Electronics

Research

16 pages, 1737 KiB

Open AccessArticle

Fast Sparse Bayesian Learning Based on Beamformer Power Outputs to Solve Wideband DOA Estimation in Underwater Strong Interference Environment

by Yahao Zhang, Ningning Liang, Yixin Yang and Yunchuan Yang

Electronics 2024, 13(8), 1456; https://doi.org/10.3390/electronics13081456 - 11 Apr 2024

Viewed by 317

Abstract

Wideband direction-of-arrival (DOA) estimation is an important task for passive sonar signal processing. Nowadays, sparse Bayesian learning (SBL) attracts much attention due to its good performance. However, performance degrades in the existence of strong interference. This problem can be solved by combining the [...] Read more.

Wideband direction-of-arrival (DOA) estimation is an important task for passive sonar signal processing. Nowadays, sparse Bayesian learning (SBL) attracts much attention due to its good performance. However, performance degrades in the existence of strong interference. This problem can be solved by combining the beamformer and the SBL. The beamformer is a useful tool to suppress interference. Then, the SBL can easily estimate the DOA of the targets from the beamformer power outputs (BPO). Unfortunately, the latter step needs to compute the matrix inversion frequently, which brings some computational burden to the sonar system. In this paper, the BPO-based SBL is modified. A sequential solution is provided for the parameters in the BPO probabilistic model. In this manner, only one signal precision parameter involved in the probabilistic model is updated in each iteration and the matrix inversion is avoided during the iteration, thus reducing the computational burden. Simulation and experimental results show that the proposed method maintains high estimation precision in the interference environment. At the same time, its computational efficiency is almost three times higher in comparison with state-of-the-art methods. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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15 pages, 3651 KiB

Open AccessArticle

Imbalanced Learning-Enhanced Beam Codebooks towards Imbalanced User Distribution in Millimeter Wave and Terahertz Massive MIMO Systems

by Zhiheng Chen, Pei Liu and Kehao Wang

Electronics 2023, 12(23), 4768; https://doi.org/10.3390/electronics12234768 - 24 Nov 2023

Viewed by 762

Abstract

Millimeter wave (mmWave) and terahertz (THz) massive MIMO architectures are pivotal in the advancement of mobile communications. These systems conventionally utilize codebooks to facilitate initial connection and to manage information transmission tasks. Traditional codebooks, however, are typically composed of numerous single-lobe beams, thus [...] Read more.

Millimeter wave (mmWave) and terahertz (THz) massive MIMO architectures are pivotal in the advancement of mobile communications. These systems conventionally utilize codebooks to facilitate initial connection and to manage information transmission tasks. Traditional codebooks, however, are typically composed of numerous single-lobe beams, thus incurring substantial beam training overhead. While neural network-based approaches have been proposed to mitigate the beam training load, they sometimes fail to adequately consider the minority users dispersed across various regions. The fairness of the codebook coverage relies on addressing this problem. Therefore, we propose an imbalanced learning (IL) methodology for beam codebook construction, explicitly designed for scenarios characterized by an imbalanced user distribution. Our method begins with a pre-clustering phase, where user channels are divided into subsets based on their power response to combining vectors across distinct subareas. Then, each subset is refined by a dedicated sub-model, which contributes to the global model within each IL iteration. To facilitate the information exchange among sub-models during global updates, we introduce the focal loss mechanism. Our simulation results substantiate the efficacy of our IL framework in enhancing the performance of mmWave and THz massive MIMO systems under the conditions of imperfect channel state information and imbalanced user distribution. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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16 pages, 8551 KiB

Open AccessArticle

Data-Driven Network Latency Processing for Auxiliary Services in Virtual Power Plant

by Chuan Liu, Jing Tao, Ying Liu, Xiangqun Wang and Wei Peng

Electronics 2023, 12(20), 4276; https://doi.org/10.3390/electronics12204276 - 16 Oct 2023

Cited by 1 | Viewed by 814

Abstract

Nowadays, with the increasingly prominent contradiction between environment and development, renewable energy technology has received extensive attention. However, due to natural fluctuation, there are many challenges in safety and stationarity in an electric power system with a large-scale portion of renewable energy. Meanwhile, [...] Read more.

