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A novel low-complexity power allocation algorithm based on the NOMA system in a low-speed environment

Digital Communications and Networks 2021年第4期7卷 580-588页

作者： Guangfu Wu Wenyi Zheng Wei Xiong Yun Li Hongcheng Zhuang Xin Tan School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing400065China Chongqing Municipal Housing Provident Fund Administration Center Chongqing401121China Chongqing Key Laboratory of Mobile Communications Technology Chongqing University of Posts and TelecommunicationsChongqing400065China Huawei Technologies Co Ltd.Shenzhen518129China

For future wireless communication systems,Power Domain Non-Orthogonal Multiple Access(PD-NOMA)using an advanced receiver has been considered as a promising radio access technology *** allocation plays an important role in the PD-NOMA system because it considerably affects the total throughput and Geometric Mean User Throughput(GMUT)***,most existing studies have not completely accounted for the computational complexity of the power allocation process when the User Terminals(UTs)move in a slow fading channel *** resolve such problems,a power allocation method is proposed to considerably reduce the search space of a Full Search Power(FSP)allocation *** initial power reallocation coefficients will be set to start with former optimal values by the proposed Lemma before searching for optimal power reallocation coefficients based on total throughput *** size and correction granularity will be adjusted within a much narrower power search range while invalid power combinations may be reasonably discarded during the search *** simulation results show that the proposed power reallocation scheme can greatly reduce computational complexity while the total throughput and GMUT performance loss are not greater than 1.5%compared with the FSP algorithm.

关键词： NOMA Power allocation Slow fading channel low computational complexity

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Coherent Optical Interleaved SC-FDM Uplink Scheme for Long-Reach Passive Optical Network

IEEE PHOTONICS JOURNAL

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IEEE PHOTONICS JOURNAL 2016年第2期8卷 1-1页

作者： Zhou, Ji Xu, Fei Sun, Erkun Zhang, Tiantian Zhang, Zhenshan Guo, Mengqi Tang, Xizi Wang, Zhansheng Qiao, Yaojun Beijing Univ Posts & Telecommun Sch Informat & Commun Engn State Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China ZTE Corp Beijing 100191 Peoples R China

In this paper, we propose a coherent optical interleaved single-carrier frequency-division multiplexing (CO-I-SC-FDM) uplink scheme for the long-reach passive optical network (LR-PON). I-SC-FDM is a modified form of orthogonal frequency-division multiplexing (OFDM) with low computational complexity and low peak-to-average power ratio (PAPR). By designing a simple encoding structure, the computational complexity of the transmitter can be reduced from O(Nlog(2)(N)) to O(N). At the probability of 10(-3), the PAPR of the I-SC-FDM is about 10.7 dB lower than that of conventional OFDM for quadrature phase-shift keying (QPSK) modulation. We experimentally demonstrate a 10-Gb/s CO-I-SC-FDM uplink scheme over 100-km standard single-mode fiber with 1:128-way passive splitter for LR-PON. In the conventional CO-OFDM uplink scheme, the splitting ratio is only 1:64. The proposed scheme shows great potential for application in access and metro networks.

关键词： Coherent optical interleaved single-carrier frequency-division multiplexing (I-SC-FDM) long-reach passive optical network (LR-PON) access and metro networks low peak-to-aveage power ratio (PAPR) low computational complexity

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Time-frequency-scale transform for analysis of PQ disturbances

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2017年第3期11卷 305-314页

作者： Singh, Utkarsh Singh, Shyam Narain Indian Inst Technol Alternate Hydro Energy Ctr Roorkee 247667 Uttar Pradesh India

