Earticle

In orthogonal frequency division multiplexing Access (OFDMA) systems resource allocation to the subcarrier is essential owing to the insufficient resources available at the base station. In OFDMA, subcarrier and power allocation are not separate; thereby this two allocation are not self-governing. This paper proposes the subcarrier allocation approach through investigating previous methods, and also the Enhanced Particle Swarm Optimization (PSO) algorithm is analyzed. The both of the algorithms cross functionality is analyzed and compared the performance of the subcarrier allocation of OFDMA systems in Heterogeneous Network (HetNet). The simulation results show that the PSO approach efficiently allocates the OFDMA subcarriers.

In order to improve serious signal interference and energy consumption of wire mesh backbone network due to omni-directional antenna communication mechanism, a topology control optimization algorithm in wireless mesh backbone networks based on directional antenna is proposed. At first, this algorithm used Delaunay graph model to quickly find gateway node by position information of network nodes. Then, in view of the relationship between network transmission distance and the node degrees, it optimizes the network topology structure and lines. In order to improve the transmission rate of wireless mesh network and solve new interference and energy loss problem after adjusting Delaunay graph to achieve a gateway deployment of wireless mesh network using directional antenna, the algorithm reduces wireless links that the transmission distance is too long and energy consumption is higher, and defines the upper limit of the number of directional antenna on routing nodes. The simulation results show that this algorithm can minimize the number of gateway and the shorten network transmission distance from route node to gateway node. This algorithm can effectively decrease the deployment cost and interference by using less antennas and promote the network performance at the same time.

In order to study impacts of awareness on the propagation of a Bluetooth worm in smartphone networks, a novel propagation model is proposed. In this model, the smartphone network is regarded as a two-layer network composed of a social network layer in which the awareness diffuses and a physical network layer in which the Bluetooth worm propagates. It is shown by theoretical analysis and simulations that: (1) awareness cannot change the propagation threshold, but can mitigate Bluetooth worm in terms of decreasing the propagation speed and the final infection size; (2) the structure of the social network layer has a profound impact on such mitigation effects. That is, for smaller effective infection rate  , BA structure is always more effective than WS structure; while for larger  , there exists a critical value of social reinforcement of awareness c b , beyond which BA structure is more effective than WS structure, or else the reverse is true. In addition, the critical value c b is larger with  increasing.

The energy-efficiency is the primary design issue, which greatly affects the lifetime of Wireless Sensor Network (WSNs). The hierarchical-based routing is a feasible solution for reducing the energy consumption in WSNs due to reduction of the redundant data transmission. In the hierarchical routing, the network is partitioned into clusters, where each cluster consists of a head node and many member nodes. Selection of the best head nodes, that improve the lifetime and the performance of WSNs, is a NP-hard problem. Thus, this paper proposes an Immune-based Energy-Efficient hierarchical Routing Protocol (IEERP) to improve the lifetime of WSNs. IEERP utilizes the Multi-Objective Immune Algorithm (MOIA) to partition the network into optimum clusters and find locations of the best cluster heads on the basis of balancing the consumption energy among the sensor nodes and minimizing the dissipated energy in communication and overhead control packets. The operation of the proposed IEERP protocol is divided into rounds, where each round consists of two phases. The first phase is the cluster building phase, in which sink uses the MOIA algorithm to find locations of the optimum cluster heads, followed by the data transmission phase, in which the sensor nodes transfer their sensed data to the sink via the determined cluster heads. Simulation results cleared that the IEERP is more reliable protocol because it improvers the stability period and the lifetime of the homogeneous and the heterogeneous WSNs as compared to the other protocols.

With the rapid development of Internet technology, more flexible applications appeared and had a higher demand on dynamic allocation of network resources. However, allocating network resources dynamically is difficult to achieve in current TCP/IP networks due to the lack of programming interface of network devices for unified and effective control and management. In recent years, a new network architecture -- software-defined networks (SDN) emerged and it provides services providers or network managers an opportunity to realize the goals. In this paper, a user-reservation-based end-to-end dynamic bandwidth allocation procedure in SDN with OpenFlow protocol is proposed. Users can reserve bandwidth and controller can allocation bandwidth dynamically to satisfy users’ demand. Experiments are designed to verify the effectiveness of the allocation procedure. Results of the experiment show that the allocation procedure works well.

