Showing papers in "International Journal of Computer Networks & Communications in 2012"

Energy Detection Technique for Spectrum Sensing in Cognitive Radio: A Survey

Abstract: Spectrum sensing is the basic and essential mechanisms of Cognitive Radio (CR) to find the unused spectrum. This paper presents an overview of CR architecture, discusses the characteristics and benefits of a CR. Energy detectionbased spectrum sensing has beenproposed and used widely because it doesn’t require transmitted signal properties, channel information, or even the type of modulation. In this paper, a surveyof energy detector over Additive White Gaussian Noise (AWGN), different fading channels for spectrum sensing methodologies in cognitive radio is presented.Theoretical analysis of time domain energy detection and threshold setting is investigated. Cooperative spectrum sensing and a multiple antenna processing based energy detector receptions are also discussed.

Intelligent Home Monitoring Using RSSI in Wireless Sensor Networks

Abstract: Automated systems have become deeply involved in our daily life these days. Every day new researches and solutions are introduced in the worldwide to utilize computer systems to satisfy human needs. In this project we propose a “Intelligent Home Security Monitoring System” (IHMS) using RSSI in Wireless Sensor Networks. This paper presents a system using Wireless sensor networks (WSNs) enabled smart home environments to create pervasive and ubiquitous applications, which give scalable services and context-aware to the end users. This system develops an application and reports its implementation on real WSN to provide remote home security. There is a plan to use variations in received signal strength indicator (RSSI) value to find intrusion activity at home. Architecture of an application has been presented consisting of Moteivs Tmote Sky motes and a base station. The application sends a piece of alarm as a short message (SMS) on cellular phone of the homeowner in case of any intrusion activity has been detected at home.

Performance Analysis of the Routing Protocols for Video Streaming Over Mobile Ad Hoc Networks

Abstract: Mobile Ad hoc Networks (MANETs) are very considered attractive for many applications. Routing protocol is considered as the most important element of MANET. However, media streaming over MANET is a quite demanding task. In this paper the performances of MANET routing protocols have been investigated for video applications. Some popular routing protocols namely Dynamic Source Routing (DSR), Ad hoc On-demand Distance Vector (AODV), Temporally-Ordered Routing Algorithm (TORA), Optimized Link State Routing Protocol (OLSR), and Geographic Routing Protocol (GRP) have been considered in this paper. A comparative performance analysis of these routing protocols has been presented in this paper for supporting video streaming applications.

Reducing Total Power Consumption Method in Cloud Computing Environments

Abstract: The widespread use of cloud computing services is expected to increase the power consumed by ICT equipment in cloud computing environments rapidly. This paper first identifies the need of the collaboration among servers, the communication network and the power network, in order to reduce the total power consumption by the entire ICT equipment in cloud computing environments. Fivefundamental policies for the collaboration are proposedand the algorithm to realize each collaboration policy is outlined.Next, this paper proposes possible signaling sequences to exchangeinformation on power consumption between network and servers, in order to realize the proposed collaboration policy. Then, in order to reduce the power consumption by the network, this paper proposes amethod of estimating the volume of power consumption by all network devices simply and assigning it to an individual user.

BitTorrent Network Traffic Forecasting With ARMA

Abstract: In recent years, there are some major changes in the way content is being distributed over the network. The content distribution techniques have recently started to embrace peer-to-peer (P2P) systems as an alternative to the traditional client-server architecture. P2P systemsthat are based on the BitTorrent protocol uses end-users’ resources to provide a cost effective distribution of bandwidth intensive content to thousands of users. The BitTorrent protocol system offers a scalable mechanism for distributing a large volume of data to a set of peers over the Internet. With the growing demand for file sharing and content distribution, BitTorrent has become one of the most popular Internet applications and contributes to a signification fraction of the Internet traffic. With the wide usage of the BitTorrent protocol system, it has basically solved one of the major problems where data can be quickly transferred to a group of interested parties. The strength of the BitTorrent protocol lies in efficient bandwidth utilization for the downloading and uploading processes. However, the usage of BitTorrent protocol also causes latency for other applications in terms of network bandwidth which in turn has caused concerns for the Internet Service Providers, who strives for quality of service for all their customers. In this paper, we study the network traffic patterns of theBitTorrent network traffic and investigate its behavior by usingthe time series ARMA model. Our experimental results show that BitTorrent network traffic can be modeled and forecasted by using ARMA models. We compared and evaluated the forecasted network traffic with the real traffic patterns. This modeling can be utilized by the Internet Service Providers to manage their network bandwidth and also detect any abnormality in their network.

