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S/MIMO MC-CDMA Heuristic Multiuser Detectors Based on Single-Objective Optimization

ABRAO, Taufik; OLIVEIRA, Leonardo D. de; CIRIACO, Fernando; Angelico, Bruno Augusto; Jeszensky, Paul Jean Etienne; PALACIO, Fernando Jose Casadevall
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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This paper analyzes the complexity-performance trade-off of several heuristic near-optimum multiuser detection (MuD) approaches applied to the uplink of synchronous single/multiple-input multiple-output multicarrier code division multiple access (S/MIMO MC-CDMA) systems. Genetic algorithm (GA), short term tabu search (STTS) and reactive tabu search (RTS), simulated annealing (SA), particle swarm optimization (PSO), and 1-opt local search (1-LS) heuristic multiuser detection algorithms (Heur-MuDs) are analyzed in details, using a single-objective antenna-diversity-aided optimization approach. Monte- Carlo simulations show that, after convergence, the performances reached by all near-optimum Heur-MuDs are similar. However, the computational complexities may differ substantially, depending on the system operation conditions. Their complexities are carefully analyzed in order to obtain a general complexity-performance framework comparison and to show that unitary Hamming distance search MuD (uH-ds) approaches (1-LS, SA, RTS and STTS) reach the best convergence rates, and among them, the 1-LS-MuD provides the best trade-off between implementation complexity and bit error rate (BER) performance.; Brazilian CAPES Agency[BEX0556/07-6]

Hybrid heuristic-waterfilling game theory approach in MC-CDMA resource allocation

Sampaio, Lucas Dias Hiera; Abrao, Taufik; Angelico, Bruno Augusto; Lima, Moises Fernando; Proenca Jr., Mario Lemes; Jeszensky, Paul Jean Etienne
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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This paper discusses the power allocation with fixed rate constraint problem in multi-carrier code division multiple access (MC-CDMA) networks, that has been solved through game theoretic perspective by the use of an iterative water-filling algorithm (IWFA). The problem is analyzed under various interference density configurations, and its reliability is studied in terms of solution existence and uniqueness. Moreover, numerical results reveal the approach shortcoming, thus a new method combining swarm intelligence and IWFA is proposed to make practicable the use of game theoretic approaches in realistic MC-CDMA systems scenarios. The contribution of this paper is twofold: (i) provide a complete analysis for the existence and uniqueness of the game solution, from simple to more realist and complex interference scenarios; (ii) propose a hybrid power allocation optimization method combining swarm intelligence, game theory and IWFA. To corroborate the effectiveness of the proposed method, an outage probability analysis in realistic interference scenarios, and a complexity comparison with the classical IWFA are presented. (C) 2011 Elsevier B.V. All rights reserved.; National Council for Scientific and Technological Development (CNPq) of Brazil; National Council for Scientific and Technological Development (CNPq) of Brazil [303426/2009-8]

Avaliação de desempenho do enlace reverso de redes celulares que utilizam a técnica CDMA com multiportadoras (MC-CDMA) em um canal rayleigh seletivo em frequência; Performance evaluation of the uplink of cellular networks that employ multicarrier CDMA technique (MC-CDMA) in a frequency selective rayleigh fading channel

Henry Ramiro Carvajal Mora
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/12/2014 Português
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Neste trabalho, é avaliado o desempenho do enlace reverso de redes celulares que utilizam a técnica de múltiplo acesso por divisão de código com multiportadoras (MC-CDMA) em termos da probabilidade de erro de bit média (BER) e da eficiência espectral média. O sistema de comunicações analisado utiliza a técnica MC-CDMA, um arranjo linear de antenas na estação rádio base, entrelaçamento em frequência, combinação de máxima razão (MRC), modulação adaptativa, controle de potência e um prefixo cíclico grande o suficiente para eliminar os efeitos da interferência intersimbólica (ISI) e da interferência entre portadoras (ICI). O cenário estudado considera a presença de interferência de múltiplo acesso (MAI) e interferência de co-canal (CCI). A caracterização do canal considera a presença de ruído aditivo gaussiano branco (AWGN), perda de propagação exponencial e desvanecimento lento e seletivo em frequência que segue a distribuição de Rayleigh. Neste contexto, expressões analíticas exatas e fechadas para a BER média tanto para a modulação BPSK, quanto para a modulação M-QAM são obtidas. A exatidão das expressões é validada através de simulações de Monte Carlo. Ademais, uma expressão para a eficiência espectral celular média é determinada...

