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The ever-increasing transmission requirements of quality of service (QoS)-sensitive applications, especially real-time multimedia applications, can hardly be met by the single path routing protocols. Multipath transmission mechanism is a feasible approach to provide QoS for various applications. On the basis of the general framework of multipath transport system based on application-level relay, we present a relay path allocation scheme, whose goal is to select suitable relay paths, while balancing the overlay traffic among the different domains and relayers. With the application-layer traffic optimization service under the standardization within the Internet Engineering Task Force (IETF), the controller has the topology-aware ability to allocate relay paths with excellent routing performance. To further develop the universality of our method, the controller perceives transmission performance of relay overlay network through relayers' performance detection processes and, thus, has the application-aware ability to allocate relay paths with excellent transmission performance for different applications by consulting application-specific transmission metrics. Simulation results demonstrate that the proposed relay path allocation algorithm performs well in allocating superior relay paths and can balance the distribution of overlay traffic across domains in different network situations. [ABSTRACT FROM AUTHOR]

It is a fact that energy consumption is a key issue in wireless sensor networks. In order to improve the energy efficiency of network utilization, distributed power control methods are advocated. However, the sensors are deployed randomly, which results in the channel gains that are difficult to be obtained; thus, how to estimate channel gains accurately to increase node communication efficiency and reduce energy consumption is the motivation of our work. In this paper, a cooperative and distributed algorithm based on diffusion least mean square (LMS) is firstly proposed to estimate channel gain by utilizing the equality and collaboration of sensor nodes. Its objective is to enhance the accuracy and convergence of the estimation process. Because the presented globe-based scheme is unrealistic for practical utilization, two distributed estimation algorithms are investigated for different network scenarios, namely, exchange diffusion combine LMS and exchange combine diffusion LMS. Simulation results demonstrate the effectiveness of our methods. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we propose a Load-Balancing and Coding-Aware Multicast (LCM) protocol for mobile ad hoc networks. In LCM protocol, a new route metric named Expected Transmission Time with Coding and Load Balancing (ETTCL) is presented at first, aiming at effectively selecting the path not only that has the possible coding opportunity but also where overflow due to network overload can be prevented. Then, we describe the route discovery phase by constructing the node-disjoint multicast tree on the basis of ETTCL and employ network coding to encode the data flows for route maintenance. The effectiveness of LCM protocol is simulated and analyzed by NS-2, which shows that this protocol has good performance in reducing average end-to-end delay and control overhead and can improve packet delivery ratio compared with the existing protocol. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we focus on physical-layer network coding (PNC) used in multiple-input multiple-output (MIMO) Y channels, where K users simultaneously exchange messages with each other via a shared relay. For MIMO-PNC, signal space alignment for network coding (SSA-NC) is a promising precoding method and can achieve K( K-1) degrees of freedom if certain conditions can be satisfied. An important one is that the number of relay antennas is less than twice of the user antennas, that is, the dimensionality constraint of SSA-NC. In this paper, we focus on a particular scenario where the dimensionality constraint is not satisfied. In order to resolve this problem, we develop a scheme of jointly selecting relay antennas and precoding vectors. In particular, a novel precoding and detection method is presented to alleviate the interference caused by simultaneous transmissions. Through analyzing the symbol error rate performance of MIMO-PNC, we establish the relationship between the achievable flow diversity gain and the optimal number of the antennas, and a precoding selection method is designed under a given relay antenna configuration. Finally, we propose a joint scheme to select the optimal relay antenna configuration and precoding vectors. Numerical results demonstrate that the presented scheme can effectively support MIMO-PNC in various scenarios. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

With the rapid development of Internet, the world has come into a new era of network interaction. Internet development in China makes various kinds of software available to users, by which relatives, close friends, and partners can achieve real-time interactions. It is acknowledged that the recommended issues and persons are the most important parts for user experience. This study concentrates on how to provide a recommendation for users with a common interest in Microblog. We first illustrate some recommended algorithms based on data mining, and the implementation process of friend-recommended system is then stated. After that, by integrating the characteristics of the user information, the forwarding and comments on information to associated users, we present an improved Apriori-based algorithm to rank the recommended information with confidence interval. Simulation results demonstrate the superiority and efficiency of our method. [ABSTRACT FROM AUTHOR]