OFDM Systems Resource Allocation using Multi- Objective Particle Swarm Optimization

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) has the inherent properties of being robust to interference and frequency selective fading and is de facto the adopted multiplexing techniques for the 4 th generation wireless network systems. In wireless system, resources such as bandwidth and power are limited, intelligent allocation of these resources to users are crucial for delivering the best possible quality of services. In this paper the problem of resource allocation in multiuser OFDM system is tackled using multi objective particle swarm optimization. Simulation results are presented for 3GPP-LTE system.

AODVSEC: A Novel Approach to Secure Ad Hoc on-Demand Distance Vector (AODV) Routing Protocol from Insider Attacks in MANETs

Abstract: Mobile Ad hoc Network (MANET) is a collection of mobile nodes that can communicate with each other using multihop wireless links without requiring any fixed based-station infrastructure and centralized management. Each node in the network acts as both a host and a router. In such scenario, designing of an efficient, reliable and secure routing protocol has been a major challenging issue over the last many years. Numerous schemes have been proposed for secure routing protocols and most of the research work has so far focused on providing security for routing using cryptography. In this paper, we propose a novel approach to secure Ad hoc On-demand Distance Vector (AODV) routing protocol from the insider attacks launched through active forging of its Route Reply (RREP) control message. AODV routing protocol does not have any security provision that makes it less reliable in publicly open ad hoc network. To deal with the concerned security attacks, we have proposed AODV Security Extension (AODVSEC) which enhances the scope of AODV for the security provision. We have compared AODVSEC with AODV and Secure AODV (SAODV) in normal situation as well as in presence of the three concerned attacks viz. Resource Consumption (RC) attack, Route Disturb (RD) attack, Route Invasion (RI) attack and Blackhole (BH) attack. To evaluate the performances, we have considered Packet Delivery Fraction (PDF), Average End-to-End Delay (AED), Average Throughput (AT), Normalized Routing Load (NRL) and Average Jitter and Accumulated Average Processing Time.

IPSec over Heterogeneous IPv4 and IPv6 Networks:Issues and Implementation

Abstract: Summary In the face of looming IPv4 address exhaustion and the slow pace of IPv4 to IPv6 migration, this work deploys the IPv4/IPv6 translation gateway as a mechanism to ensure most of IPv6 mission critical applications to continuously interoperate with legacy IPv4 nodes. However, the existence of translation gateway between two IPSec nodes from disparate address realms imposes some incompatibility issues due to the violation of TCP/UDP and IPSec intrinsic functionalities by the gateway. In this work, we study and explore the incompatibility issues of applying IPSec across the translation gateway and then propose a workable solution to implement end to end IPSec in heterogeneous IPv4 and IPv6 networks. Experimental results show that our mechanism is feasible to establish a successful IPSec connection across IPv4/IPv6 translation gateway. Moreover, the proposed mechanism provides automatic detection of IPv4/IPv6 translation gateway or Network Address Translation (NAT) gateway, so that it can be backward compatible with NAT-Traversal in homogeneous IPv4 networks.

Fast emergency paths schema to overcome transient link failures in ospf routing

Abstract: A reliable network infrastructure must be able to sustain traffic flows, even when a failure occurs and changes the network topology. During the occurrence of a failure, routing protocols, like OSPF, take from hundreds of milliseconds to various seconds in order to converge. During this convergence period, packets might traverse a longer path or even a loop. An even worse transient behaviour is that packets are dropped even though destinations are reachable. In this context, this paper describes a proactive fast rerouting approach, named Fast Emergency Paths Schema (FEP-S), to overcome problems originating from transient link failures in OSPF routing. Extensive experiments were done using several network topologies with different dimensionality degrees. Results show that the recovery paths, obtained by FEPS, are shorter than those from other rerouting approaches and can improve the network reliability by reducing the packet loss rate during the routing protocols convergence caused by a failure.

