2017/1

Browse

Recent Submissions

Now showing 1 - 5 of 50
  • Thumbnail Image
    Item
    Novel Design of Recursive Differentiator Based on Lattice Wave Digital Filter
    (Společnost pro radioelektronické inženýrství, 2017-04) Barsainya, Richa; Rawat, Tarun K.
    In this paper, a novel design of third and fifth order differentiator based on lattice wave digital filter (LWDF), established on optimizing L_1-error approximation function using cuckoo search algorithm (CSA) is proposed. We present a novel realization of minimum multiplier differentiator using LWD structure leading to requirement of optimizing only N coefficients for Nth order differentiator. The gamma coefficients of lattice wave digital differentiator (LWDD) are computed by minimizing the L_1-norm fitness function leading to a flat response. The superiority of the proposed LWDD is evident by comparing it with other differentiators mentioned in the literature. The magnitude response of the designed LWDD is found to be of high accuracy with flat response in a wide frequency range. The simulation and statistical results validates that the designed minimum multiplier LWDD circumvents the existing one in terms of minimum absolute magnitude error, mean relative error (dB) and efficient structural realization, thereby making the proposed LWDD a promising approach to digital differentiator design.
  • Thumbnail Image
    Item
    2-D DOA Estimation of LFM Signals Based on Dechirping Algorithm and Uniform Circle Array
    (Společnost pro radioelektronické inženýrství, 2017-04) Cui, Kaibo; Wu, Weiwei; Chen, Xi; Huang, Jingjian; Yuan, Naichang
    Based on Dechirping algorithm and uniform circle array(UCA), a new 2-D direction of arrival (DOA) estimation algorithm of linear frequency modulation (LFM) signals is proposed in this paper. The algorithm uses the thought of Dechirping and regards the signal to be estimated which is received by the reference sensor as the reference signal and proceeds the difference frequency treatment with the signal received by each sensor. So the signal to be estimated becomes a single-frequency signal in each sensor. Then we transform the single-frequency signal to an isolated impulse through Fourier transform (FFT) and construct a new array data model based on the prominent parts of the impulse. Finally, we respectively use multiple signal classification (MUSIC) algorithm and rotational invariance technique (ESPRIT) algorithm to realize 2-D DOA estimation of LFM signals. The simulation results verify the effectiveness of the algorithm proposed.
  • Thumbnail Image
    Item
    Watermark Detection in Impulsive Noise Environment Based on the Compressive Sensing Reconstruction
    (Společnost pro radioelektronické inženýrství, 2017-04) Lutovac, Budimir; Dakovic, Milos; Stankovic, Srdjan; Orovic, Irena
    The watermark detection procedure for images corrupted by impulsive noise is proposed. The procedure is based on the compressive sensing (CS) method for the reconstruction of corrupted pixels. It is shown that the proposed procedure can extract watermark with a moderate impulsive noise level. It is well known that most of the images are approximately sparse in the 2D DCT domain. Moreover, we can force sparsity in the watermarking procedure and obtain almost strictly sparse image as a desirable input to the CS based reconstruction algorithms. Compared to the state-of-the-art methods for impulse noise removal, the proposed solution provides much better performance in watermark extraction.
  • Thumbnail Image
    Item
    Optimal Energy-Efficient Power Allocation Scheme with Low Complexity for Distributed Antenna System
    (Společnost pro radioelektronické inženýrství, 2017-04) Wang, Hao; Yu, Xiangbin; Xu, Weiye; Wen, Benben
    In this paper, by maximizing the energy efficiency (EE), an optimal power allocation scheme is developed for downlink distributed antenna system (DAS). Different from conventional optimal power allocation schemes that need iterative calculation, the developed scheme can provide closed-form power allocation and no iteration is required. Based on the definition of EE, the optimized objective function is firstly formulated, and then a computationally efficient algorithm is proposed to obtain the optimal number of active remote antennas and the corresponding power allocation. Using the optimal number, the multidimensional solution for the optimized function is transformed into searching one-dimensional solution. As a result, closed-form expression of power allocation coefficients is attained. Numerical results verify the effectiveness of the proposed scheme. The scheme can obtain the same EE as the conventional optimal scheme but with lower complexity, and it has more accuracy than the existing low-complexity scheme.
  • Thumbnail Image
    Item
    A Cascaded Reduced-Dimension STAP Method for Airborne MIMO Radar in the Presence of Jammers
    (Společnost pro radioelektronické inženýrství, 2017-04) Wang, Ting; Zhao, Yongjun; Chen, Shiwen; Zhang, Kunfan
    A cascaded reduced-dimension (RD) space-time adaptive processing (STAP) method for airborne multiple-input multiple-output (MIMO) radar in the presence of jammers is proposed in this paper. The proposed MIMO-STAP method for clutter plus jamming suppression proceeds in two steps. Firstly, the jamming is suppressed by its orthogonal complementary subspace obtained in the passive radar mode, while the receive dimension is reduced. Secondly, the tri-iterative algorithm (TRIA) is utilized to suppress the clutter combining the remaining receive degree of freedom (DOF) with the transmit DOF and the Doppler DOF, and further dimension reduction is implemented. The proposed method can effectively realize the separate jamming and clutter elimination. Moreover, the training sample number and the computational complexity are significantly decreased. Simulation results verify the validity of the proposed cascaded RD MIMO-STAP method under jamming condition.