Transmission strategies for MISO downlink MC-CDMA mobile systems

Silva, Adão; Gameiro, Atílio
Fonte: Springer Verlag Publicador: Springer Verlag
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
68.91768%
This paper proposes two space-frequency schemes with a multi-user pre-filtering technique for downlink (DL) multicarrier code division multiple access (MC-CDMA) systems. We consider the use of antenna arrays at the base station (BS) and a single antenna at the mobile terminal (MT) and derive the proposed multi-user pre-filtering technique that modulates the transmitted signal to eliminate the effects of multiple access interference (MAI) and channel distortions at the mobile terminals, while maintaining low MT complexity. Two types of detectors are considered at the MT: simple despreading and single user equalizers. The performances of the proposed schemes are compared to those of other transmit signal design approaches that have been recently proposed for DL MC-CDMA, considering both typical indoor and pedestrian scenarios, and channel coding based on UMTS specifications. © Springer Science+Business Media, LLC. 2009.

Downlink space-frequency preequalization techniques for TDD MC-CDMA mobile radio systems

Silva, Adão; Gameiro, Atílio
Fonte: SpringerOpen Publicador: SpringerOpen
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
68.637847%
The paper considers downlink space-frequency preequalizations techniques for time division duplex (TDD) MC-CDMA. We consider the use of antenna arrays at the base station (BS) and analytically derive different preequalization schemes for two different receiver configurations at the mobile terminal: a simple despread receiver without channel equalization and an equal-gain combiner (EGC) conventional receiver. We show that the space-frequency preequalization approach proposed allows to format the transmitted signals so that the multiple access interference at mobile terminals is reduced allowing to transfer the most computational complexity from mobile terminal to the BS. Simulation results are carried out to demonstrate the effectiveness of the proposed preequalization schemes.; European project IST-2001-32620 - MATRICE; FCT - POSI/CPS/46701/2002

Multi-user frequency pre-filtering technique for MIMO SFBC MC-CDMA systems

Silva, Adão; Silva, Elídio; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
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This paper deals with downlink space-frequency block coding (SFBC) with a multi-user pre-filtering technique for MIMO MC-CDMA systems. We consider the use of an antenna array at both the base station (BS) and the user terminal (UT). The space-frequency block codes allow that the spatial diversity be efficiently exploited and the linear multi-user frequency pre-filtering technique modulates the transmitted signal to eliminate the effects of multiple access interference (MAI) and channel distortions at the user terminals. The aim of this technique is to transfer the most computational complexity from UT to the BS, keeping the first one at very low complexity. The performance of the proposed scheme is evaluated, considering typical pedestrian scenario and both uncoded data and channel turbo coding based on UMTS specifications. © 2008 IEEE.; FCT - FFT-XXI (POSI/CPS/4670/2007); PHOTON(PTDC/EEA-TEL/72890/06)

Comparison of single and multi-user pre-filtering techniques using different chip mapping for DL MC-CDMA systems

Silva, Adão; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
68.637847%
In this paper we compare the performance of the joint space-frequency single and multi-user pre-filtering techniques that have been proposed recently for DL MC-CDMA systems. We consider the use of antenna arrays at the base station and a single antenna at the mobile terminal (MT). We investigate how the chip mapping strategy impacts on the performance of the pre-filtering approaches. Thus, practical combinations of prefiltering and chip mapping are discussed. The performance is evaluated for different chip mapping strategies, considering typical indoor and pedestrian scenarios and both uncoded data and channel turbo coding based on UMTS specifications. © 2007 IEEE.; European WISQUAS Celtic project CP2-035; FCT FFTXXI project POSI/CPS/4670/2002

SFBC with pre-filtering technique for DL TDD MC-CDMA systems in high data rate context

Silva, Adão; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
68.637847%
This paper deals with downlink space-frequency block coding with a pre-filtering technique for time division duplex MC-CDMA. We consider the use of antenna arrays at the base station (BS) and a single antenna at the mobile terminal (MT). The space-frequency block codes allow that the spatial diversity be efficiently exploited and the linear multi-user pre-filtering technique allows to format the transmitted signals so that the multiple access interference (MAI) and channel distortions at mobile terminals are completely removed. The aim of this technique is to transfer the most computational complexity from MT to the BS, keeping the first one at very low complexity. Simulations results are carried out in high data rate scenarios with the channel turbo code specified for the current UMTS system, to demonstrate the effectiveness of the proposed multi-user pre-filtering algorithm with SFBC. © 2005 IEEE.; IST-2001-507039 4MORE; FCT - POSI/CPS/46701/2002