Nowadays, with the increasingly prominent contradiction between environment and development, renewable energy technology has received extensive attention. However, due to natural fluctuation, there are many challenges in safety and stationarity in an electric power system with a large-scale portion of renewable energy. Meanwhile, the conventional electric power system in which the power supply follows the load change paradigm is gradually broken. Thanks to advanced information and communication technology, energy storage technology, and automatic control technology, the power supply, grid, load, and energy storage interactive electric power system regulation paradigm came into being. A virtual power plant (VPP) is a concrete realization of this regulation paradigm. In this paper, based on the characteristics of VPP service requirements, we propose a data-driven method to estimate and predict the network latency. First, we investigate and summarize the characteristics of a VPP participating in various auxiliary services and their demand for communication networks. Second, the practical implementation of a VPP network architecture, which combines the local network and the backhaul network, is presented based on a secure access gateway and VPP monitoring and scheduling platform for flexible resource aggregation and regulation. Then, based on a delay probe, a network latency acquisition method is proposed for a public backhaul network. Finally, a data-driven network latency processing method is proposed to support the VPP’s participation in different communication requirements of auxiliary services. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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15 pages, 3419 KiB

Open AccessArticle

Generation of Terahertz OAM Waves with Six Modes Based on Three-Layer Z-Shaped Reflective Metasurface

by Qibiao Zhu, Xiangzhong Xiao, Lisu Yu and Nanrun Zhou

Electronics 2023, 12(13), 2859; https://doi.org/10.3390/electronics12132859 - 28 Jun 2023

Viewed by 1127

Abstract

In this paper, a broadband and efficient three-layer Z-shaped reflective metasurface for linear polarization conversion is designed and six different modes of orbital angular momentum (OAM) waves are generated in the terahertz band. The designed metasurface consisted of several units, and it is [...] Read more.

In this paper, a broadband and efficient three-layer Z-shaped reflective metasurface for linear polarization conversion is designed and six different modes of orbital angular momentum (OAM) waves are generated in the terahertz band. The designed metasurface consisted of several units, and it is divided into twelve regions. The phase difference is achieved by changing the structural parameters of the units, and then different modes of OAM waves are generated. The terahertz OAM waves with the modes of

\pm 1

,

\pm 2

, and

\pm 3

are generated by metasurface with high efficiency and wide bandwidth. The results show that the designed metasurface could produce high purity terahertz OAM waves with six different modes, and the reflection amplitude of the metasurface unit is more than 0.9 in the frequency range of 1.0 THz to 1.8 THz. The generated OAM waves with the modes of

\pm 1

and

\pm 2

have a mode purity more than 90%. The designed metasurface has good wavefront control ability, which provides an effective method to generate multimode OAM waves. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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17 pages, 1367 KiB

Open AccessArticle

Soft Decision Decoding with Cyclic Information Set and the Decoder Architecture for Cyclic Codes

by Weigang Chen, Tian Zhao and Changcai Han

Electronics 2023, 12(12), 2693; https://doi.org/10.3390/electronics12122693 - 16 Jun 2023

Cited by 1 | Viewed by 1233

Abstract

The soft decision decoding algorithm for cyclic codes, especially the maximum likelihood (ML) decoding algorithm, can obtain significant performance superior to that of algebraic decoding, but the complexity is much higher. To deal with this problem, an improved soft decision decoding algorithm based [...] Read more.

The soft decision decoding algorithm for cyclic codes, especially the maximum likelihood (ML) decoding algorithm, can obtain significant performance superior to that of algebraic decoding, but the complexity is much higher. To deal with this problem, an improved soft decision decoding algorithm based on a cyclic information set and its efficient implementation architecture are proposed. This algorithm employs the property of the cyclic codes to generate a series of cyclic information sequences by circularly shifting, constructing the cyclic information set. Then, a limited number of candidate information sequences are efficiently generated using an iterative computation method, and the candidate codewords are generated using the very concise encoding method of the cyclic codes. Furthermore, the efficient hardware architecture based on systolic arrays is also proposed to generate candidate information sequences and to select the optimal candidate codewords. An emulation platform is constructed to verify the error correction performance and to determine the optimal decoder parameters. Emulation results indicate that, with appropriate parameter selection, the proposed decoding algorithm can achieve a bit error rate approaching the ML performance while maintaining low complexity. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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11 pages, 688 KiB

