Journal of Computer Networks and Communications The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. SEMAN: A Novel Secure Middleware for Mobile Ad Hoc Networks Mon, 23 May 2016 12:26:38 +0000 As a consequence of the particularities of Mobile Ad Hoc Networks (MANETs), such as dynamic topology and self-organization, the implementation of complex and flexible applications is a challenge. To enable the deployment of these applications, several middleware solutions were proposed. However, these solutions do not completely consider the security requirements of these networks. Based on the limitations of the existing solutions, this paper presents a new secure middleware, called Secure Middleware for Ad Hoc Networks (SEMAN), which provides a set of basic and secure services to MANETs aiming to facilitate the development of distributed, complex, and flexible applications. SEMAN considers the context of applications and organizes nodes into groups, also based on these contexts. The middleware includes three modules: service, processing, and security. Security module is the main part of the middleware. It has the following components: key management, trust management, and group management. All these components were developed and are described in this paper. They are supported by a cryptographic core and behave according to security rules and policies. The integration of these components provides security guarantees against attacks to the applications that usethe middleware services. Eduardo da Silva and Luiz Carlos Pessoa Albini Copyright © 2016 Eduardo da Silva and Luiz Carlos Pessoa Albini. All rights reserved. A Hybrid Energy Efficient Protocol for Mobile Ad Hoc Networks Tue, 17 May 2016 13:42:47 +0000 We proposed an energy conservation technique called Location Based Topology Control with Sleep Scheduling for ad hoc networks. It uses the feature of both topology control approach and power management approach. Like the topology control approach, it attempts to reduce the transmission power of a node, which is determined from its neighborhood location information. A node goes to sleep state based on the traffic condition as that of power management approach. In the proposed scheme, a node goes to sleep state only when its absence does not create local partition in its neighborhood. We preformed extensive simulation to compare the proposed scheme with existing ones. Simulation results show that the energy consumption is lower with increase in the network lifetime and higher throughput in the proposed scheme. Niranjan Kumar Ray and Ashok Kumar Turuk Copyright © 2016 Niranjan Kumar Ray and Ashok Kumar Turuk. All rights reserved. Performance Analysis of Cooperative Spectrum Sensing under Guaranteed Throughput Constraints for Cognitive Radio Networks Mon, 09 May 2016 13:06:55 +0000 One of the main challenges in cognitive radio networks is the ability of secondary users to detect the primary user presence with high probability of detection. In previous research, optimizing cooperative sensing in cognitive radio networks is performed for either a targeted probability of detection or a false alarm. After setting one of the probabilities as an optimization constraint, the other is optimized. In this paper, a guaranteed constant throughput at the secondary users is introduced as a target while optimizing probability of detection for cooperative sensing. Both sensing time values and number of cooperated cognitive radio secondary users are investigated to maximize the probability of detection of primary user. AND and OR hard decision schemes are considered and compared with soft decision scheme which is weighted modified deflection coefficient scheme (W-MDC). It is illustrated that cooperation of all users and utilizing full frames for sensing time will not provide maximum probability of detection. A tradeoff between performances of cognitive radio networks with and without optimization is presented. The effects of varying network sizes, normalized target throughput, maximum frame duration times, and received signal-to-noise ratio at the fusion center are investigated for different fusion rules. H. F. Al-Doseri and M. A. Mangoud Copyright © 2016 H. F. Al-Doseri and M. A. Mangoud. All rights reserved. An Overview on SDN Architectures with Multiple Controllers Wed, 27 Apr 2016 14:04:19 +0000 Software-defined networking offers several benefits for networking by separating the control plane from the data plane. However, networks’ scalability, reliability, and availability remain as a big issue. Accordingly, multicontroller architectures are important for SDN-enabled networks. This paper gives a comprehensive overview of SDN multicontroller architectures. It presents SDN and its main instantiation OpenFlow. Then, it explains in detail the differences between multiple types of multicontroller architectures, like the distribution method and the communication system. Furthermore, it provides already implemented and under research examples of multicontroller architectures by describing their design, their communication process, and their performance results. Othmane Blial, Mouad Ben Mamoun, and Redouane Benaini Copyright © 2016 Othmane Blial et al. All rights reserved. Bounds on Worst-Case Deadline Failure Probabilities in Controller Area Networks Thu, 21 Apr 2016 08:42:42 +0000 Industrial communication networks like the