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Quadrature spatial modulation (QSM), where the real and imaginary parts of the transmitted symbol are transmitted separately, was recently proposed to increase the spectral efficiency of spatial modulation. An optimum maximum likelihood (ML) detection was introduced in QSM systems, which leads to high complexity as the exhausting search of all possible transmit antennas. In this paper, a low complexity detection, called signal vector based minimum mean square error (SVMMSE), is proposed for QSM systems. In the proposed SVMMSE detection, we estimate the transmit antenna indices and the transmitted symbol by considering the active transmit antennas in two different scenarios. Simulation results show that the performance of our SVMMSE detection is very close to the ML detection and complexity analysis shows that the computational complexity of the proposed SVMMSE detection is significantly reduced compared with that of the ML detection.

Crosstalk is a major issue in modern ADSL and VDSL systems. Static spectrum management (SSM), the traditional way to guarantee spectrum compatibility, employs spectral masks which can be overly restrictive and result in poor performance. In this paper, fixed margin iterative water-filling algorithm is investigated in downstream VDSL and ADSL2+ scenario when they are in the same binder. The algorithm can minimize the transmission power and at the same time the overall high-quality service is guaranteed for all the users of the same binder. Simulation results show that ADSL2+ can realize performance gains of up to 80% compared with SSM techniques or ADSL.

Multiple antennas can provide huge capacity gains when the transmitter knows the channel state information (CSI). In multiple-input multiple- output (MIMO) wireless system, CSI at transmitter (CSIT) side can significantly improve system performance by increasing the transmission rate and enhancing reliability. Precoding is a technique that exploits CSIT by processing the signal before transmitting. In this paper, a new precoding scheme called hybrid multiple-input multiple-output precoding (HMP) is proposed. HMP is the combination of a linear and a nonlinear precoder. In HMP, nonlinear precoding in the good channel and linear precoding in the bad channel is used. The well-known Tomlinson-Harashima precoding (THP) is considered as nonlinear precoding. If number of transmit antennas is chosen less than or equal to four, HMP has no use, conventional antenna selection scheme would better perform. Therefore, for perform better at least four or more Tx antennas need to be chosen. The system achievable rate is calculated to show the performance of HMP scheme compared with the conventional scheme.

In this paper, we mainly focused on achieve the desired degree of freedom. Channel state information at the transmitter (CSIT) plays major role for K-user Multiple Input and Multiple Output (MIMO) M × N interference channels. Span Interference alignment method is used in order to align the interference. Each transmitter has two antennas which help to communicate with transmitter and relay node in an efficient way. In addition, by adding the relay nodes with the desired system model is helps to recover the Degree of Freedom (DoF) which is ideal for these models with global channel state information (CSI). Recently studies have shown that relay cannot improve the DoF of wireless interference networks but it helps to give some partial solutions to approach the interference alignment. The relay nodes which helps to steer directions of transmitter signals to expedite the interference alignment in order to achieve optimal DoF. A new performance method has been proposed in order to estimate the efficiency of an interference alignment.

With large-scale Multiple-input Multiple-output (MOMO), we think of a system that use antenna arrays with an order of magnitude more elements than in systems being built nowadays, say a hundred antennas or more. As it is known that, the more antennas the transmitter/receiver is equipped with, the more the possible signal paths, the better the performance in terms of data rate and link reliability. However, channel estimation in large-scale MIMO is said to be hampered by the pilot contamination effect, constitute a major reduction for overall system performance. In this paper, we present a novel approach which tackles this problem by enabling a covariance formulation between cells during the channel estimation phase itself, could leads to improver the system performance. Here we present a noble scheme title as large-scale MIMO channel estimation based on circularly symmetric Gaussian covariance matrix. The numerical result shows the significance of proposed scheme.

To apply the superconducting wire to power machines, it is necessary to conduct research on the characteristics of wire phase changes in connection with insulating layers. In this study, according to the presence or absence of insulating layers in the wire, and to the thickness of such layers, the wire's resistance increase trends and the characteristics of its recovery from quenching were examined by current-applied cycle at the temperatures of 90 K, 180 K and 250 K. Towards this end, YBCO thin-film wires that have the same critical temperatures and that have copper and stainless-steel stabilizing layers were prepared. One level and three and five levels of superior-performance polyimide pressure-sensitive adhesive tape was attached to the wires at a very low temperature. The eight prepared test samples were wound around the linear frames, then the wire's voltage and current created owing to the phase change characteristics were measured at each prescribed temperature, using the four-point probe method. Further, near the examination temperatures of 90 K, 180 K and 250 K the wire's resistance and recovery characteristics were examined by cycle.

In the paper, a method for designing 2D FIR linear-phase half-band filters is proposed. The method is based on two error criteria, i.e., equiripple error criterion in the passband and least-squared error criterion in the stopband. The filter design problem is transformed into an equivalent bicriterion optimization problem. A two-step solution procedure of the considered problem is presented. In the first step, a genetic algorithm is applied. The final point from the genetic algorithm is used as the starting point for a local optimization method. Two design examples are given to illustrate the proposed technique.

It is widely known that constant coefficient multiplications can be efficiently realized using only shift and add operations. In addition, substantial gains in circuit area can be achieved by sharing the hardware units that are common among the filter coefficients. In this paper, a constrained quantization algorithm is proposed to increase the number of shared terms. By examples, it is shown that the use of the proposed quantization scheme can result in reduction in the number of binary adders up to 30%. In addition, it is shown that the critical path of an IIR filter can be reduced by constraining pole locations. The Remez exchange algorithm is used to compensate for the error introduced by pole location constraints. Thus, high performance IIR filter implementation can be achieved without any hardware overhead (with only slight degradation in frequency spectrum characteristics).