Open AccessArticle

An Efficient Random Access Reception Algorithm for ToA Estimation in NB-IoT

by Shengyong Li, Tian Xiang, Ding Huang, Ling Han, Qi Wu and Dejin Kong

Electronics 2023, 12(12), 2636; https://doi.org/10.3390/electronics12122636 - 12 Jun 2023

Viewed by 771

Abstract

Narrowband Internet of Things (NB-IoT) aims to provide wide coverage for a massive number of low-cost devices. Therefore, an NB-IoT physical random access channel (NPRACH) preamble based on a single tone signal with frequency hopping was designed, enabling the base station to estimate [...] Read more.

Narrowband Internet of Things (NB-IoT) aims to provide wide coverage for a massive number of low-cost devices. Therefore, an NB-IoT physical random access channel (NPRACH) preamble based on a single tone signal with frequency hopping was designed, enabling the base station to estimate the time-of-arrival (ToA) values for realizing uplink synchronization among multiple users. However, due to residual carrier frequency offset (RCFO) in the NPRACH preamble, it is crucial to keep the accuracy of the ToA estimation. Recognizing this urgency, in this paper we first judiciously investigate the effect of the hooping distance on ToA estimation. With which, we propose an efficient receiving algorithm to improve the accuracy of ToA estimation. The main aim of the algorithm is to treat two consecutive symbol groups as a whole and then carry out difference calculations on the two newly constituted symbol groups to construct a more logical frequency hopping distance. Extensive numerical results validate the superiorly of our proposed scheme compared against conventional strategies, showing that the probability of the ToA estimation obtained by this method is 99% within the acceptable error range. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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15 pages, 7234 KiB

Open AccessArticle

Method for Digital Cancellation of System Interference in a Full-Duplex Power Line Communication System

by Semen Mukhamadiev, Eugeniy Rogozhnikov, Edgar Dmitriyev, Dmitriy Pokamestov, Yakov Kryukov, Serafim Novichkov and Dmitry Lakontsev

Electronics 2023, 12(10), 2211; https://doi.org/10.3390/electronics12102211 - 12 May 2023

Viewed by 939

Abstract

Every year the number of IoT devices is growing, which gives a boost to development of such technology as Power Line Communication (PLC). The term PLC refers to the use of a power supply circuit to transmit data. Full-duplex technology can be applied [...] Read more.

Every year the number of IoT devices is growing, which gives a boost to development of such technology as Power Line Communication (PLC). The term PLC refers to the use of a power supply circuit to transmit data. Full-duplex technology can be applied to increase the data transfer rate in a PLC. The difficulty in using a full duplex is the need to suppress the transmitter’s own signal (interference signal). Analog cancellation and digital cancellation are used for this purpose. Common algorithms for digital cancellation are adaptive algorithms. In this paper adaptive algorithms such as Particle Swarm Optimization (PSO) and Recursive Least Squares (RLS) are considered and a modification of the classical RLS is proposed. The proposed algorithm uses precalculated weight coefficients together with periodic reinitialization of the filter. This avoids the influence of significant changes in the input signal on the further process of filter adaptation and provides the highest level of echo suppression. The proposed algorithm provides an improvement of parameters such as Error Vector Magnitude (EVM) and Signal-to-Interference Ratio (SIR) in comparison with classical RLS and PSO, according to the results of the study. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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13 pages, 8204 KiB

Open AccessCommunication

Motion-Induced Noise Detection of Electrode-Pair Towed Antennas Using Helix Coil Sensors

by Xu Xie, Hao Zuo, Shize Wei and Qin Wu

Electronics 2023, 12(7), 1677; https://doi.org/10.3390/electronics12071677 - 02 Apr 2023

Viewed by 1093

Abstract

Electrode-pair towed antennas are widely utilized for marine electromagnetic detection, underwater communication, and other purposes. However, the motion-induced noise created by antenna vibrations due to environmental turbulence affects extremely low frequency and super low frequency (ELF/SLF) communications. In this article, we presented a [...] Read more.

