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Chen Z.,Nanjing University of Posts and Telecommunications | Chen Z.,HIGH-TECH | Chen Z.,Nanjing University | Li S.,Nanjing University of Posts and Telecommunications | Yue W.,Key Laboratory of Broadband Wireless Communication and Sensor Network Technology
Sensors (Switzerland) | Year: 2014

Maintaining effective coverage and extending the network lifetime as much as possible has become one of the most critical issues in the coverage of WSNs. In this paper, we propose a multi-objective coverage optimization algorithm for WSNs, namely MOCADMA, which models the coverage control of WSNs as the multi-objective optimization problem. MOCADMA uses a memetic algorithm with a dynamic local search strategy to optimize the coverage of WSNs and achieve the objectives such as high network coverage, effective node utilization and more residual energy. In MOCADMA, the alternative solutions are represented as the chromosomes in matrix form, and the optimal solutions are selected through numerous iterations of the evolution process, including selection, crossover, mutation, local enhancement, and fitness evaluation. The experiment and evaluation results show MOCADMA can have good capabilities in maintaining the sensing coverage, achieve higher network coverage while improving the energy efficiency and effectively prolonging the network lifetime, and have a significant improvement over some existing algorithms. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Wu D.,PLA University of Science and Technology | Cai Y.,PLA University of Science and Technology | Zhou L.,Key Laboratory of Broadband Wireless Communication and Sensor Network Technology | Rodrigues J.,University of Beira Interior
GLOBECOM - IEEE Global Telecommunications Conference | Year: 2012

In this work, with respect to the uncertainty about the individual information, we investigate the relay power allocation problem from the energy-efficient, Pareto optimal, and competitive fairness perspective. At first, we design an easy-implementation energy efficiency metric, which aims at striking a balance between the QoS provisioning and the energy consumption. Then, an auction mechanism is proposed for relay power allocation. By transferring the auction mechanism into a game, we prove the existence, uniqueness, and Pareto optimality of the Nash equilibrium (NE) for our auction game, and show that the allocation strategies from the NE can achieve the energy efficiency in terms of the proposed metric. Next, we develop a distributed relay power allocation algorithm based on our best-response functions to reach the Pareto optimal NE. Importantly, we not only certify the convergence of the proposed algorithm, but also provide quantitative analysis on it. Extensive simulations results are conducted to confirm the validity of the analytical results. © 2012 IEEE.

Chi X.-S.,Nanjing University of Posts and Telecommunications | Chi X.-S.,Key Laboratory of Broadband Wireless Communication and Sensor Network Technology | Zheng B.-Y.,Nanjing University of Posts and Telecommunications | Yao G.,Nanjing University of Posts and Telecommunications | Chen J.-B.,Nanjing University of Posts and Telecommunications
Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology | Year: 2012

This paper proposes a scheme of network coding for asymmetric data transmission in three-point cooperative communication system. Since the joint using both cooperative diversity and network coding, the diversity gain and coding gain are achieved in wireless communications transmission system. In this paper, the differences of wireless communication environment are fully considered. The scheme with asymmetric modulation ensures the reliability of communication in the poor environment. Meanwhile, it transmits more data in better links to make full use of system resource. The main idea to realize network coding of asymmetric data transmission is to add prior known information in the relay. The prior known information can enhance the coding performance of the system. Simulations show that the proposed transmission scheme can achieve the diversity gain and reduce the BER compared to non-cooperative transmission system. In addition, it can improve the transmission capacity of the communication system.

Zhou L.,Key Laboratory of Broadband Wireless Communication and Sensor Network Technology | Wang H.,TCL Research America | Guizani M.,Qatar University
IEEE Transactions on Communications | Year: 2012

In this work, we investigate the impact of mobility on video streaming over multi-hop wireless networks by utilizing a class of scheduling schemes. We show that node spatial mobility has the ability to improve video quality and reduce the transmission delay without the help of advanced video coding techniques. To describe a practical mobile scenario, we consider a random walk mobility model in which each node can randomly and independently choose its mobility direction, and all the nodes can identically and uniformly visit the entire network. The contributions of this work are twofold: 1) It studies the optimal node velocity for the mobile video system. In this case, it is possible to achieve almost constant transmission delay and video quality as the number of nodes increases; 2) It derives an achievable quality-delay tradeoff range for different node velocities. Therefore, it is helpful to shed insights on network design and fundamental guidelines on establishing an efficient mobile video transmission system. © 1972-2012 IEEE.

Lin M.,PLA University of Science and Technology | Lin M.,Nanjing Southeast University | Ouyang J.,Nanjing University of Posts and Telecommunications | Ouyang J.,Key Laboratory of Broadband Wireless Communication and Sensor Network Technology | And 2 more authors.
IEEE Journal on Selected Areas in Communications | Year: 2016

In this paper, we address the issue of joint beamforming (BF) and power control for a device-to-device (D2D) communication underlaying cellular network, where the wireless channels of the D2D link and the base station to user equipment link experience Rician and correlated Rayleigh fading, respectively. Based on the property of the integral network, we first formulate a constrained optimization problem to minimize the total transmit power of the devices in the network, while meeting the qualityof- service requirement of both the D2D and cellular users and suppressing the mutual interference to a certain level. Then, by adopting the available statistical channel state information and proposing an approximation method to relax the constraints, a support-vector-machine-based algorithm is presented to solve the optimization problem for the transmit powers and BF weight vectors of each user. Furthermore, we derive the analytical expressions for the cumulative density function and the generalized moments of the output signal-to-interference-plus-noise ratios, thereby developing some novel theoretical formulas for the ergodic capacity and the average symbol error rate of each user in the network. Finally, computer simulation results are provided to demonstrate the validity and efficiency of the proposed scheme and its performance analysis. © 2015 IEEE.

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