Transmit space-frequency prefiltering technique for downlink TDD MC-CDMA systems

Silva, Adão; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
69.107246%
In this communication we present a space-frequency pre-filtering technique, for downlink time division duplex (TDD) MC-CDMA systems, where the base station is equipped with an antenna array. We show that the pre-filtering approach can considerably reduce the multiple access interference at the mobile terminals allowing to transfer a significant part of the computational complexity to the base station, using a very low complex receiver at mobile. This approach relies on the availability of the channel state information at transmission, i.e., uses the time division duplex channel reciprocity between alternative uplink and downlink to obtain the channel state information. Simulation results are presented to demonstrate the effectiveness of the proposed prefiltering algorithm. Moreover, the performance of the proposed pre-filtering algorithm is assessed in two distinct scenarios: beamforming and diversity.; European IST-2001-32620 MATRICE project (MC-CDMA Transmission Techniques for Integrated Broadband Cellular Systems); FCT

Pre-filtering antenna array for downlink TDD MC-CMA systems

Silva, Adão; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
58.756885%
This communication deals with downlink time division duplex MC-CDMA system, and presents a frequency domain pre-filtering technique, where the base station is equipped with an antenna array. We show that the space-filtering approach proposed allows to format the transmitted signals so that the multiple access interference at the mobile terminals is reduced allowing to transfer a significant part of the computational burden to the base station, and therefore enabling the use of a very low complex receiver at mobile. This approach uses the time division duplex channel reciprocity between uplink and downlink to obtain the channel state information. Simulation results are presented to demonstrate the effectiveness of the proposed pre-filtering algorithm.; European IST-2001-32620 MATRICE project (MC-CDMA Transmission Techniques for Integrated Broadband Cellular Systems); FCT

Prefiltering techniques using antenna arrays for downlink tdd mc-cdma systems

Adão Silva; Atílio Gameiro
Fonte: Kluwer Academic Publishers Publicador: Kluwer Academic Publishers
Tipo: Parte de Livro
Português
Relevância na Pesquisa
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This paper deals with downlink time division duplex MC-CDMA system, and presents a space-frequency pre-filtering technique designed for two different receivers: an advanced one and an EGC conventional receiver, where the base station e equipped with an antenna array. We show that the space-frequency pre-filtering approach proposed allows to format the transmitted signals so that the multiple access interference at mobile terminals is reduced allowing to transfer the most computational burden to the base station. Simulations results are carried out to demonstrate the effectiveness of the proposed pre-filtering schemes.; European IST-2001-32620 MATRICE project

The IST project MATRICE on MC-CDMA transmission techniques for future Cellular Systems

Herault, Laurent; Noes, Mathieu des; Berens, Friedbert; Chalard, Laurent; Mottier, David; Hélard, Jean-François; Rodriguez, Jonathan; Tafazolli, Rahim; Acx, Anne-Gaële; Gameiro, Atilio; Aguiar, Rui L.; Zazo Bello, Santiago; Bauer, Franziskus
Fonte: ST Micro-electronics Publicador: ST Micro-electronics
Tipo: Artigo de Revista Científica
Português
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This paper presents an overview of the European IST project MATRICE (MC-CDMA Transmission Techniques for Integrated Broadband Cellular Systems, IST-2001-3220), describing its tasks, goals and preliminary achievements. The main focus of the MATRICE project is the definition of a new air-interface for future cellular mobile radio systems based on Multicarrier-CDMA modulation techniques and the study of its key building blocks like receiver algorithms and flexible TX components. The nine European partners participating in this project are CEA-LETI (F), France Telecom (F), Instituto de Telecommonicaçõ (P), Mitsubishi Electric ITE-TCL (F), University of Madrid (E), University of Surrey (UK), STMicroelectronics (CH), INSA-IETR (F) and Nokia (D).

