NS2 Project Titles 2016-2017

1. Network Topology Tomography Under Multipath Routing

Network topology tomography can infer a tree topology for single-source networks using end-to-end measurements. However, multipath routing, which introduces multiple paths between end-hosts, violates the tree topology model. In this letter, we demonstrate that such nontree topologies are also identifiable. We employ graph cuts and show the nontree topology can be decomposed into two identifiable subtopologies. And by reconnecting the cut paths, the nontree topology can be recovered after obtaining these subtopologies. To detect the paths that share cuts, we propose a scheme based on measurements of the end-to-end packet arrival order. Simulation results show that our scheme achieves the desirable detection accuracy.

2. HDEER: A Distributed Routing Scheme for Energy-Efficient Networking

The proliferation of new online Internet services has substantially increased the energy consumption in wired networks, which has become a critical issue for Internet service providers. In this paper, we target the network-wide energy-saving problem by leveraging speed scaling as the energy-saving strategy. We propose a distributed routing schemeHDEERto improve network energy efficiency in a distributed manner without significantly compromising traffic delay. HDEER is a two-stage routing scheme where a simple distributed multipath finding algorithm is firstly performed to guarantee loop-free routing, and then a distributed routing algorithm is executed for energy-efficient routing in each node among the multiple loop-free paths. We conduct extensive experiments on the NS3 simulator and simulations with real network topologies in different scales under different traffic scenarios. Experiment results show that HDEER can reduce network energy consumption with a fair tradeoff between network energy consumption and traffic delay.

3. Mobile Coordinated Wireless Sensor Network: An Energy Efficient Scheme for Real-Time Transmissions

This paper introduces the mobile access coordinated wireless sensor network (MC-WSN)a novel energy efficient scheme for time-sensitive applications. In conventional sensor networks with mobile access points (SENMA), the mobile access points (MAs) traverse the network to collect information directly from individual sensors. While simplifying the routing process, a major limitation with SENMA is that data transmission is limited by the physical speed of the MAs and their trajectory length, resulting in low throughput and large delay. In an effort to resolve this problem, we introduce the MC-WSN architecture, for which a major feature is that: through active network deployment and topology design, the number of hops from any sensor to the MA can be limited to a pre-specified number. In this paper, we investigate the optimal topology design that minimizes the average number of hops from sensor to MA, and provide the throughput analysis under both single-path and multipath routing cases. Moreover, putting MC-WSN in the bigger picture of network design and development, we provide a unified framework for wireless network modeling and characterization. Under this general framework, it can be seen that MC-WSN reflects the integration of structure-ensured reliability/efficiency and ad-hoc enabled flexibility.

4. A secure-efficient data collection algorithm based on self-adaptive sensing model in mobile Internet of vehicles

Existing research on data collection using wireless mobile vehicle network emphasizes the reliable delivery of information. However, other performance requirements such as life cycle of nodes, stability and security are not set as primary design objectives. This makes data collection ability of vehicular nodes in real application environment inferior. By considering the features of nodes in wireless IoV, such as large scales of deployment, volatility and low time delay, an efficient data collection algorithm is proposed for mobile vehicle network environment. An adaptive sensing model is designed to establish vehicular data collection protocol. The protocol adopts group management in model communication. The vehicular sensing node in group can adjust network sensing chain according to sensing distance threshold with surrounding nodes. It will dynamically choose a combination of network sensing chains on basis of remaining energy and location characteristics of surrounding nodes. In addition, secure data collection between sensing nodes is undertaken as well. The simulation and experiments show that the vehicular node can realize secure and real-time data collection. Moreover, the proposed algorithm is superior in vehicular network life cycle, power consumption and reliability of data collection by comparing to other algorithms.

5. Resisting blackhole attacks on MANETs

MANET routing protocols are designed based on the assumption that all nodes cooperate without maliciously disrupting the operation of the routing protocol. AODV is a reactive MANET routing protocol that is vulnerable to a dramatic collapse of network performance in the presence of blackhole attack. The paper introduces a new concept of Self-Protocol Trustiness (SPT) in which detecting a malicious intruder is accomplished by complying with the normal protocol behavior and lures the malicious node to give an implicit avowal of its malicious behavior. We present a Blackhole Resisting Mechanism (BRM) to resist such attacks that can be incorporated into any reactive routing protocol. It does not require expensive cryptography or authentication mechanisms, but relies on locally applied timers and thresholds to classify nodes as malicious. No modifications to the packet formats are needed, so the overhead is a small amount of calculation at nodes, and no extra communication. Using NS2 simulation, we compare the performance of networks using AODV under blackhole attacks with and without our mechanism to SAODV, showing that it significantly reduces the effect of a blackhole attack.

6. Secret Common Randomness From Routing Metadata in Ad Hoc Networks

Establishing secret common randomness between two or multiple devices in a network resides at the root of communication security. In its most frequent form of key establishment, the problem is traditionally decomposed into a randomness generation stage (randomness purity is subject to employing often costly true random number generators) and an information-exchange agreement stage, which relies either on public-key infrastructure or on symmetric encryption (key wrapping). In this paper, we propose a secret-common-randomness establishment algorithm for ad hoc networks, which works by harvesting randomness directly from the network routing metadata, thus achieving both pure randomness generation and (implicitly) secret-key agreement. Our algorithm relies on the route discovery phase of an ad hoc network employing the dynamic source routing protocol, is lightweight, and requires relatively little communication overhead. The algorithm is evaluated for various network parameters in an OPNET ad hoc network simulator. Our results show that, in just 10 min, thousands of secret random bits can be generated network-wide, between different pairs in a network of 50 users.

