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Robust blind beamforming using neural network

IEE PROCEEDINGS-RADAR SONAR AND NAVIGATION 2000年第1期147卷 41-46页

作者： He, Z Chen, Y DSP Division Department of Radio Engineering Southeast University Nanjing People's Republic of China

Many blind beamforming algorithms, such as C-CAB, use cyclostationarity to estimate the steering vector and adaptively obtain the LCMV optimum solution. However, LCMV methods are sensitive to the mismatch caused by the uncalibration array or estimate error. After discussion of this mismatch, a robust blind beamforming algorithm is presented in the paper. Implemented as a neural network, this algorithm reduces computational complexity for real-time use. Computer simulations verify the analysis.

关键词： adaptive estimation array signal processing computational complexity Simulation, modelling and identification Signal processing and detection computer simulations covariance analysis robust blind beamforming Neural nets blind beamforming algorithms Signal processing theory computational complexity reduction steering vector estimation neural network C-CAB linearly constrained minimum variance cyclostationarity LCMV optimum solution estimate error improved Hopfield network Hopfield neural nets

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Passive Synthetic Aperture Radar Imaging Using Kalman Reflection Coefficients Estimation Algorithm with DVB-T Signal

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JOURNAL OF REAL-TIME IMAGE PROCESSING 2021年第6期18卷 2097-2109页

作者： Ansari, Farzad Samadi, Sadegh Mohseni, Reza Shiraz Univ Technol Shiraz Iran

In this paper, a new method is presented for image formation in a Multistatic Passive Synthetic Aperture Radar (SAR), whose receiver is moving and transmitters are stationary in a multistatic structure, and the signal used to create the image is DVB-T. The proposed method uses multiple transmitters of opportunity to improve the range resolution of a Passive SAR. First, a linear observation model is developed for multistatic structure of the Passive SAR system. Then, the image of the underlying scene is obtained through a new Kalman-based estimation algorithm. In this algorithm, range migration error is completely corrected, and the use of Kalman recursive filter reduces the computational complexity of the reflection coefficients estimation algorithm. Experimental results indicate that the proposed algorithm is effective.

关键词： Real time processing computational complexity reduction DVB-T signal Estimation Kalman recursive filter Linear model Passive synthetic aperture radar

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Time scale analysis and scalability issues for explicit rate allocation in ATM networks

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IEEE-ACM TRANSACTIONS ON NETWORKING 1996年第4期4卷 569-581页

作者： Charny, A Ramakrishnan, KK Lauck, A AT&T BELL LABS MURRAY HILLNJ 07974

End-to-end rate based congestion management has been extensively studied for control of computer communication networks, In this paper, we examine some of the properties of end-to-end rate based algorithms for congestion management using explicit rate feedback, to achieve maxmin fair rate allocation in the network, We formulate a requirement on a switch's local rate allocation computation sufficient to ensure convergence of the distributed algorithm to the global maxmin fair rate allocation, We provide an upper bound on the convergence time when the switch algorithm satisfies this requirement. We propose a requirement of feasibility of the transmission rates, maintaining which results in oscillation-tree operation of the algorithm while maintaining small queues at the switches, Feasibility implies that the capacity of any of the resources is not exceeded at any time, We suggest a source policy to ensure feasibility of transmission rates, the essence of which is to delay a rate increase by a certain time, while decreasing the transmission rate immediately upon receiving the appropriate feedback, Finally, we seek ways of improving scalability of the computation of maxmin fair rates in the presence of a large number of flows, We suggest using a discrete set of rates, which as we show, reduces the computational complexity and the state requirement at the switches,

关键词： Asynchronous Transfer Mode Computer Network Management Feedback Convergence Of Numerical Methods Telecommunication Congestion Control Distributed Algorithms Queueing Theory computational complexity Time Scale Analysis Scalability Explicit Rate Allocation ATM Networks Congestion Management Computer Communication Networks Rate Based Algorithms Explicit Rate Feedback Upper Bound Local Rate Allocation Distributed Algorithm Convergence Global Maxmin Fair Rate Allocation Convergence Time Switch Algorithm Transmission Rates Feasibility Oscillation Free Operation Queues Source Policy computational complexity reduction State Requirement Scalability Switches Computer Network Management Feedback Convergence Communication System Control Computer Networks Communication Networks Communication Switching Distributed Computing

