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Under the condition of limited feedback, due to the multiple antennas cognitive two-way relay system due to the relay node have been the channel state information and the actual channel state information is error, caused the user system interference to primary user system increases, at the same time reduces the transmission rate of user system. Aiming at this problem, this paper on the basis of the statistical features of quantization error, put forward an algorithm to overcome the quantization error of beam forming. This algorithm under the condition of limited interference to primary user system, with the minimum mean square error (mse) is a standard, improved the user's transmission rate, the simulation results show that the proposed algorithm compared with other algorithm, effectively suppress the influence of quantization error, improve the transmission rate of user system, reduces the error rate of user system.

Traffic classification is critical to effective network control and management. Recent researches on Internet traffic classifications have developed several methods for identifying types of application, which have advantages in certain types of network traffic. However, these methods are powerless to measure the network traffic with dynamic port, encrypted payloads, mixing traffic, and real-time traffic. In response to the growing requirements of traffic classification for increasingly complex network environment, this paper introduces network traffic classification architecture (NTCA) with high performance. By combining port-based, signature string matching, regular expression matching, and machine learning methods, NTCA achieves high speed and accuracy traffic classification. The experimental results show that our proposed method is able to achieve over 95.0% in average accuracy for all testing traces.

The deterministic energy efficient protocol for adjustable sensing range (ADEEPS) is one of the important protocols for enhancing the lifetime of a wireless sensor network. This protocol however considers the underlying network of homogeneous nature. In this paper, we propose hetADEEPS (heterogeneous ADEEPS) protocol that considers the underlying network of heterogeneous nature. The heterogeneous network model is parameterized that has 3-level heterogeneity. The proposed model can describe 1-level, 2-level and 3-leel heterogeneity and accordingly the hetADEEPS is referred as hetADEEPS-1, hetADEEPS-2 and hetADEEPS-3. The performance of the hetADEEPS is compared with that of the hetALBP. The hetALBP is Load Balancing Protocol with Adjustable sensing range (ALBP) that has the underlying network of heterogeneous nature. As the level of heterogeneity increases, the network lifetime increases. Furthermore, decreasing the value of the model parameter increases the network lifetime.

Deploying roadside access points (APs) or infrastructures can improve data delivery. However, a solution that tries to cover every point in an entire road network with APs (a full coverage) is not very practical due to prohibitive deployment and operational costs. In this paper, we used a new Infrastructure, i.e., WiFi to Mesh (W2M), which used to improve the performance of vehicular internet. Through analyze the heterogeneity of function between AP and W2M, including coverage area, we propose an infrastructures deployment strategy for Vehicular Internet which is supported by a variety of infrastructures. In particular, we used a new metric, called Contact Opportunity, such a metric is closely related to the quality of data service that a mobile user might experience while driving through the system. We then present an efficient deployment method of APs and W2Ms that maximizes the worst case contact opportunity with the minimum cost. The problem of finding an economic deployment of APs and W2Ms that is depends on the quality of service (QoS) turns out to be NP-hard. The efficiency of our strategy is demonstrated via simulations using data from real-world road networks.

As one of the most important applications of wireless sensor network, positioning technology has become a extremely hot research filed. Taking into account of the position of beacon nodess, they make an effect on the positioning accuracy of unknown nodes. Therefore, in this paper, it proposes a new weighted centroid localization algorithm based on the traditional algorithm. For the selection of weight, the distance between beacon nodes and unknown nodes, and the slide length of the triangle are used to formed as the weighted factor. Experiment Simulation results show that this algorithm increased localisition accuracy than that of traditional algorithm.

With the development of smart-phone devices, media stream transmission is bound to make wireless network communication resources that are in short supply cause greater pressure. Due to the user's move in the media stream transmission process in the mobile wireless network, it may be possible to lead to the following questions: the established connection is interrupted; the effect in data transmission structure becomes poor or invalid; wireless connection changes more frequently. All these problems will directly result in the QoS of media stream transmission. Back pressure algorithm is a control method which is firstly proposed by Tassinlas and Ephremides in the control theory. We choose back pressure algorithm as the basic research method of mobile media stream transmission because of the conclusion that back pressure algorithm can make the network load balance and maximize network utilization. According to the above problem, the article proposes the back-pressure algorithm guaranteeing deadline, and the proposed algorithm can well guarantee deadline of packet transmission. It not only can remove the packets which are redundant or staying too long time in the network, but also can make network throughput optimal. And in order to speed up the network's convergence speed and improve user's satisfaction index. We proposed cluster-based back pressure algorithm guaranteeing deadline.

This paper proposes a useful algorithm to count the metrological parameter center in wireless sensor network. By setting assigned threshold in Mean shift iteration, this algorithm lessens the computation load and can control the center points to be extracted. Experiments verify the efficient center finding algorithm and the control factors in center finding. This algorithm can be extended to more wide range for application. Because the mean shift is robust in convergence, the WSNs is utilized in many metrological area, the algorithm can be used widely in these domains. For the stability of image data, we use color space transform to decrease the illumination influence.

