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Two-Dimensional 15/24 Non-Isolated Patterned modulation Codes With Minimum Hamming Distance 3 in Bit-Patterned Media Recording

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IEEE ACCESS 2024年 12卷 115597-115604页

作者： Nguyen, Thien An Lee, Jaejin Soongsil Univ Dept Informat Commun Convergence Technol Seoul 06978 South Korea

Reducing the distance between magnetic islands is essential for increasing the areal density in bit-patterned media recording (BPMR). Consequently, significant two-dimensional (2D) interference emerges, encompassing inter-symbol interference (ISI) and inter-track interference (ITI) along the cross- and down-tracks, respectively. To address the 2D interference, modulation with non-isolated patterns can be employed to mitigate the interference from neighboring bits. In previous studies, authors relied on the Hamming code to propose a non-isolated modulation code with a minimum Hamming distance (MHD) of 3. However, for encoding, authors utilized a mapping method with a large look-up table, resulting in prolonged delay for the decoder. Therefore, in this paper, we proposed a generator matrix for creating the Hamming code with an MHD of 3, thereby generating reverse codewords in the look-up table. Consequently, only half of the look-up table needs to be stored, leading to reduced complexity and delay time in the decoder for non-isolated modulation code with an MHD of 3. Simulation results demonstrate that our proposed model can enhance bit error rate performance and decrease delay time compared to previous studies.

关键词： Codes Magnetohydrodynamics Interference modulation Table lookup Decoding Generators Error correction codes Bit-patterned media recording (BPMR) error correction codes (ECCs) Hamming code modulation coding non-isolated pattern

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Joint Subcarrier Time Reference Index- modulation-Aided Differential Chaos Shift Keying Communication System

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IEEE ACCESS 2024年 12卷 159935-159951页

作者： Hasan, Fadhil S. Valenzuela, Alejandro A. Mustansiriyah Univ Coll Engn Baghdad 14022 Iraq Bonn Rhein Sieg Univ Appl Sci Dept Engn & Commun D-53757 St Augustin Germany

A novel multidimensional index modulation-based differential chaos shift keying (DCSK) technique, designated as Joint Subcarrier Time Reference Index modulation-aided Differential Chaos Shift Keying (JSTRIM-DCSK), is proposed for efficient data transmission in chaotic communication systems. The JSTRIM-DCSK system integrates subcarrier, time slot, and reference signal indexing to transmit information and offers two variants: JSTRIM-DCSK-I and JSTRIM-DCSK-II. The data is organized into L subblocks, each containing N(s )subcarrier index bits p(s) and N-t time slot index bits p(t), reference index bits p(r), and modulated bits p(m). The subcarrier and time slot index bits jointly select an active or inactive subcarrier time slot combination from a total of NsNt possibilities, categorizing the system as either JSTRIM-DCSK-I (active) or JSTRIM-DCSK-II (inactive). The reference indexed bits select a single chaotic reference signal from Nr orthogonal chaotic vectors generated using the Gram-Schmidt orthogonalization process. The modulated bits are transmitted using a DCSK modulation scheme. Analytical expressions for the bit error rate (BER) performance of the JSTRIM-DCSK system are derived under both additive white Gaussian noise (AWGN) and multipath Rayleigh fading channel (MRFC) conditions. Furthermore, the potential for energy savings, bandwidth efficiency, and system complexity of the JSTRIM-DCSK system are thoroughly analyzed and compared with those of the existing techniques. The simulation results validate the analytical expressions and demonstrate the potential of JSTRIM-DCSK to achieve high data rates, efficient energy savings, and a competitive BER performance.

关键词： Indexes modulation Chaotic communication Vectors Bit error rate Communication systems Symbols Energy efficiency Complexity theory Generators Chaos communications modulation coding multidimensional coding multipath channels subcarrier multiplexing

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Frequency Stability Requirements in Quasi-Integer-Ratio Time-Expanded Phase-Sensitive OTDR