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Simplified QR-decomposition based and lattice reduction-assisted multi-user multiple-input-multiple-output precoding scheme

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IET COMMUNICATIONS 2016年第5期10卷 586-593页

作者： Fang, Shu Wu, Jian Lu, Chengyi Yue, Zong-di Han, Yuan-chao Univ Elect Sci & Technol China Dept Natl key Lab Commun Chengdu 611731 Peoples R China

Future wireless communication systems require more and more antennas at the transceiver to improve the achievable rates. Multi-user multiple-input multiple-output (MU-MIMO) technique is regarded as a potential technique to serve large number of users simultaneously to further increase the achievable rates in MIMO systems. If the number of antennas at the transceiver is large, the computational complexity of precoding becomes the bottleneck and a big challenge in MU-MIMO system. In this paper, a simplified QR decomposition with lattice reduction assisted MU-MIMO precoding scheme named S-QR-LR is proposed as a low-complexity MU-MIMO transmission scheme. The simplified QR decomposition method is delicately designed and operated twice for the proposed precoding scheme not only to achieve good performance but also reduce the computational complexity significantly. The proposed S-QR-LR scheme first uses the simplified QR decomposition operation to balance the multi-user interference and the noise. Then, the proposed S-QR-LR precoding scheme utilizes the simplified QR decomposition method again with the assist of lattice reduction to obtain the precoding gain to further improve the performance with low computational complexity. Analytical and simulation results show that the proposed S-QR-LR precoding scheme achieves best performance among the existing precoding schemes, but requires the lowest computational complexity.

关键词： multiuser channels MIMO communication radio transceivers antenna arrays linear codes precoding least mean squares methods singular value decomposition computational complexity lattice theory simplified QR-decomposition MU-MIMO precoding scheme lattice reduction-assisted MU-MIMO precoding scheme multiuser multiple-input-multiple-output technique future wireless communication systems transceiver achievable rate improvement computational complexity reduction block diagonalisation linear precoding scheme singular value decomposition operations LR-S-GMI precoding scheme generalised minimum mean square error channel inversion utilisation large matrix pseudo-inverse computation S-QR-LR precoding scheme LR-assisted MU-MIMO precoding scheme low-complexity MU-MIMO transmission precoding gain

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Delay-sensitive user scheduling and power control in heterogeneous networks

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IET NETWORKS 2015年第3期4卷 175-184页

作者： Cheng, Aolin Li, Jian Yu, Yuling Jin, Hao Beijing Univ Posts & Telecommun Key Lab Univ Wireless Commun Wireless Signal Proc & Network Lab Minist Educ Beijing 100876 Peoples R China

Delay-sensitive traffic services, such as live streaming video, voice over IP and multimedia teleconferencing, requires low end-to-end delay in order to maintain its interactive and streaming nature. In recent years, the popularity of delay-sensitive applications has been rapidly growing. In this study, the authors consider the delay-sensitive user scheduling and power control design for heterogeneous networks (HetNets). They model the problem as an infinite-horizon average cost Markov decision process MDP. Based on the dynamics of channel state information (CSI) and queue state information (QSI), they focus on finding an adaptive user scheduling and power control policy to minimise the average delay of network subjected to the power constraints of heterogeneous base stations. In order to reduce the computational complexity and facilitate the distributive implementation, the authors derive a distributive stochastic learning algorithm which only requires local CSI and local QSI to determine the optimal user scheduling and power control policy. The simulation results confirm that significant delay performance gain can be achieved compared with various baseline schemes.

关键词： power control scheduling cellular radio delays infinite horizon Markov processes wireless channels minimisation computational complexity learning (artificial intelligence) adaptive control Markov decision process optimal user scheduling QSI dynamics CSI dynamics distributive stochastic learning algorithm distributive implementation computational complexity reduction heterogeneous base stations power constraints average delay minimisation power control policy adaptive user scheduling queue state information channel state information MDP infinite horizon delay sensitive traffic service heterogeneous networks delay sensitive user scheduling

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Reducing the PAPR of OFDM Systems by Random Variable Transformation

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ETRI JOURNAL 2013年第4期35卷 714-717页

作者： Taher, Montadar Abas Singh, Mandeep Jit Bin Ismail, Mahamod Samad, Salina Abdul Islam, Mohammad Tariqul Univ Kebangsaan Malaysia Dept Elect Elect & Syst Engn Bangi Malaysia Univ Kebangsaan Malaysia Inst Space Sci Bangi Malaysia

