Guan Z.-J.,Shanghai Radio Equipment Research Institute |
Zhou X.-L.,Shanghai JiaoTong University
International Journal of Communication Systems | Year: 2015
A kind of amplify-and-forward (AF) and decode-and-forward (DF) mixed relay communication system is proposed in this letter. The source broadcasts the signal to all the relays. Relays that can decode the signal adopt DF scheme to retransmit the signal, while the rest adopt AF scheme for retransmission. The destination employs maximum ratio combining technique tomaximize the received signal-to-noise ratio. Another situation concerned in this letter is that when the relay cannot decode the source signal, it may retransmit the interference signal with AF scheme. Closed-form expressions of outage probability are derived. Simulation results show that the analytical curves agree with the simulated ones very well, and the AF-DF mixed relay system can improve the availability of the relays. Copyright © 2013 John Wiley & Sons, Ltd.
Tang W.,Shanghai Radio Equipment Research Institute |
Zhou Y.,University of Sichuan
Electronics Letters | Year: 2012
A power pattern synthesis technique for a wideband array including mutual coupling (MC) is proposed. A frequency-dependent MC (FDMC) matrix is obtained accurately via the complex curve fitting technique. With the FDMC matrix the mutual coupling effect is included in the synthesis procedure automatically, resulting in an MC-compensated frequency-invariant power pattern. © 2012 The Institution of Engineering and Technology.
Chao S.,Shanghai Radio Equipment Research Institute
IET Conference Publications | Year: 2013
A model of multiple-input multiple-output (MIMO) radar combining widely separated and colocated antennas is developed and the joint Cramer-Rao bounds (CRBs) for estimating the target location and the target velocity are derived for this type of MIMO radar system in order to analyze its estimation performance and the factors affecting on the performance. Simulation results are presented and illustrate that MIMO radar with more separated subarrys consisting of colocated antenna elements has better and more stable performance on the location and velocity estimation for a moving target.
Li X.,Huazhong University of Science and Technology |
Qiu H.,Huazhong University of Science and Technology |
Chen Z.,Shanghai Radio Equipment Research Institute |
Gao L.,Huazhong University of Science and Technology |
Shao X.,Huazhong University of Science and Technology
Computers and Structures | Year: 2016
Kriging approximation has been widely used in reliability-based design optimization (RBDO) to replace the complex black-box performance functions. In this paper, a new local approximation method using the most probable point (LMPP) is proposed to improve the accuracy and efficiency of RBDO methods using Kriging model. In the LMPP, the concept of local sampling region is used and the most probable point (MPP) is chosen as the sampling center. The size of the local region is determined by target reliability and the linearity of probability constraint around MPP. Rather than fitting the Kriging model for all the probabilistic constraints, the new method uses the MPP to find feasible constraints, and only these feasible constraints are accurately approximated, which can significantly improve the optimization efficiency. Importance Sampling method using the MPP obtained above as sampling center is utilized to perform reliability analysis and reliability sensitivity calculation. A numerical example, a honeycomb material design problem and a box girder design application are used to demonstrate the computational capability of the LMPP method. The comparison results demonstrate that RBDO using the proposed method is very effective. © 2015 Elsevier Ltd. All rights reserved.
Jiang Y.,Harbin Engineering University |
Zhang S.,Harbin Engineering University |
Guo Q.,Harbin Engineering University |
Li M.,Shanghai Radio Equipment Research Institute
IEEE Antennas and Wireless Propagation Letters | Year: 2016
An improved integer genetic algorithm (IIGA) that overcomes the inefficient searching and the severe computational effort of genetic algorithms (GAs) has been presented. Uniformly excited concentric ring arrays with aperture sizes from the small to the medium (the array diameter is up to 50 wavelengths) are synthesized with IIGA. All the obtained arrays meet the minimum element spacing constraint of a half-wavelength. Numerical results show IIGA can search out a lower peak sidelobe level with less iterations, which provides an alternative global optimum approach to the synthesis of planar arrays with thousands of elements. © 2002-2011 IEEE.