7. Queue Stability Analysis in Network Coded Wireless Multicast Network

This letter considers a single hop wireless multicast network. We first introduce a new two-level queuing system consisting of a main queue and a virtual queue, where each packet in the virtual queue is associated with a user index set. Then, we propose a network coding based packet scheduling method to maximize the system input rate under the queue stability constraint. Our analytical and simulation results demonstrate the effectiveness of the proposed solution.

8. Delay-Energy Tradeoff in Multicast Scheduling for Green Cellular Systems

Multicast transmission based on real-time network state information is a resource-friendly technique to improve the energy efficiency and reduce the traffic burden for cellular systems. This paper evaluates the effectiveness of this technique for downlink transmissions. In particular, a scenario is considered in which multiple mobile users (MUs) asynchronously request to download one common message locally cached at a base station (BS). Due to the randomness of both the channel conditions and the request arrivals from the MUs, the BS may choose to intelligently hold the arrived requests, especially when the channel conditions are bad or the number of requests is small, and then serve them in one shot later via multicasting. Clearly it is of great interest to balance the delay (incurred by holding the requests) and the energy efficiency (EE, defined as the energy cost per request), and this motivates us to quantify the fundamental tradeoff for the proposed hold-then-serve scheme. For the scenario with single channel and unit message sizes, it is shown that for a fixed channel bandwidth, the delay-EE tradeoff reduces to judiciously choosing the optimal stopping rule for when to serve all the arrived requests, where the effect of the bandwidth on the achievable delay-EE region is discussed further. By using optimal stopping theory, it is shown that the optimal stopping rule exists for general Markov channel models and request arrival processes. Particularly, for the hard deadline and proportional delay penalty cases, it is shown that the optimal stopping rule exhibits a threshold structure, and the corresponding threshold in the former case is time varying while in the latter case it is a constant. Finally, for the more general scenario with multiple channels and arbitrary message sizes, the optimal scheduling is formulated as a Markov decision process problem, where some efficient suboptimal scheduling algorithms are proposed.

9. Delay Analysis of Social Group Multicast-Aided Content Dissemination in Cellular System

Based on the common interest of mobile users (MUs) in a social group, the dissemination of content across the social group is studied as a powerful supplement to conventional cellular communication with the goal of improving the delay performance of the content dissemination process. The content popularity is modeled by a Zipf distribution to characterize the MUs' different interests in different contents. The factor of altruism (FA) terminology is introduced for quantifying the willingness of content owners to share their content. We model the dissemination process of a specific packet by a pure-birth-based Markov chain and evaluate the statistical properties of both the network's dissemination delay as well as of the individual user-delay. Compared to the conventional base station (BS)-aided multicast, our scheme is capable of reducing the average dissemination delay by about 56.5%. Moreover, in contrast to the BS-aided multicast, increasing the number of MUs in the target social group is capable of reducing the average individual user-delay by 44.1% relying on our scheme. Furthermore, our scheme is more suitable for disseminating a popular piece of content.

10. End-to-End coding for TCP

Although widely used, TCP has many limitations in meeting the throughput and latency requirements of applications in wireless networks, high-speed data center networks, and heterogeneous multi-path networks. Instead of relying purely on retransmission upon packet loss, coding has potential to improve the performance of TCP by ensuring better transmission reliability. Coding has been verified to work well at the link layer but has not been fully studied at the transport layer. There are many advantages but also challenges in exploiting coding at the transport layer. In this article, we focus on how to leverage end-to-end coding in TCP. We reveal the problems TCP faces and the opportunities coding can bring to improve TCP performance. We further analyze the challenges faced when applying the coding techniques to TCP and present the current applications of coding in TCP.

11. Link Allocation for Multiuser Systems With Hybrid RF/FSO Backhaul: Delay-Limited and Delay-Tolerant Designs

In this paper, we consider a cascaded radio frequency (RF) and hybrid RF/free space optical (FSO) system where several mobile users transmit their data over an RF link to a decode-and-forward relay node (e.g., a small cell base station) and the relay forwards the information to a destination (e.g., a macro-cell base station) over a hybrid RF/FSO backhaul link. The relay and the destination employ multiple antennas for transmission and reception over the RF links while each mobile user has a single antenna. The RF links are orthogonal to the FSO link but half-duplex with respect to each other, i.e., either the user-relay RF link or the relay-destination RF link is active. For this communication setup, we derive the optimal fixed and adaptive link allocation policies for sharing the transmission time between the RF links based on the statistical and instantaneous channel state information (CSI) of the RF and FSO links, respectively. Thereby, we consider the following two scenarios depending on the delay requirements: 1) delay-limited transmission where the relay has to immediately forward the packets received from the users to the destination, and 2) delay-tolerant transmission where the relay is allowed to store the packets received from the users in its buffer and forward them to the destination when the quality of the relay-destination RF link is favorable. Our numerical results illustrate the effectiveness of the proposed communication architecture and link allocation policies, and their superiority compared to existing schemes, which employ only one type of backhaul link.