Peak power reduction techniques in orthogonal frequency division multiplexing (OFDM) has been an important subject for many researchers for over 20 years. In this letter;we propose a side-information-free technique that is based on the concept of random variable (RV) transformation. The suggested method transforms RVs into other RVs, aiming to reshape the constellation that will consequently produce OFDM symbols with a reduced peak-to-average power ratio. The proposed method has no limitation on the mapping type or the mopping order and has no significant effect on the bit error rate performance compared to other methods presented in the literature. Additionally, the computational complexity does not increase.

关键词： Peak-to-average power ratio OFDM sum of two random variables transformation of random variables PAPR computational complexity reduction

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Massive MIMO antenna selection algorithms based on iterative swapping

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ELECTRONICS LETTERS 2018年第4期54卷 190-U8页

作者： Tang, Hua Nie, Zaiping Univ Elect Sci & Technol China Sch Elect Engn Chengdu Sichuan Peoples R China

Based on capacity maximisation metric, an iterative swapping antenna selection method is proposed for massive multiple-input multiple-output (MIMO). Then a local' swapping algorithm is proposed for massive MIMO antenna selection, which swaps the target antennas locally'. A global' swapping algorithm is also proposed to reduce the computational complexity, which exchanges the target antennas globally'. Both of the proposed algorithms are near optimal, due to the consideration of the influences of the unselected antennas and the selected ones on the antenna to be selected. Last, numerical simulations are provided to validate the proposed algorithms.

关键词： MIMO communication antenna arrays iterative methods computational complexity optimisation massive MIMO antenna selection algorithms capacity maximisation metric iterative swapping antenna selection method massive multiple input multiple output local swapping algorithm global swapping algorithm computational complexity reduction numerical simulations

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complexity reduction IN FULLY VECTOR QUANTIZED STOCHASTIC CODERS

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ELECTRONICS LETTERS 1987年第6期23卷 253-254页

作者： HAMMETT, PG British Telecom Research Laboratories Ipswich UK

Stochastic linear predictive coders can produce good quality speech at low bit rates but are computationally very demanding. A method for reducing the computational complexity of the selection process for the optimum innovation sequence is described. The improved efficiency can be achieved without any reduction in the performance of the coder.

关键词： fully vector quantised stochastic coders speech analysis and processing stochastic linear predictive coders computational complexity reduction encoding optimum innovation sequence Codes vocoders Speech and audio signal processing speech processing stochastic systems computational complexity

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Low complexity motion estimation utilising spatial correlation

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ELECTRONICS LETTERS 2006年第9期42卷 523-525页

作者： Park, S. -, I Park, I. -C. Korea Adv Inst Sci & Technol Dept Elect Engn & Comp Sci Div Elect Engn 373-1Guseong Dong Taejon 305701 South Korea

An efficient algorithm is proposed to reduce the computational complexity of block matching motion estimation by using the characteristics of spatial correlation. The proposed algorithm is to skip the motion vector search of inside macroblocks surrounded by identical motion vectors. Experimental results show that the proposed algorithm reduces computational complexity by 52.5% compared to conventional motion estimation at the cost of negligible performance degradation.

关键词： computational complexity image matching motion estimation block matchingmotion estimation computational complexity reduction motion vector search spatial correlation

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FHT algorithm for length N=q.2^m

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ELECTRONICS LETTERS 1999年第12期35卷 966-968页

作者： Vijayakumar, N Prabhu, KMM Indian Inst Technol Dept Engn Chennai 600036 India

Of late, the discrete Hartley transform (DHT) has become an important real-valued transform. Many fast algorithms for computing the DHT of sequence length N = 2(m) have been reported. Fast computation of the DHT of length N = q.2(m), where q is an odd integer, is proposed. The key feature of the algorithm is its flexibility in the choice of sequence length N, when N need not necessarily be a power of 2, while giving rise to a substantial reduction in computational complexity when compared to other algorithms.

关键词： sequence length sequences fast algorithm DHT signal processing tool computational complexity reduction real-valued transform Integral transforms in numerical analysis discrete Hartley transforms fast Hartley transform computational complexity Signal processing and detection signal processing Signal processing theory FHT algorithm discrete Hartley transform computational complexity

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