Controller Area Network (CAN) are often required to operate reliably in harsh environments which expose the communication network to random errors. Probabilistic schedulability analysis can employ rich stochastic error models to capture random error behaviors, but this is most often at the expense of increased analysis complexity. In this paper, an efficient method (of time complexity ) to bound the message deadline failure probabilities for an industrial CAN network consisting of periodic/sporadic message transmissions is proposed. The paper develops bounds for Deadline Minus Jitter Monotonic (DMJM) and Earliest Deadline First (EDF) message scheduling techniques. Both random errors and random bursts of errors can be included in the model. Stochastic simulations and a case study considering DMJM and EDF scheduling of an automotive benchmark message set provide validation of the technique and highlight its application. Michael Short Copyright © 2016 Michael Short. All rights reserved. Secure Mix-Zones for Privacy Protection of Road Network Location Based Services Users Wed, 20 Apr 2016 13:06:28 +0000 Privacy has been found to be the major impediment and hence the area to be worked out for the provision of Location Based Services in the wide sense. With the emergence of smart, easily portable, communicating devices, information acquisition is achieving new domains. The work presented here is an extension of the ongoing work towards achieving privacy for the present day emerging communication techniques. This work emphasizes one of the most effective real-time privacy enhancement techniques called Mix-Zones. In this paper, we have presented a model of a secure road network with Mix-Zones getting activated on the basis of spatial as well as temporal factors. The temporal factors are ascertained by the amount of traffic and its flow. The paper also discusses the importance of the number of Mix-Zones a user traverses and their mixing effectiveness. We have also shown here using our simulations which are required for the real-time treatment of the problem that the proposed transient Mix-Zones are part of a viable and robust solution towards the road network privacy protection of the communicating moving objects of the present scenario. Rubina S. Zuberi and Syed N. Ahmad Copyright © 2016 Rubina S. Zuberi and Syed N. Ahmad. All rights reserved. Detecting and Mitigating Smart Insider Jamming Attacks in MANETs Using Reputation-Based Coalition Game Mon, 18 Apr 2016 08:34:35 +0000 Security in mobile ad hoc networks (MANETs) is challenging due to the ability of adversaries to gather necessary intelligence to launch insider jamming attacks. The solutions to prevent external attacks on MANET are not applicable for defense against insider jamming attacks. There is a need for a formal framework to characterize the information required by adversaries to launch insider jamming attacks. In this paper, we propose a novel reputation-based coalition game in MANETs to detect and mitigate insider jamming attacks. Since there is no centralized controller in MANETs, the nodes rely heavily on availability of transmission rates and a reputation for each individual node in the coalition to detect the presence of internal jamming node. The nodes will form a stable grand coalition in order to make a strategic security defense decision, maintain the grand coalition based on node reputation, and exclude any malicious node based on reputation value. Simulation results show that our approach provides a framework to quantify information needed by adversaries to launch insider attacks. The proposed approach will improve MANET’s defense against insider attacks, while also reducing incorrect classification of legitimate nodes as jammers. Ashraf Al Sharah, Taiwo Oyedare, and Sachin Shetty Copyright © 2016 Ashraf Al Sharah et al. All rights reserved. Secure Multicast Routing Algorithm for Wireless Mesh Networks Wed, 06 Apr 2016 14:17:23 +0000 Multicast is an indispensable communication technique in wireless mesh network (WMN). Many applications in WMN including multicast TV, audio and video conferencing, and multiplayer social gaming use multicast transmission. On the other hand, security in multicast transmissions is crucial, without which the network services are significantly disrupted. Existing secure routing protocols that address different active attacks are still vulnerable due to subtle nature of flaws in protocol design. Moreover, existing secure routing protocols assume that adversarial nodes cannot share an out-of-band communication channel which rules out the possibility of wormhole attack. In this paper, we propose SEMRAW (SEcure Multicast Routing Algorithm for Wireless mesh network) that is resistant against all known active threats including wormhole attack. SEMRAW employs digital signatures to prevent a malicious node from gaining illegitimate access to the message contents. Security of SEMRAW is evaluated using the simulation paradigm approach. Rakesh Matam and Somanath Tripathy Copyright © 2016 Rakesh Matam and Somanath Tripathy. All rights reserved. Review of Adaptive Cell Selection Techniques in LTE-Advanced Heterogeneous Networks Thu, 31 Mar 2016 11:58:56 +0000 Poor cell selection is the main challenge in Picocell (PeNB) deployment in Long Term Evolution- (LTE-) Advanced heterogeneous networks (HetNets) because it results