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A method is proposed to generate the optical vortex beam with angular momentum by waveguide surface holographic grating. The results of the orbital angular momentum beam with first, second, and third orders are given. The obtained beams are proved to carry orbital angular momentum by giving the phase distributions and the fidelities. This work opens an available avenue towards the integrated orbital...
Gradient descent bit-flipping (GDBF) decoding for low-density parity-check (LDPC) codes has gained great attentions because of low complexity and relatively good performance. However, the performance of the GDBF decoding is still much poorer than that of the MS algorithm. To further improve the performance, the iterative decoding process is introduced to GDBF decoding in this paper. At the end of...
Active attacks threat the security of communication dramatically. In this paper, we propose a secure transmission scheme based on random orthogonal pilots to detect the presence of active eavesdropping attacks on channel estimation in time-division-duplex (TDD) systems. The scheme only needs to replace some regular pilot sequences with random orthogonal pilot sequences occasionally without any prior...
In this paper, we propose a novel method to annotate the image of power grid objects (i.e., the electric equipment, the workers with different behaviors). This method is based on the convolutional neural networks (CNN). First, we obtain the attribute list of the image under the multi-label networks. Second, we employ the attribute-specific segmentation model to annotate the image. In this paper, we...
In recent years the field studies on collective behaviors have revealed that topological interaction of k nearest neighbors plays a the key role in flocking. In this work, we show a model of flocking through adaptation to k nearest topological neighbors, and examine the influence of the number of topological neighbors on flocking dynamics with different group size. The model is validated by simulations.
Massive multiple-input and multiple-output (MIMO) technique is regarded as one of the most promising technique in the fifth-generation (5G) wireless communication systems. However, accurate channel estimation technique poses a challenge for spatial correlated 3D MIMO systems. Based on the conventional general sparse channel model, sparse channel estimation method using compressive sampling matching...
A method for minimax design of linear phase finite impulse response (FIR) digital filters using cuckoo search algorithm (CSA) is presented. Lowpass and bandpass digital filters are used as filter examples. Equiripple linear phase FIR digital filter design results indicate that the peak errors in passband and stopband(s) obtained using the cuckoo search algorithm are similar to those obtained by the...
The higher order constellation scheme, i.e., 128AP-SK, has been adopted in the latest generation satellite digital video broadcasting (DVB-S2X) standard. It significantly improves the spectral efficiency, but also introduces serious complexity problems in the implementation of the demapper. This paper presents an efficient soft demapper for 128APSK of DVB-S2X based on the concept of decision region...
Channel reciprocity is a key characteristic in massive multiple-input multiple-output (MIMO) systems in time division duplex (TDD) mode, by which the downlink channel state information (CSI) can be obtained easily. However, the hardware mismatch of the transceiver radio frequency (RF) chains disables the channel reciprocity. Considering the application complexity of full calibration of massive MIMO,...
A novel self-normalized weighted bit-flipping (SNWBF) decoding algorithm for low-density parity-check (LDPC) codes is proposed. Compared to the best known weighted bit-flipping decoding, the SNWBF algorithm converges significantly faster but with little performance penalty. For decoding of LDPC codes, the proposed SNWBF algorithm considers not only the reliability of the neighboring check nodes, but...
Base station sleep mode is an effective method to reduce the energy consumption of cellular networks. Taking into account a cellular network, its central base station (BS) can turn into sleep mode when the traffic is low and the users in this cell can access to neighbor active cells. A user offloading algorithm for the sleeping cell is investigated. The energy consumption of the cellular network in...
With the development of smart of grid, the traditional wireless communication cannot meet the new service requirement. In this paper, we propose a blind spots coverage based on D2D communication scheme to solve the problems of blind spots coverage and service access imbalance for power LTE private network. Meanwhile, we analyze the application of D2D communication technology based on LTE in power...
In HEVC, prediction mode decision is essential for efficient coding in applications. While many fast algorithms have been designed to reduce the candidate modes, the features of scene switch frames have seldom been considered. These frames usually have no relationship with the previous frames. Thus, intra modes should be used. In this paper, we propose a simple and efficient Hash-based algorithm....
The transmission distance of continuous variable QKD (CV QKD) protocol based on Gaussian modulation has been quite limited by the low efficient reconciliation protocol. On the other hand, noiseless linear amplifier (NLA) have greatly enhanced the ability of CV QKD. In this paper, we propose a Gaussian post-selection method simulating NAL in CV QKD, followed by a reconciliation process based on systematic...
In this paper, we consider a multi-input-multi-output cognitive radio (MIMO-CR) system which consists of one secondary user (SU) and one secondary destination (SD), in which one eavesdropper (E) attempts to tap the information from SU to SD. All of the aforementioned nodes are equipped with multiple antennas. For enhancing physical layer security, we propose so-called optimal antenna selection (OAS)...
Artificial bee colony (ABC) algorithm is a swarm based meta-heuristic algorithm inspired by the foraging behavior of honey bees. Due to its simplicity, the ABC algorithm is used for minimax design of linear phase FIR fullband digital differentiators in this paper. Results in term of peak error obtained from designed digital differentiator examples indicate that the approach can reach smaller peak...
Considering the three dimensional (3D) channel with elevation effect, a two dimensional (2D) antenna array was employed in a generic ray-based 3D multi-input multi-output (MIMO) system. Through utilizing the channel spatial correlation between antennas at the transmitter side, we propose a cascaded MMSE channel estimation with low computational complexity. Numerical results show that the proposed...
Low Rank Matrix Factorization (LRMF) is a classical problem that arises in a wide range of practical contexts, especially in collaborative filtering, dimension reduction, etc. In this paper, a stochastic alternating minimization approach applied to LRMF problem is proposed. The main idea of the approach is to randomly sample partial rows of the matrix to perform parameter update during training using...
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