Electrode-pair towed antennas are widely utilized for marine electromagnetic detection, underwater communication, and other purposes. However, the motion-induced noise created by antenna vibrations due to environmental turbulence affects extremely low frequency and super low frequency (ELF/SLF) communications. In this article, we presented a method for detecting the motion-induced noise of electrode-pair towed antennas using helix coil sensors. The equivalent resistance, inductance, capacitance, and conductance (RLCG) transmission model and parameters were derived based on the mirror method of the twisted structure with a shielding layer inside. A water-flow cycling experimental platform was constructed to evaluate two types of antenna sections. Electrode-pair, accelerators, and helix coils sensors signals were sampled and analyzed in time and frequency domain. The comparison results demonstrated that the helix coil sensors achieved a high correlation with the electrode-pair towed antenna in various vibration speeds ranging from 0.7 to 0.9. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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9 pages, 1954 KiB

Open AccessCommunication

High-Performance QC-LDPC Code Co-Processing Approach and VLSI Architecture for Wi-Fi 6

by Yujun Wu, Bin Wu and Xiaoping Zhou

Electronics 2023, 12(5), 1210; https://doi.org/10.3390/electronics12051210 - 03 Mar 2023

Cited by 1 | Viewed by 1227

Abstract

The QC-LDPC code, with its excellent error correction performance and hardware friendliness, has been identified as one of the channel encoding schemes by Wi-Fi 6. Shorting, puncturing, or repeating operations are needed to ensure that user data can be sent with integer symbols [...] Read more.

The QC-LDPC code, with its excellent error correction performance and hardware friendliness, has been identified as one of the channel encoding schemes by Wi-Fi 6. Shorting, puncturing, or repeating operations are needed to ensure that user data can be sent with integer symbols and complete rate matching. Due to the uncertainty of the user data size, the modulation’s selectivity, and the difference in the number of spatial streams, the receiver must deal with more than 10⁶ situations. At the same time, other computationally intensive tasks occupy the time slot budget of the receiver. Typical are demodulation and decoding. Hence, the receiver needs to quickly reverse the demodulated data process. This paper first proposes a co-processing method and VLSI architecture compatible with all code lengths, code rates, and processing parameters. The co-processor separates field and block splicing, simplifying the control logic. There is no throughput rate bottleneck, and the maximum delay is less than 1 us. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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14 pages, 431 KiB

Open AccessArticle

A Tensor-Based Approach to Blind Despreading of Long-Code Multiuser DSSS Signals

by Liangliang Li, Tao Liang, Huaguo Zhang, Songmao Du and Lin Gao

Electronics 2023, 12(5), 1097; https://doi.org/10.3390/electronics12051097 - 22 Feb 2023

Viewed by 1007

Abstract

In this paper, a tensor-based approach to blind despreading of long-code multiuser DSSS signals is proposed. We aim to generalize the tensor-based methods originally developed for blind separation of short-code multiuser DSSS signals to long-code cases. Firstly, we model the intercepted long-code multiuser [...] Read more.

In this paper, a tensor-based approach to blind despreading of long-code multiuser DSSS signals is proposed. We aim to generalize the tensor-based methods originally developed for blind separation of short-code multiuser DSSS signals to long-code cases. Firstly, we model the intercepted long-code multiuser DSSS signals with an antenna-array receiver as a three-order tensor with missing values, and then, the blind separation problem can be formulated as a canonical or parallel factor (CANDECOMP/PARAFAC) decomposition problem of the missing-data tensor, which can be solved using optimum methods. Secondly, a constrained Cramér–Rao Bound (CRB) is also derived to provide a performance benchmark for the proposed approach. Simulation results verify the feasibility of our proposed approach in the case of low signal-to-noise (SNR) conditions. Full article

(This article belongs to the Special Issue Advanced Digital Signal Processing for Future Digital Communications)

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