Ad Hoc network is a temporal network which is managed by autonomous nodes which have the ability to communicate with each other without having fixed network infrastructure or any central base station. Due to some reasons such as dynamic changes of the network topology, trusting the nodes to each other, lack of fixed substructure for the analysis of nodes' behaviours and loss of specific offensive lines, this type of networks is not supportive against malicious nodes' attacks. One of these attacks is black hole attack. In this attack, the malicious nodes absorb data packets and destroy them. Thus, it is essential to present an algorithm against the black hole attacks. This article suggests a new algorithm which enhances the security of AODV routing protocol to encounter the black hole attacks. This algorithm tries to identify malicious nodes according to nodes' behaviours in an Ad Hoc network and delete them from routing. The suggested algorithm is simulated by NS2. The simulation results show some improvements in end-to-end delay and packet delivery rate in the suggested algorithm.

A modified algorithm to improve security and performance of AODV protocol against black hole attack

A new quad-band bandpass filter using asymmetric stepped impedance resonators

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.

Resisting blackhole attacks on MANETs

In this manuscript, a compact superwideband monopole antenna with triple notched band characteristics is presented and is experimentally investigated. Proposed antenna is also suitable for lower band of applications including Bluetooth and LTE2600 bands. Superwideband bandwidth with bandwidth ratio ≥ 10:1 is obtained by using two identical ellipse which are placed at 70° with reference to major axis. A fractal stub is used to notch WiMAX interfering band while WLAN and DSS bands are notched by etching modified rectangular slots on the radiating patch. Antenna also constitutes slotted ground with chamfered corners for better matching of impedance. Proposed antenna is also investigated in terms of frequency, time and space domain. Antenna offers a wider superwideband bandwidth with VSWR ≤ 2 for 2.34 GHz to 20.00 GHz. In time domain, antenna offers constant group delay in entire operating bandwidth and acceptable impulse response for input signal. Also, antenna offers maximum gain of 4.98 dBi and radiation efficiency of 89%. Stable radiation pattern and above features of proposed antenna suggest antenna to be a good candidate for numerous applications in wireless system.

Integrated bluetooth/LTE2600 superwideband monopole antenna with triple notched (WiMAX/WLAN/DSS) band characteristics for UWB/X/Ku band wireless network applications

Mobile Ad Hoc NETworks (MANETs) have become eminent resources for providing communication to military and other defence establishments operating in the conventional battlefield scenario in enemy territory or Counter Insurgency/Counter Terrorism operations beyond the reach of a permanent network infrastructure. However, MANET's inherent topology lack in defensive procedures and are thus, vulnerable to security attacks. Single and Cooperative Black hole attacks are one of the prominent security coercions in MANET wherein malicious nodes deceives source node by promoting self-destined routes during the route discovery process and absorbs the packets meant for Destination node. A black hole node might cooperate with other black hole node resulting in a cooperative Black hole Attack. Researchers around the globe have proposed diverse detection techniques and schemes to detect this type of security attack. This paper proposes a hybrid technique to alleviate the effects of Black hole attack keeping the military perspective in mind. Simulations have been done using NS-2 simulator. Metrics used are Delay, throughput and Packet Delivery Ratio.

Mitigating effects of Black hole Attack in Mobile Ad-Hoc NETworks: Military perspective

Mobile ad hoc networks (MANET) are collections of self-organizing mobile nodes with dynamic topologies and have no fixed infrastructure. MANET do not have centralized administration, here nodes act as both host as well as router and communicate by forwarding packets for each other in multi hop way, because of the fundamental characteristics like, the open medium, dynamic network topology, lack of centralized monitoring and management these networks are particularly vulnerable to various types of attacks. One of the routing protocol being used for wireless network is Ad hoc on demand distance vector (AODV). Black hole is one of the attack that is launched on AODV. In this attack, the attacker claims the shortest route to the destination and hinders the communication by dropping all the packets. In this paper, a new solution against the Black Hole attack is proposed. This paper demonstrates a timer based detection approach for identifying black hole node. In network layer we proposed a Timer based method to overhear the next node action. The simulation results using EXata-Cyber shows that in a dynamic network most of the malicious nodes can be detected and that results in an improved packet delivery ratio.

