Earticle

A new CDMA system which uses fractional chip shift expanded generalized complementary orthogonal code groups as spectrum spreading code sequences and offer high spectral efficiency is introduced in the paper. This new CDMA system is totally different with conventional CDMA system in access codes designing and spectrum spreading process. In this CDMA system, the access codes of different cells keep orthogonality, which eliminates inter cells interferences (ACI) by aperiodic cross-correlation function (CCF). The spreading process of new CDMA system introduces inter symbols interference like overlap time division multiplexing (OVTDM) deliberately so as to improve spectral efficiency. The construction of expanded generalized complementary orthogonal code groups, shift method, principle of new CDMA system are explained respectively. Analysis and simulation results verify the validity of this new CDMA system.

This research study has been made on the quality assessment of the multiview video signal transmitted in a correlated MIMO fading channel. In matlab based simulated system, pre- zero forcing channel Equalization/ precoding, two-dimensional nonlinear Median filtering for impulsive noise reduction schemes have been implemented under scenario of adding no additional redundant data for desired video signal protection. It is noteacable from such study that themultiview video signal with quite reasonably acceptable image quality is retrieved.

Cell edge effect has been recently paid much attention in the development of new mobile communication systems because it can cause serious performance degradation in the cell edge. The cell edge problem is essentially due to non-uniform distribution of the radio power of cellular systems. It can be softened to a certain extent by using new radio architecture called distributed antenna system (DAS). In traditional collocated antenna system (CAS), multiple antennas are centrally located at the BSs, while in the DAS, multiple antennas of BS called remote antenna unit (RAUs) are separately and remotely located in a cell and connected to a baseband processing unit (BPU) via high speed backbone links. Since the distance between the mobile terminals (MTs) and the antenna of the BS is greatly reduced by introducing RAUs, the large path loss of the radio signals can be avoided. The objective is to tackle the shortcomings due to the cell edge effects in a cellular system by suitably changing the existing collocated antenna system (CAS) to a distributed antenna system (DAS) and to compare its performance. The performance analysis namely bit error rate (BER) and capacity were performed and the results are shown. It is inferred from the results that the proposed DAS scheme outperforms the existing CAS scheme.

In the data communication, a time-frequency hopping resonance signal will be created, and this network fluctuation hopping signal must be suppressed in order to improve the network stability. An algorithm for network fluctuation hopping signal suppression based on disturbance characteristics decomposition and feed-forward modulation is proposed, and the disturbance characteristics decomposition for a network fluctuation hopping signal is done in a Hilbert space. A feed-forward modulation filter is created to get the feed-forward modulation suppression of the network fluctuation hopping signal. The simulation results indicate that this algorithm has good real-time data transmission, which can effectively suppress the resonance signal in the network fluctuation hopping, low loss of information, and has the obvious function to resolve the startup hysteresis, server load, tremble and other problems in the large-scale hybrid networking.

MRAGA (Multicast Routing Algorithm based on Genetic algorithm) for the Delay-Constrained Minimum-Energy Multicast Routing problem was presented. The genetic operators of this algorithm reduce the transmission delay and energy consumption of multicast trees, thus accelerating the convergence speed of the algorithm. Experiment results show that the multicast tree found by this algorithm not only guarantee the delay constraint, but also has the minimum energy consumption. Furthermore, this algorithm converges quickly.

In wireless sensor networks (WSN) research area, node localization is one of the most important techniques. An improved Centroid localization algorithm is analyzed and an improved Centroid algorithm with selective anchor node localization algorithm (CSA) for WSN will proposed in this paper. The key point of the algorithm is the most discrepant estimation nodes are selected by the nearest reference anchor node around a distance unknown node. The triangle centroid and the polygon centroid are employed to calculate the coordinates of the estimation nodes to improve node locating precision. MATLAB simulation illustrate that the algorithm is valid and feasible.

