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Li M.,Institute of China Electronic System Engineering Corporation | Bai L.,Beihang University | Yu Q.,Institute of China Electronic System Engineering Corporation | Yu Q.,Xidian University | And 2 more authors.
IEEE Transactions on Signal Processing | Year: 2017

In this paper, we investigate a beamforming (BF) scheme for a dual-hop multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay network in the presence of multiple cochannel interferences (CCIs) at both the relay and the destination nodes. In order to maximize the signal-to-interference-plus-noise ratio at the destination node, the optimal BF weights for the relay network in the presence of CCIs are derived. A tight lower bound on the outage probability (OP) is derived in a closed form by assuming that multiple CCIs have equal power at the relay and destination nodes. Through computer simulations, it is shown that the proposed BF scheme can outperform the existing schemes. Furthermore, the impacts of antenna configurations, CCIs, and power allocation on the outage performance of the MIMO AF relay systems have been demonstrated with simulations. © 2016 IEEE.

Luan T.,Tsinghua National Laboratory for Information Sciences and Technology | Luan T.,Institute of China Electronic System Engineering Company | Gao F.,Tsinghua University | Gao F.,Nanjing Southeast University | And 4 more authors.
IEEE Transactions on Vehicular Technology | Year: 2012

This paper studies the rate maximization problem and designs the beamforming strategy for relay-aided multiuser multiantenna cognitive radio (CR) network that coexists with a primary radio (PR) system via opportunistic spectrum sharing (OSS). The beamforming is characterized by two layers: 1) Cognitive beamforming (CB) is employed by CR base station (BS), CR relay station (RS), and secondary users (SUs) to mitigate the interference to and from the PR. 2) Joint CR-BS and CR-RS beamforming is used to maximize the weighted sum rate of the SUs. Since the optimization turns out to be nonconvex, we apply the classic Blahut-Arimoto algorithm and solve the original problem through an iterative approach. Interestingly, each iterative step involves only convex optimizations whose closed forms can be found. Moreover, we derive an upper bound for the sum rate to assist system analysis. Numerical results show that the proposed approach achieves higher performance, compared with the widely studied diagonally structured beamformer design. © 2012 IEEE.

Ma Y.,Institute of China Electronic System Engineering Corporation | Ma Y.,Wuhan University | Liu Y.,Institute of China Electronic System Engineering Corporation | Zhang H.,PLA University of Science and Technology | Chen G.,Institute of China Electronic System Engineering Corporation
Journal of Convergence Information Technology | Year: 2012

Requirement prioritization of software products is a key factor to their successes. Most of existing methods for prioritizing software requirements put particular emphasis on their value, cost, risk, etc., and only a few of them take the dependencies among requirements into account. In this paper, we proposed a two-step hybrid method in consideration of both dependency structure and requirement value. Based on a new metric that measures mutual influence of nodes in a local region, the first step is importance-based node ranking in a directed use case network, where each node represents a use case and each directed edge indicates a relationship between use cases. For those nodes with the same value of topological potential, the second step is elaborate prioritization based on requirement value by using existing methods such as the Analytic Hierarchy Process. Eventually, a case study of our selfdeveloped commercial software system is shown to demonstrate the validity of our approach, which would be a sound complement to traditional requirement prioritization methods within the community of requirements engineering.

Ma Y.-T.,Wuhan University | Ma Y.-T.,Institute of China Electronic System Engineering Corporation | He K.-Q.,Wuhan University | Li B.,Wuhan University | Liu J.,Wuhan University
Ruan Jian Xue Bao/Journal of Software | Year: 2011

The popularity of the Internet and the boom of the World Wide Web foster innovative changes in software technology that give birth to a new form of software-networked software, which delivers diversified and personalized on-demand services to the public. With the ever-increasing expansion of applications and users, the scale and complexity of networked software are growing beyond the information processing capability of human beings, which brings software engineers a series of challenges to face. In order to come to a scientific understanding of this kind of ultra-large-scale artificial complex systems, a survey research on the infrastructure, application services, and social interactions of networked software is conducted from a three-dimensional perspective of cyberization, servicesation, and socialization. Interestingly enough, most of them have been found to share the same global characteristics of complex networks such as "Small World" and "Scale Free". Next, the impact of the empirical study on software engineering research and practice and its implications for further investigations are systematically set forth. The convergence of software engineering and other disciplines will put forth new ideas and thoughts that will breed a new way of thinking and input new methodologies for the study of networked software. This convergence is also expected to achieve the innovations of theories, methods, and key technologies of software engineering to promote the rapid development of software service industry in China. © ISCAS.