Deployment of Mobile Routers Ensuring Coverage and Connectivity

Abstract: Maintaining connectivity among a group of autonomous agents exploring an area is very important, as it promotes cooperation between the agents and also helps message exchanges which are very critical for their mission. Creating an underlying Ad-hoc Mobile Router Network (AMRoNet) using simple robotic routers is an approach that facilitates communication between the agents without restricting their movements. We address the following question in our paper: How to create an AMRoNet with local information and with minimum number of routers? We propose two new localized and distributed algorithms 1) agent-assisted router deployment and 2) a self-spreading for creating AMRoNet. The algorithms use a greedy deployment strategy for deploying routers effectively into the area maximizing coverage and a triangular deployment strategy to connect different connected component of routers from different base stations. Empirical analysis shows that the proposed algorithms are the two best localized approaches to create AMRoNets.

Acapacity -based load balancing and job m igration algorithm for h eterogeneous computational grids

Abstract: This paper addresses the problem of scheduling and load balancing in heterogeneous computational grids. We proposed a two-level load balancing policy for the multi -cluster grid environment where computational resources are dispersed in different adm inistrative domains or clusters which are located in different local area networks. The proposed load balancing policy takes into account the heterogeneity of the computational resources. It distributes the system workload based on the processing elements capacity which leads to minimize the overall job mean response time and maximize the system utilization and throughput at the steady state. To evaluate the performance of the proposed load balancing policy, an analytical model is developed. The results ob tained analytically are validated by simulating the model using Arena simulation package. The results show that the overall mean job response time obtained by simulation is very close to that obtained analytically. Also, the simulation results show that th e performance of the proposed load balancing policy outperforms that of theRandom and Uniform distribution load balancing policies in terms of mean job response time. The maximumimprovement ratio obtained when the system workload is low. It decreases slowly as the system workload gradually increases and it decreases rapidly when the system arrival rate λ approaches the system processing rate µ because the system gradually approaches its saturation point.

Deciding on the type of the degree distribution of a graph from traceroute-like measurements

Abstract: The degree distribution of the Internet topology is considered as one of its main properties. However, it is only known through a measurement procedure which gives a biased estimate. This measurement may in first approximation be modeled by a BFS (Breadth-First Search) tree. We explore here our ability to infer the type (Poisson or power-law) of the degree distribution from such a limited knowledge. We design procedures which estimate the degree distribution of a graph from a BFS of it, and show experimentally (on models and real-world data) that this approach succeeds in making the difference between Poisson and power-law degree distributions.

Study the Effect of Base Frequency on the Performance of WiMAX Network Carrying Voice

Abstract: WiMAX is stand for Worldwide Interoperability for Microwave Access. (WiMAX) embodies the IEEE 802.16 family of standards that provide wireless broadband access to residential and commercial Internet subscribers. This technology takes the first position among the technologies these days. WiMAX can offers or adds some qualifications to the wireless technologies like high data rate, long coverage area and offers several types Quality of service to the customers. The long coverage area of WiMAX coming from the high transmit power and from the architecture of the network which is similar to mobile network, where the WiMAX base station architecture, is similar to GSM base station, need tower and can be sectorized, etc. One of the feature of WiMAX devises is the wide range of base frequency from 2 to 66 GHz, on both licensed and free licensed spectrum [1] .In this paper the effect of base frequency on the WiMAX network performance will be studied .we concern on three famous frequency (2.4,3.5 and 5.8GHz ) [2],which most of the WiMAX devises work on them. OPNET MODELER is a simulation program used to simulate the work of networks with different values of base frequency. We use the modeler to study network of 12 WiMAX workstation connect and call each other by one WiMAX base station during 300 second. The results show that the higher the base frequency the higher the Signal to Noise Ratio ,that lead to high throughput ,low packet end to end delay, finally lead to high mean opinion score (MOS) which mean good quality of voice. In the same time the results show that increase in the coverage area will lead to drop in Signal to Noise Ratio and MOS which will effect negatively in the quality of voice.

