si segmented Mach-Zehnder modulator for optical DAC transmitters was conducted, achieving successful generation of 90-Gbaud NRZ signals and 70-Gbaud PAM4 waveforms. The compact device size, excellent bit error rates, and wide bandwidth make it a promising solution for next-generation high-speed multilevel transmitters.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Tomoyuki Akiyama, Shoichiro Oda, Yasuhiro Nakasha, Akinori Hayakawa, Shinsuke Tanaka, Yu Tanaka, Takeshi Hoshida
Summary: A novel class of WDM demultiplexers with a unique control scheme for Si nano-waveguide photonic integrated circuits was proposed, showing excellent performance in computer simulations and experimental evaluations. This technology is expected to significantly reduce the size of dense WDM transceivers, enabling sustainable scalability in optical transceiver systems.
Article
Engineering, Electrical & Electronic
Kiichi Sugitani, Yohei Koganei, Hiroyuki Irie, Hisao Nakashima
Summary: Partial multilevel coding (MLC) with probabilistic shaping (PS) in optical communications improves signal-to-noise ratio performance, adaptability of information rates, and reduces the power consumed by forward error correction. Simulation results show that partial-MLC model has almost the same transmission performance as bit-interleaved coded modulation (BICM) model but with lower power consumption. Nonlinear effects on fiber wavelength division multiplexing (WDM) channels were evaluated, demonstrating the usefulness of MLC with PS for optical transmissions on WDM channels regardless of nonlinear noise.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Yuki Yoshida, Setsuo Yoshida, Shoichiro Oda, Takeshi Hoshida, Naokatsu Yamamoto, Atsushi Kanno
Summary: Small mismatches between in-phase and quadrature tributaries in an electro-optic IQ modulator, known as IQ imbalance, can greatly impact high baud-rate and/or high modulation-order signals in coherent optical communications systems. In this study, a low-complexity IQ monitoring technique based on direct detection with phase retrieval, called SP-OMA, is proposed for in-service in-field monitoring of frequency-dependent imbalance profile without requiring dedicated pilot tones or being affected by receiver/monitor-side IQ imbalance. The feasibility of SP-OMA is demonstrated both numerically and experimentally with a 63.25-Gbaud 16QAM signal.
Article
Optics
Guoxiu Huang, Hisao Nakashima, Takeshi Hoshida
Summary: Experimental results confirm that TH pre-coding can enhance the speed and capacity of PDM-16QAM signals in optical coherent systems, showing significant improvement in performance under optical back-to-back conditions. The ratio of symbol rate to DAC sampling rate achieved in this study is the highest reported for DAC-based optical coherent systems to date, demonstrating promising potential for long-distance transmission.
Article
Optics
Kazuaki Honda, Kazutaka Hara, Hirotaka Nakamura, Kyosuke Sone, Goji Nakagawa, Yoshio Hirose, Takeshi Hoshida, Jun Terada
Summary: The demand for fifth generation (5G) mobile systems is increasing rapidly, especially in the mobile fronthaul section of optical fiber. Wavelength division multiplexing passive optical network (WDM-PON) systems are being considered to meet high traffic demands. However, the wavelength management in WDM-PON systems has not been thoroughly studied at the system level. This paper reviews and compares superimposition schemes of the AMCC in order to clarify operating conditions and proposes a WDM-PON system managed using AMCC for various functions. The results show that the WDM-PON prototype system did not significantly degrade downlink throughput, even with wavelength adjustment against drift.
Article
Engineering, Electrical & Electronic
Tomoyuki Akiyama, Motoyuki Nishizawa, Akio Sugama, Yasuhiro Nakasha, Shinsuke Tanaka, Yu Tanaka, Takeshi Hoshida
Summary: We have demonstrated a crosstalk-free (-38.5 dB) 32-channel DWDM demultiplexer on a standard Si PIC platform, enabled by an autonomous calibration mechanism. The precise fabrication control required for suppressing crosstalk in large-channel-count DWDM systems has made this platform impractical. To overcome this, we proposed a calibration mechanism that can be fully integrated into an assembly composed of an electric IC and a standard Si PIC. This device provides a path to ultrahigh-capacity integrated DWDM transceivers, compatible with the vast component libraries of the standard Si PIC platform.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Yuki Yoshida, Setsuo Yoshida, Shoichiro Oda, Takeshi Hoshida, Naokatsu Yamamoto, Atsushi Kanno
Summary: In-service monitoring and adaptive digital compensation of analog imperfections in optical transponders are essential for next-generation optical coherent transmission systems. The IQ imbalance, as a notable example of analog impairments in optical IQ modulators, can be monitored using the single-pixel optical modulation analyzer (SP-OMA) technique. This work extends the concept of SP-OMA to dual-polarization IQ modulators and proposes a novel phase retrieval algorithm for identifying frequency-dependent IQ imbalances on both polarization channels.
Article
Engineering, Electrical & Electronic
Takeshi Hoshida, Vittorio Curri, Lidia Galdino, David T. Neilson, Wladek Forysiak, Johannes K. Fischer, Tomoyuki Kato, Pierluigi Poggiolini
Summary: The enhancement of spectral efficiency has been the main driver for capacity increase in optical networks. As spectral efficiency matures, the extension of optical bandwidth beyond conventional bands is expected to play a significant role in future capacity upgrades of optical networks.
PROCEEDINGS OF THE IEEE
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Olga Vassilieva, Inwoong Kim, Hiroyuki Irie, Yohei Koganei, Hisao Nakashima, Yuichi Akiyama, Takeshi Hoshida, Paparao Palacharla
Summary: We discuss the performance and implementation aspects of geometric and probabilistic constellation shaping, and how they can be optimized for different applications. Our study shows that symbol rate optimization with probabilistic shaping can further improve the reach or capacity.
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)
Proceedings Paper
Computer Science, Information Systems
Yuki Yoshida, Takahito Tanimura, Setsuo Yoshida, Takeshi Hoshida, Naokatsu Yamamoto
2020 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATIONS (ECOC)
(2020)
Proceedings Paper
Computer Science, Information Systems
Guoxiu Huang, Hisao Nakashima, Yuichi Akiyama, Takeshi Hoshida
2020 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATIONS (ECOC)
(2020)
Proceedings Paper
Computer Science, Information Systems
Jingnan Li, Yangyang Fan, Zhenning Tao, Hisao Nakashima, Takeshi Hoshida
2020 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATIONS (ECOC)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Tomoyuki Kato, Shigeki Watanabe, Tomohiro Yamauchi, Goji Nakagawa, Hidenobu Muranaka, Yu Tanaka, Yuichi Akiyama, Takeshi Hoshida
2020 OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC 2020)
(2020)
Proceedings Paper
Engineering, Electrical & Electronic
Goji Nakagawa, Tomohiro Yamauchi, Tomoyuki Kato, Shigeki Watanabe, Hidenobu Muranaka, Yu Tanaka, Yuichi Akiyama, Takeshi Hoshida
2020 IEEE PHOTONICS CONFERENCE (IPC)
(2020)