Iterative frequency-domain detection for IA-precoded MC-CDMA systems

Silva, Adão; Teodoro, Sara; Dinis, Rui; Gameiro, Atílio
Fonte: Institute of Electrical and Electronics Engineers (IEEE) Publicador: Institute of Electrical and Electronics Engineers (IEEE)
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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Interference alignment (IA) is a promising technique that allows high capacity gains in interfering channels. On the other hand, iterative frequency-domain detection receivers based on the IB-DFE concept (Iterative Block Decision Feedback Equalization) can efficiently exploit the inherent space-frequency diversity of the MIMO MC-CDMA systems. In this paper we combine iterative IA precoding at the transmitter with IB-DFE based processing at the receiver for MC-CDMA systems. The receiver is designed in two steps: first a linear filter is used to mitigate the inter-user aligned interference, and then an iterative frequency-domain receiver is designed to efficiently separate the spatial streams in the presence of residual inter-user aligned interference at the output of the filter. The matrices for this non- linear space-frequency equalizer are obtained by minimizing the overall mean square error (MSE) of all data streams at each subcarrier. Our receiver structure is explicitly designed taking into account the residual inter-user interference, allowing both an efficient separation of the spatial streams and a reduction in the number of iterations of the IA procedure. We also propose a simple, yet accurate analytical approach for obtaining the performance of the proposed receiver structure. Our scheme achieves the maximum degrees of freedom provided by the IA precoding...

IB-DFE-based Receivers for MC-CDMA Systems with Interference Alignment

Assunção, José; Silva, Adão; Dinis, Rui; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
68.637847%
In this paper we design two multi-user receivers based on the iterative block decision feedback equalization (IB-DFE) concept for MC-CDMA systems with closed-form interference alignment (IA). The receivers are designed in two steps: first a linear equalizer is used to mitigate the inter-user aligned interference; then iterative frequency - domain receivers are designed to efficiently separate the spatial streams, in the presence of both residual inter-user and inter-carrier interferences at the output of the first equalizer. Two strategies are considered: in the first one the matrices are obtained by minimizing the mean square error (MSE) of each individual data stream at each subcarrier, while in the second approach the matrices are computed by minimizing the overall MSE of all data streams at each subcarrier. Our schemes achieve the maximum degrees of freedom provided by the IA precoding, while allowing a close-to-optimum space-diversity gain, with performance approaching the matched filter bound (MFB).

IB-DFE SIC based Receiver Structure for IA-Precoded MC-CDMA Systems

João, Alicia; Silva, Adão; Dinis, Rui; Assunção, José; Gameiro, Atílio
Fonte: EURASIP Publicador: EURASIP
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
68.91768%
Interference alignment (IA) is a promising technique that allows high capacity gains in interfering channels. On the other hand, iterative frequency-domain detection receivers based on the IB-DFE concept (Iterative Block Decision Feedback Equalization) can efficiently exploit the inherent space-frequency diversity of the MIMO MC-CDMA systems. In this paper we design a joint iterative IA precoding at the transmitter with IB-DFE successive interference cancellation (SIC) based receiver structure for MC-CDMA systems. The receiver is designed in two steps: first a linear filter is used to mitigate the inter-user aligned interference, and then an iterative frequency-domain receiver is designed to efficiently separate the spatial streams in the presence of residual inter-user aligned interference at the output of the filter. Our scheme achieves the maximum degrees of freedom provided by the IA precoding, while allowing an almost optimum space-diversity gain, with performance close to the matched filter bound (MFB).

IB-DFE with interference alignment precoding scheme for MC-CDMA systems; Esquemas de pré-codificação IA com IB-DFE para sistemas MC-CDMA

Moreira, José Eduardo Leal
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
69.493813%
To achieve high bit rates, needed to meet the quality of service requirements of future multimedia applications, multi-carrier code division multiple access (MC-CDMA) has been considered as a candidate air-interface. Interference alignment (IA) is a promising technique that allows high capacity gains in interfering channels. On the other hand, iterative block decision feedback equalization (IB-DFE) based receivers can efficiently exploit the inherent space-frequency diversity of the MIMO MC-CDMA systems. In this thesis we proposed an IA precoding at the transmitter with IB-DFE based processing at the receiver for MC-CDMA systems. The IA precoding is applied at chip level instead of the data symbols level, as in the conventional IA based systems. The receiver is designed in two steps: first the equalizers based on zero forcing (ZF) or minimum mean square error (MMSE) are used to remove the aligned users´ interference. Then and after a whitening noise process, an IB-DFE based equalizer is designed to remove both the residual inter-user aligned and inter-carrier interferences. The results have shown that the obtained performance is very close to the one obtained by the optimal matched filter, with few iterations at the receiver side.; Para atingir maiores ritmos de transmissão...