A distributed mutual exclusion algorithm for mobile ad hoc networks

Abstract: We propose a distributed mutual exclusion algorithm for mobile ad hoc networks. This algorithm requires a ring of cluster coordinators as the underlying topology. The topology is built by first providing clusters of mobile nodes in the first step and then forming a backbone consisting of the cluster heads in a ring as the second step. The modified version of the Ricart-Agrawala Algorithm on top of this topology provides analytically and experimentally an order of decrease in message complexity with respect to the original algorithm. We analyze the algorithm, provide performance results of the implementation, discuss the fault tolerance and the other algorithmic extensions, and show that this architecture can be used for other middleware functions in mobile networks.

On throughput performance of decode and forward cooperative relaying with packet combining and arq

Abstract: Cooperative Diversity can be used by wireless nodes to take the benefit of broadcast nature and inherent spatial diversity of wireless channel to relay messages for each others. This helps to propagate redundant signals over multiple paths, which can be used to combat the channel noise and fading effects. We investigate the use of packet combining in cooperative diversity scenario. In our approach we exploit this inherent spatial diversity alongwith the inherent time diversity in ARQ retransmissions. Further different channels have different fade levels or channel conditions. Maximal Ratio Combining of packets at the receiver improves the total Signal to Noise Ratio at the receiver, improving the throughput in wireless channel. Decode and Forward Relay can allow the opportunistic relay of the packets. In opportunistic relay of packets, the packet is relayed only when the direct transmission from source to destination fails. This saves the resources by avoiding the relay of packets, when not required. In this paper we propose the relaying scheme with packet combining at the destination. We investigate the BER and throughput performance of the scheme in AWGN and fading channel with and without MRC combining and compare them.

Determination of optimal number of clusters in wireless sensor networks

Abstract: Prolonged network lifetime, scalability and efficient load balancing are essential for optimal performance of a wireless sensor network. Clustering provides an effective way of extending the lifetime of a sensor network. Clustering is the process that divides sensor networks into smaller localized group (called clusters) of members with a cluster head. Clustering protocols need to elect optimal number of clusters in hierarchically structured wireless sensor networks. Any clustering scheme that elects clusters uniformly (irrespective of the distance from Base Station) incurs excessive energy usage on clusters proximal and distant to Base Station. In single hop networks a gradual increment in the energy depletion rate is observed as the distance from the cluster head increases[17]. This work focuses on the analysis of wasteful energy consumption within a uniform cluster head election model (EPEM) and provides an analytical solution to reduce the overall consumption of energy usage amongst the clusters elected in a wireless sensor network. A circular model of sensor network is considered, where the sensor nodes are deployed around a centrally located Base Station. The sensor network is divided into several concentric rings centred at the Base Station. A model, Unequal Probability Election Model (UEPEM), which elects cluster heads non-uniformly is proposed. The probability of cluster head election depends on the distance from the Base Station. UEPEM reduces the overall energy usage by about 21% over EPEM. The performance of UEPEM improves as the number of rings is increased.

Tcp-ub: a new congestion aware transmission control protocol variant

Abstract: Transmission control protocol (TCP) is a connection oriented protocol for several types of distributed applications. TCP is reliable particularly for traditional fixed networks. With emergence of faster wireless networks, TCP has been performing poorly in its original format. The performance of TCP is affected due to assorted factors including congestion window, maximum packet size, retry limit, recovery mechanism, backup mechanism and mobility. To overcome deficiency of original TCP, Several modifications have been introduced to improve network quality. The mobility is a major hurdle in degrading the performance of mobile wireless networks. In this paper, we introduce and implement new TCP variant University of Bridgeport (UB) that combines the features of TCP Westwood and Vegas. We examine the performance of TCP-UB, Vegas and Westwood using different realistic scenarios. NS2 simulator demonstrates the stability of TCP-UB as compared with TCP Vegas and Westwood in highly congested networks from the mobility point of view.

Dynamic policy management in mobile grid environments

Abstract: Mobile Grid Services has given the ability to move jobs, data and application software from nodes to nodes during jobs execution in the grid environment. These migrations depend on the grid’s users and the grid’s nodes policies. The heterogeneity, diversity of policies and attributes leads to a need for policy management tools that can handle these problems. Also, before the users can submit their jobs or run their applications on a certain resource or system they may need to guarantee that this resource or system has not been compromised, which could result in their own application or data being stolen or asking for certain users to be allowed to access the service. To date, not enough attention has been paid to policies that deal with such concerns. Most existing grid systems have support only limited types of policies (e.g. CPU resources). A few designs consider enforcing data policies in their architecture. Therefore, we propose a dynamic policy framework that addresses these issues (user-submitted policy, data policy and multiple Virtual Organizations (VOs).

