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IEEE International Conference on Communications (ICC)

作者： Rachinger, Christoph Sedaghat, Mohammad A. Mueller, Ralf R. Huber, Johannes B. Friedrich Alexander Univ Erlangen Nurnberg Erlangen Germany

ISBN: (纸本)9781467389990

We introduce pi/2-shifted Phase Shift Keying on the Hypersphere (pi/2-PSKH), a new modulation scheme for multipleinput multiple-output (MIMO) systems. pi/2-PSKH is a multidimensional extension of shifted QAM which allows to use loadmodulated MIMO transmitters with a highly efficient power amplifier with reduced backoff. We propose pi/2-PSKH constellations and explain how a pi/2-PSKH signal is generated. The signal point sequence for pi/2-PSKH is time-varying and as such has an inherent code. For the receiver, three algorithms are introduced and numerical simulations are used to examine their performance. These algorithms are further modified in order to reduce their complexity. We discuss the effect of this complexity reduction and the trade-off between receiver complexity and performance. It is shown that due to its inherent code, pi/2-PSKH shows excellent performance in terms of power efficiency even if used with conventional amplifiers.

关键词： multiple-input multiple-output systems wireless communications peak-to-average-power-ratio load-modulation continuous phase modulation shifted QAM

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The Least Squares SVM Approach for a Non-linear Channel Prediction in the MIMO System

The Least Squares SVM Approach for a Non-linear Channel Pred...

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18th Conference on Computer Networks (CN 2011)

作者： Martyna, Jerzy Jagiellonian Univ Inst Comp Sci PL-30348 Krakow Poland

ISBN: (纸本)9783642217708

In this paper we investigate the problem of a multiple-input multiple-output (MIMO) frequency in a non-selective channel prediction. We develop a new method for the channel prediction which is based on the Least Squares Support Vector Machine (SVM). We develop a new method for the channel which allows us to predict a signal. The proposed method is evaluated through simulation in a MIMO system under a channel prediction.

关键词： multiple-input multiple-output systems Least Squares Support Vector Machine channel prediction

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Effects of Antenna Correlation and Mutual Coupling on the Carrier Frequency Offset Estimation in MIMO systems

Effects of Antenna Correlation and Mutual Coupling on the Ca...

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6th International Conference on Wireless Communications, Networking and Mobile Computing (WICOM)

作者： Wu, Yan Bergmans, J. W. M. Attallah, S. Eindhoven Univ Technol Dept Elect Engn NL-5600 MB Eindhoven Netherlands

ISBN: (纸本)9781424437092

In practical multiple-input multiple-output (MIMO) systems, due to the close proximity among the antennas, the channels between different transmit and receive antennas are spatially correlated. Besides spatial correlation, closely placed antennas also experience mutual coupling among the antennas, which is due to the interaction of electro-magnetic fields at different antennas. In this paper, we present a study on the effects of spatial correlation and mutual coupling and in particular, their impacts on the performance of the carrier frequency offset (CFO) estimation in MIMO systems. The simulation results show that spatial correlation degrades the performance of the CFO estimation. Mutual coupling has two effects. Firstly it reduces the spatial correlation, which is beneficial. On the other hand, it also reduces the power of the desired signal, which is detrimental. Simulations results show that the combined effects of mutual coupling introduces additional degradation on the CFO estimation.

关键词： MIMO communication MIMO systems antenna arrays antenna correlation carrier frequency offset estimation close proximity electromagnetic fields frequency estimation multiple-input multiple-output systems mutual coupling receive antennas spatial correlation transmit antennas

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Neural Feedback for Instantaneous Spatiotemporal Modulation of Afferent Pathways in Bi-Directional Brain-Machine Interfaces

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IEEE TRANSACTIONS ON NEURAL systems AND REHABILITATION ENGINEERING 2011年第5期19卷 521-533页

作者： Liu, Jianbo Khalil, Hassan K. Oweiss, Karim G. Michigan State Univ Dept Elect & Comp Engn E Lansing MI 48823 USA Michigan State Univ Neurosci Program E Lansing MI 48823 USA

In bi-directional brain-machine interfaces (BMIs), precisely controlling the delivery of microstimulation, both in space and in time, is critical to continuously modulate the neural activity patterns that carry information about the state of the brain-actuated device to sensory areas in the brain. In this paper, we investigate the use of neural feedback to control the spatiotemporal firing patterns of neural ensembles in a model of the thalamocortical pathway. Control of pyramidal (PY) cells in the primary somatosensory cortex (S1) is achieved based on microstimulation of thalamic relay cells through multiple-input multiple-output (MIMO) feedback controllers. This closed loop feedback control mechanism is achieved by simultaneously varying the stimulation parameters across multiple stimulation electrodes in the thalamic circuit based on continuous monitoring of the difference between reference patterns and the evoked responses of the cortical PY cells. We demonstrate that it is feasible to achieve a desired level of performance by controlling the firing activity pattern of a few "key" neural elements in the network. Our results suggest that neural feedback could be an effective method to facilitate the delivery of information to the cortex to substitute lost sensory inputs in cortically controlled BMIs.