in load imbalance and intercell interference. A selection technique based on cell range extension (CRE) has been proposed for LTE-Advanced HetNets to extend the coverage of PeNBs for load balancing. However, poor CRE bias setting in cell selection inhibits the attainment of desired cell splitting gains. By contrast, a cell selection technique based on adaptive bias is a more effective solution to traffic load balancing in terms of increasing data rate compared with static bias-based approaches. This paper reviews the use of adaptive cell selection in LTE-Advanced HetNets by highlighting the importance of cell load estimation. The general performances of different techniques for adaptive CRE-based cell selection are compared. Results reveal that the adaptive CRE bias of the resource block utilization ratio (RBUR) technique exhibits the highest cell-edge throughput. Moreover, more accurate cell load estimation is obtained in the extended RBUR adaptive CRE bias technique through constant bit rate (CBR) traffic, which further improved load balancing as against the estimation based on the number of user equipment (UE). Finally, this paper presents suggestions for future research directions. M. A. Gadam, Maryam Abdulazeez Ahmed, Chee Kyun Ng, Nor Kamariah Nordin, Aduwati Sali, and Fazirulhisyam Hashim Copyright © 2016 M. A. Gadam et al. All rights reserved. ASEP of MIMO System with MMSE-OSIC Detection over Weibull-Gamma Fading Channel Subject to AWGGN Sun, 13 Mar 2016 11:27:16 +0000 Ordered successive interference cancellation (OSIC) is adopted with minimum mean square error (MMSE) detection to enhance the multiple-input multiple-output (MIMO) system performance. The optimum detection technique improves the error rate performance but increases system complexity. Therefore, MMSE-OSIC detection is used which reduces error rate compared to traditional MMSE with low complexity. The system performance is analyzed in composite fading environment that includes multipath and shadowing effects known as Weibull-Gamma (WG) fading. Along with the composite fading, a generalized noise that is additive white generalized Gaussian noise (AWGGN) is considered to show the impact of wireless scenario. This noise model includes various forms of noise as special cases such as impulsive, Gamma, Laplacian, Gaussian, and uniform. Consequently, generalized -function is used to model noise. The average symbol error probability (ASEP) of MIMO system is computed for 16-quadrature amplitude modulation (16-QAM) using MMSE-OSIC detection in WG fading perturbed by AWGGN. Analytical expressions are given in terms of Fox-H function (FHF). These expressions demonstrate the best fit to simulation results. Keerti Tiwari, Davinder S. Saini, and Sunil V. Bhooshan Copyright © 2016 Keerti Tiwari et al. All rights reserved. IDHOCNET: A Novel ID Centric Architecture for Ad Hoc Networks Thu, 03 Mar 2016 15:17:18 +0000 Ad hoc networks lack support of infrastructure and operate in a shared bandwidth wireless environment. Presently, such networks have been realized by various adaptations in Internet Protocol (IP) architecture which was developed for infrastructure oriented hierarchical networks. The IP architecture has its known problem and issues even in infrastructure settings, like IP address overloading, mobility, multihoming, and so forth. Therefore, when such architecture is implemented in ad hoc scenario the problems get multiplied. Due to this fact, ad hoc networks suffer from additional problems like IP address autoconfiguration, service provisioning, efficient bandwidth utilization, and node identification. In this paper we present IDHOCNET which is a novel implementation of service provisioning and application development framework in the ad hoc context. We illustrate a number of implemented features of the architecture which include IP address autoconfiguration, identification of nodes by using real world identifiers, IP based services support in ad hoc networks, and a new class of application known as ID based application. Moreover how identifiers can completely replace the IP addresses to run the IP based applications is shown. It is expected that this work will open new research horizons and paradigms for ad hoc networks. Shahrukh Khalid, Athar Mahboob, Choudhry Fahad Azim, and Aqeel Ur Rehman Copyright © 2016 Shahrukh Khalid et al. All rights reserved. Vertical Handover Decision Algorithm Using Ants’ Colonies for 4G Heterogeneous Wireless Networks Sun, 28 Feb 2016 09:25:25 +0000 With the development of 4G mobile telecommunication systems, providing users with the convenience of a seamless continuous connection is not enough anymore. Users want to be connected through the best available network with the best quality of service. It is necessary to have a good decision-making algorithm which decides whether it is necessary to perform handoff to another network, the best network to vertically perform handoff to, and the right time to initiate the handover. This paper proposes a new approach in which mobile terminals (MTs) continuously analyze the network and keep a database of the best available networks. The concept is based on QoS aware ant colony built on the vertical handoff mechanism that uses an updated version of ants’ colony optimization decision algorithm (), the dynamic and static factors such as RSS, the cost of service, bandwidth, the