12. Fair Routing for Overlapped Cooperative Heterogeneous Wireless Sensor Networks

In recent years, as wireless sensor networks (WSNs) are widely diffused, multiple overlapping WSNs constructed on the same area become more common. In such a situation, their lifetime is expected to be extended by cooperative packet forwarding. Although some researchers have studied about cooperation in multiple WSNs, most of them do not consider the heterogeneity in the characteristics of each WSN such as battery capacity, operation start time, the number of nodes, nodes locations, energy consumption, packet size and/or data transmission timing, and so on. In a heterogeneous environment, naive lifetime improvement with cooperation may not be fair. In this paper, we propose a fair cooperative routing method for heterogeneous overlapped WSNs. It introduces an energy pool to maintain the total amount of energy consumption by cooperative forwarding. The energy pool plays a role of broker for fair cooperation. Finally, simulation results show the excellent performance of the proposed method.

13. Adaptive and Channel-Aware Detection of Selective Forwarding Attacks in Wireless Sensor Networks

Wireless sensor networks (WSNs) are vulnerable to selective forwarding attacks that can maliciously drop a subset of forwarding packets to degrade network performance and jeopardize the information integrity. Meanwhile, due to the unstable wireless channel in WSNs, the packet loss rate during the communication of sensor nodes may be high and vary from time to time. It poses a great challenge to distinguish the malicious drop and normal packet loss. In this paper, we propose a channel-aware reputation system with adaptive detection threshold (CRS-A) to detect selective forwarding attacks in WSNs. The CRS-A evaluates the data forwarding behaviors of sensor nodes, according to the deviation of the monitored packet loss and the estimated normal loss. To optimize the detection accuracy of CRS-A, we theoretically derive the optimal threshold for forwarding evaluation, which is adaptive to the time-varied channel condition and the estimated attack probabilities of compromised nodes. Furthermore, an attack-tolerant data forwarding scheme is developed to collaborate with CRS-A for stimulating the forwarding cooperation of compromised nodes and improving the data delivery ratio of the network. Extensive simulation results demonstrate that CRS-A can accurately detect selective forwarding attacks and identify the compromised sensor nodes, while the attack-tolerant data forwarding scheme can significantly improve the data delivery ratio of the network.

14. Reverse Update: A Consistent Policy Update Scheme for Software-Defined Networking

Policy and path updates are common causes of network instability, leading to service disruptions or vulnerable intermediate states. In this letter, we propose the reverse update, an update scheme for software-defined networking that guarantees to preserve properties of flows during the transition time. We prove through a formal model that the proposal achieves consistent policy updates, in which in-transit packets are always handled in the next forwarding hops by the same or a more recent policy. The main contributions are: 1) a relaxation of the concept of per-packet-consistency in the data plane of software-defined networking; and 2) a policy update scheme, proved to be consistent and efficient. A software-defined networking simulator was developed and validated. The results of our simulations show that the proposed reverse update scheme is faster and has lower overhead than the current two-phase update proposed in the literature.

15. On the Throughput-Delay Tradeoff in Georouting Networks

We study the scaling properties of a georouting scheme in a wireless multi-hop network of n mobile nodes. Our aim is to increase the network capacity quasi-linearly with n , while keeping the average delay bounded. In our model, we consider mobile nodes moving according to an independent identically distributed random walk with velocity v and transmitting packets to randomly chosen fixed and known destinations. The average packet delivery delay of our scheme is of order 1/v , and it achieves network capacity of order ({n}/{\log n\log \log n}) . This shows a practical throughput-delay tradeoff, in particular when compared with the seminal result of Gupta and Kumar, which shows network capacity of order {(n/\log n)}^{1/2} and negligible delay and the groundbreaking result of Grossglauser and Tse, which achieves network capacity of order n but with an average delay of order \sqrt {n}/v . The foundation of our improved capacity and delay tradeoff relies on the fact that we use a mobility model that contains straight-line segments, a model that we consider more realistic than classic Brownian motions. We confirm the generality of our analytical results using simulations under various interference models.

16. An Ecient Tree-based Self-Organizing Protocol for Internet of Things

Tree networks are widely applied in Sensor Networks of Internet of Things (IoTs). This paper proposes an Efficient Tree-based Self-organizing Protocol (ETSP) for sensor networks of IoTs. In ETSP, all nodes are divided into two kinds: network nodes and non-network nodes. Network nodes can broadcast packets to their neighboring nodes. Non-network nodes collect the broadcasted packets and determine whether to join the network. During the self-organizing process, we use different metrics such as number of child nodes, hop, communication distance and residual energy to reach available sink nodes weight, the node with max weight will be selected as sink node. Non-network nodes can be turned into network nodes when they join the network successfully. Then a tree-based network can be obtained one layer by one layer. The topology is adjusted dynamically to balance energy consumption and prolong network lifetime. We conduct experiments with NS2 to evaluate ETSP. Simulation results show that our proposed protocol can construct a reliable tree-based network quickly. With the network scale increasing, the self-organization time, average hop and packet loss ratio wont increase more. Furthermore, the success rate of packet in ETSP is much higher compared with AODV and DSDV.