Due to the limited energy resources of sensor node, energy conservation has become one of the key in the design of route in wireless sensor networks (WSNs). In this paper, we propose a distance clustering routing algorithm considering energy (DCE), which selects cluster heads and construct multi-hop route according to the distance factor and the energy factor. Simulation results show that DCE can save energy and the saving energy can contribute to prolonging the network lifetime. Compared with LEACH, DCE has a better performance in energy consumption and network lifetime.

The Multiprotocol Label Switching (MPLS) technology is currently the most deployed technology by service providers over backbone networks. The highly useful MPLS application nowadays is the MPLS Virtual Private Network (VPN). Due to the enterprises and organizations demand of allowing the remote sites and users to connect to enterprise network, MPLS VPNs have become more attractive. The service providers are using MPLS VPN technology to provide the end users a secure channel across the public internet, with flexibility and scalability. MPLS VPNs have the functionality to operate over both MPLS networks as well as existing IP networks. Variety of research has been conducted in this area and many researchers have proposed different models and solutions to implement MPLS VPN technology more effectively and efficiently. This paper presents the detail analysis of the existing and future techniques and models which are used to implement, optimize, secure MPLS VPN technology.

Due to a wide range of applications, wireless sensor networks (WSNs) have recently attracted a lot of interest to the researchers. Limited computational capacity and power usage are two major challenges to ensure security in WSNs. Recently, more secure communication or data aggregation techniques have discovered. So, familiarity with the current research in WSN security will benefit researchers greatly. In this paper, security related issues and challenges in WSNs are investigated. We identify the security threats and review proposed security mechanisms for WSNs. Moreover, we provide a brief discussion on the future research direction in WSN security.

Wireless sensor networks (WSN) are good at security monitoring in coal mine. It is able to rapidly detect diverse parameters, which can reduce human and material losses. And it is an important application that has commercial potential. Coal mine pivotal parameters include Dust Density (Dust), Temperature (Temp), Wind Speed (WindS), Gas Density (GasD) and Carbonic Oxide Density (COD). The data collected by the sensors are sent to the sink node to be processed with information fusion technology. This work presents a strategy for the classification of coal mine status based on sensed data by WSN and the use of unsupervised neural network-the Self-Organizing Map (SOM). The SOM application classifies the coal mine environment into four clusters. An experiment confirms the effectiveness of the proposed approach.

The abstract Data delivery in vehicular ad hoc networks (VANETs) has become one of the most challenging problems due to the rapid movement of vehicles and their bounded communication ranges. How to more efficiently transmit the sensing data about the region of interest to AP is discussed in this paper. Previous work hasn’t distinguished node types to forward data packet commonly, the delivery ratio and delivery latency is highly possible to reach intolerable dimensions. This paper utilizes the prominent characteristic of buses, and proposes a data forwarding scheme（MUQ） based mobile roadside unit (MU) with quality of service (QoS) guarantee for VANET applications that support both periodic and event-based data reporting. The aim of this paper is to minimize expected minimum delay (EMD) of the packet under the premise of guaranteeing QoS. The performance measures of MUQ are evaluated using simulation. The simulation results indicate the efficiency and availability of MUQ scheme presented in this paper.

Wireless Sensor Networks (WSNs) enable applications where target state estimation is essential. To deal with the energy source and communication bandwidth constraints, an energy-aware adaptive probabilistic tracking mechanism based on quantization was proposed. According to the relationship between the sensing radius and node properties which include stored information and position, a part of redundant nodes were removed under the condition on accuracy. An energy optimization model was established using the quantitative observations and an adaptive sampling interval strategy to reduce traffic for communication between sensor nodes. After that, a probabilistic sensor selection algorithm based on the sensing model of the node is creatively proposed to further reduce energy. In order to show the ascendant functions of the proposed mechanism, numerical simulation results including two scenarios, the single target and multiple Targets, showed that the algorithm can achieve the required tracking accuracy, effectively reduce energy consumption, and distinctly improve the performance of WSNs.

Rician noise pollutes Magnetic Resonance Imaging (MRI) image and makes later work worse. In allusion to remove noise while lessen the loss of details as low as possible, this paper proposed an filter algorithm which comprehensive utilize Genetic Algorithm (GA), PDE and TV, based on 4th order Partial Differential Equations (PDE) and Total Variation (TV) theory. First, it calculates the Total Variation(TV) and the 4th order PDE of kth image, and gives them weight coefficients. Then, it finds the optimal Standard deviation of image of kth image by adjusting weight coefficients based on GA algorithm. Third, it compares PSNR of kth image and PSNR of k+1th image to find whether the algorithm is over. Experimental results show that our new algorithm presented in this paper is more effective in removing Rician noise and giving better Peak Signal Noise Ratio (PSNR) gains without manual intervention in comparison with other traditional filters.

Transmit diversity generally requires more than one antenna at the transmitter. However, many wireless devices are limited by size or hardware complexity to one antenna. Recently, a new class of methods called cooperative communication has been proposed that enables singleantennamobiles in a multi-user environment to share their antennas and generate a virtual multiple-antenna transmitter that allows them to achieve transmit diversity. This paper gives an overview of cooperative communication which is a technique that acts as virtual MIMO. Inthis paper we analyze cooperative communication in detail. We study the steps to cooperation and differentcombining strategies at the destination.