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2023年第2期41卷 777-783页

作者： Soriano-Amat, Miguel Martins, Hugo F. Duran, Vicente Fermoso, Pablo Martin-Lopez, Sonia Gonzalez-Herraez, Miguel Fernandez-Ruiz, Maria R. Univ Alcala Alcala De Henares 28805 Spain IO CSIC Inst Opt Daza de Valdes Madrid 28006 Spain Univ Jaume 1 Inst New Imaging Technol GROC UJI Castellon de La Plana 12071 Spain

phase sensitive (TE-?)OTDR is a recently reported technique for distributed fiber sensing that relies on the use of an electro-optic dual frequency comb (DFC) scheme. A distinctive feature of this approach is its ability to provide high spatial resolution (on the centimeter scale) with detection bandwidths orders of magnitude lower than those of conventional phi OTDR systems. The stringent trade-off between resolution, range and sensing bandwidth that exists in TE-?OTDR has demonstrated to be substantially relaxed by implementing two frequency combs with quasi-integer-ratio repetition rates. However, employing very dissimilar line separations (with a ratio between them > 100) is challenging due to the need of keeping the coherence over long sequences of interferograms, which eventually limits the attainable range. In this paper, we formulate the requirements for the frequency stability of the reference clock used in a quasi-integer-ratio DFC scheme. This analysis allows us to stablish the limits on the number of comb lines (i.e., on the number of available independent sensing points) fora particular reference clock. By using a rubidium atomic clock (with a relative frequency stability of similar to 10(-13)), we demonstrate up to 10(5) sensing points along 2 km of fiber with tens of Hz sensing bandwidth.

关键词： Probes Bandwidth Optical fibers Optical fiber sensors Frequency measurement Spatial resolution Clocks Dual frequency comb modulation coding optical time-domain reflectometry quasi-integer-ratio scattering Rayleigh

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Learning Joint Detection, Equalization and Decoding for Short-Packet Communications

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IEEE TRANSACTIONS ON COMMUNICATIONS 2023年第2期71卷 837-850页

作者： Dorner, Sebastian Clausius, Jannis Cammerer, Sebastian ten Brink, Stephan Univ Stuttgart Inst Telecommun I-70569 Stuttgart Germany NVIDIA D-10623 Berlin Germany

We propose and practically demonstrate a joint detection and decoding scheme for short-packet wireless communications in scenarios that require to first detect the presence of a message before actually decoding it. For this, we extend the recently proposed serial Turbo-autoencoder neural network (NN) architecture and train it to find short messages that can be, all "at once ", detected, synchronized, equalized and decoded when sent over an unsynchronized channel with memory. The conceptional advantage of the proposed system stems from a holistic message structure with superimposed pilots for joint detection and decoding without the need of relying on a dedicated preamble. This results not only in a higher spectral efficiency, but also translates into the possibility of shorter messages compared to using a dedicated preamble. We compare the detection error rate (DER), bit error rate (BER) and block error rate (BLER) performance of the proposed system with a hand-crafted state-of-the-art conventional baseline and our simulations show a significant advantage of the proposed autoencoder-based system over the conventional baseline in every scenario up to messages conveying k= 96 information bits. Finally, we practically evaluate and confirm the improved performance of the proposed system over-the-air (OTA) using a software-defined radio (SDR)-based measurement testbed.

关键词： Digital communication wireless communication modulation coding signal detection machine learning

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Time Expansion in Distributed Optical Fiber Sensing

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2023年第11期41卷 3305-3315页

作者： Fernandez-Ruiz, Maria R. Soriano-Amat, Miguel Duran, Vicente Martins, Hugo F. Martin-Lopez, Sonia Gonzalez-Herraez, Miguel Univ Alcala Alcala De Henares 28805 Spain IO CSIC Inst Opt Daza De Valdes Madrid 28006 Spain Univ Jaume 1 Inst New Imaging Technol GROC UJI Castellon de La Plana 12071 Spain

Distributed optical fiber sensing (DOFS) technology has recently experienced an impressive growth in various fields including security, structural monitoring and seismology, among others. This expansion has been accompanied by a speedy development of the technology in the last couple of decades, reaching remarkable performance in terms of sensitivity, range, number of independent sensing points and affordable cost per monitored point as compared with competing technologies such as electrical or point optical sensors. Phase-sensitive Optical Time-Domain Reflectometry (fOTDR) is a particularly interesting DOFS technique, since it enables real-time monitoring of dynamic variations of physical parameters over a large number of sensing points. Compared to their frequency-domain counterparts (OFDR), fOTDR sensors typically provide higher dynamics and longer ranges but significantly worse spatial resolutions. Very recently, a novel fOTDR approach has been introduced, which covers an existing gap between the long range and fast response of fOTDR and the high spatial resolution of OFDR. This technique, termed time-expanded (TE) fOTDR, exploits an interferometric scheme that employs two mutually coherent optical frequency combs. In TE-fOTDR, a probe comb is launched into the fiber under test. The beating of the backscattered light and a suitable LO comb produces a multi-heterodyne detection process that compresses the spectrum of the probe comb, in turn expanding the detected optical traces in the time-domain. This approach has allowed sensing using fOTDR technology with very high resolution (in the cm scale), while requiring outstandingly low detection and acquisition bandwidths (sub-MHz). In this work, we review the fundamentals of TE-fOTDR technology and describe the recent developments, focusing on the attainable sensing performance, the existing trade-offs and open working lines of this novel sensing approach.