In wireless sensor networks (WSNs), localization is one of the most important topics because the location information is typically useful for many applications. The primary data used in a localization process include the locations of anchor nodes and the distances between neighboring nodes. However, these data may contain outliers that deviate from their true values. The existence of the outliers might make the estimated positions not accurate. Thus, it is important to detect and handle outliers in order to achieve high localization accuracy. In this paper, we survey the existing outlier detection techniques for localization in wireless sensor networks. We provide taxonomy for classifying outlier detection techniques in WSNs localization based on different features. In addition, we present comparisons of these techniques. Finally, we discuss the future research directions in this area.

Outsourcing a file to a remote cloud storage provides several benefits, including scalability, accessibility, data replication and considerable cost saving. Unfortunately, when we send a file to a remote cloud storage server, we do not know if this file is intact. To address this problem, we present a remote file possession checking protocol. In this protocol, we use three technologies: Firstly, we design a kind of file block tag whose security is based on the discrete logarithm problem (DLP); secondly, we use probability checking method to improve its effectiveness; thirdly, we use tag aggregation method to reduce its communication cost. Our theory analysis and experiment results show that our protocol is practical and secure.

Since multiple VMs share the same network interface card (NIC). The I/O operation of one virtual machine is affected by others. The quality of service (QoS) of the network is hardly guaranteed. This paper presents a queuing based I/O scheduling for big data processing via the cloud, an efficient scheduling strategy with quality of service (QoS) guarantee. Our proposed scheme uses a queuing system to control the I/O bandwidth and provide QoS guarantee for each application. The proposed techniques are implemented on the xen virtual machine monitor (VMM) and evaluated with micro-benchmarks on Linux operation system.

Providing a suitable authenticated key establishment protocol in MANETs is challenging due to all the characteristics of networks, such as communication capability, computation capability and storage resources. This paper presents an efficient and flexible authenticated key agreement protocol without bilinear pairings for MANET. Our proposed protocol not only provides mutual authentication between users and servers but also supports session key agreement. In addition, in our protocol the user does not need to perform the expansive bilinear operations, so it reduces the computation loads.

Mobile wireless sensor networks without infrastructure are constructed including the mobile sink layer and the fixed sensor layer. The mobile sinks can communicate with the other mobile sinks. Every mobile sink receives data from the sensors and fuses to build a message. The message is copied, stored, and carried by mobile sinks and then it is transferred to the access point. In this paper, with multiple copies method of epidemic routing we present a probability forwarding scheme for message copies based on the threshold of nodes encountering each other. The method can decrease the message redundancy effectively, and control the waste of resource, bandwidth and energy arisen by a great deal of copies. At the same time, it guarantees the message transferred successfully. The theory analysis and the simulation experiment show that the delivery efficiency of our method is the same as one of epidemic routing, while the delay and the hop count do not increase and copies are fewer.

This paper proposes a routing protocol for the Wireless Sensor Network (WSN). It is a protocol based on the PEGASIS protocol but using an improved ant colony algorithm and neural network rather than the greedy algorithm to build the chain. Compared with the original PEGASIS, the ACON-PEG can achieve a global optimization. It forms a chain that makes the path more even-distributed and the total square of transmission distance much less. The protocol uses the thought of neural network algorithm to select the chain head, it utilizes ant colony algorithm to find the best path to send data to the BS and the whole area divided into multiple equal parts. It brings about a balance of energy consumption between nodes. Simulation results have shown that the proposed protocol significantly prolongs the network lifetime.

This paper presents Long Reach Orthogonal frequency Division multiplexing Wavelength Division Multiplexing (OFDM-WDM) system capable of delivering downstream 40 Gbit/s data. The optical source for downstream data is CW Laser at central office. We use four OFDM transmitter at central office for the 40-Gb/s downstream transmission .We have used direct detection technique for OFDM and did analysis of OFDM WDM using direct detection technique for without compensation and with compensation. We extend the maximum reach of this WDM PON to be 96 km by using Erbium-doped fiber amplifiers at the RN. Bit error rate was measured and constellation diagram observed to demonstrate the proposed scheme. In this paper Long reach and large data service aspects of a OFDM WDM is presented. The results show that the error-free transmission can be achieved for all WDM channels with sufficient power margins.