In this paper, we develop an analytical method in order to derive approximated average symbol error expressions as tractable and closed forms in amplify-and-forward with relay receiving diversity (AFwRRD) and amplify-and-forward with relay transmission diversity (AFwRTD) systems. In AFwRRD system, each relay receives two signals from the source node and the previous relay node and transmits to the next relay or the destination node. In AFwRTD scheme, it is assumed that each relay can receive a signal from the source node or the previous relay node and transmit to the next relay and the destination node. In the proposed analytical method, we modify a dual-hop relay scheme as a single branch channel over Rayleigh fading channels. Furthermore, it is confirmed that the derived performance expressions can be applied to both AFwRRD and AFwRTD schemes. Through a numerical simulation, the analyzed performance well concurs the simulation results and it is confirmed that the performance is well analyzed in terms of the diversity order and the signal to noise ratio (SNR) gain for the different number of relays.

With the continued requirement of internet of things (IoT) development, many researchers focused on developing access and routing algorithms optimization of wireless sensor networks (WSNs) for communications quality guarantee, but less research has focused on the optimization of WSNs based on the mobile cellular networks (MCNs) assist. In this paper, we propose a convergence architecture of WSN and MCN for IoT applications, especially on the smart user equipment (UE) acting as a mobile gateway for WSN data transmission. And then, we investigate system application requirement for IoT. Finally, we discuss the key technical challenges and research points based on an analysis of smart gateway.

This paper studies the problem of optimal multicast routing with multiple Quality-of- Service (QoS) constrains (OMRMC), which is regarded as a critical component in networks. However, it is not very efficient and effective for the existing algorithms. An undirected and connected graph G with m edges and n nodes is modeled to find a multicast routing tree from source to destination subset D in this paper, and a novel approximation algorithm called APP-OMRMC is proposed for OMRMC. The theoretical validations for the proposed method are presented to show its efficiency. After that, the different networks with different types of service are evaluated. Experimental results show that the proposed method APP-OMRMC is capable of finding the optimal (or minimum-cost) multicast routing tree with the approximation factor (1+ε) and time complexity of O(mτK-1).

The routing protocol allows routing data from source to destination through intermediate nodes up to the sink. In the hierarchical routing based on the clustering, every cluster head node forms its cluster with their neighbor nodes. The cluster heads are responsible of their clusters. In fact, they coordinate between nodes in the cluster for intra-cluster communication and route data to the other clusters for inter-cluster communication. In this article we propose a centralized and periodic protocol named Efficient Clustering Routing Protocol (ECRP). Our protocol is based on a modified version of CLARANS algorithm; it takes into account the location and the remaining energy of the sensor nodes to divide the sensed area to disjoint and balanced clusters. The simulation results show that the proposed protocol is more efficient than the existing hierarchical protocols in terms of packet delivery ratio, and energy consumption.

In this paper, we research on the modern Internet of things system structure optimization methodology based on the information theory and the communication signal transmission model. We analyze the current IOT system from the following aspects. (1) Reliable delivery, that is, through some of the Internet and telecommunication network integration, it will send some information about the object accurately in real time; For the Internet of things, it is an integrated which is by a variety of network and the access and application technology of an integrated, at the same time it is also a can make the objects and people, nature and people as well as a platform for communication between objects and the objects. (2) The comprehensive perception which is to use some of the perception, capture and real-time measurement technology to information acquisition and access to an object with the sensing device can achieve data readout and data sent and no contact some automated to realize long-distance induction. (3) Intelligent processing, is one of the core content of the Internet of things, is to use some intelligent computing some analysis was carried out on large amount of information and data disposal, the Internet of things is able to intelligently control object by the computer network technology, micro processing technology, wireless communication technology and sensor technology product of development of fusion, therefore the Internet of things can be representative even instead of rational analysis. Through combining the information theory and the efficient signal transmission models, we optimize the current IOT architecture and the final experiment result indicates the feasibility of the proposed methodology.

In wireless sensor networks, the main work of nodes is for data collection and transmission. CTP (Collected Tree Protocol) had been widely applied, and proved to be reliable, robust, efficient data collection protocol. Its independent with hardware and the data delivery rate is relatively high, but CTP also has some shortcomings: the protocol only relied on the ETX value of next hop node selection, there need other factors to consider. In the original CTP protocol, the energy consumption of a node with a better ETX value was too fast. It would cause the whole network time decreased quickly. Then, the node with better ETX value may have low package rate, and would affect the delivery rate of the whole networks. This paper was aimed at this two aspects of CTP, based on the original CTP, the probability of selection mechanism was introduced, proposed ACTP, lead the node load equilibrium and improved the delivery rate. Through the experimental data of TelosB nodes in real analysis, we had improved the whole network time and increased the number of successful packets delivery.