关键词： Sensors Optical fiber sensors Spatial resolution Optical fibers Probes Optical pulses Bandwidth Dual frequency comb modulation coding optical time-domain reflectometry quasi-integer-ratio scattering rayleigh

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Adaptive hierarchical coding and modulation scheme over satellite channels

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IET COMMUNICATIONS 2019年第17期13卷 2834-2839页

作者： He, Rui Yang, Dewei Wang, Hua Kuang, Jingming Beijing Inst Technol Sch Informat & Elect Beijing Peoples R China

In this study, a new scheme called adaptive hierarchical coding and modulation has been proposed, based on Adaptive coding and modulation (ACM) and hierarchical modulation (HM). The primary contribution of this study is summarised as the following aspects. Firstly, 16- to 64-APSK constellations with size and labelling optimisation method are proposed for HM, which can be adapted to transmitting multiple hierarchies with different QoS streams and to the non-linear satellite channels due to a lower peak-to-average power ratio compared to traditional hierarchical QAM modulation. Bit channel capacity and Chernoff error bound are introduced to optimise size and labelling of the constellation with interior-point algorithm and modified binary switch algorithm for a specific channel model to get a better performance. Secondly, combining with optimised constellations, coding and modulation modes set is obtained from using constellation design and optimisation method, with different modulation orders and code rates. And over satellite channels with rain and location attenuation, the proposed scheme is able to adapt itself to a changing channel condition and increase the transmission rate compared with ACM schemes of DVB-S2 and DVB-S2X standard.

关键词： optimisation modulation coding phase shift keying quadrature amplitude modulation quality of service satellite communication error statistics channel capacity adaptive codes adaptive modulation wireless channels telecommunication switching adaptive hierarchical coding hierarchical modulation HM labelling optimisation method nonlinear satellite channels peak-to-average power ratio traditional hierarchical QAM modulation bit channel capacity specific channel model optimised constellations modulation modes constellation design code rates ACM schemes adaptive coding and modulation scheme modulation orders channel condition QoS streams 16-to 64-APSK constellations interior-point algorithm modified binary switch algorithm modulation modes set location attenuation rain attenuation transmission rate DVB-S2X standard DVB-S2 standard Chernoff error bound

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Performance Evaluation of Autoencoder for coding and modulation in Wireless Communications 11

Performance Evaluation of Autoencoder for Coding and Modulat...

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11th IEEE International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Xu, Jialong Chen, Wei Ai, Bo He, Ruisi Li, Yujian Wang, Junhong Juhana, Tutun Kurniawan, Adit Beijing Jiaotong Univ State Key Lab Rail Traff Control & Safety Beijing Peoples R China Beijing Jiaotong Univ Key Lab All Opt Network & Adv Telecommun Network Minist Educ Beijing Peoples R China Beijing Jiaotong Univ Sch Elect & Informat Engn Beijing Peoples R China Sch Elect Engn & Informat Inst Technol Bandung Bandung Indonesia

ISBN: (纸本)9781728135557

The end-to-end autoencoder is a novel and attracting concept to innovate communication system architecture. In its training stage, the end-to-end autoencoder needs differentiable channel models to execute back-propagation algorithm. This shortage impedes the further development of the end-to-end autoencoder. Estimating the channel model by reinforcement learning is a good way to alleviate this problem. However, these training methods increase the difficulty in the training stage. In this paper, we set up a general channel model and employ the measured channel data as input data to alleviate this problem. We compare the performance of the end-to-end autoencoder and Hamming code modulated by Binary Phase Shift Keying under additive white Gaussian noise channel and Rayleigh channel and explore the performance of the end-to-end encoder under the real scenarios. Furthermore, we investigate the performance of the end-to-end autoencoder under mismatched channels. The results demonstrate that the performance of the end-to-end autoencoder is similar with Hamming code and has a significant performance improvement under mismatched channels.