To increase LTE (long time evolution) networks spectrum utilization and interference mitigation, a LTE system overlaid with femtocells is studied. This paper will focus a self-optimized power control scheme for LTE-femtocell networks, in which the transmitted power of a femtocell base station is adjusted based on the optimal SINR threshold. It is known that game theory is a useful tool for analyzing outage probabilities and optimal power in wpszireless networks. In this paper, Bayes-Nash equilibrium theory is used to derive a optimal SINR (signal-interference-noise-ratio) threshold from each femtocell. The power control scheme can be applied to realistic LTE-femtocell networks to enable robust communication against cross-tier interference thereby obtaining a substantial link quality.

In this paper, we perform the analysis of cost effective capacity expansion strategies with incremental deployment aspects of the forthcoming mobile heterogeneous networks from beyond 4th and 5th generation. We consider different over time (up to year 2025) increasing traffic volumes in order to determine the most cost-effective capacity expansion that would minimize aggregate incremental cost. In this aspect, we determine that deployments with base stations having smaller ranges offer a lower investment risk on long term, because incremental capacity can be satisfied in smaller stages. This is especially due to the fact that the cost structure of smaller base stations is dominated by operational expenditures as compared to, in the other extreme, a new macro base station site. From this perspective, our techno-economic analysis proposes a model that would be useful to analyze the economic viability of different type of traffic growth volumes and for various forthcoming heterogeneous network configurations.

Software-Defined Networking (SDN) is a new-generation network that decouples the control plane and the data plane, and an additional management plane still lacks a mature implementation solution. In this case, monitoring service level parameters is of great significance to study issues related to service management for SDN. This paper then aims to apply the queuing theory and the extension theory to monitor service level parameters of SDN and propose an integrated approach based on both two theories from the formalization point of view. Simulation result and scenario analysis validate that, the proposed integrated approach prospects a feasible way of formalizing the solution to monitor service level parameters of SDN.

Security problems with network are significant, such as network failures and malicious attacks. Monitoring network traffic and detect anomalies of network traffic is one of the effective manner to ensure network security. In this paper, we propose a hybrid method for network traffic prediction and anomaly detection. Specifically, the original network traffic data is decomposed into high-frequency components and low-frequency components. Then, non-linear model Relevance Vector Machine (RVM) model and ARMA (Auto Regressive Moving Average) model are employed respectively for prediction. After combining the prediction, a self-adaptive threshold method based on Central Limit Theorem (LCT) is introduced for anomaly detection. Moreover, our extensive experiments evaluate the efficiency of proposed method.

Mobile ad-hoc networks (MANETs) are recently attracting a lot of interest due to their widely available wireless devices and low communication cost. MANET comprises a set of wireless communicating devices able to connect instantaneously without any pre-existing base station. Due to a limited transmission range of mobile devices, they need multi-hop routing for communication. In MANET nodes can change topology in an unpredictable manner so they need an efficient routing protocol which can handle the changing topology. However, MANET suffers from many challenges, including decentralization, low memory device, infrastructure less, bandwidth and limited battery reservoir. Different modes of the nodes like active-communication mode and non-active-communication mode consume available energy of a node. This paper presents an energy measurement model which shows the remaining energy level in each mobile node after some activity. The parameters required for designing energy measurement model consist of initialEnergy, txPower, rxPower, and idlePower. This paper also evaluates the performance measure metrics of two routing protocols such as Ad hoc On Demand Distance Vector (AODV) and Destination Sequenced Distance Vector (DSDV). This paper analyzes these routing protocols by simulation tested in network simulator (NS2). The performance will be studied based on Throughput, Packet loss, Routing delay, Cumulative sum of dropped packets, Calculate energy consumption and remaining energy at each node.

As one of the most effective measures to solve the lack of spectrum, identification of radio technology is becoming more and more attention by the people, a large number of scholars and research institutions devoted to energy to study. For identification of multi-channel characteristics of radio network, extend multiple channel interface structure model, node model and using expanded NS2 network simulation tool for the proposed capacity satisfaction and link stability for routing metrics routing protocol based on genetic algorithm and simulation results proved that the proposed algorithm has good performance and usage of the group can pass spontaneously, but slightly on the routing cost.