17. Modified AODV Routing Protocol to Improve Security and Performance against Black Hole Attack

A Mobile Ad hoc NETwork (MANET) is a collection of autonomous nodes that have the ability to communicate with each other without having fixed infrastructure or centralized access point such as a base station. This kind of networks is very susceptible to adversary's malicious attacks, due to the dynamic changes of the network topology, trusting the nodes to each other, lack of fixed substructure for the analysis of nodes behaviors and constrained resources. One of these attacks is black hole attack. In this attack, malicious nodes inject fault routing information to the network and lead all data packets toward themselves, then destroy them all. In this paper, we propose a solution, which enhances the security of the Ad-hoc On-demand Distance Vector (AODV) routing protocol to encounter the black hole attacks. Our solution avoids the black hole and the multiple black hole attacks. The simulation results using the Network Simulator NS2 shows that our protocol provides better security and better performance in terms of the packet delivery ratio than the AODV routing protocol in the presence of one or multiple black hole attacks with marginal rise in average end-to-end delay and normalized routing overhead.

18. Resisting Blackhole Attacks on MANETs

MANET routing protocols are designed based on the assumption that all nodes cooperate without maliciously disrupting the operation of the routing protocol. AODV is a reactive MANET routing protocol that is vulnerable to a dramatic collapse of network performance in the presence of blackhole attack. The paper introduces a new concept of Self-Protocol Trustiness (SPT) in which detecting a malicious intruder is accomplished by complying with the normal protocol behavior and lures the malicious node to give an implicit avowal of its malicious behavior. We present a Blackhole Resisting Mechanism (BRM) to resist such attacks that can be incorporated into any reactive routing protocol. It does not require expensive cryptography or authentication mechanisms, but relies on locally applied timers and thresholds to classify nodes as malicious. No modifications to the packet formats are needed, so the overhead is a small amount of calculation at nodes, and no extra communication. Using NS2 simulation, we compare the performance of networks using AODV under blackhole attacks with and without our mechanism to SAODV, showing that it significantly reduces the effect of a blackhole attack.

19. Constructing A Shortest Path Overhearing Tree With Maximum Lifetime In WSNs

Secure data collection is an important problem in wireless sensor networks. Different approaches have been proposed. One of them is overhearing. We investigate the problem of constructing a shortest path overhearing tree with the maximum lifetime. We propose three approaches. The first one is a polynomial-time heuristic. The second one uses ILP (Integer Linear Programming) to iteratively find a monitoring node and a parent for each sensor node. The last one optimally solves the problem by using MINLP (Mixed-Integer Non-Linear Programming). We have implemented the three approaches using MIDACO solver and MATLAB Intlinprog, and performed extensive simulations using NS2.35. The simulation results show that the average lifetime of all the network instances achieved by the heuristic approach is 85.69% of that achieved by the ILP-based approach and 81.05% of that obtained by the MINLP-based approach, and the performance of the ILP-based approach is almost equivalent to that of the MINLP-based approach.

20. Energy-Efcient Adaptive Forwarding Scheme for MANETs

Flooding is the simplest way of broadcasting, in which each node in the network retransmits an incoming message once. Simple flooding technique in wireless Ad-hoc networks causes the broadcast storm problem. However, this technique is inefficient in terms of resource consumption such as bandwidth and energy. This paper presents a new hybrid scheme that combines different techniques that collaborate to reduce overhead and conserve energy. We propose an Energy-Efficient Adaptive Forwarding Scheme, that utilizes the information of the 1-hop neighbouring radios. In this scheme nodes do not need a positioning system or distance calculation to determine their location. In addition to the previous works, the proposed protocol divides the network into different groups based on their transmission-power levels. Therefore, the node which receives HELLO message from different groups is considered a Gateway node. This node efficiently participates in forwarding RREQ packets and the unnecessary redundant retransmission is avoided. The performance evaluation of the proposed protocol shows a reduction in the routing overhead and in energy consumption, when compared with the Pure-Flooding AODV and Dynamic-Power AODV using NS2.

21. Trusted Secure Adhoc On-Demand Multipath Distance Vector Routing in MANET

A mobile ad hoc network (MANET) is a collectionof wireless nodes, which works well only if those mobile nodes aregood and behave cooperatively. The lack of infrastructuresupport and resource constraint is the key issue that causesdishonest and non-co-operative nodes. Therefore, MANET isvulnerable to serious attacks. To reduce the hazards from suchnodes and enhance the security of the network, this paperextends an Ad hoc On-Demand Multipath Distance Vector(AOMDV) Routing protocol, named as Trust-based Secured Adhoc On-demand Multipath Distance Vector (TS-AOMDV), whichis based on the nodes' routing behavior. The proposed TSAOMDVaims at identifying and isolating the attacks such asflooding, black hole, and gray hole attacks in MANET. With thehelp of Intrusion Detection System (IDS) and trust-based routing, attack identification and isolation are carried out in two phases ofrouting such as route discovery and data forwarding phase. IDSfacilitates complete routing security by observing both controlpackets and data packets that are involved in the routeidentification and the data forwarding phases. To improve therouting performance, the IDS integrates the measured statisticsinto the AOMDV routing protocol for the detection of attackers. This facilitates the TS-AOMDV to provide better routingperformance and security in MANET. Finally, the Trust basedSecured AOMDV, TS-AOMDV is compared with the existingAOMDV through the NS2 based simulation model. Theperformance evaluation reveals that the proposed TS-AOMDVimproves the performance in terms of throughput by 57.1%more than that of an AOMDV under adversary scenario. Thesimulated results show that the TS-AOMDV outperforms theAOMDV routing protocol.

