Time filter

Source Type

Xu X.,Science and Technology on Communication Information Security Control Laboratory | Wang C.,Beijing University of Posts and Telecommunications
International Conference on Communication Technology Proceedings, ICCT | Year: 2015

Interference alignment (IA) is a promising technique to effectively mitigate interference in wireless communication systems. In this paper, a novel IA based scheme is proposed, which is jointed design of transmit precoding matrices and receive beam forming matrices for the three-cell multiple-input multiple-output (MIMO). Gaussian interfering broadcast channels (MIMO-IFBC) with constant channel between each node, where each base station (BS) is equipped with M antennas, each mobile station (MS) is equipped with N antennas on the cell boundary, and each BS sends d data streams to each user in its cell. This corresponds to a down link scenario for cellular networks, where K users with the user cooperation in each cell. It is also analytically shown that total 3Kd degrees of freedom (Do F) is achievable if M = N ≥ 2Kd. The simulations demonstrate the sum-rate of our proposed scheme also out performs those of conventional techniques, especially in the high signal-To-noise ratio (SNR) regime. © 2015 IEEE.


Zheng S.,Science and Technology on Communication Information Security Control Laboratory | Yang X.,Science and Technology on Communication Information Security Control Laboratory
11th International Symposium on Communications and Information Technologies, ISCIT 2011 | Year: 2011

Wideband spectrum sensing is a fundamental problem in cognitive radio networks. In this paper, a wideband spectrum sensing procedure which consists of four steps, i.e., coarse support recovery, fine binary detection, band edges detection and clustering, for modulated wideband converter (MWC) based cognitive radio system at sub-Nyquist rate is proposed. Simulations show that with a sub-Nyquist sampling rate, the proposed spectrum sensing procedure can locate spectrum holes correctly. © 2011 IEEE.


Zhang H.,University of Electronic Science and Technology of China | Zhang H.,Science and Technology on Communication Information Security Control Laboratory | Wei P.,University of Electronic Science and Technology of China
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2013

In this paper, a spreading sequence estimation algorithm based on constant modulus property is proposed for the QPSK-DSSS signals in low signal to noise ratio and non-cooperative scenarios. First, the single-user QPSK-DSSS signal can be equivalently represented as a two-user BPSK-DSSS signal, and then the two-dimensional signal subspace spanned by the in-phase and quadrature binary spreading sequences is estimated by the eigen-decomposition of the covariance matrix. Finally, to estimate the spreading sequences accurately, its constant modulus property is exploited to cope with the unitary matrix ambiguity resulting from eigen-decomposition. The proposed algorithm is simple and easy to implement, and has a lower computational complexity compared to existing methods. And simulation results demonstrate the significant performance gains of the proposed algorithm in low signal to noise ratio situations.


Zhu L.,Harbin Institute of Technology | Meng F.-Y.,Harbin Institute of Technology | Fu J.-H.,Harbin Institute of Technology | Wu Q.,Harbin Institute of Technology | And 2 more authors.
Optics Express | Year: 2012

In this paper, a multi-band slow light metamaterial is presented and investigated. The metamaterial unit cell is composed of three cut wires of different sizes and parallel to each other. Two transparency windows induced by two-two overlaps of absorption bands of three cut wires are observed. The multi-band transmission characteristics and the slow light properties of metamaterial are verified by numerical simulation, which is in a good agreement with theoretical predictions. The impacts of structure parameters on transparency windows are also investigated. Simulation results show the spectral properties can be tuned by adjusting structure parameters of metamaterial. The equivalent circuit model and the synthesis method of the multi-band slow light metamaterial are presented. It is seen from simulation results that the synthesis method accurately predicts the center frequency of the multi-band metamaterial, which opens a door to a quick and accurate construction for multi-band slow light metamaterial. © 2012 Optical Society of America.