Energy Consumption Model in ad hoc Mobile Network

Abstract: The aim of this work is to model the nodes battery discharge in wireless ad hoc networks. Many work focus on the energy consumption in such networks. Even, the research in the highest layers of the ISO model, takes into account the energy consumption and efficiency. Indeed, the nodes that form such network are mobiles, so no instant recharge of battery. Also with special type of ad hoc networks are wireless sensors networks using non-rechargeable batteries. All nodes with an exhausted battery are considered death and left the network. To consider the energy consumption, in this work we model using a Markov chain, the discharge of the battery considering of instant activation and deactivation distribution function of these nodes.

A Review of Fair Exchange Protocols

Abstract: Recently, the Internet has become an essential business platform, aiding trading, distribution and sales between organisations, consumers and even between consumers themselves. This technology revolution has brought e-commerce to an entirely new level, which therefore has raised some new security issues . Security protocols in e-commerce are required to manage the transactions between buyers and sellers. In order to engage customers in e-commerce, these protocols should be well formulated and secured; they should protect both parties from fraudulent users and subsequently promote the growth of e-commerce. There are some protocols, known as fair exchange protocols, in e-commerce that are designed to guarantee fairness between the customer and the merchant so that neither party gains any advantage over the other. Therefore, in this paper, we review these protocols in detail. In addition, we present a survey of three fair exchange protocols based on online TTP from different application areas. In particular, we review these protocols with regard to certain properties, namely, fairness, correctness of product, customer's anonymity, timeliness and channel requirement.

Throughput Analysis for Cognitive Radio (CR) Systems

Abstract: In cognitive radio networks, the secondary network (users) are allowed to utilize the frequency bands of primary network (users) when they are not currently being used. To support this function, the secondary users are required to sense the radio frequency environment, and once the primary user is found to be active, the secondary users have to vacate the channel within certain amount of time. There are two parameters related to channel sensing: probability of detection and probability of false alarm. The higher the detection probability, the better the primary users can be protected. However, from the secondary users’ perspective, the lower the false alarm probability, the more chances the channel can be reused, thus the higher the achievable throughput for the secondary users. In this paper, we study the fundamental tradeoff between sensing capability and achievable throughput of the secondary users. Also, we present a design for sensing slot duration to maximize the achievable throughput for the secondary users under the constraint that the primary users are sufficiently protected. Using energy detection scheme, an optimal sensing time which provides the best tradeoff is given. Cooperative sensing is also studied based on the methodology of the proposed sensing throughput tradeoff. Computer simulations are presented to evaluate the proposed tradeoff methodology.

A Reliable Semi-Distributed Load Balancing Architecture of Heterogeneous Wireless Networks

Abstract: Now a day’s Heterogeneous wireless network is a promising field of research interest. Various challenges exist in this hybrid combination like load balancing, resource management and so on. In this paper we introduce a reliable load balancing architecture for heterogeneous wireless communications to ensure certain level of quality of service. To conquer the problem of centralized and distributed design, a semi distributed load balancing architecture for multiple access networks is introduced. In this grid based design multiple Load and Mobile Agent Management Units is incorporated. To prove the compac tness of the design, integrated reliability, signalling overhead and total processing time is calculated. And finally simulation result shows that overall system performance is improved by enhancing reliability, reducing signalling overhead and processingtime.

Complex support vector machines regression for robust channel estimation in LTE downlink system.

Abstract: In this paper, the problem of channel estimation for LTE Downlink system in the environment of high mobility presenting non-Gaussian impulse noise interfering with reference signals is faced. The estimation of the frequency selective time varying multipath fading channel is performed by using a channel estimator based on a nonlinear complex Support Vector Machine Regression (SVR) which is applied to Long Term Evolution (LTE) downlink. The estimation algorithm makes use of the pilot signals to estimate the total frequency response of the highly selective fading multipath channel. Thus, the algorithm maps trained data into a high dimensional feature space and uses the structural risk minimization principle to carry out the regression estimation for the frequency response function of the fading channel. The obtained results show the effectiveness of the proposed method which has better performance than the conventional Least Squares (LS) and Decision Feedback methods to track the variations of the fading multipath channel.