22. QoS and Security in VOIP Networks through Admission Control Mechanism

With the developing understanding of Information Security and digital assets, IT technology has put on tremendous importance of network admission control (NAC). In NAC architecture, admission decisions and resource reservations are taken at edge devices, rather than resources or individual routers within the network. The NAC architecture enables resilient resource reservation, maintaining reservations even after failures and intra-domain rerouting. Admission Control Networks destiny is based on IP networks through its Security and Quality of Service (QoS) demands for real time multimedia application via advance resource reservation techniques. To achieve Security & QoS demands, in real time performance networks, admission control algorithm decides whether the new traffic flow can be admitted to the network or not. Secure allocation of Peer for multimedia traffic flows with required performance is a great challenge in resource reservation schemes. In this paper, we have proposed our model for VoIP networks in order to achieve security services along with QoS, where admission control decisions are taken place at edge routers. We have analyzed and argued that the measurement based admission control should be done at edge routers which employs on-demand probing parallel from both edge routers to secure the source and destination nodes respectively. In order to achieve Security and QoS for a new call, we choose various probe packet sizes for voice and video calls respectively. Similarly a technique is adopted to attain a security allocation approach for selecting an admission control threshold by proposing our admission control algorithm. All results are tested on NS2 based simulation to evalualate the network performance of edge router based upon network admission control in VoIP traffic.

23. An Energy Consumption Evaluation of Reactive and Proactive Routing Protocols in Mobile Ad-hoc Network

In Mobile Ad-hoc NETwork (MANET) each node has the possibility to move freely in the space and communicate with each other over wireless link without any centralized controller or base station. These characteristics makes MANET useful and practical in several fields like military scenarios, sensor networks, Rescue operations, students on campus, etc. but this kind of network still suffers from a number of problems, power consumption is one of the most crucial design concerns in Mobile Ad-hoc networks as the nodes in MANET have battery limited. In this paper, we will discuss about the aspect of energy consumption in MANET's routing protocols. A performance comparison of four routing protocols Dynamic Source Routing (DSR), Ad hoc On-Demand Distance Vector (AODV), Destination-Sequenced Distance Vector (DSDV) and Optimized Link State Routing (OLSR) with respect to average energy consumption are explained thoroughly. Then, an evaluation of how the varying parameters of network in diverse scenarios affect the power consumption in these four protocols is discussed. A detailed simulation model using Network Simulator 2 (NS2) with different mobility and traffic models is used to study their energy consumption.

24. Energy Detection Analytical Model for Handoff Process to Support Mobile Cloud Computing Environment

Mobile devices play an integral role in our day lives and have brought the revolutionary change in business, education, and entertainment. Moreover, the emergence of cloud computing technology greatly extended the significance of smart device. On the other hand, the smart devices experience the problem when obtaining the multiple cloud services during the handoff process. In this paper, we propose an energy detection (ED) analytical model for handoff process that calculates the energy consumption for each handoff process in the cloud computing environment. Our ED analytic model is developed to examine the consumed energy for different handoff processes in cloud computing. The model helps the mobile users to get prior information for the status of the mobile when executing the handoff process. To reconfirm the validity of ED analytical model, we have test programmed in NS2. The results demonstrate that the ED analytical model efficiently detects the energy consumption of mobile devices during the handoff process in cloud computing environment.

25. Nonsmooth Nonconvex Optimization for Low-Frequency Geosounding Inversion

A study of the application of nonconvex regularization operators to the electromagnetic sounding inverse problem is presented. A comparison is presented among three nonconvex regularization algorithms: one smooth usually considered, two nonsmooth, and a convex one, the total variation (TV) operator. One of the nonsmooth nonconvex regularization methods is a novel implementation based on the LegendreFenchel transform and the Bregman iterative algorithm. The nonconvex regularization operator is approximated by the convex dual, and the minimization is then implemented considering the equivalence between the Bregman iteration and the augmented Lagrangian methods. The algorithm is simple and provides for better models when applied to synthetic data, than those obtained with TV, and other nonconvex smooth regularizers. Results of the application to field data are also presented, observing that NS2 recovers a model in better agreement with the truth, compared to those obtained with additional magnetometric resistivity data by other researchers.