velocity of MT, the power consumption and security, and the module for predicting the traveling distance within an IEEE 802.11 WLAN cell. Simulation results show that we can not only meet the individual needs of users in terms of QoS, but also improve the whole system performance by reducing the number of handover failures and unnecessary handover instances by up to 95%. Imad El Fachtali, Rachid Saadane, and Mohammed ElKoutbi Copyright © 2016 Imad El Fachtali et al. All rights reserved. The Impact of Noise Models on Capacity Performance of Distribution Broadband over Power Lines Networks Thu, 25 Feb 2016 16:47:46 +0000 This paper considers broadband potential of distribution Broadband over Power Lines (BPL) networks when different well-known noise models of the BPL literature are applied. The contribution of this paper is twofold. First, the seven most representative and used noise models of the BPL literature are synopsized in this paper. With reference to this set, the broadband performance of a great number of distribution BPL topologies either Overhead (OV) or Underground (UN), either Medium-Voltage (MV) or Low-Voltage (LV), is investigated in terms of suitable capacity metrics. Second, based on the proposed capacity metrics, a comparative capacity analysis is performed among various well-validated noise models. Through the careful study of its results, it is demonstrated that during capacity computations of distribution BPL networks, the flat Additive White Gaussian Noise (FL noise model) can be comfortably assumed as an efficient noise model either in 3–30 MHz or in 3–88 MHz frequency range since its capacity differences with the other well-proven noise models are negligible. Athanasios G. Lazaropoulos Copyright © 2016 Athanasios G. Lazaropoulos. All rights reserved. Markov Model-Based Energy Efficiency Spectrum Sensing in Cognitive Radio Sensor Networks Mon, 15 Feb 2016 09:13:57 +0000 Cognitive Radio Sensor Network (CRSN), incorporating cognitive radio capability in wireless sensor networks, is a new paradigm of the next-generation sensor network. Sensor nodes are usually battery powered and hence have strict energy constraints. As a result, energy efficiency is also a very critical problem in the CRSN. In this paper, we focus on energy consumption because of spectrum sensing. Furthermore, we present an adaptive spectrum sensing time interval strategy, in which SUs can adjust the next spectrum sensing time interval according to the current spectrum sensing results (namely, channel status). In order to find an optimal spectrum sensing time interval, we introduce the Markov model. Then, we establish a Markov model-based mathematical modeling for analyzing the relationship between spectrum sensing time interval and prior spectrum sensing results. Finally, numerical results demonstrate that the proposed strategy with dynamic adaptive spectrum sensing time interval exceeded listen before talk (LBT) strategy which is widely used for traditional wireless sensor networks. Yan Jiao and Inwhee Joe Copyright © 2016 Yan Jiao and Inwhee Joe. All rights reserved. The Improved Overhearing Backup AODV Protocol in MANET Sun, 24 Jan 2016 09:04:51 +0000 Mobile ad hoc network (MANET) is one of the most widely used networks, which has attracted attentions, having features such as limited energy resources, limited bandwidth, and security weaknesses due to lack of a central infrastructure. Safe and suitable routing is one of the research aspects of MANET. In this paper, a proposed method, called M-AODV, which is a type of overhearing backup protocol, based on AODV, is presented. The simulation results of this protocol, applied by NS2 simulator, showed the improvement of packet delivery rate and reduction of overhead and delay. Moreover, to assess the security of the proposed protocol, we simulated M-AODV and AODV protocols under black hole and wormhole attacks, using no security solution. The results showed that M-AODV had been improved in terms of packet delivery ratio, and the delay had been reduced as well, but the amount of overhead had been increased. Elham Zamani and Mohammadreza Soltanaghaei Copyright © 2016 Elham Zamani and Mohammadreza Soltanaghaei. All rights reserved. Game-Theory-Based Approach for Energy Routing in a Smart Grid Network Thu, 14 Jan 2016 07:24:35 +0000 Small power plants and buildings with renewable power generation capability have recently been added to traditional central power plants. Through these facilities, prosumers appear to have a concurrent role in both energy production and consumption. Based on bidirectional power transfers by large numbers of prosumers, a smart microgrid has become an important factor in efficiently controlling the microgrids used in power markets and in conducting effective power trades among grids. In this paper, we present an approach utilizing the game theory for effective and efficient energy routing, which is a novel and challenging procedure for a smart microgrid network. First, we propose strategies for choosing the desired transaction price for both electricity surpluses and shortages to maximize profits through energy transactions. An optimization scheme is utilized to search for an energy route with minimum cost using the solving method used in a traditional transportation problem by treating the sale and purchase quantities as transportation