LTE-A networks provide excellent wireless connectivity for MTC (Machine Type Communication). In order to connect a large number of MTC devices into one network, many signaling messages should be transmitted. The signaling channel is overloaded for the messages and accesses of MTC devices are failed. 3GPP specifies access class barring scheme to resolve the overload problem but leaves a specific algorithm to configure a parameter as an implementation issue. In this paper, we present an algorithm to dynamically configure a parameter based on the number of colliding devices in access class barring scheme. Through simulations, it is shown that our algorithm improves the performance compared to the original access class barring in terms of access success, access failure, collision, and access delay.

In this paper, we propose a robust blind multiuser detector for code-division multiple access (CDMA) systems against signature waveform mismatch (SWM) derived from the influences of time asynchronization or channel distortion. This blind detection method with SWM problem is formulated as blind source separation (BSS) model subject to the second-order cone (SOC) constraint. The resulting blind separation based on SOC programming problem is solved by approximate negentropy maximization using quasi-Newton iterative methods. Theoretical analysis and simulation results show that the performance of the proposed blind detector is superior to those of the existing methods.

During the past time information on internet increasing enormously which greed the attacker and invite them for attack. In order to provide protection from illegal access the concept of Intrusion Detection System (IDS) is introduced. Intrusion detection system recognized as a powerful tool for identifying malicious attacks over the network. IDS works on the concept of string matching with the help of Detection engine. Detection engine of IDS uses String matching algorithm for comparing against malicious activities. This comparison takes enough processing time nearly 70% of the whole IDS processing time by improving performance of searching algorithm. In this paper, we proposed an enhanced version of Hash-Boyer-Moore-Horspool string matching algorithm by adding a single digit hash function for reduced the number of character comparisons and improve the efficiency of IDS by reducing the number of false positive match.

The majority of recent embedded systems are based on MPSoCs (Multi-Processors System on Chip) architectures. The topologies and the interconnections inside multi processors almost adopt NoCs (Networks on Chip) whose topology and task scheduling algorithm have a direct impact on its performances. In this paper, by using static data flow, a task scheduling algorithm which would automatically assign the application tasks onto different processors is proposed based on complex network. The goal of our algorithm is to replace the static data flow subnetwork by a single dynamic data flow actor such that the global performance in terms of latency and throughput is optimized. Through complex network, it greatly enhances the power of our algorithm in terms of avoiding deadlock, saving energy and providing for integration with more general models of computation. Experimental results show up to 60% performance improvement for real-world examples.

With the continuous development of information technology and the growing popularity of the Internet, the E-commerce system based on the traditional distributed technology has exposed more and more problems and the development of dynamic E-commerce system has become the target of the next generation of E-commerce. Middleware technology is the trend of the development of software, which is famed and the software developing fastest. So the middleware technology is used to develop the E-commerce system in order to propose a new generation dynamic E-commerce system. Several key techniques J2EE architecture and MVC design pattern are introduced. Then a service-oriented architecture(SOA) and a service-oriented dynamic E-commerce system based on middleware technology and web services are researched and designed. Web services can provide exchange of information and system integration for dynamic E-commerce, support more complex types of web interaction and collaboration. J2EE technology and MVC design pattern can simplify the software development, improve the software performance and quickly construct the dynamic E-commerce system with the good expansibility, maintainability, dependability and high usability.

Orthogonal frequency division multiplexing (OFDM) can accomplish high use effectiveness. Various system impairments affect the performance of system. So mechanisms should be adopted to improve the performance of the system. In this paper, a 40 Gbps optical OFDM system is designed. Comparative analysis of the designed system is done using different fiber standards and dispersion compensating mechanisms on the basis of transmission distance and SNR. From the present research, it is clear that pre dispersion compensating mechanisms perform better than post ones. The fiber standards considered in present research are SMF, ALCATEL, ITU G.652, ITU G.654, and ITU G.655. Of all the fibers, ALCATEL (D=8 ps/nm/km) is able to cover maximum distance i.e. 660km with SNR 30.08 dB. For rest of fibers, the performance was remarkable for few hundreds of kilometres and then degraded. ITU G.655 (D=3.78ps/nm/km) gives the best SNR i.e. 32.08 dB upto 418km then degrades due to less DCF fiber length to compensate for dispersion.

