Power spectrum characterization of systematic coded UW-OFDM systems

Unique word (UW)-OFDM is a newly proposed multicarrier technique that has shown to outperform cyclic prefix (CP)-OFDM in fading channels. Until now, the spectrum of UW-OFDM is not thoroughly investigated. In this paper, we derive an analytical expression for the spectrum taking into account the DFT based implementation of the system. Simulations show that the proposed analytical results are very accurate. Compared to CP-OFDM, we show that UW-OFDM has much lower out-of-band (OOB) radiation, which makes it suitable for systems with strict spectral masks, as e. g. cognitive radios. Further, in this paper, we evaluate the effect of the redundant carrier placement on the spectrum

Multiple-access interference rejecting receivers in DS-CDMA communication system

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN037068 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Development of group method of data handling based on genetic algorithm to predict incipient motion in rigid rectangular storm water channel

Sediment transport is a prevalent vital process in uvial and coastal environments, and \incipient motion" is an issue inseparably bound to this topic. This study utilizes a novel hybrid method based on Group Method of Data Handling (GMDH) and Genetic Algorithm (GA) to design GMDH structural (GMDH-GA). Also, Singular Value Decomposition (SVD) was utilized to compute the linear coe�cient vectors. In order to predict the densimetric Froude number (Fr), the ratio of median diameter of particle size to hydraulic radius (d=R) and the ratio of sediment deposit thickness to hydraulic radius (ts=R) are utilized as e�ective parameters. Using three di�erent sources of experimental data and GMDH-GA model, a new equation is proposed to predict incipient motion. The performance of development equation is compared using GMDH-GA and traditional equations . The results indicate that the presented equation is more accurate (RMSE = 0:18 and MAP E = 6:48%) than traditional methods. Also, a sensitivity analysis is presented to study the performance of each input combination in predicting incipient motio

Rank-defective millimeter-wave channel estimation based on subspace-compressive sensing

Millimeter-wave communication (mmWC) is considered as one of the pioneer candidates for 5G indoor and outdoor systems in E-band. To subdue the channel propagation characteristics in this band, high dimensional antenna arrays need to be deployed at both the base station (BS) and mobile sets (MS). Unlike the conventional MIMO systems, Millimeter-wave (mmW) systems lay away to employ the power predatory equipment such as ADC or RF chain in each branch of MIMO system because of hardware constraints. Such systems leverage to the hybrid precoding (combining) architecture for downlink deployment. Because there is a large array at the transceiver, it is impossible to estimate the channel by conventional methods. This paper develops a new algorithm to estimate the mmW channel by exploiting the sparse nature of the channel. The main contribution is the representation of a sparse channel model and the exploitation of a modified approach based on Multiple Measurement Vector (MMV) greedy sparse framework and subspace method of Multiple Signal Classification (MUSIC) which work together to recover the indices of non-zero elements of an unknown channel matrix when the rank of the channel matrix is defected. In practical rank-defective channels, MUSIC fails, and we need to propose new extended MUSIC approaches based on subspace enhancement to compensate the limitation of MUSIC. Simulation results indicate that our proposed extended MUSIC algorithms will have proper performances and moderate computational speeds, and that they are even able to work in channels with an unknown sparsity level

GMDH-type neural network approach for modeling the discharge coefficient of rectangular sharp-crested side weirs

Estimating the discharge coefficient using hydraulic and geometrical specifications is one of the influential factors in predicting the discharge passing over a side weir. Taking into account the fact that existing equations are incapable of estimating the discharge coefficient well, artificial intelligence methods are used to predict it. In this study, Group Method of Data Handling (GMDH) was used for the purpose of predicting the discharge coefficient in a side weir. The Froude number (F1), weir dimensionless length (b/B), ratios of weir length to depth of upstream flow (b/y1) and weir height to its length (p/y1) were taken as input parameters to express a new model for predicting the discharge coefficient. Two different sets of laboratory data were used to train the artificial network and test the new model. Different statistical indexes were used to evaluate the performance of the GMDH model presented for two states, training and testing. The results indicate that the proposed model predicts the discharge coefficient precisely (MAPE = 5.263 & RMSE = 0.038) and this model is more accurate in predicting than the feed-forward neural network model and existing nonlinear regression equations

Sidelobe suppression for non-systematic coded UW-OFDM in cognitive radio networks

In this paper, a novel non-contiguous non-systematic coded unique word (UW)-OFDM system is proposed to opportunistically transmit data on the spectrum holes available in a cognitive radio network. In such a system, the spectral sidelobes of the active subcarriers interfere with the adjacent spectral band used by the primary system. In the proposed scheme, the code generator matrix of the UW-OFDM is designed to suppress the sidelobes. So, there is no need to add any extra processing to the transmitter for suppressing sidelobes. The derived code generator matrix is optimum in the sense of being matched to the best linear unbiased estimator and to the linear minimum mean square error data estimators. The achieved sidelobe suppression is a function of the number of transmitted data symbols. Simulation results show that by a slight decrease in the number of transmitted data symbols, the sidelobes power can be suppressed to zero