supply and demand, respectively. To evaluate the effect of the proposed decision strategies, we simulated our mechanism, and the results proved that our mechanism yields results pursued by each strategy. Our proposed strategies will contribute to spreading a smart microgrid for enhancing the utilization of microgrids. June S. Hong and Mihui Kim Copyright © 2016 June S. Hong and Mihui Kim. All rights reserved. Replica Node Detection Using Enhanced Single Hop Detection with Clonal Selection Algorithm in Mobile Wireless Sensor Networks Mon, 04 Jan 2016 13:28:57 +0000 Security of Mobile Wireless Sensor Networks is a vital challenge as the sensor nodes are deployed in unattended environment and they are prone to various attacks. One among them is the node replication attack. In this, the physically insecure nodes are acquired by the adversary to clone them by having the same identity of the captured node, and the adversary deploys an unpredictable number of replicas throughout the network. Hence replica node detection is an important challenge in Mobile Wireless Sensor Networks. Various replica node detection techniques have been proposed to detect these replica nodes. These methods incur control overheads and the detection accuracy is low when the replica is selected as a witness node. This paper proposes to solve these issues by enhancing the Single Hop Detection (SHD) method using the Clonal Selection algorithm to detect the clones by selecting the appropriate witness nodes. The advantages of the proposed method include (i) increase in the detection ratio, (ii) decrease in the control overhead, and (iii) increase in throughput. The performance of the proposed work is measured using detection ratio, false detection ratio, packet delivery ratio, average delay, control overheads, and throughput. The implementation is done using ns-2 to exhibit the actuality of the proposed work. L. S. Sindhuja and G. Padmavathi Copyright © 2016 L. S. Sindhuja and G. Padmavathi. All rights reserved. Survey of QoS Routing Protocols in Wireless Multimedia Sensor Networks Thu, 10 Dec 2015 05:57:36 +0000 The emergence of Wireless Multimedia Sensor Networks (WMSNs) has stimulated the refocusing of research from conventional scalar Wireless Sensor Networks (WSNs) to WMSNs. Currently, because of their prevalence WMSNs are used in different applications. Due to the unique features of WMSNs, fulfilling Quality of Service (QoS) requirements for a variety of applications is the challenge. QoS routing is a backbone of WMSNs and plays a vital role in satisfying QoS requirements. The performance of QoS routing depends upon the selection of an optimal path or paths. Path selection is based on evaluation of a cost function using various routing metrics. A careful blend of such metrics in a routing cost function guarantees a committed level of QoS. This survey uses number of routing metrics as criteria for categorizing state-of-the-art QoS WMSNs routing techniques. In addition, open issues and future research directions to further develop efficient routing protocols to guarantee QoS are discussed. Shailendra Aswale and Vijay R. Ghorpade Copyright © 2015 Shailendra Aswale and Vijay R. Ghorpade. All rights reserved. Autonomous QoS Management and Policing in Unmanaged Local Area Networks Thu, 26 Nov 2015 07:53:03 +0000 The high increase of bandwidth-intensive applications like high definition video streaming in home and small office environments leads to QoS challenges in hybrid wired/wireless local area networks. These networks are often not QoS aware and may contain bottlenecks in their topology. In addition, they often have a hybrid nature due to the used access technology consisting of, for example, Ethernet, wireless, and PowerLAN links. In this paper, we present the research work on a novel autonomous system for hybrid QoS in local area networks, called QoSiLAN, which does not rely on network infrastructure support but on host cooperation and works independently of the access technology. We present a new QoS Signalling Protocol, policing and admission control algorithms, and a new lightweight statistical bandwidth prediction algorithm for autonomous resource management in LANs. This new QoS framework enables link based, access-medium independent bandwidth management without network support. We provide evaluation results for the novel bandwidth prediction algorithm as well as for the QoSiLAN framework and its protocol, which highlight the features, robustness, and the effectiveness of the proposed system. Christopher Köhnen, Christian Überall, Muttukrishnan Rajarajan, Rudolf Jäger, and Veselin Rakočević Copyright © 2015 Christopher Köhnen et al. All rights reserved. Patient Data Prioritization in the Cross-Layer Designs of Wireless Body Area Network Wed, 04 Nov 2015 11:22:02 +0000 In Wireless Body Area Network (WBAN), various biomedical sensors (BMSs) are deployed to monitor various vital signs of a patient for detecting the abnormality of the vital signs. These BMSs inform the medical staff in advance before the patient’s life goes into a threatening situation. In WBAN, routing layer has the same challenges as generally seen in WSN, but the unique requirements of WBANs need to be addressed by the novel routing mechanisms quite differently from the routing mechanism in Wireless Sensor Networks (WSNs). The slots allocation to