In order to implement big data access and process with high efficiency, an algorithm of nodes location was proposed according to the state of computable resources. In this paper, we first describe and map the computational resource with javascript object notation(JSON) in P2P network system. Regarding the computational nodes as spatial points, then we present a generalized euclid distance(GED) model using the method of spatial points clustering. Through this model, the computational nodes can partition into multiple sub-group upon the characteristic attributes. After that, we calculate the spatial distance and attribute distance by spatial geometric model of global network positioning(GNP), ultimately implement the computable nodes location with efficiency, to provide the basis of load balance, especially in cloud computing. Experimental results show that our method not only can significantly improve system performance, also in accuracy of nodes location.

It is widely accepted that SC-FDE (Single-Carrier Frequency Domain Equalization) is an excellent candidate for broadband wireless systems. Channel estimation is one of the key challenges in SC-FDE, since accurate channel estimation can significantly improve the equalization at the receiver and consequently enhance the communication performances. In this paper, we proposed a simple sparse channel estimation method for SC-FDE system based on noise space, through sorting the results of the Least-squares (LS) channel estimation, channel tap locations and value are evaluated. The proposed system can realize channel estimation at a very low complexity, and simulation result shows that it can achieve significantly improved performance in frequency selective fading sparse channel.

Web and its applications have turned into an essential piece of today's human way of life. Because of the colossal interest and need, analysts went past associating only PCs into the web. These inquires about prompted the introduction of an astounding thingamabob, Internet of Things (IoT). Correspondence over the web has developed from client - client cooperation to gadget – gadget collaborations nowadays. The fundamental target of this paper is to give a review of Internet of Things, structures, key innovations and their utilizations in our day by day life. In any case, this composition will give great appreciation for the new scientists, who need to do look into in this field of Internet of Things and encourage learning collection in effectively.

The process of random deployments, Coverage holes’ phenomena were appeared in wireless sensor network system. This paper presents a probabilistic model by means of event-driven policy coverage holes’ compensation method (Coverage Holes Compensation Algorithms Based on Event-Driven Strategy, CHCAEDS). Firstly, the characteristics of random deployment verified, given the random deployment of representation, followed by the use of probabilistic knowledge within the surveillance area coverage desired and the number of nodes is solved using the minimum number of nodes in order to achieve maximum coverage area; and finally, simulation experiment show, CHCAEDS algorithm with other algorithms in the network life cycle and the algorithm running time increased by 12.59% and10.82%.

With the rapid development of cellular networks, wireless communication industry has brought huge energy consumption and becomes the major consumer of environmental degradation inevitably. Thus, it is undoubtedly that realizing the sustainable development of green wireless communication has become the primary goal of global information and communications technology industry. Particularly, in cellular networks, sleep mode applied to base station (BS) is an efficient way. According to the cell traffic intensity, BS switching off/on strategy can reduce power consumption of BS effectively with a pre-condition that the quality of service (QoS) of users must be ensured. In the heterogeneous cellular networks, we proposed a BS sleeping scheme based on the traffic load varying in each cell, which is able to optimize both energy efficiency and power consumption by a multi-objective optimization problem. Then a sub-optimal solution is obtained according to a heuristic algorithm. The simulation results verified that the proposed scheme can improve the network performance.

The future of mobile communications is expected to be very diverse from the way it works today. Researches in 5G wireless networks are actively developing and improving nowadays technologies. To assist the enormous mobile data, a huge amount of very small cells are expected to be deployed everywhere, including buildings and indoors, providing progress in the heterogeneous networks, which is considered as the main method towards 5G. Also, the 5G air interface and spectrum should be linked together with LTE and Wi-Fi to provide universal high-rate coverage. There are three technologies, mobile computing, wireless networks, and cloud computing that are converging into a field of Mobile Cloud Computing. With such massive heterogeneous networks, providers will face many difficult challenges in terms of procedure and administration, tiny cell deployment in economical manner, and intercell interference mitigation. Hence, cloud-based platform solution is great challenge for heterogeneous mobile and wireless networks in 5G.