26. Hierarchical Location-Based Services for Wireless Sensor Networks

Nowadays Wireless Sensor Networks have attracted worldwide research and industrial interest, because they can be applied in various areas. Geographic routing protocols are very suitable to wireless sensor networks because they use location information when they need to route packets. Obviously, location information is maintained by Location-Based Services provided by network nodes in a distributed way. The location based services can be classified into two classes: Flooding-Based and Rendezvous-based location services.In this paper we choose to compare two hierarchical rendezvous location based-services, GLS (Grid Location Service) and HLS (Hierarchical Location Service) coupled to the GPSR routing protocol (Greedy Perimeter Stateless Routing).The simulations were performed using NS2 simulator for wireless sensor networks to evaluate the performance and power of the two services in term of location overhead, the request travel time (RTT) and the query Success ratio (QSR).This work presents also the scalability performance study of both GLS and HLS, specifically, what happens if the number of nodes N increases. The study will focus on three qualitative metrics: The location maintenance cost,the location query cost and the storage cost.

27. Modified AODV Routing Protocol to Improve Security and Performance against Black Hole Attack

A Mobile Ad hoc NETwork (MANET) is a collection of autonomous nodes that have the ability to communicate with each other without having fixed infrastructure or centralized access point such as a base station. This kind of networks is very susceptible to adversary's malicious attacks, due to the dynamic changes of the network topology, trusting the nodes to each other, lack of fixed substructure for the analysis of nodes behaviors and constrained resources. One of these attacks is black hole attack. In this attack, malicious nodes inject fault routing information to the network and lead all data packets toward themselves, then destroy them all. In this paper, we propose a solution, which enhances the security of the Ad-hoc On-demand Distance Vector (AODV) routing protocol to encounter the black hole attacks. Our solution avoids the black hole and the multiple black hole attacks. The simulation results using the Network Simulator NS2 shows that our protocol provides better security and better performance in terms of the packet delivery ratio than the AODV routing protocol in the presence of one or multiple black hole attacks with marginal rise in average end-to-end delay and normalized routing overhead.

28. Attacks against AODV Routing Protocol in Mobile Ad-HocNetworks

A Mobile Ad hoc NETwork (MANET) is much more vulnerable to attack than a wired network due to the dynamic changes of the network topology, high mobility, limited physical security and lack of centralized administration. Unfortunately, the routing protocols are designed based on the assumption that all nodes trust each other and cooperate without maliciously disrupting the operation of routing. This paper analyzes the impact of security attacks on the performance of the AODV routing protocol. Simulations are setup in the NS-2 network simulator and the performance of the AODV routing protocol is discussed under black hole, flooding and rushing attacks. This analysis is provided in terms of performance metrics, such as a packet delivery ratio, the average end-to-end delay and normalized routing load.

29. Novel Scheme to Heal MANET in Smart City Network

Today's generation has perceived wireless networking prospective applications in tremendously erratic and vibrant surroundings. Businesses as well as individuals pick wireless medium as their choice as it facilitates flexibility of location. It's obvious due to its convenience in terms of mobility, portability or even ease of installation at any preferred location. Mobile network has an intrinsic scalability restraint in terms of attainable network capability. The potential challenge of wireless communication in Smart cities network is, the environs that these communications travel through is changeable. So, the wireless networks which have ability to resolve their own fragmented communication links will definitely enhance their pervasive recognition. Due to the expansion of network capability changes are made to the network design and infrastructures giving way to new techniques for system development for this type of medium. Since it's the beginning there are initial hiccups, despite that, the modern advances in self-healing wireless networks are good enough in resolving the problem. The downlinks are repaired by using power conscious steady nodes. Authors have proposed, a self-healing structure and mobile Power aware stable nodes for smart city networks. Proposed design has been checked using NS2 simulator with existing schemes and show good results in most of the cases.

30. Flow Allocation for Maximum Throughput and Bounded Delay on Multiple Disjoint Paths for Random Access Wireless Multihop Networks

In this paper, we consider random access, wireless, multi-hop networks, with multi-packet reception capabilities, where multiple flows are forwarded to the gateways through node disjoint paths. We explore the issue of allocating flow on multiple paths, exhibiting both intra- and inter-path interference, in order to maximize average aggregate flow throughput (AAT) and also provide bounded packet delay. A distributed flow allocation scheme is proposed where allocation of flow on paths is formulated as an optimization problem. Through an illustrative topology it is shown that the corresponding problem is non-convex. Furthermore, a simple, but accurate model is employed for the average aggregate throughput achieved by all flows, that captures both intra- and inter-path interference through the SINR model. The proposed scheme is evaluated through Ns2 simulations of several random wireless scenarios. Simulation results reveal that, the model employed, accurately captures the AAT observed in the simulated scenarios, even when the assumption of saturated queues is removed. Simulation results also show that the proposed scheme achieves significantly higher AAT, for the vast majority of the wireless scenarios explored, than the following flow allocation schemes: one that assigns flows on paths on a round-robin fashion, one that optimally utilizes the best path only, and another one that assigns the maximum possible flow on each path. Finally, a variant of the proposed scheme is explored, where interference for each link is approximated by considering its dominant interfering nodes only.