emergency and nonemergency patient’s data is one of the challenging issues in IEEE 802.15.4 and IEEE 802.15.6 MAC Superframe structures. In the similar way, IEEE 802.15.4 and IEEE 802.15.6 PHY layers have also unique constraints to modulate the various vital signs of patient data into continuous and discrete forms. Numerous research contributions have been made for addressing these issues of the aforementioned three layers in WBAN. Therefore, this paper presents a cross-layer design structure of WBAN with various issues and challenges. Moreover, it also presents a detail review of the existing cross-layer protocols in the WBAN domain by discussing their strengths and weaknesses. Fasee Ullah, Abdul Hanan Abdullah, Muhammad Qasim Jan, and Kashif Naseer Qureshi Copyright © 2015 Fasee Ullah et al. All rights reserved. Definition of an 802.11 Interface Management Process in a Proposed System for Transmission Capacity Enhancement in Wireless Mesh Networks Sun, 28 Jun 2015 11:13:32 +0000 802.11-based wireless mesh networks (WMNs) as last mile solutions frequently become bottlenecks in the overall Internet communication structure. The lack of end-to-end capacity on routes also affects vertical traffic coming from or flowing towards external networks, such as the Internet. The presented approach aims to increase the overall network performance by exploiting channel diversity and to additionally favor vertical traffic. To achieve this, first we propose a general system that modifies an existing mesh node architecture, in order to prepare a more efficient resource management and to enhance the restricted transmission capacity in standard WMNs. The parallel use of nonoverlapping channels, based on a multiradio node, marks the starting point. The system treats aspects of channel assignment, traffic analysis, and fast layer 2 forwarding. Then, the impact of a novel Multihop Radio Resource Management process is discussed as a relevant component of this new system architecture. The process combines per-hop priority queuing and load balancing in a novel way. It was designed, developed, and evaluated in the presented paper, resulting in the fact that capacity in WMNs was significantly increased, Quality-of-Service parameters were improved, and more efficient use of multiple radios could be reached. The proposed process was validated using a simulation approach. Christian Köbel, Walter Baluja García, and Joachim Habermann Copyright © 2015 Christian Köbel et al. All rights reserved. Improving VANETs Connectivity with a Totally Ad Hoc Living Mobile Backbone Sun, 14 Jun 2015 13:33:32 +0000 The vehicular ad hoc network (VANET) for intelligent transportation systems is an emerging concept to improve transportation security, reliability, and management. The network behavior can be totally different in topological aspects because of the mobility of vehicular nodes. The topology can be fully connected when the flow of vehicles is high and may have low connectivity or be invalid when the flow of vehicles is low or unbalanced. In big cities, the metropolitan buses that travel on exclusive lanes may be used to set up a metropolitan vehicular data network (backbone), raising the connectivity among the vehicles. Therefore, this paper proposes the implementation of a living mobile backbone, totally ad hoc (MOB-NET), which will provide infrastructure and raise the network connectivity. In order to show the viability of MOB-NET, statistical analyses were made with real data of express buses that travel through exclusive lanes, besides evaluations through simulations and analytic models. The statistic, analytic, and simulation results prove that the buses that travel through exclusive lanes can be used to build a communication network totally ad hoc and provide connectivity in more than 99% of the time, besides raising the delivery rate up to 95%. Joilson Alves Junior and Emilio C. G. Wille Copyright © 2015 Joilson Alves Junior and Emilio C. G. Wille. All rights reserved. Analyzing the Evolution and the Future of the Internet Topology Focusing on Flow Hierarchy Sun, 31 May 2015 08:40:56 +0000 In the Internet, Autonomous Systems (ASes) exchange traffic through interconnected links. As traffic demand increases, more traffic becomes concentrated on such links. The traffic concentrations depend heavily on the global structure of the Internet topology. Therefore, a topological evolution considering the global structure is necessary to continually accommodate future traffic amount. In this paper, we first develop a method to identify the hierarchical nature of traffic aggregation on the Internet topology and use this method to discuss the long-term changes in traffic flow. Our basic approach is to extract the “flow hierarchy,” which is a hierarchical structure associated with traffic aggregation. Our results show that the current connection policy will lead to a severe traffic concentration in the future. We then examine a new evolution process that attempts to reduce this traffic concentration. Our proposed evolution process increases the number of links in the deeper level in the hierarchy, thus relaxing the traffic concentration. We apply our evolution process to the Internet topology in 2000 and evolve this scenario over 13 years. The results show that our evolution process could reduce the traffic concentration by more than half compared