关键词： deep learning modulation coding performance evaluation

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Joint relay selection and adaption of modulation, coding and transmit power for spectral efficiency optimisation in amplify-forward relay network

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IET COMMUNICATIONS 2014年第11期8卷 1955-1964页

作者： Taki, Mehrdad Sadeghi, Mohammad Univ Isfahan Dept Elect Engn Esfahan Iran

Three schemes are designed for joint relay selection and link adaption in amplify and forward relay network which are called RS-CAP (joint relay selection with continuous adaptation of powers), RS-DAP (joint relay selection with discrete adaptation of powers) and OTD-DAP (optimised time division with discrete adaptation of powers). In all schemes spectral efficiency is optimised using adaptive modulation, coding and transmit power subject to average power constraint of each node and a bit error rate constraint of detection. The main idea behind all designs is to save power of relays in inactive time to be utilised for active time. In RS-CAP and RS-DAP, optimised relay selection is done based on channel state information of all corresponding paths, however, in OTD-DAP just an optimised time percentage is allocated to each relay to cooperate in signal transmission. Considerable less channel estimation load is imposed on the receiver in the OTD-DAP scheme compared with the others. In RS-CAP power of nodes are continuously adapted, however, in RS-DAP and OTD-DAP, powers are discrete adaptive. Thus there is a considerable decrease in feedback rate in the RS-DAP and OTD-DAP schemes in comparison with RS-CAP. A trade-off between the performance and channel estimation load and feedback rate is seen in numerical evaluations. Noticeable improvement in achievable rates is seen by using proposed schemes compared with the previous works.

关键词： amplify and forward communication relay networks (telecommunication) modulation coding adaptive modulation channel estimation spectral efficiency optimisation link adaption amplify and forward relay network joint relay selection with continuous adaptation of powers joint relay selection with discrete adaptation of powers optimised time division with discrete adaptation of powers adaptive modulation channel state information signal transmission channel estimation

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On modulation coding for channels with cost constraints

On modulation coding for channels with cost constraints

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IEEE International Symposium on Information Theory

作者： Victor Y. Krachkovsky Razmik Karabed Shaohua Yang Bruce A. Wilson Avago Technologies Allentown Pennsylvania USA Avago Technologies San-Jose California USA

We consider the problem of designing modulation codes for magnetic recording (MR) channels and other binary channels with ISI, where Markov sources are known to provide the best known lower bound on capacity. Our approach includes computing a costly channel matching a Markov source optimized for a given ISI channel. We then construct encoders and decoders for a modulation code matched to this costly channel.

关键词： Markov processes Vectors Encoding Decoding Entropy modulation coding

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High Power Amplifier Nonlinearity Models and Digital Predistortion Techniques in DVB-S2X

High Power Amplifier Nonlinearity Models and Digital Predist...

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International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB)

作者： Batov, Yuri Puzko, Danila Gelgor, Aleksandr Tkachenko, Dmitry Montalban, Jon Angueira, Pablo Peter Great St Petersburg Polytech Univ St Petersburg Russia Univ Basque Country UPV EHU Dept Elect Technol Bilbao Spain Univ Basque Country UPV EHU Dept Commun Engn Bilbao Spain

ISBN: (纸本)9781665469012

Energy efficiency is a must in satellite communications and highly nonlinear High Power Amplifiers (HPAs) are used. Nonlinearities must be mitigated, specially in use cases like Direct to Home Broadcasting where the amplifier is operated close to the saturation point. There are various choices to compensate nonlinearity. This paper analyzes predistortion techniques in view of different HPA models available in the literature. The paper discusses possible predistortion parametres and evaluates the impact of predistortion and High Power Amplifier modeling on the DVB-S2X reception thresholds using a DVB-S2X standard simulation platform. The simulation results show that that different types of HPAs described with significantly different models present similar performance metrics after applying carefully-tuned predistortion techniques.

关键词： Satellite Communication Satellite Broadcasting modulation coding Multiplexing Predistortion Amplifier Non-linearities TWTA Ku Band Ka Band

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