In forest fire monitoring, in order to achieve the goal of reducing a large number of invalid and redundant data in wireless sensor network, improving the convergence rate of the wireless sensor network, prolonging the life cycle of nodes, improving the accuracy of fire report, this paper proposed an improved data integration method based on BP neural network. Data generated by various sensors can be integrated on the nodes with this method, the convergence speed of BP neural network can be improved by reference of real-time processing capacity of the node, and thus the energy consumption was reduced to a great extent. The experimental results showed that the proposed method can be well applied in fire monitoring sensor network, the monitoring accuracy was improved and the energy consumption of nodes was reduced, the capacity of wireless sensor network for forest fire monitoring was increased significantly.

Localization as a key problem of wireless sensor network technology, has been the subject of widespread attention. This paper presents an improved positioning algorithm of wireless sensor network based on differential evolution(DE). Firstly, the algorithm improves on each jump distance measurement method in the traditional DV-hop algorithm, thereby reducing distance estimation error between anchor nodes and the unknown nodes, and then through the DE algorithm to obtain better positioning accuracy. Simulation results show that improved positioning algorithm has improved significantly in positioning accuracy compared to the previous DE positioning algorithm and least-squares algorithm, under different error factor and the density of anchor nodes. The algorithm has features of good robustness, global search capability and the ability to inhibit the accumulation of errors, suitable for a variety of applications in wireless sensor networks localization.

The co-primary basis operation between long term evolution-advanced (LTE-A) and current digital television (TV) receiver systems is a significant issue when working in co-channel or adjacent channel in the 800 MHz. This policy aims to efficient use of frequency spectrum, but leads to an intersystem interference phenomenon, which may disturb the Interoperability between LTE-A and digital TV receiver. In this paper, we propose an effective, simple and graphical approach based on the operating band unwanted emission technique to evaluate all possible intersystem interference scenarios. A variety of practical and substantial spectrum sharing elements that can seriously influence the coexistence situation of LTE-A and TV receiver have been studied. The findings show that co-channel sharing scenario will have much more coexistence difficulty for macro (urban/suburban/rural) areas without employing some interference mitigation techniques. However, in order to make the two systems interoperate in adjacent channel situation, the minimum frequency shift should be at least half of the interferer system bandwidth without mitigation technique. Additionally, the wider channel bandwidth of LTE-A system is preferable more than narrower bandwidth for peaceful compatibility, which helps to support high data rate for LTE-A system.

Wireless Mesh network, a typical wireless ad hoc network, can effectively solve the “last one thousand meters” problem of broadband access. It, with features of self-forming, self-healing and high bandwidth, provides its users with better service by integrating the advantages of WLAN and ad hoc network and fully utilizing and combining with WiMAX, WiFi and other wireless technologies. In network planning, the effective configuration of access point is of great importance for network set-up cost control. A good topological structure, in addition, plays a decisive role in network throughput capacity. The research stated in the thesis studied the configuration of wireless Mesh network access point and internet topology control, simulating a pure Mesh network connecting to external networks. By studying the relationships between such parameters as gateway connection and broadcast interval with transfer rate of packets, end to end delay and system overhead, their relationships were able to be confirmed and the correctness of the analysis results was tested by the comparative studies of the simulation results.

A developable surface is a surface that can be flattened onto a plane without distortion, neither in angle nor in area. In mathematics, it is a collection of points with zero Gaussian curvature. The developable surfaces are of vital importance in modern industry modeling, whereas current business modeling software could only transfer a 3D model into an approximation of a developable surface. In this way, a methodology that could directly generate developable surfaces with no intermediate transformation is in need. This paper illustrated a modeling method based on dynamic programming, and further proposed a method for variational developable surface design. Finally, algorithm in this paper would be verified as valid and practicable by some design cases.

Three-dimensional (3D) face models can handle large pose face recognition problem. In this paper, we propose survey on pose-invariant face recognition method. By scrutinizing study depth, here we only analysis on pose invariant technique in face recognition method is able to handle self-occlusion and deformation, both of which are challenging problems in two-dimensional (2D) face recognition. Texture images of the face in the database can be the same view as the probe during surveillance. In this survey of face detection technology has been presented in this work feature based approach with low level analysis has been done. Information, color, shape, model etc. has been considered for investigation. The technique considered here also explained in other papers. Depth information has improved the performance of face recognition with large pose variations up to the mark able angle and under even more challenging conditions.