Home About us Contact
|
Home About us Contact | ||
|
|
||
Multiple Input Multiple Output (multiple + input_multiple_output)
Selected AbstractsCompact dual-band multiple input multiple output antenna with high isolation performanceMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2010Insu Yeom Abstract A compact dual-band (WLAN 11b; 2.4 GHz , 2.5 GHz, 11a; 5.15 GHz , 5.825 GHz) 2-channel Multiple Input Multiple Output (MIMO) antenna for portable media player (PMP) applications is presented. The proposed antenna is composed of a planar inverted F-shape antenna (PIFA) operating at 2 GHz band and a loop antenna operating at 5-GHz band. The antenna made up of the composite loop and PIFA antenna (CLPA) with connecting line face to the feed point and is orthogonally arranged at the edge of the ground plane for reducing mutual coupling. The antenna shows polarization and pattern diversities with excellent isolation characteristics. The two antennas were connected with each other in the bottom side to improve the isolation at 5-GHz band. The proposed antenna has a sufficient gain in WLAN service band and is compact sized for the PMP applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2808,2811, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25614 [source] Investigating the performance of MIMO systems from an electromagnetic perspectiveMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2006Marek E. Bialkowski Abstract Multiple input multiple output (MIMO) wireless systems use multiple element antennas (MEAs) at the transmitter (TX) and the receiver (RX) in order to offer improved information rates (capacity) over conventional single antenna systems in rich scattering environments. In this paper, an example of a simple MIMO system is considered in which both antennas and scattering objects are formed by wire dipoles. Such a system can be analyzed in the strict electromagnetic (EM) sense and its capacity can be determined for varying array size, interelement spacing, and distributions of scatterers. The EM model of this MIMO system can be used to assess the validity of single- or double-bounce scattering models for mixed line of sight (LOS) and non-line of sight (NLOS) signal-propagation conditions. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1233,1238, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21664 [source] Performance analysis of nonlinearly amplified M-QAM signals in MIMO channelsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2008Ahmed Iyanda Sulyman In this paper, we investigate the effect of nonlinearity in multiple input multiple output (MIMO) channels. New results on the error rate performance of several M-QAM constellations in linear and nonlinear MIMO channels are presented. The results show that for any MIMO configuration, performance degradation due to nonlinearity reduces as the fading gets more severe, and for a particular fading channel, the degradation increases as the MIMO dimension is increased. Optimum operating points for nonlinear amplifiers in MIMO channels are then reported. At these points, highly efficient utilisation of the amplifiers are achieved at minimal performance loss. Copyright © 2007 John Wiley & Sons, Ltd. [source] Gaussian inputs: performance limits over non-coherent SISO and MIMO channelsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2007Rasika R. Perera Performance limits of information transfer over a discrete time memoryless Rayleigh fading channel with neither the receiver nor the transmitter knowing the fading coefficients except its statistics is an important problem in information theory. We derive closed form expressions for the mutual information of single input single output (SISO) and multiple input multiple output (MIMO) Rayleigh fading channels for any antenna number at any signal to noise ratio (SNR). Using these expressions, we show that the maximum mutual information of non-coherent Rayleigh fading MIMO channels is achieved with a single transmitter and multiple receivers when the input distribution is Gaussian. We show that the addition of transmit antennas for a fixed number of receivers result in a reduction of mutual information. Furthermore, we argue that the mutual information is bounded by the SNR in both SISO and MIMO systems showing the sub-optimality of Gaussian signalling in non-coherent Rayleigh fading channels. Copyright © 2006 AEIT [source] Broadband wireless access based on VSF-OFCDM and VSCRF-CDMA and its experimentsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2004Hiroyuki Atarashi This paper presents broadband packet wireless access schemes based on variable spreading factor (VSF)-orthogonal frequency and code division multiplexing (OFCDM) in the downlink and variable spreading and chip repetition factors (VSCRF)-CDMA in the uplink for the systems beyond IMT-2000. In our design concept for wireless access in both links, radio parameters such as the spreading factor (SF) are optimally controlled so that the system capacity is maximized according to the cell configuration, channel load and radio channel conditions, based on the tradeoff between efficient suppression of other-cell interference and the capacity increase in the target cell by exploiting orthogonality in the time and frequency domains. We demonstrate