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Simplification of I-Vector Extraction for Speaker Identification

Chinese Journal of Electronics 2016年第6期25卷 1121-1126页

作者： XU Longting YANG Zhen SUN Linhui Broadband Wireless Communication and Sensor Network Technology Key Lab Nanjing University of Posts and Telecommunications

The identity vector(i-vector) approach has been the state-of-the-art for text-independent speaker recognition, both identification and verification in recent years. An i-vector is a low-dimensional vector in the socalled total variability space represented with a thin and tall rectangular matrix. This paper introduces a novel algorithm to improve the computational and memory requirements for the application. In our method, the series of symmetric matrices can be represented by diagonal expression,sharing the same dictionary, which to some extent is analogous to eigen decomposition, and we name this algorithm Eigen decomposition like factorization(EDLF). Similar algorithms are listed for comparison, in the same condition,our method shows no disadvantages in identification accuracy.

关键词： Speaker identification Closed-set I-vector Symmetric matrix factorization

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Speech Signal Processing on Graphs: Graph Topology, Graph Frequency Analysis and Denoising

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Chinese Journal of Electronics 2020年第5期29卷 926-936页

作者： WANG Tingting GUO Haiyan LYU Bin YANG Zhen Broadband Wireless Communication and Sensor Network Technology Key Lab Nanjing University of Posts and Telecommunications

The paper investigates the hidden relationships among speech samples by applying graph tools. Specifically, we first estimate an applicable graph topology for unstructured speech signals, which can map speech signals into the vertex domain successfully and construct as Speech graph signals(SGSs). On the basis, we define a new graph Fourier transform for SGSs, which can investigate its related graph Fourier analysis. Moreover,we propose a new Graph structure spectral subtraction(GSSS) method for speech enhancement under different noisy environments. Simulation results show that the performance of the GSSS method can be significantly improved than the classical Basic spectral subtraction(BSS) method in terms of the average Segmental signal-tonoise ratio(SSNR), Perceptual evaluation of speech quality(PESQ) and the computational complexity.

关键词： Graph Fourier transform Graph topology graph frequency analysis speech processing graph topology unstructured speech signals GSSS method Speech graph Fourier analysis graph theory Fourier transforms speech quality classical Basic spectral subtraction method Denoising speech signal processing perceptual evaluation of speech quality computational complexity speech samples Graph structure spectral subtraction method Graph signal processing segmental signal-to-noise ratio speech enhancement graph tools Fourier analysis SGSs

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Cross-layer resource allocation based on equivalent bandwidth in OFDMA systems

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Journal of Systems Engineering and Electronics 2016年第4期27卷 754-762页

作者： Su Pan Cheng Li Sheng Zhang Danwei Chen Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts & Telecommunications

A quality of service（QoS） guaranteed cross-layer resource allocation algorithm with physical layer, medium access control（MAC） layer and call admission control（CAC） considered simultaneously is proposed for the full IP orthogonal frequency division multiple access（OFDMA） communication system, which can ensure the quality of multimedia services in full IP *** algorithm converts the physical layer resources such as subcarriers, transmission power, and the QoS metrics into equivalent bandwidth which can be distributed by the base station in all three layers. By this means, the QoS requirements in terms of bit error rate（BER）, transmission delay and dropping probability can be guaranteed by the cross-layer optimal equivalent bandwidth allocation. The numerical results show that the proposed algorithm has higher spectrum efficiency compared to the existing systems.

关键词： resource allocation equivalent bandwidth crosslayer optimization orthogonal frequency division multiple access(OFDMA)

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Cross-Layer in MIMO-OFDM System with Adaptive Modulation and Coding: Design and Analysis

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Chinese Journal of Electronics 2025年第2期23卷 371-376页

作者： Junhui Zhao Xin Guan Xiuping Li Longji Zeng State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China National Mobile Communications Research Laboratory Southeast University Nanjing China Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai China School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing China

The queuing performance of the cross-layer system with Space-time block code (STBC) over Multi-input-multi-output (MIMO) channel is analyzed. The Adaptive modulation and coding (AMC) in physical layer and finite length of buffer in data-link layer are combined with this model. A simple cross-layer design and the queue state process are proposed based on finite state Markov channel model, which is to solve the service process. The proposed cross-layer design is also incorporated with STBC to further improve the system performance. Simulation results illustrate the dependence of system performance on various parameters, and quantify the performance gain due to cross-layer optimization. The adjustment of target packet loss rate of adaptive modulation coding in physical layer can maximize average throughput of the system, meanwhile a significant improvement of the system performance is brought.