关键词： Bi-directional brain-machine interface (BMI) feedback control multichannel microstimulation multiple-input multiple-output systems spatiotemporal activity thalamocortical networks

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Spatial Parameter Identification for MIMO systems in the Presence of Non-Gaussian Interference

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REMOTE SENSING 2024年第7期16卷 1243页

作者： Zhang, Junlin Shi, Zihui Chen, Yunfei Liu, Mingqian Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Peoples R China Univ Durham Dept Engn Durham DH1 3LE England

Reliable identification of spatial parameters for multiple-input multiple-output (MIMO) systems, such as the number of transmit antennas (NTA) and the direction of arrival (DOA), is a prerequisite for MIMO signal separation and detection. Most existing parameter estimation methods for MIMO systems only consider a single parameter in Gaussian noise. This paper develops a reliable identification scheme based on generalized multi-antenna time-frequency distribution (GMTFD) for MIMO systems with non-Gaussian interference and Gaussian noise. First, a new generalized correlation matrix is introduced to construct a generalized MTFD matrix. Then, the covariance matrix based on time-frequency distribution (CM-TF) is characterized by using the diagonal entries from the auto-source signal components and the non-diagonal entries from the cross-source signal components in the generalized MTFD matrix. Finally, by making use of the CM-TF, the Gerschgorin disk criterion is modified to estimate NTA, and the multiple signal classification (MUSIC) is exploited to estimate DOA for MIMO system. Simulation results indicate that the proposed scheme based on GMTFD has good robustness to non-Gaussian interference without prior information and that it can achieve high estimation accuracy and resolution at low and medium signal-to-noise ratios (SNRs).

关键词： direction of arrival generalized multi-antenna time-frequency distribution multiple-input multiple-output systems number of transmit antennas

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A Novel Signal Detector in MIMO systems Based on Complex Correntropy

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IEEE ACCESS 2019年 7卷 137517-137527页

作者： De Souza, Pedro T., V Fontes, Aluisio I. R. De Souza, Vinicius S. V. Silveira, Luiz F. Fed Rural Univ Semiarid Engn & Technol Dept BR-59900000 Pau Dos Ferros RN Brazil Sci & Technol Rio Grande do Norte Fed Inst Educ BR-59900000 Pau Dos Ferros RN Brazil Univ Fed Rio Grande do Norte Dept Comp Engn & Automat BR-59064741 Natal RN Brazil

In cellular systems, information signals must be transmitted at high rates and with high reliability. One of the possible solutions to meet such criteria is the use of systems with multiple transmitting and/or receiving antenna arranged in the form of a multiple-input, multiple-output (MIMO) system. However, signal processing techniques in MIMO systems are developed under the assumption of transmission on Gaussian channels, which may lead to the decrease of efficiency in non-Gaussian communication scenarios. In this context, the widespread use of MIMO systems in recent years has motivated the development of new processing techniques that can be employed in scenarios that also consider the presence of non-Gaussian noise in communication channels. This work proposes a novel signal detection technique for MIMO systems, which is called maximum correntropy detector (MCD), being adequate to environments characterized by Gaussian and non-Gaussian noise. The introduced approach is based on complex correntropy function and can be seen as a generalization of the maximum likelihood detector (MLD) concept. The MCD is evaluated on Gaussian and non-Gaussian channels, where superior performance is achieved when compared with the classic detectors, without significant increase of the computational complexity.

关键词： Complex correntropy maximum correntropy detector multiple-input multiple-output systems non-Gaussian noise signal detectors.

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Design of a MIMO PID Controller by Integral-Type Optimal Servomechanism and Fractional Balanced Reduction

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SICE Journal of Control, Measurement, and System Integration 2013年第6期6卷 411-418页

作者： Yoshimasa Ochi Hiroyuki Kondo Department of Aerospace Engineering National Defense Academy

The present paper proposes an efficient design method for a multiple-input multiple-output (MIMO) integral preceded by a proportional and derivative (I-PD) controller, which is a type of PID controller. In the proposed method, a given plant model is first reduced to a lower-order model using fractional balanced reduction, and an integral-type or robust optimal servomechanism is then designed for the reduced plant, which is expressed in a peculiar state-space form, where the state vector is composed of outputs, their derivatives, and control inputs. The resultant optimal feedback control law is immediately transformed into a MIMO I-PD control law. The optimal servomechanism, which is based on a linear quadratic regulator, provides a controller with desirable control performance, adequate stability margins, and easy trade-off between the control performance and stability margins attained through weight selection of the quadratic cost function. Although these features are not perfectly guaranteed in the resulting control system due to the model reduction, if the properties are adequately preserved, they make the controller design very simple and efficient. A design example illustrates the effectiveness of the proposed design method as well as its limitations.