that the peak throughput of greater than 100,Mbps and 20,Mbps is achieved by the implemented base station and mobile station transceivers using the 100-MHz and 40-MHz bandwidths in the downlink and uplink respectively. Moreover, the simulation results show the possibility of the peak throughput of approximately 1,Gbps for short-range area applications using the 100-MHz bandwidth OFCDM downlink by applying four-branch multiple input multiple output (MIMO) multiplexing with 16,QAM data modulation and punctured turbo coding. Copyright © 2004 AEI [source] Experimental evaluation of indoor MIMO channel capacity for compact arrays of planar inverted-F antennasMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2007Héctor Carrasco Abstract Empirical results on indoor multiple input multiple output (MIMO) channel capacity obtained through the use of planar inverted-F antennas (PIFA) are presented. An extensive statistical study done at 2.45 GHz reveals how antenna proximity and array configuration affects MIMO capacity. It is concluded that certain linear or square PIFA based arrays allow very compact multi-antenna arrangements without significant capacity loss. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1754,1756, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22526 [source] Three-antenna MIMO system for WLAN operation in a PDA phoneMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2006Kin-Lu Wong Abstract A multiple input multiple output (MIMO) system using three EMC (electromagnetic compatible) chip antennas in a personal digital assistant (PDA) phone is demonstrated. The three EMC chip antennas are mounted at three corners of the system ground plane of the PDA phone and all generate a wide bandwidth covering the wireless local area network (WLAN) operation in the 2.4-GHz band (2400,2484 MHz). By adding a T-shaped shorted strip in the proposed MIMO antenna system, large improvements in the isolation (S12, S13, and S23 all less than ,20 dB) between any two antennas of the MIMO system are achieved. Detailed effects of the T-shaped shorted strip on the isolation improvement in the proposed MIMO antenna system are analyzed. Radiation characteristics of the three antennas are also studied. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1238,1242, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21665 [source] Dynamic Process Modelling using a PCA-based Output Integrated Recurrent Neural NetworkTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2002Yu Qian Abstract A new methodology for modelling of dynamic process systems, the output integrated recurrent neural network (OIRNN), is presented in this paper. OIRNN can be regarded as a modified Jordan recurrent neural network, in which the past values for certain steps of the output variables are integrated with the input variables, and the original input variables are pre-processed using principal component analysis (PCA) for the purpose of dimension reduction. The main advantage of the PCA-based OIRNN is that the input dimension is reduced, so that the network can be used to model the dynamic behavior of multiple input multiple output (MIMO) systems effectively. The new method is illustrated with reference to the Tennessee-Eastman process and compared with principal component regression and feedforward neural networks. On présente dans cet article une nouvelle méthodologie pour la modélisation de systèmes de procédés dynamiques, soit le réseau neuronal récurrent avec intégration de la réponse (OIRNN). Ce dernier peut être vu comme un réseau neuronal récurrent de Jordan modifié, dans lequel les valeurs passées pour certaines étapes des valeurs de sortie sont intégrées aux variables d'entrée et les variables d'entrée originales pré-traitée par l'analyse des composants principaux (PCA) dans un but de réduction des dimensions. Le principal avantage de l'OIRNN basé sur la PCA est que la dimension d'entée est réduite de sorte que le réseau peut servir à modéliser le comportement dynamique de systèmes à entrée et sorties multiples (MIMO) de façon efficace. La nouvell méthod est illustrée dans le cas du procédé Tennessee-Eastman et est comparée aux réseaux neuronaux anticipés et à régression des composants principaux. [source] The long term evolution towards a new 3GPP* air interface standardBELL LABS TECHNICAL JOURNAL, Issue 4 2007Rainer Bachl The performance targets for the long term evolution (LTE) of the Universal Mobile Telecommunication System (UMTS) into a 4th generation system have been chosen to be very ambitious. While all of these targets may not be achievable in practice, they have served to motivate the decisions for a particular LTE design. Specifically, we discuss the choice of the multiple access scheme for LTE, provide details on the uplink and downlink transmission formats, analyze the benefits of multiple input multiple output (MIMO), and outline approaches for intercell interference mitigation. The trade-off between usage of MIMO spatial multiplexing and beamforming is shown for a practical system. The required signaling overhead is weighed against the performance improvements available from the additional information. Finally, some examples for the achievable physical layer performance are given. © 2007 Alcatel-Lucent. [source] | ||||||||||