31. Analysis and Comparison of EEEMR Protocol with the Flat Routing Protocols of Wireless Sensor Networks

Wireless Sensor Communication Networks have more concern on its routing techniques. Since the WSCNs nodes are battery powered, routing algorithms should assure the concept of energy saving without affecting the other performance metric like Throughput, Delay and Packet delivery ratio etc. The modified AOMDV called as Enhanced Energy Efficient Multipath Routing Protocol (EEEMRP) is a proposed algorithm with the concept of crossbreed the AOMDV routing with the Cuckoo Search algorithm. In this paper, we compare the QoS parameters such as Throughput, Average Delay and Packet Delivery ratio with Traditional Flat Routing Protocols such as DSR, DSDV and with AODV. Simulation is performed using NS2 and the results show that the proposed EEEMRP routing protocol is better than DSR, DSDV and AODV.

32. P-LEACH: Energy Efficient Routing Protocol for Wireless Sensor Networks

Wireless Sensor Network (WSN) are of paramount significance since they are responsible for maintaining the routes in the network, data forwarding, and ensuring reliable multi-hop communication. The main requirement of a wireless sensor network is to prolong network energy efficiency and lifetime. Researchers have developed protocols Low Energy Adaptive Clustering Hierarchy (LEACH) and Power-Efficient Gathering in Sensor Information Systems (PEGASIS) for reducing energy consumption in the network. However, the existing routing protocols experience many shortcomings with respect to energy and power consumption. LEACH features the dynamicity but has limitations due to its cluster-based architecture, while PEGASIS overcomes the limitations of LEACH but lacks dynamicity. In this paper, we introduce PEGASIS-LEACH (P-LEACH), a near optimal cluster-based chain protocol that is an improvement over PEGASIS and LEACH both. This protocol uses an energy-efficient routing algorithm to transfer the data in WSN. To validate the energy effectiveness of P-LEACH, we simulate the performance using Network Simulator (NS2) and MATLAB.

33. A Novel Framework to Enhance the Performance of Contention Based Synchronous MAC Protocol

In this paper, We propose a novel framework to improve the end-to-end transmission delay (E2ETD) and packet delivery ratio (PDR) of existing contention based synchronous MAC protocols designed for wireless sensor networks, without increasing the duty cycle (DC). This is achieved by partitioning the n deployed sensor nodes into k disjoint sets (DSs) which are of almost equal size. It then suitably modifies the cycle structure followed by the existing contention based synchronous MAC protocols by mapping the data transmission process of k existing cycles into one restructured cycle. To evaluate the performance of this approach, we implement RMAC, PRMAC, and CLMAC protocols in the proposed framework using ns2.35 simulator. Results indicate that our scalable framework reduces the E2ETD and increases the PDR significantly at the cost of a very small increase in average energy consumption.

34. Efcient Wireless Multimedia Multicast in Multi-rate Multi-channel Mesh Networks

Devices in wireless mesh networks can operate on multiple channels and automatically adjust their transmission rates for the occupied channels. This paper shows how to improve performance-guaranteed multicasting transmission coverage for wireless multi-hop mesh networks by exploring the transmission opportunity offered by multiple rates (MR) and multiple channels (MC). Based on the characteristics of transmissions with different rates, we propose and analyze parallel low-rate transmissions (PLT) and alternative rate transmissions (ART) to explore the advantages of MRMC in improving the performance and coverage tradeoff under the constraint of limited channel resources. We then apply these new transmission schemes to improving the WMN multicast experience. Combined with the strategy of reliable interference-controlled connections, a novel MRMC multicast algorithm (LC-MRMC) is designed to make efficient use of channel and rate resources to greatly extend wireless multicast coverage with high throughput and short delay performance. Our NS2 simulation results prove that ART and LC-MRMC achieve improved wireless transmission quality across much larger areas as compared to other related studies.

WIRELESS SENSOR NETWORK

Analysis of PKF: A Communication Cost Reduction Scheme for Wireless Sensor Networks

Energy efficiency is a primary concern for wireless sensor networks (WSNs). One of its most energy-intensive processes is the radio communication. This work uses a predictor combined with a Kalman filter (KF) to reduce the communication energy cost for cluster-based WSNs. The technique, called PKF, is suitable for typical WSN applications with adjustable data quality and tens of picojoule computation cost. However, it is challenging to precisely quantify its underlying process from a mathematical point of view. Through an in-depth mathematical analysis, we formulate the tradeoff between energy efficiency and reconstruction quality of PKF. One of our prominent results for that is the explicit expression for the covariance of the doubly truncated multivariate normal distribution; it improves the previous methods and has generality. The validity and accuracy of the analysis are verified with both artificial and real signals. The simulation results, using real temperature values, demonstrate the efficiency of PKF: without additional data degradation, it reduces the communication cost by more than 88%. Compared to previous works based on KF, PKF requires less computational effort while improving the reconstruction quality; compared with the techniques without KF, the advantages of PKF are even more significant. It reduces the transmission rate of them by at least 29%. Besides, it can be integrated into network level techniques to further extend the whole network lifetime.