关键词： Cross layer design Adaptive systems System performance Simulation Packet loss Physical layer Throughput Block codes Modulation coding Optimization

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Precision flatness measurement based on orbital angular momentum

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CHINESE PHYSICS B 2025年第5期34卷 054204-054204页

作者： Han, Feifei Wang, Zhiwan Wang, Le Zhao, Shengmei Nanjing Univ Posts & Telecommun Inst Signal Proc & Transmiss Nanjing 210003 Peoples R China Minist Educ Key Lab Broadband Wireless Commun & Sensor Network Nanjing 210003 Peoples R China Nanjing Univ Natl Lab Solid State Microstruct Nanjing 210093 Peoples R China

We propose a method to measure the flatness of an object with a petal-like pattern generated by the interference of the measured orbital angular momentum (OAM) beam and the reference OAM beam which carries the opposite OAM state. By calculating the difference between the petal rotation angle without/with the object, the thickness information of the object, and then the flatness information, can be evaluated. Furthermore, the direction of the object's flatness can be determined by the petal's clockwise/counterclockwise rotation. We theoretically analyze the relationship between the object's thickness and petal rotation angle, and verify the proposed method by experiment. The experimental results show that the proposed method is a high precision flatness measurement and can obtain the convex/concave property of the flatness. For the 1.02 mm glass sample, the mean deviation of the flatness is 1.357 x 10-8 and the variance is 0.242 x 10-16. For the 0.50 mm glass sample, the mean deviation of the flatness is 1.931 x 10-8 and the variance is 2.405 x 10-16. Two different topological charges are adopted for the 2.00 mm glass sample, and their flatness deviations are 0.239 x 10-8 (& ell;= 1) and 0.246 x 10-8 (& ell;= 2), where their variances are 0.799 x 10-18 (& ell;= 1) and 0.775 x 10-18 (& ell;= 2), respectively. It is shown that the flatness measured by the proposed method is the same for the same sample when different topological charges are used. All results indicate that the proposed method may provide a high flatness measurement, and will be a promising way to measure the flatness.

关键词： orbital angular momentum flatness measurement interference petal rotation angle 42.50.Tx 42.25.Hz 43.20.Ye

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Analysis of connectivity in Ad-hoc network based on interference and fading channel

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 77-82页

作者： XU Bin-tai ZHU Qi HU Han Jiangsu Key Lab of Wireless Communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education

In Ad-hoc wireless network, connectivity is a fundamental issue which restricts the design of system protocol. Based on the theory of stochastic geometry, a connectivity model focused on signal-to-interference （SIR） ratio is set up in presence of Nakagami-m fading and interference. This paper derives a close formula of connectivity probability with interference and Nakagami-m fading which is never obtained in previous works. Two-dimension shot-noise theory in stochastic geometry for interference is well applied. The formula is verified by simulation. The results show that the connectivity is affected by the scatter of users, wireless propagation environment, interference and so on.

关键词： Ad-hoc wireless network connectivity the probability of isolated node interference Nakagami-m fading

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On Least Squares Weighted Recursive Estimation of Clock Skew and Offset in wireless sensor networks

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Chinese Journal of Electronics 2017年第5期26卷 1041-1047页

作者： HU Bing SUN Zhixin Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and Telecommunications

Three clock synchronization algorithms for wireless sensor networks(WSNs) in Pairwise broadcast synchronization(PBS) mechanism are *** include the joint Least squares estimator(LS),joint Least squares weighted estimator(LSW) and joint Least squares weighted Recursive estimator(R-LSW).For these estimators,the corresponding algorithms are derived and described by assuming a Gaussian random delay *** PBS,these estimators can achieve the Cramer-Rao lower bound(CRLB) for both listening node and active node without knowledge of the deterministic *** purpose of considering R-LSW is to reduce the use of storage space with the method of estimating while *** and analytical results verify that the estimators are efficient.