Equalization and precoding techniques for future MC-CDMA systems; Técnicas de equalização e pré-codificação para sistemas MC-CDMA

João, Alícia Mafalda de Figueiredo Paiva
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
69.592036%
O número de dispositivos com ligações e aplicações sem fios está a aumentar exponencialmente, causando problemas de interferência e diminuindo a capacidade do sistema. Isto desencadeou uma procura por uma eficiência espectral superior e, consequentemente, tornou-se necessário desenvolver novas arquitecturas celulares que suportem estas novas exigências. Coordenação ou cooperação multicelular é uma arquitectura promissora para sistemas celulares sem fios. Esta ajuda a mitigar a interferência entre células, melhorando a equidade e a capacidade do sistema. É, portanto, uma arquitectura já em estudo ao abrigo da tecnologia LTE-Advanced sob o conceito de coordenação multiponto (CoMP). Nesta dissertação, considerámos um sistema coordenado MC-CDMA com pré-codificação e equalização iterativas. Uma das técnicas mais eficientes de pré-codificação é o alinhamento de interferências (IA). Este é um conceito relativamente novo que permite aumentar a capacidade do sistema em canais de elevada interferência. Sabe-se que, para os sistemas MC-CDMA, os equalizadores lineares convencionais não são os mais eficientes, devido à interferência residual entre portadoras (ICI). No entanto, a equalização iterativa no domínio da frequência (FDE) foi identificada como sendo uma das técnicas mais eficientes para lidar com ICI e explorar a diversidade oferecida pelos sistemas MIMO MC-CDMA. Esta técnica é baseada no conceito Iterative Block Decision Feedback Equalization (IB-DFE). Nesta dissertação...

Analytical evaluation of nonlinear effects in MC-CDMA signals

Dinis, Rui; Silva, Paulo
Fonte: ACTA Press Publicador: ACTA Press
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2005 Português
Relevância na Pesquisa
68.91768%
In this paper we present an analytical tool for the per formance evaluation of nonlinear effects in MC-CDMA signals. This tool takes advantage of the Gaussian-like behavior of MC-CDMA signals with a large number of subcarriers and employs results on memoryless nonlinear devices with Gaussian inputs so as to characterize statis tically the signals at the output of the nonlinear device. This characterization is then used for an analytical com putation of the SIR levels (Signal-to-Interference Ratio) and the BER performance (Bit Error Rate). A set of numerical results is presented and discussed, showing the accuracy of the proposed analytical BER per formance analysis.

Joint interference alignment and IB-DFE scheme for MC-CDMA systems

Silva, Adão; Dinis, Rui; Moreira, José; Gameiro, Atílio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
68.91768%
Interference alignment (IA) is a promising technique that allows high capacity gains in interfering channels. On the other hand, iterative block decision feedback equalization (IB-DFE) based receivers can efficiently exploit the inherent space-frequency diversity of the MIMO MC-CDMA systems. In this paper we combine IA precoding at the transmitter with IB-DFE based processing at the receiver for MC-CDMA systems. The IA precoding is applied at chip level instead of the data symbols level. The receiver is designed in two steps: first an equalizer based on zero forcing (ZF) is used to remove the aligned users' interference, then and after a whitening noise process, an IB-DFE based equalizer is designed to remove the residual inter-carrier interference. Our proposed scheme achieves the maximum degrees of freedom provided by the IA precoding, while allowing a close-to-optimum diversity gain, with performance close to the matched filter bound (MFB).

Vectorial channel estimation for uplink MC-CDMA in beyond 3G wireless systems

Marques, P.; Gameiro, A. S.
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
68.91768%
In beyond 3G wireless systems the bandwidth efficiency can be increased with the use of adaptive antenna arrays. This paper focus on a key issue for adaptive antenna arrays, that is, channel parameters estimation including Direction-Of-Arrival (DOA). In order to estimate DOA. the channel frequency responses for the links between the mobile users and each of base station array elements are estimated by pilot-aided minimum mean square error (MMSE) algorithm. This estimator is not sensitive to the channel statistics. Based on frequency response estimatives DOA's of impinging multipath components to the base station are estimated by a low complex Wlauimuni Likelihood (ML) approach. Furthermore an uplink burst structure with specifically designed midamble field for multiuser channel estimation in MC-CDMA is proposed. The performance is assessed in terms of channel estimation errors for a MC-CDMA TDD system over fast and slow fading mobile channels.