Online Packet Dispatching for Delay Optimal Concurrent Transmissions in Heterogeneous Multi-RAT Networks

In this paper, we consider the problem of concurrent transmissions in a wireless network consisting of multiple radio access technologies (multi-RATs). That is, a single flow of packets is dispatched over multiple RATs so that the complementary advantages of different RATs can be exploited. One of the challenging issues arising in concurrent transmissions is the packet outof- order problem due to diverse wireless channel states and scheduling policies of different RATs, leading to substantial performance degradation to delay sensitive applications. To address this problem, we firstly propose a state-independent packet dispatching (SIPD) policy, which attempts to find the traffic dispatching ratios over multiple RATs to minimize the maximum average delay across different RATs in the long run. We further propose a state-dependent packet dispatching (SDPD) policy, which achieves fine-grained packet dispatching in the short-term. We use the value function as a measure of the admittance cost for packet dispatching given the current queueing states, and formulate the SDPD problem as a convex programming problem. We derive the close-form solutions for both problems for the special case of two RATs, and adopt the dual decomposition technique as the solution for the general cases. Simulation results are presented to compare the performance of the proposed schemes with existing solutions.

Toward Optimal Adaptive Wireless Communications in Unknown Environments

Designing efficient channel access schemes for wireless communications without any prior knowledge about the nature of environments has been a very challenging issue, in which the channel state distribution of all spectrum resources could be entirely or partially stochastic or adversarial at different times and locations. In this paper, we propose an online learning algorithm for adaptive channel access of wireless communications in unknown environments based on the theory of multiarmed bandits (MAB) problems. By automatically tuning two control parameters, i.e., learning rate and exploration probability, our algorithms could find the optimal channel access strategies and achieve the almost optimal learning performance over time in different scenarios. The quantitative performance studies indicate the superior throughput gain when compared with previous solutions and the flexibility of our algorithm in practice, which is resilient to both oblivious and adaptive jamming attacks with different intelligence and attacking strength that ranges from no-attack to the full-attack of all spectrum resources. We conduct extensive simulations to validate our theoretical analysis.

Adaptive Pilot Clustering in Heterogeneous Massive MIMO Networks

We consider the uplink of a cellular massive MIMO network. Acquiring channel state information at the base stations (BSs) requires uplink pilot signaling. Since the number of orthogonal pilot sequences is limited by the channel coherence, pilot reuse across cells is necessary to achieve high spectral efficiency. However, finding efficient pilot reuse patterns is nontrivial especially in practical asymmetric BS deployments. We approach this problem using coalitional game theory. Each BS has a few unique pilots and can form coalitions with other BSs to gain access to more pilots. The BSs in a coalition thus benefit from serving more users in their cells, at the expense of higher pilot contamination and interference. Given that a cells average spectral efficiency depends on the overall pilot reuse pattern, the suitable coalitional game model is in partition form. We develop a low-complexity distributed coalition formation based on individual stability. By incorporating a base station intercommunication budget constraint, we are able to control the overhead in message exchange between the base stations and ensure the algorithms convergence to a solution of the game called individually stable coalition structure. Simulation results reveal fast algorithmic convergence and substantial performance gains over the baseline schemes with no pilot reuse, full pilot reuse, or random pilot reuse pattern.

Data Aggregation and Principal Component Analysis in WSNs

Data aggregation plays an important role inWireless Sensor Networks (WSNs) as far as it reduces power consumption and boosts the scalability of the network, specially in topologies that are prone to bottlenecks (e.g. cluster-trees). Existing works in the literature use clustering approaches, Principal Component Analysis (PCA) and/or Compressed Sensing (CS) strategies. Our contribution is aligned with PCA and explores whether a projection basis that is not the eigenvectors basis may be valid to sustain a Normalized Mean Squared Error (NMSE) threshold in signal reconstruction and reduce the energy consumption. We derivate first the NSME achieved with the new basis and elaborate then on the Jacobi eigenvalue decomposition ideas to propose a new subspace-based data aggregation method. The proposed solution reduces transmissions among the sink and one or more Data Aggregation Nodes (DANs) in the network. In our simulations we consider without loss of generality a single cluster network and results show that the new technique succeeds in satisfying the NMSE requirement and gets close in terms of energy consumption to the best possible solution employing subspace representations. Additionally the proposed method alleviates the computational load with respect to an eigenvector-based strategy (by a factor of six in our simulations).

A New cost-effective approach for Battlefield Surveillance in Wireless Sensor Networks

Assuring security (in the form of attacking mode as well as in safeguard mode) and at the same time keeping strong eye on the opposition's status (position, quantity, availability) is the key responsibility of a commander in the battlefield. Battlefield surveillance is one of the strong applications of Wireless Sensor Networks (WSNs). A commander is not only liable to his above responsibilities, but also to manage his duties in an efficient way. For this reason, ensuring maximum destruction with minimum resources is a major concern of a commander in the battlefield. This paper focuses on the maximum destruction problem in military affairs. In the work of Jaigirdar and Islam (2012), the authors proposed two novel algorithms (Maximum degree analysis and Maximum clique analysis) that ensure the efficiency and cost-effectiveness of the above problem. A comparative study explaining the number of resources required for commencing required level of destruction made to the opponents has been provided in the paper. In this paper the authors have come forward with another algorithm for the same problem. With the simulation studies and comparative analysis of the same example set the authors in this paper demonstrate the effectiveness (in both the quality and quantity) of the new method to be best among the three.