Deng J.-Y.,Xidian University | Deng J.-Y.,Institute of China Electronic System Engineering Corporation | Guo L.-X.,Xidian University
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2015

A double-folded inverted-L antenna with directional radiation for indoor access points applications is presented. The antenna comprises a microstrip fed double-folded inverted-L radiator and a centrally slotted ground. The radiator is a printed inverted-L antenna whose arm is extended and folded. A directional radiation is obtained by mounting the radiator above the ground. A vertical slot is etched at the center of the ground to get a better impedance match over desired frequency band. The simple structure can be easily integrated with the RF circuits on PCB of the access point systems. The antenna is simulated, fabricated and measured. The result indicates a bandwidth with S11 better than -10dB from 2.38 to 3.6GHz and directional patterns, showing the presented antenna is a good candidate for wireless access points for WLAN, LTE and WiMAX at 2.4, 2.6 and 3.5GHz respectively. © 2015 IEEE.

Zhang H.C.,Chongqing Communication College | Wen X.,Institute of China Electronic System Engineering Company | Mo D.H.,Institute of China Electronic System Engineering Company
WIT Transactions on Information and Communication Technologies | Year: 2014

Mainly due to lack of protected physical boundary and limited energy resources, security and lifetime optimization are becoming the two of the vital issues for multi-hop wireless sensor networks. This paper presents a novel secure routing protocol to provide the security through probabilistic random walking and extends the network lifetime by balancing the energy consumption. The routing protocol is designed with two configurable parameters, security level and energy balance control (EBC). The security level provides the source location privacy by determining the probabilistic distribution of the random walking. According to the network energy consumption, EBC is used to enforce the energy balance and extend the lifetime. Theoretical analysis and simulation results show that the proposed routing protocol can provide excellent balance between routing efficiency and energy consumption while preventing routing trace-back attacks. © 2014 WIT Press.

Deng J.-Y.,Xidian University | Deng J.-Y.,Institute of China Electronic System Engineering Corporation | Guo L.-X.,Xidian University
IEEE Antennas and Wireless Propagation Letters | Year: 2015

In this letter, an efficient MoM-PO hybrid Method is proposed to calculate radiation patterns of the antennas around electrically large and complex metallic platforms. The computational intensity can be decreased from N2 to NlogN by using the octree accelerating the shadow patches cutting, where N is the number of patches of platform. In this way, the Method of Moments (MoM)-Physical Optics (PO) hybrid method yields a superior performance for antenna pattern calculation on large and complex platforms. Simulation results obtained from this model are compared to FEKO MOM-PO results, which prove excellent accuracy of computations. The antenna patterns of the antenna on a ship are also calculated, showing the proposed hybrid method can finish antenna pattern predictions fast and accurately on electrically large and complex platform. © 2002-2011 IEEE.

Han Y.,National University of Defense Technology | Chen Q.,Institute of China Electronic System Engineering Corporation | Li Y.,Institute of China Electronic System Engineering Corporation
Proceedings - 2012 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring, CDCIEM 2012 | Year: 2012

Ad hoc network is a kind of centerless, selforganized wireless network, in which all network transmitters are considered to be independent of any management infrastructure and to have the freedom to choose their own transmit power. Power control is one important component of radio resource management in Ad hoc network. In this paper, a new utility function with pricing of interference is presented and a game-theoretic approach to power control in Ad hoc network is proposed. We assume that the utility function only depends on SINR and the price function is proportional to interference. The existence and uniqueness of the Nash equilibrium in the non-cooperative power control game with pricing of interference are proved. As shown in simulation, the proposed distributed algorithm has a much faster convergence rate. © 2012 IEEE.

Deng J.-Y.,Xidian University | Deng J.-Y.,Institute of China Electronic System Engineering Corporation | Guo L.-X.,Xidian University | Liu X.-L.,Xidian University
IEEE Antennas and Wireless Propagation Letters | Year: 2016

In this letter, a compact ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna with a high isolation covering 2.4 GHz WLAN and 3.1-10.6 GHz UWB bands is presented. The proposed antenna is based on meandering monopoles; an ultrawide bandwidth is achieved by involving two inverted L-shape parasitic strips and two smaller L-shape stubs, and a high isolation is obtained by etching a slot at the center of the ground. The prototype is simulated, fabricated, and measured. A good agreement between the measured and simulated results shows that an ultrawide bandwidth and a high isolation are successfully achieved. © 2002-2011 IEEE.

Nan J.,Institution of Communication Engineering | He Y.Z.,Institute of China Electronic System Engineering Corporation
Applied Mechanics and Materials | Year: 2014

Communications satellite payload directly determines the performance of the satellite. In this paper, we focus on these advanced satellite communications systems of representative: WGS, MUOS and AEHF, including function and structure of the payload. Then the development trend of communications satellite payload is analyzed. Some suggestions for the development of China's communications satellite payload are proposed at last. © (2014) Trans Tech Publications, Switzerland.

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