The advancements in signal processing have broadened the scope of research in power quality (PQ) analysis. Recent literature on PQ also highlights the need of signal processing tools, which offer high resolution, noise immunity and feature extraction capabilities. This study thus presents a time-frequency-scale transform (TFST) based on chirplet transform (CT) for PQ analysis. CT is a multi-domain transform with each domain having specific effect on time-frequency representations (TFRs). CT cannot be directly applied to PQ analysis, and therefore, TFST is derived from it which limits the TFR operations to shifting and scaling. A Hann window is preferred for signal truncation due to its aptness for sinewave, high frequency resolution and reduced spectral leakage. The proposed transform resembles the short-time Fourier transform with an added scaling feature. It has low computational complexity, and the resulting TFRs can provide signal information and features just like Stockwell transform. Seven case studies are presented for performance assessment. The typical trade-off situation persists in some PQ disturbances due to windowing, but the results show appreciable time-frequency resolution and noise immunity.

关键词： signal processing Fourier transforms time-frequency-scale transform PQ disturbances chirplet transform power quality analysis multidomain transform time-frequency representations Hann window short-time Fourier transform low computational complexity Stockwell transform performance assessment

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Spatiotemporal feature extraction for facial expression recognition

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IET IMAGE PROCESSING 2016年第7期10卷 534-541页

作者： Kamarol, Siti Khairuni Amalina Jaward, Mohamed Hisham Parkkinen, Jussi Parthiban, Rajendran Monash Univ Malaysia Sch Engn Elect & Comp Syst Engn Petaling Jaya 46150 Selangor Malaysia Univ Eastern Finland Sch Comp Joensuu 80100 Finland

A key issue regarding feature extraction is the capability of a technique to extract distinctive features to represent facial expressions while requiring a low computational complexity. In this study, the authors propose a novel approach for appearance-based facial feature extraction to perform the task of facial expression recognition on video sequences. The proposed spatiotemporal texture map (STTM) is capable of capturing subtle spatial and temporal variations of facial expressions with low computational complexity. First, face is detected using Viola-Jones face detector and frames are cropped to remove unnecessary background. Facial features are then modelled with the proposed STTM, which uses the spatiotemporal information extracted from three-dimensional Harris corner function. A block-based method is adopted to extract the dynamic features and represent the features in the form of histograms. The features are then classified into classes of emotion by the support vector machine classifier. The experimental results demonstrate that the proposed approach shows superior performance compared with the state-of-the-art approaches with an average recognition rate of 95.37, 98.56, and 84.52% on datasets containing posed expressions, spontaneous micro-expressions, and close-to-real-world expressions, respectively. They also show that the proposed algorithm requires low computational cost.

关键词： face recognition emotion recognition image sequences image classification image representation video signal processing support vector machines image texture spatiotemporal feature extraction facial expression recognition appearance-based facial feature extraction video sequences spatiotemporal texture map STTM spatial facial expression variation temporal facial expression variation low computational complexity Viola-Jones face detector facial feature modelling 3D Harris corner function block-based method feature representation support vector machine classifier posed expressions spontaneous microexpressions close-to-real-world expressions

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A study on actuator delay compensation using predictive control technique with experimental verification

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MECHATRONICS 2019年 57卷 140-149页

作者： Nahidi, Asal Khajepour, Amir Kasaeizadeh, Alireza Chen, Shih-Ken Litkouhi, Bakhtiar Univ Waterloo Dept Mech & Mechatron Engn Waterloo ON N2L 3G1 Canada Gen Motors LLC Warren MI 48090 USA