Vehicular Ad-hoc Networks (VANETs) are rapidly emerging networks that are a particularly challenging subset of Mobile Ad Hoc Networks (MANETs). Open medium is one of the main features of VANET due to which it often suffers from security attacks and changing its topology dynamically, lack of management and central monitoring, and there is no clear defence mechanism. In this paper, we investigated the impact of Black Hole attack, Worm-Hole attack and Sybil attack on network performance towards VANET environment. We have also analysed which routing protocol is more vulnerable to the different attacks mentioned earlier in VANET. We have also determined that AODV is the most vulnerable routing protocol to attacks in VANET compared to OLSR routing protocol.

In time division duplex Long Term Evolution (TD-LTE) system, the protocol provides 7 different time slot configurations. Only one fixed time slot deployed in mobile network. This paper proposed a dynamic time slot allocation algorithm, the system according to the user equipment (UE) detected the environmental signal to interference and noise ratio (SINR) to dynamically decide the time slot configuration, especially the UE in the situation of relatively bad wireless environment and the lower SINR value, can adopt the polling algorithm, obtained the dynamic time slot configuration. This method is simple in calculation, can reduce redundant computational burden in the system. The result of simulation demonstrated that the algorithm has significant effect in improving the networking throughput、 increasing the system spectrum utilization rate.

An ideal routing strategy shall be able to help the delay tolerant network (DTN) achieve an optimal transmission performance under the premise of lower energy consumption. However, due to the diverse of the application scenarios, it is hard to use one or more types of routing strategies as a universal optimum solution. There is a need to establish a routing strategy model of the corresponding DTN network for different application scenarios, analyze and evaluate the strategy model in combination of the knowledge of the operational research and statistics. For a complex data transmission DTN network scenario, with the introducing of a line programming method, the big-data and multi-node network transmission problem can be abstracted to a large-scale line programming problem. In this paper, the feasibility of solving the large-scale line programming problem by the column generation algorithm has been analyzed, and a column generation algorithm-based DTN routing strategy under the complex data transmission scenario has been designed. This routing strategy can realize the quantization of the routing strategy performance by the column generation algorithm. Also, by the simulation experiments, the performance of complex data transmission DTN routing strategy under different factors has been analyzed, and the performance of the column generation algorithm-based DTN routing strategy has been compared with the performance of the traditional jet waiting routing strategy

A rising horizon in on-chip interconnection is the design of high-radix routers as the ever increasing pin bandwidth. Compared to mesh, DMesh introduces many crossing physical channels, and effectively lower down the diameter and average distance, which directly influence performance of the overall chip. However, the original algorithm DXY could not efficiently make use of physical channels, as it always prefers to use the crossing links. In this paper, we present a novel deadlock-free and livelock-free routing algorithm based on DMesh network in order to make better use of different channels. Moreover, the new scheme can be used to both wormhole and virtual-cut-through switched networks. Extensive simulation results validate the effectiveness of novel proposed routing scheme as compared to the original DXY routing, originally proposed for DMesh networks.

In order to achieve the balance between implementation complexity and system performance, a new hybrid combining technique named SEC-SC is proposed in this paper, which is composed of switch-and-examine combining (SEC) and selection combining(SC).The average symbol error probability (ASEP) and outage probability (OP) of the SEC-SC system over N-Nakagami fading channels is investigated. The exact ASEP expressions are derived for several modulation schemes, including phase shift keying (PSK), quadrature amplitude modulation (QAM), and pulse amplitude modulation (PAM). The exact closed-form OP expressions are also presented. Then the ASEP and OP performance under different conditions is evaluated through numerical simulations to verify the analysis. The simulation results showed that the performance of the SEC-SC system is improved with the diversity branches and the fading coefficient increased, but the level of improvement is declined as the number of cascaded components increased.