with that without our evolution process. Yu Nakata, Shin’ichi Arakawa, and Masayuki Murata Copyright © 2015 Yu Nakata et al. All rights reserved. A Mac Protocol Implementation for Wireless Sensor Network Sun, 29 Mar 2015 13:02:15 +0000 IEEE 802.15.4 is an important standard for Low Rate Wireless Personal Area Network (LRWPAN). The IEEE 802.15.4 presents a flexible MAC protocol that provides good efficiency for data transmission by adapting its parameters according to characteristics of different applications. In this research work, some restrictions of this standard are explained and an improvement of traffic efficiency by optimizing MAC layer is proposed. Implementation details for several blocks of communication system are carefully modeled. The protocol implementation is done using VHDL language. The analysis gives a full understanding of the behavior of the MAC protocol with regard to backoff delay, data loss probability, congestion probability, slot effectiveness, and traffic distribution for terminals. Two ideas are proposed and tested to improve efficiency of CSMA/CA mechanism for IEEE 802.15.4 MAC Layer. Primarily, we dynamically adjust the backoff exponent (BE) according to queue level of each node. Secondly, we vary the number of consecutive clear channel assessment (CCA) for packet transmission. We demonstrate also that slot compensation provided by the enhanced MAC protocol can greatly avoid unused slots. The results show the significant improvements expected by our approach among the IEEE 802.15.4 MAC standards. Synthesis results show also hardware performances of our proposed architecture. Jamila Bhar Copyright © 2015 Jamila Bhar. All rights reserved. A Novel Scheme to Minimize Hop Count for GAF in Wireless Sensor Networks: Two-Level GAF Wed, 18 Feb 2015 13:50:22 +0000 In wireless sensor networks, geographic adaptive fidelity (GAF) is one of the most popular energy-aware routing protocols. It conserves energy by identifying equivalence between sensors from a routing perspective and then turning off unnecessary sensors, while maintaining the connectivity of the network. Nevertheless, the traditional GAF still cannot reach the optimum energy usage since it needs more number of hops to transmit data packets to the sink. As a result, it also leads to higher packet delay. In this paper, we propose a modified version of GAF to minimize hop count for data routing, called two-level GAF (T-GAF). Furthermore, we use a generalized version of GAF called Diagonal-GAF (DGAF) where two diagonal adjacent grids can also directly communicate. It has an advantage of less overhead of coordinator election based on the residual energy of sensors. Analysis and simulation results show significant improvements of the proposed work comparing to traditional GAF in the aspect of total hop count, energy consumption, total distance covered by the data packet before reaching the sink, and packet delay. As a result, compared to traditional GAF, it needs 40% to 47% less hop count and consumes 27% to 35% less energy to extend the network lifetime. Vaibhav Soni and Dheeresh K. Mallick Copyright © 2015 Vaibhav Soni and Dheeresh K. Mallick. All rights reserved. An Energy-Efficient Clustering Routing Algorithm Based on Geographic Position and Residual Energy for Wireless Sensor Network Tue, 10 Feb 2015 06:20:34 +0000 Recently wireless sensor network (WSN) has become one of the most interesting networking technologies, since it can be deployed without communication infrastructures. A sensor network is composed of a large number of sensor nodes; these nodes are responsible for supervision of the physical phenomenon and transmission of the periodical results to the base station. Therefore, improving the energy efficiency and maximizing the networking lifetime are the major challenges in this kind of networks. To deal with this, a hierarchical clustering scheme, called Location-Energy Spectral Cluster Algorithm (LESCA), is proposed in this paper. LESCA determines automatically the number of clusters in a network. It is based on spectral classification and considers both the residual energy and some properties of nodes. In fact, our approach uses the K-ways algorithm and proposes new features of the network nodes such as average energy, distance to BS, and distance to clusters centers in order to determine the clusters and to elect the cluster's heads of a WSN. The simulation results show that if the clusters are not constructed in an optimal way and/or the number of the clusters is greater or less than the optimal number of clusters, the total consumed energy of the sensor network per round is increased exponentially. Ali Jorio, Sanaa El Fkihi, Brahim Elbhiri, and Driss Aboutajdine Copyright © 2015 Ali Jorio et al. All rights reserved. Analysis of the Deployment Quality for Intrusion Detection in Wireless Sensor Networks Thu, 05 Feb 2015 07:00:28 +0000 The intrusion detection application in a homogeneous wireless sensor network is defined as a mechanism to detect unauthorized intrusions or anomalous moving attackers in a field of interest. The quality of deterministic sensor nodes deployment can be determined sufficiently by a rigorous analysis before the deployment. However, when random deployment is required, determining the deployment quality becomes challenging. An area may require that multiple nodes monitor each point