In this paper, a model predictive control (MPC) method for actuator delay compensation in vehicle stability control is presented. At each sampling time, an MPC controller computes required torque adjustments in order to follow desired vehicle dynamics on slippery road condition. Actuator delay in a control loop can diminish controller effectiveness to a great extent and may even engender instability in a critical driving situation. Two control structures with different computational complexities are presented. In the first approach, the MPC problem is formulated such that actuator dynamics is considered in prediction model. Whereas, the second approach investigates actuator lag impact on control action allocation (distribution) through a transfer matrix. In contrast to common delay handling approaches, the proposed method is simply real-time implementable and does not necessitate an intricate design procedure. The complication of model predictive controller remains intact, since online computation load is not substantially altered. Discussions are presented on computational burden and performance of two control schemes using computer-aided simulations in MATLAB/CarSim environment as well as experiments. A rear-wheel-drive sport utility vehicle equipped with differential braking is utilized for numerical simulations and experimentations. According to the simulation results, success of the proposed method in tackling actuator delay in vehicle stabilization is inquired. Experimental tests also demonstrate competency of the proposed technique. Although this technique is applied to a vehicle stability control with a particular actuator, it is not limited to a certain set of problems and can be employed for a broad variety of actuators or more generally, model predictive control problems with actuator identifiable time delays.

关键词： Model predictive control Actuator dynamic delay Differential braking Real-time implementation low computational complexity Simulation and experimental verifications

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Transmission Efficient Channel Estimation for OFDM System Under Multi-path Fast Fading Channel

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WIRELESS PERSONAL COMMUNICATIONS 2015年第2期84卷 1561-1575页

作者： Jan, Yih-Haw Nan Kai Univ Technol Dept Digital Living Innovat Caotun Township 54243 Nantou County Taiwan

This paper considers the channel estimation method in the case of a high mobility communication in orthogonal frequency-division multiplexing (OFDM) systems. In this paper, several successive OFDM symbols experienced channel are treated as a window. The polynomial approximation of the channel parameters in the time domain is considered. We show that the low order polynomials are good enough to model the channel within a window. Hence the interpolation performing over a whole window profits pilot reduction. Moreover, the method has an advantage of computational complexity because of the low order polynomial approximation and without the requirement of inter-carrier interference mitigation. The method is derived with the least-square approach for polynomial interpolation of arbitrary order. Simulation results show that the proposed method is robust to high Doppler frequency and enhancing the transmission efficiency.

关键词： Channel estimation OFDM Fast time varying channel Transmission efficiency low computational complexity

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Reduced complexity and near optimum detector for linear-frequency-modulated and phase-modulated LPI radar signals

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IET RADAR SONAR AND NAVIGATION 2019年第4期13卷 593-600页

作者： Dezfuli, Ali Abbasi Shokouhmand, Arash Oveis, Amir Hosein Norouzi, Yaser Ferdowsi Univ Mashhad Dept Elect Engn Azadi Sq Mashhad Razavi Khorasan Iran Amirkabir Univ Technol Dept Elect Engn Hafez St Tehran Iran KN Toosi Univ Technol Dept Elect Engn Shariati St Tehran Iran

Dealing with low probability of intercept (LPI) radar signals in very low signal-to-noise ratio (SNR) stages requires reconnaissance systems to employ an effectively practical method for detecting and fully characterising the received signals. Following the aim of LPI signal detection, in this study, a novel method based on concentrating the energy of the signal in one particular row of the time-frequency domain matrix is proposed. It is shown that the proposed method enables to detect and estimate the parameters of multiple low-power linear-frequency-modulated signals. A comparison has been made between the performance of the matched filter and the proposed method, and it is shown the proposed method has approximately the same performance and low computational complexity as matched filters. This method is also able to detect the poly-phase signals such as Frank-coded signals and also non-linear-frequency-modulated signals, as well. To show the effectiveness of the method, extensive simulations are carried out with different LPI radar waveforms corrupted with additive white Gaussian noise of SNR down to -25 dB.