关键词： PID control multiple-input multiple-output systems linear quadratic regulator balanced truncation

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PhantomNet: Exploring optimal multicellular multiple antenna systems

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第5期2004卷 591-604页

作者： Jafar, SA Foschini, GJ Goldsmith, AJ Univ Calif Irvine Irvine CA 92697 USA Bell Labs Lucent Technol Holmdel NJ 07733 USA Stanford Univ Wireless Syst Lab Stanford CA 94305 USA

We present a network framework for evaluating the theoretical performance limits of wireless data communication. We address the problem of providing the best possible service to new users joining the system without affecting existing users. Since, interference-wise, new users are required to be invisible to existing users, the network is dubbed PhantomNet. The novelty is the generality obtained in this context. Namely, we can deal with multiple users, multiple antennas, and multiple cells on both the uplink and the downlink. The solution for the uplink is effectively the same as for a single cell system since all the base stations (BSs) simply amount to one composite BS with centralized processing. The optimum strategy, following directly from known results, is successive decoding (SD), where the new user is decoded before the existing users so that the new users' signal can be subtracted out to meet its invisibility requirement. Only the BS needs to modify its decoding scheme in the handling of new users, since existing users continue to transmit their data exactly as they did before the new arrivals. The downlink, even with the BSs operating as one composite BS, is more problematic. With multiple antennas at each BS site, the optimal coding scheme and the capacity region for this channel are unsolved problems. SD and dirty paper (DP) are two schemes previously reported to achieve capacity in special cases. For PhantomNet, we show that DP coding at the BS is equal to or better than SD. The new user is encoded before the existing users so that the interference caused by his signal to existing users is known to the transmitter. Thus the BS modifies its encoding scheme to accommodate new users so that existing users continue to operate as before: they achieve the same rates as before and they decode their signal in precisely the same way as before. The solutions for the uplink and the downlink are particularly interesting in the way they exhibit a remarkable simplicit

关键词： channel capacity dirty paper coding duality broadcast channel successive decoding multiple-input multiple-output systems

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Subspace-based Blind Channel Estimation for MIMO-OFDM systems with New Signal Permutation Method

Subspace-based Blind Channel Estimation for MIMO-OFDM System...

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IEEE Vehicular Technology Conference

作者： Shih-Hao Fang Ju-Ya Chen Jing-Shiun Lin Ming-Der Shieh Jen-Yuan Hsu Industrial Technology Research Institute Institute of Communications Engineering National Sun Yat-sen University Department of Electrical Engineering National Cheng Kung University

ISBN: (纸本)9781479944811

Subspace-based blind channel estimation for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with repetition index has been proposed in the literature. However, the full-row-rank probability of the signal matrix using the MIMO-based repetition index method is extremely low, especially when low-order modulation or few received OFDM symbols are used. In this paper, the MIMO-based repetition index method with a new signal permutation method is proposed. The proposed method solves the problem of previous MIMO-based repetition index method. Additionally, the proposed method performs well even if low-order modulation or few revived OFDM symbols are applied. Simulation results show that proposed method not only has high full-row-rank probability, but also outperforms conventional blind channel estimation approaches in terms of normalized mean-square error (NMSE).

关键词： MIMO communication OFDM modulation channel estimation matrix algebra mean square error methods MIMO-based repetition index method NMSE full-row-rank probability low-order modulation multiple-input multiple-output systems normalized mean-square error orthogonal frequency division multiplexing systems revived OFDM symbols signal matrix signal permutation method subspace-based blind channel estimation Blind equalizers Channel estimation Indexes Modulation OFDM Receiving antennas Vectors Orthogonal frequency division multiplexing channel estimation Mean square error multiple input multiple output systems Receiving antennas MIMO communication matrix algebra Blind equalizers channel blind estimation index method

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A new space-time-doppler code for time-selective fading channels

A new space-time-doppler code for time-selective fading chan...

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2008 IET International Conference on Wireless, Mobile and Multimedia Networks

作者： N. Wei X. Y. Yang T. C. Li S. G. Zhang S. J. Ding China Research Institute of Radiowave Propagation Qingdao Shandong China Coilegc of Information and Communication Engineering Harbin Engineering of Technology Harbin Heilongjiang China

ISBN: (纸本)9780863418877

Relying on a layered algebraic design, we derive a new space-time-Doppler (STD) code for multiple input multiple output (MIMO) time-selective fading channels. The proposed STD code achieves rate N t and enables full-diversity N t N r N b (Q + 1), i.e., the product of the number of transmit antennas N t , receive antennas N r , coding blocks N b and channel complex exponential bases (Q +1) . Simulation results show that the proposed STD codes achieve higher diversity gain in time-selective channels than some existing STD codes.

关键词： multiple-input multiple-output systems Space-time-Doppler codes Time-selective fading channels

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