from the sensing area; this constraint is known as k-coverage where k is the number of nodes. The deployment quality of sensor nodes depends directly on node density and sensing range; mainly a random sensor nodes deployment is required. The major question is centred around the problem of network coverage, how can we guarantee that each point of the sensing area is covered by the required number of sensor nodes and what a sufficient condition to guarantee the network coverage? To deal with this, probabilistic intrusion detection models are adopted, called single/multi-sensing detection, and the deployment quality issue is surveyed and analysed in terms of coverage. We evaluate the capability of our probabilistic model in homogeneous wireless sensor network, in terms of sensing range, node density, and intrusion distance. Noureddine Assad, Brahim Elbhiri, Moulay Ahmed Faqihi, Mohamed Ouadou, and Driss Aboutajdine Copyright © 2015 Noureddine Assad et al. All rights reserved. Energy Efficient and High Capacity Tradeoff in Distributed Antenna System for a Green Cellular Network Thu, 29 Jan 2015 07:11:16 +0000 Two main concerns for designing a wireless system are more network capacity and less energy consumption. Recently, distributed antenna system (DAS) has received considerable attention due to its potential to provide higher spectral efficiency (SE) and uniform coverage for cellular networks. In this regard, this paper compares the performance of DAS with centralized antenna system (CAS) in LTE-A system in terms of energy efficiency (EE), where practical restrictions such as out-of-cell interference, path loss, and small scale fading are taken into account. Furthermore, the EE and system power consumption are investigated under three different cell-load scenarios (high, moderate, and low load) where different numbers of antennas are activated and remaining of antennas are under sleep mode. Finally, based on the tradeoff between power-saving and EE, two optimal DAS antenna deployments are proposed for low and moderate cell-load scenarios. The results reveal that DAS considerably outperforms CAS in terms of EE and by optimal deploying antennas of DAS significant power-saving and EE are achievable. The proposed methodology achieved savings of up to 27.63% in terms of energy savings in a macrocell with guarantee of a high capacity of data. Mehran Behjati, Mohammed H. Alsharif, Rosdiadee Nordin, and Mahamod Ismail Copyright © 2015 Mehran Behjati et al. All rights reserved. Adaptive Conflict-Free Optimization of Rule Sets for Network Security Packet Filtering Devices Wed, 28 Jan 2015 09:35:12 +0000 Packet filtering and processing rules management in firewalls and security gateways has become commonplace in increasingly complex networks. On one side there is a need to maintain the logic of high level policies, which requires administrators to implement and update a large amount of filtering rules while keeping them conflict-free, that is, avoiding security inconsistencies. On the other side, traffic adaptive optimization of large rule lists is useful for general purpose computers used as filtering devices, without specific designed hardware, to face growing link speeds and to harden filtering devices against DoS and DDoS attacks. Our work joins the two issues in an innovative way and defines a traffic adaptive algorithm to find conflict-free optimized rule sets, by relying on information gathered with traffic logs. The proposed approach suits current technology architectures and exploits available features, like traffic log databases, to minimize the impact of ACO development on the packet filtering devices. We demonstrate the benefit entailed by the proposed algorithm through measurements on a test bed made up of real-life, commercial packet filtering devices. Andrea Baiocchi, Gianluca Maiolini, Annachiara Mingo, and Daniele Goretti Copyright © 2015 Andrea Baiocchi et al. All rights reserved. XCP-Winf and RCP-Winf: Improving Explicit Wireless Congestion Control Mon, 12 Jan 2015 06:50:55 +0000 Congestion control in wireless networks is strongly dependent on the dynamics and instability of wireless links. Therefore, it is very difficult to accurately evaluate the characteristics of the wireless links. It is known that TCP experiences serious performance degradation problems in wireless networks. Moreover, congestion control mechanisms that rely on network interaction and network parameters, such as XCP and RCP, do not evaluate accurately the capacity and available link bandwidth in wireless networks. In this paper we propose new explicit flow control protocols for wireless mesh networks, based on XCP and RCP. We name these protocols XCP-Winf and RCP-Winf. They rely on the MAC layer information gathered by a new method to accurately estimate the available bandwidth and the path capacity over a wireless network path. The estimation is performed in real time and without the need to intrusively inject packets in the network. These new congestion control mechanisms are evaluated in different scenarios in wireless mesh and ad hoc networks and compared against several new approaches for wireless congestion control. It is shown that both XCP-Winf and RCP-Winf outperform the evaluated approaches, showing its stable behavior and better channel utilization. Luís Barreto Copyright © 2015 Luís Barreto. All rights reserved.