关键词： frequency-domain analysis radar signal processing radar detection filtering theory phase modulation radar receivers matched filters computational complexity probability AWGN FM radar matrix algebra reduced complexity phase-modulated LPI radar signals low signal-to-noise ratio SNR reconnaissance systems LPI signal detection low-power linear-frequency-modulated signals matched filter low computational complexity poly-phase signals Frank-coded signals nonlinear-frequency-modulated signals near optimum detector low probability-of-intercept radar signals time-frequency domain matrix LPI radar waveforms additive white Gaussian noise noise figure-25 dB

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complexity-adjustable SC decoding of polar codes for energy consumption reduction

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IET COMMUNICATIONS 2019年第14期13卷 2088-2096页

作者： Zheng, Haotian Chen, Bin Abanto-Leon, Luis F. Cao, Zizheng Koonen, Ton Eindhoven Univ Technol NL-5600 MB Eindhoven Netherlands Hefei Univ Technol HFUT Sch Comp & Informat Hefei Anhui Peoples R China Tech Univ Darmstadt Dept Comp Sci Darmstadt Germany

This study proposes an enhanced list-aided successive cancellation stack (ELSCS) decoding algorithm with adjustable decoding ***, a logarithmic likelihood ratio-threshold based path extension scheme is designed to further reduce the memory consumption of stack decoding. Numerical simulation results show that without affecting the error correction performance, the proposed ELSCS decoding algorithm provides a flexible trade-off between time complexity and computational complexity, while reducing storage space up to 70%. Based on the fact that most mobile devices operate in environments with stringent energy budget to support diverse applications, the proposed scheme is a promising candidate for meeting requirements of different applications while maintaining a low computational complexity and computing resource utilisation.

关键词： error correction codes computational complexity decoding complexity-adjustable SC decoding polar codes energy consumption reduction enhanced list-aided successive cancellation stack decoding algorithm ELSCS adjustable decoding complexity memory consumption numerical simulation results error correction performance time complexity stringent energy budget low computational complexity logarithmic likelihood ratio-threshold logarithmic likelihood ratio-threshold path extension scheme

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computational Efficient SLM-OFDM Receiver for Time-Invariant Indoor Fading Channel

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WIRELESS PERSONAL COMMUNICATIONS 2017年第1期97卷 661-674页

作者： Adegbite, Saheed A. McMeekin, Scott Stewart, Brian G. Glasgow Caledonian Univ Sch Engn & Built Environm 70 Cowcaddens Rd Glasgow G4 0BA Lanark Scotland Univ Strathclyde Dept Elect & Elect Engn Glasgow Lanark Scotland

This paper addresses receiver related side information (SI) estimation issues when selected mapping is used to reduce peak-to-average power ratio in orthogonal frequency division multiplexing (OFDM) systems. The SI contains critical information and its accurate estimation is required to enable successful recovery of payload data regardless of the channel condition. However, the need for SI estimation poses some practical issues in the form of high computational complexity and implementation challenges. Through simulations, this paper investigates the performance of an alternative data decoding approach called Embedded Coded Modulation (ECM), which requires no SI estimation. Using a form of block-type OFDM frame structure, results show that the ECM technique produces identical data decoding performance as other methods even in the presence of some non-linear amplifier distortions. In addition, it is shown that the ECM method eliminates SI related computational complexity and implementation problems.

关键词： Block-type OFDM frame low computational complexity OFDM PAPR SLM Side information (SI) estimation

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low complexity Linear Channel Estimation for MIMO Communication Systems

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WIRELESS PERSONAL COMMUNICATIONS 2017年第4期97卷 5031-5044页

作者： Raza, Hasan Khan, Noor M. Capital Univ Sci & Technol Dept Elect Engn Islamabad 44000 Pakistan

Channel estimation is employed to get the current knowledge of channel states for an optimum detection in fading environments. In this paper, a new recursive multiple input multiple output (MIMO) channel estimation is proposed which is based on the recursive least square solution. The proposed recursive algorithm utilizes short training sequence on one hand and requires low computational complexity on the other hand. The algorithm is evaluated on a MIMO communication system through simulations. It is realized that the proposed algorithm provides fast convergence as compared to recursive least square (RLS) and robust variable forgetting factor RLS (RVFF-RLS) adaptive algorithms while utilizing lesser computational cost and provides independency on forgetting factor.

关键词： low computational complexity MIMO systems Channel estimation

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