Parallel computation of crc using special generator polynomials

Abstract: CRC (Cyclic Redundancy Check) is an error detection method commonly used in data communication systems, computer networksand storage environments. In this method, the transmitter divides the message by an agreed upon polynomial called the generator and concatenates the calculated residue to the message. The properties of the generator determine the range of errors which are detectable in the receiver side. The division operation is currently performed using serial circuits called Linear Feedback Shift Registers especially in the Ethernetnetwork access protocol. Developing methods for parallel computation of the residue makes CRC suitable for higher layer protocols and software applications. This paper studies a case for parallel CRC computation using special generators which have special multiples called OZO (One-Zero-One) polynomials are divisible. We first provide a system atic approach to finding such polynomials and then design and evaluate the algorithm and the hardware required to perform the parallel division.

An Intelligent Mobile-Agent Based Scalable Network Management Architecture for Large-Scale Enterprise System

Abstract: Several Mobile Agent based distributed network management models have been proposed in recent times to address the scalability and flexibility problems of centralized (SNMP or CMIP management models) models. Though the use of Mobile Agents to distr ibute and delegate management tasks comes handy in dealing with the previously stated issues, many of the agent -based management frameworks like initial flat bed models and static mid-level managers employing mobile agents models cannot efficiently meet th e demands of current networks which are growing in size and complexity. Moreover, varied technologies, such as SONET, ATM, Ethernet, DWDM etc., present at different layers of the Access, Metro and Core (long haul) sections of the network, have contributedto the complexity in terms of their own framing and protocol structures. Thus, controlling and managing the traffic in these networks is a challenging task. This paper presents an intelligent scalable hierarchical agent based model for the management of la rge-scale complex networks to address aforesaid issues. The cost estimation, carried out with a view to compute the overall management cost in terms of management data overhead, is being presented. The results obtained thereafter establish the usefulness of the presented architecture as compare to centralized and flat bed agent based models.

CRAW: Combination of Re-Keying and Authentication in Wireless Networks for Secure Multicast Increasing Efficiency of Member Join/Leave and Movement

Abstract: Recently, the number of requests for multicast services through the wireless networks has been increased. However, for successful deployment, security and efficiency of content delivery must be provided at first. This paper presents a new approach for secure multicast in wireless networks. This approach, CRAW (Combination of Re-keying and Authentication in Wireless networks) combines member authentication procedure with group key management protocol to provide an efficient group re-keying process. Onetime password is proposed for member authentication and CKC (Code for Key Calculation) is suggested for group key management in wireless networks. In fact, the combination of authentication with group key management in wireless networks results in a simple and secure mechanism both for authentication and group key management while mobile members join/leave a group or move inter-area. Simulation results show that CRAW reduces re-keying overhead at join from O(log 2n+1) to O(1) while security requirements are saved. Also, CRAW introduces storing a main list to manage mobile members' location while they move intra-group inter-area.

Automated inference system for end -to - end diagnosis of network performance issues in client -terminal devices

Abstract: Traditional network diagnosis methods of Client-Terminal Device (CTD) problems tend to be laborintensive, time consuming, and contribute to increased customer dissatisfaction. In this paper, we propose an automated solution for rapidly diagnose the root causes of network performance issues in CTD. Based on a new intelligent inference technique, we create the Intelligent Automated Client Diagnostic (IACD) system, which only relies on collection of Transmission Control Protocol (TCP) packet traces. Using soft-margin Support Vector Machine (SVM) classifiers, the system (i) distinguishes link problems from client problems and (ii) identifies characteristics unique to the specific fault to report the root cause. The modular design of the system enables support for new access link and fault types. Experimental evaluation demonstrated the capability of the IACD system to distinguish between faulty and healthy links and to diagnose the client faults with 98% accuracy. The system can perform fault diagnosis independent of the user’s specific TCP implementation, enabling diagnosis of diverse range of client devices.