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MIMO Channels (mimo + channel)
Selected AbstractsPerformance 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] Iterative channel estimation and data detection in frequency-selective fading MIMO channels,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2004Maja Lon Signals transmitted through multiple-input multiple-output (MIMO) wireless channels suffer from multiple-access interference (MAI), multipath propagation and additive noise. Iterative multiuser receiver algorithms mitigate these signal impairments, while offering a good tradeoff between performance and complexity. The receiver presented in this paper performs channel estimation, multiuser detection and decoding in an iterative manner. The estimation of the frequency selective, block-fading channel is initiated with the pilot symbols. In subsequent iterations, soft decisions of all the data symbols are used in an appropriate way to improve the channel estimates. This approach leads to significant improvement of the overall receiver performance, compared to other schemes. The bit-error-rate (BER) performance of the receiver is evaluated by simulations for different parameter setups. Copyright © 2004 AEI. [source] Performance of multi level-turbo coding with neural network-based channel estimation over WSSUS MIMO channelsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2009Ersin Gose Abstract This paper presents the performance of the transmit diversity-multi level turbo codes (TD-MLTC) over the multiple-input,multiple-output (MIMO) channels based on the wide sense stationary uncorrelated scattering (WSSUS). The multi level-turbo code (ML-TC) system contains more than one turbo encoder/decoder block in its structure. At the transmitter side, the ML-TC uses the group partitioning technique that partitions a signal set into several levels and encodes each level separately by a proper component of the encoder to improve error performance. The binary input sequence is passed through the MLTC encoder and mapped to 4-PSK and then fed into the transmit diversity scheme for high data transmission over wireless fading channels. At the receiver side, distorted multi-path signals are received by multiple receiver antennae. WSSUS MIMO channel parameters are estimated by using an artificial neural network and an iterative combiner. Input sequence of the first level of the MLTC encoder is estimated at the first level of MLTC decoder. Subsequently, the other input sequences are computed by using the estimated input bit streams of the previous levels. 4-PSK two-level turbo codes are simulated for 2Tx,1Rx and 2Tx,2Rx antenna configurations over WSSUS MIMO channels. Here, TD-MLTC and its efficient implementations are discussed and simulation results are given. Copyright © 2008 John Wiley & Sons, Ltd. [source] On the performance of recursive space,frequency codes and iterative decoding in wideband OFDM-MIMO systems: simulated and measured resultsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2004Paul N. Fletcher Abstract In this paper, we study the performance of a bandwidth efficient space,frequency turbo encoding scheme over wideband channels. Results are presented for simulated wideband MIMO channels consisting of two transmit antennas and up to two receive antennas. In addition, wideband channel measurements undertaken with practical multi-element antenna structures at both the access point (AP) and mobile terminal (MT) are presented. Analysis is in terms of channel capacity, 10% channel outage capacity and space,frequency iterative decoding for an lEEE802.11a physical layer complaint modem. It is shown when operating with a spectral efficiency of 1.2 bits/s/Hz, the iterative decoded space,time codes comes within approximately 4.7 dB of 10% outage capacity over Rayleigh fading wideband channels with two transmit and two receive antennas. Over measured channels the iterative decoding scheme performs within 7.7 dB 10% of outage capacity. Losses due to channel state information estimation are also investigated. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||