Preventing Black Hole Attack in AODV using timer-based detection mechanism

Routes discovery that can provide reliable data transmission in Mobile Ad-hoc Networks is challenging due to its wireless channel characteristics and dynamic transmission environment. Link failure frequently occurs in ad-hoc networks due to nodes' mobile nature, which is not static to their position. The dynamic characteristic of the mobile ad hoc network facilitates multi-path routing protocols as a novel research area. This paper comprises an approach based on ACO acknowledge as NDLR-MP, an ACO-based node-disjoint multi-path routing protocol using AODV protocol. The proposed protocol intends to find all node-disjoint paths from source to destination in a single route discovery process that will conclusively minimize the routing control overhead. In this approach (NDLR-MP), the data packet transportation is initialized just after the first path is determined, wherein all the other secondary routes are also concurrently discovered. Additionally, we have also suggested an efficient local route repair method that redirects the current traffic to an available route if a broken link to the next hop is positioned towards the destination. The proposed route detection and maintenance methods can be considered as performance evaluation metrics. Moreover, results obtained on the Network Simulator (EXata 2.0) have shown the performance and effectiveness of the proposed approach of NDLR-MP in contrast to the AODV protocol, which has significantly amplified the performance of the provided protocol. The parameters like route availability, control overhead, average E-2-E, and PDR are comparing with the existing protocol.

Ant Colony Based Node Disjoint Local Repair in Multipath Routing in MANET Network

This paper presents the results related to performance evaluation of 4-stage multiuser detector for asynchronous DS-CDMA system To meet the real-time requirements for asynchronous multiuser detection, a bit streaming, parallel interference cancellation (PIC) cascade architecture is used An asynchronous multiuser detection involves block-based computations and matrix inversions The paper covers iterative-based suboptimal schemes that have been used to decrease the computational complexity, eliminate the need for matrix inversions, decreases the execution time, reduces the memory requirements by making use of joint estimation and detection process that gives better performance than the independent parameter estimation method The stages of the iteration are cascaded and bits processed in a streaming fashion The simulation has been carried out for asynchronous DS-CDMA system by varying two parameters, ie, number of users and number of stages The simulation results exhibit that system gives better performance at 3rd stage and the number of users decrease with increase in signal to noise ratio (SNR)

Performance Evaluation of Multistage Multiuser Detector for Asynchronous DS-CDMA System

In this article, the authors present a hepta band metamaterial inspired hybrid fractal octagonal shape antenna for wireless applications. Multiband characteristics in the proposed design are achieved by hybrid fractal form of Moore curve and Koch curve with metamaterial loading. A well matched impedance bandwidth (S11 ≤ −10 dB) is accomplished at seven microwave frequency bands, Upper L band (1.93 ∼ 2.08 GHz), S band, WiMAX (3.3 ∼ 3.7 GHz), C band, WLAN (5.4 ∼ 5.9 GHz), C band, IEEE INSAT application (6.5 ∼ 7.2 GHz), X band terrestrial broadband, space communication and Radio Navigation (RN) application (8.51 ∼ 11.05 GHz), Lower Ku band direct broadcast satellite service (12.2 ∼ 12.7 GHz), and Middle Ku band satellite communication operating band (14.73 ∼ 15.84 GHz) covering various wireless applications. The antenna achieves hexa/penta band characteristics during switching ON/OFF state of PIN diode placed between the Moore curve structure (attached with centered SRR cell) and feedline. Radiation patterns are found in stable forms at all the resonant frequencies. Measured results of the proposed design are compared with simulated ones indicating good agreement between them.

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A Metamaterial Loaded Hybrid Fractal Hepta-Band Antenna for Wireless Applications with Reconfigurability Characteristics

Free space optics systems (FSO) has been proved to be for cost effective providing high security, easy installation, wider bandwidth and high data rate information exchange. FSO also solve the last mile problem to solution. Main limitation of FSO is the attenuation effect due to environment. Haze and rain are the most important factor to the free space optical (FSO) link. Signal power has been increased using optical amplifier in FSO by WDM and then analyzed at 2.5 Gbps to get the desired signal. The WDM based FSO system for worst weather condition using hybrid configuration of optical amplifier (EDFA, SOA) is proposed which provide a solution for more efficient system and low cost. Further the system is compared with the existing results. The proposed model enhance the performance in terms of BER and Q-factor at the receiver end of the system.

Lokesh Tharani

Papers

Preventing Black Hole Attack in AODV using timer-based detection mechanism

Ant Colony Based Node Disjoint Local Repair in Multipath Routing in MANET Network

Performance Evaluation of Multistage Multiuser Detector for Asynchronous DS-CDMA System

A Metamaterial Loaded Hybrid Fractal Hepta-Band Antenna for Wireless Applications with Reconfigurability Characteristics

Performance Evaluation of WDM-FSO Based Hybrid Optical Amplifier Using Bessel Filter