Han Y.,Science and Technology on Communication Information Security Control Laboratory | Han Y.,China Electronics Technology Group Corporation
International Conference on Communication Technology Proceedings, ICCT | Year: 2015

This paper presents a compact and efficient hard output MIMO detection and its FPGA implementation. Our method is based on a complex-valued decomposition and a highly compact expansion, which needs least number of visited nodes and a half of tree depth than previously published K-best designs. We propose a fully pipelined architecture, combining with resource sharing to realize the detector. Furthermore, our complex-valued MIMO detector is implemented and validated on a Xilinx FPGA device for a 16-QAM modulation and 4×4 antenna configuration. The implementation results show that the proposed detector is hardware efficient and has a 395 Mbps throughput with about 0.2dB performance loss. © 2015 IEEE.


Zhang Y.,Science and Technology on Communication Information Security Control Laboratory | Zhang Y.,China Electronics Technology Group Corporation
Xi'an Dianzi Keji Daxue Xuebao/Journal of Xidian University | Year: 2011

In order to solve the problem of the blind recognition of Turbo codes, some methods for blind recognition of the Turbo coding parameter with trellis termination are proposed for the first time. Based on the analysis of the sub-encoder structure of Turbo codes, some analytical models of convolutional codes at a rate of 1/2 are proposed, and by recoverying the interleaver sequence of Turbo codes, interleaver mapping is decided by exhaust comparison, and blind recognition of Turbo codes with trellis termination is realized. Simulation results illustrate that given the unknown Turbo encoded data sequence, the recognized coding parameters are correct by comparing prior conditions which validates the accuracy of the proposed methods.


Zhang W.,Science and Technology on Communication Information Security Control Laboratory
2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014 | Year: 2014

Automatic classification of the modulation format of a detected signal plays an important role in cognitive radio system and several military and civilian applications. Without previous knowledge of the received data, automatic modulation classification (AMC) becomes a difficult task. This paper discusses AMC of digital schemes which are commonly used in today's communication systems. Several statistical features are extracted to represent signals and Support Vector Machines (SVMs) are then applied to classify the unknown modulation schemes. Experiment results demonstrate that the proposed AMC algorithm is a practical algorithm and it has high robustness in a wide range of SNR. © 2014 IEEE.


Bin Y.Z.,Science and Technology on Communication Information Security Control Laboratory | Yan Q.,Science and Technology on Communication Information Security Control Laboratory | Nan L.A.,Science and Technology on Communication Information Security Control Laboratory
Proceedings - 2011 10th IEEE/ACIS International Conference on Computer and Information Science, ICIS 2011 | Year: 2011

Passive localization using TDOA and FDOA measurements usually does not have direct solution and requires numerical methods to determine the emitter's geolocation. We examine a satellite passive localization method based on particle swarm optimization(PSO), which provides an evolutionary computation method to solve the nonlinear optimal problem. However, PSO can not be straightforwardly applied to satellite passive localization because it is a constrained nonlinear optimal problem when using the constraint condition of the earth surface. We suggest "flying" the particle swarm directly using the earth surface constraint. Computer simulation results show the effectiveness of the new localization method. © 2011 IEEE.


Zheng S.-L.,Xidian University | Zheng S.-L.,Science and Technology on Communication Information Security Control Laboratory | Yang X.-N.,Xidian University | Yang X.-N.,Science and Technology on Communication Information Security Control Laboratory
Wuli Xuebao/Acta Physica Sinica | Year: 2012

The model for parameter adaptation problem in green cognitive radio and a particle swarm optimization based solution are proposed. Simulations are conducted to show the performance of the proposed method. Results show that given different quality of service (QoS) requirements, the proposed method can reduce the total transmit power of the system while maintaining the QoS requirements. Thus the goal of reducing energy consumption is reached. © 2012 Chinese Physical Society.


Wang W.,Science and Technology on Communication Information Security Control Laboratory | Wang W.,China Electronics Technology Group Corporation
Journal of Digital Information Management | Year: 2012

Focusing on the protection of privacy and non- publicity of special networks, the CPN model is extended to PCPN by the protocol factor and the formal model. The FPCPN (Formal Protocol Colored Petri Net) is presented to analyze the operation mechanism of protocols. It is introduced by four steps, such as the whole structure, the network element conversion, the conditions of transition triggers/executions and sub-system partitions. Finally, the feasibility and efficiency of FPCPN is validated by an example.

Loading Science and Technology on Communication Information Security Control Laboratory collaborators
Loading Science and Technology on Communication Information Security Control Laboratory collaborators