关键词： Clock synchronization wireless sensor networks(WSNs) Pairwise broadcast synchronization(PBS) Least squares estimator(LS)

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LANDMARC Localization Algorithm Based on Weight Optimization

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Chinese Journal of Electronics 2018年第6期27卷 1291-1296页

作者： HU Bing PENG Huijun SUN Zhixin Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and Telecommunications

In order to solve the problem that the difference of Received signal strength(RSS) between tags will become large when tags are close to the reader, which exists in LANDMARC system, a LANDMARC localization algorithm based on weight optimization is proposed in the paper. We optimize the weight by redefining the formulas of in-weight and ex-weight. In-weight formula is discussed under the free space propagation model. The definition of ex-weight is obtained by analyzing the relationship between RSS and distance under the log-distance path loss model. We evaluate the performance of the proposed algorithm and compare it with the algorithm based on normalized weight. The simulation results show the superior performance of the proposed algorithm in terms of location accuracy.

关键词： Location identification based on dynamic active RFID calibration(LANDMARC) system Radio frequency identification(RFID) Indoor localization Weight optimization

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Energy-Efficient Interference Cancellation for Coordinated Multi-Point ISAC Systems

IEEE Transactions on Green Communications and Networking

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IEEE Transactions on Green communications and networking 2025年

作者： Niu, Yangyang Wei, Zhiqing Song, Zhiqun Feng, Zhiyong Wu, Huici Ma, Dingyou Liu, Haotian Zhang, Jinbo Beijing University of Posts and Telecommunications Key Laboratory of Universal Wireless Communications Ministry of Education Beijing100876 China National Key Laboratory of Advanced Communication Networks Hebei Shijiazhuang China Beijing University of Posts and Telecommunications National Engineering Lab for Mobile Network Technologies Beijing100876 China Pengcheng Laboratory Department of Broadband Communiation Shenzhen518006 China

Integrated sensing and communication (ISAC) systems leverage coordinated multi-point (CoMP) base stations (BSs) to deliver high-accuracy sensing and robust connectivity. However, the integration of sensing and communication in CoMP-ISAC systems faces significant challenges from interference within and among BSs, which adversely affects performance and increases energy consumption, thereby limiting commercial adoption. This paper proposes a CoMP-ISAC system design aimed at enabling energy-efficient interference cancellation through the collaborative optimization of BS mode selection and transceiver design among distributed BSs, while satisfying constraints related to communication quality of service (QoS), sensing output signal-to-clutter-plus-noise ratio (SCNR), and total transmit power budget. The BS mode selection involves identifying the sensing receiver by selecting the BS that maximally contributes to the SCNR and establishing associations between BSs and user equipment (UE). A branch-and-bound (B&B) algorithm is employed to address the mixed Boolean nonlinear problem associated with BS-UE associations, specifically focusing on the mitigation of multi-user interference at each branching step. Further, transmit beamforming and receive filters are alternately optimized using the zero-forcing (ZF) method to enhance interference suppression. To ensure convexity in the multi-scale fractional objective function, the dual quadratic transform (QT) is applied. Simulation results validate the effectiveness of the proposed algorithm. © 2017 IEEE.

关键词： Budget control

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Outage performance analysis in cognitive wireless relay networks

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Research Journal of Applied Sciences, Engineering and Technology 2012年第20期4卷 3958-3964页

作者： Yue, Wenjing Chen, Zhi Wang, Anyi Hu, Luoquan Wang, Lei Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunication Nanjng China

The analysis the outage performance of suggested Cognitive wireless Relay network (CWRN) which consists of a source, a destination and M cognitive relay nodes and M primary user nodes. In this study, we mainly study that the cognitive relay nodes impact on the outage performance of proposed CWRN over Rayleigh channels under both the peak and average interference power constraints. Firstly, considering a scenario with a single cognitive relay node, the optimal power control policies of the cognitive relay nodes are derived in order to achieve the minimum system outage probability under different interference power constraints. Then, to further improve outage performance, a scenario with multi-relay is also studied. Finally, the numerical simulations are presented. Numerical results show that substantial performance improves with the increase of the number of cognitive relay nodes and the power control policy under the average interference power constraint is more effective than that under the peak interference power constraint. © Maxwell Scientific Organization, 2012.

关键词： Cognitive radio

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