A mobile ad hoc network (MANET) consists of mobile wireless nodes. The communication between these mobile nodes is carried out without any centralized control. The ease of deployment and the infrastructure less nature of Mobile Ad hoc Networks (MANETs) make them highly desirable for the present day multi media communications. Traditional routing protocols may not suffice for real time communications it depends upon the conditions and our requirements. Though there has been considerable research in this area. In this paper, we are analyzing the performance of reactive routing protocol via increasing number of nodes and observing its effect on Quality of Service (QoS) of Mobile Adhoc Network. As we know routing protocols make an important role for improving QoS in Mobile Adhoc Network. The QoS depends upon several parameters like end-end delay, throughput, date drop and network load. The reactive routing protocol which we are considering is AODV for this scenario with MCHG [1] [2]. Here we are observing performance of Routing Protocol via enhancing the network size on the basis of following parameters: delay, throughput, traffic sent, traffic received, data dropped and network load. Network simulation tool used in simulation is OPNET Modeler (Ver. 14.0). Finally, this paper conducts simulation experiments in the conditions where we can improve QoS of MANET Network performance.

Performance of AODV Routing Protocol with Increasing the MANET Nodes and Its Effects on QoS of Mobile Ad Hoc Networks

Cognitive radio (CR) is a regulated technique for opportunistic access of idle resources. In CR, spectrum sensing is one of the key functionalities. It is used to sense the unused spectrum in an opportunistic manner. In this paper, we have proposed two-stage detectors for spectrum sensing in cognitive radio networks (CRN). The first stage consists of multiple energy detectors (MED), where each energy detector (ED) is having single antenna with fixed threshold (MED&#x5f;FT) for making a local binary decision, and if required, the second stage comprised of ED with adaptive double threshold (ED&#x5f;ADT) is invoked. The detection performance of the proposed scheme is compared with cyclostationary-based sensing method and adaptive spectrum sensing scheme. Numerical results show that the proposed scheme improves detection performance and outperforms the cyclostationary-based sensing method and adaptive spectrum sensing by 12.3&#x25; and 14.4&#x25; at signal to noise ratio (SNR) setting of as low as &#x2212;8&#x2009;dB, respectively. Performance was also measured in terms of sensing time. It is shown that the proposed scheme yields smaller sensing time than cyclostationary detection and adaptive spectrum sensing scheme in the order of 4.3&#x2009;ms and 0.1&#x2009;ms at &#x2212;20&#x2009;dB SNR, respectively.

https://journals.sagepub.com/doi/pdf/10.1155/2013/656495

Two-Stage Detectors with Multiple Energy Detectors and Adaptive Double Threshold in Cognitive Radio Networks

Cognitive Radio (CR) is a regulated technique for opportunistic access of idle resources. In CR, Spectrum sensing is one of its important key functionalities. It is used to sense the unused spectrum in an opportunistic manner. Energy detection constitutes a preferred approach for spectrum sensing in cognitive radio due to its simplicity and applicability. The traditional energy detection technique, which is based upon fixed threshold, is sensitive to noise uncertainty which is unavoidable in practical cases. This noise uncertainty gets the fixed threshold energy detector un-optimized in its performance. In this paper, an efficient energy detector is proposed for optimal CR performance. The proposed scheme is a dynamic threshold energy detection algorithm, in which, two threshold levels are utilized based upon the average energy received from the primary user (PU) during a specified period of observation. Thresholds evaluations are based upon estimating the noise uncertainty factor. These thresholds are used to maximize the probability of detection (Pd) and minimize the probability of false alarm (Pfa). Theoretical analysis and simulation results show the effectiveness of the proposed scheme in comparison to the traditional energy detection method with less increase in complexity.

Improved Cognitive Radio energy detection algorithm based upon noise uncertainty estimation

Cognitive Radio (CR) is an intelligent technique for opportunistic access of idle resources. In CR, Spectrum sensing is one of its important key functionalities. It is used to sense the unused spectrum in an opportunistic manner. Energy detection constitutes a preferred approach for spectrum sensing in cognitive radio due to its simplicity and applicability. The conventional energy detection technique, which is based upon fixed threshold, is sensitive to noise uncertainty which is unavoidable in practical cases. This noise uncertainty gets the fixed threshold energy detector un-optimized in its performance. In this paper, an efficient energy detector is proposed for optimal CR performance. The proposed scheme is based upon a dynamic threshold energy detection algorithm, in which, the decision threshold is toggled between two levels based upon the average energy received from the primary user (PU) during a specified period of observation. Thresholds evaluations are based upon estimating the noise uncertainty factor. These thresholds are used to maximize the probability of detection (P d ) and minimize the probability of false alarm (P fa ). Theoretical analysis and simulation results show the effectiveness of the proposed scheme in comparison to the conventional energy detection method with less increase in complexity.

An efficient dynamic thresholds energy detection technique for Cognitive Radio spectrum sensing

Cognitive Radio (CR) is a regulated technique for opportunistic access of idle resources and it is expected that the golden service of spectrum sensing is to be achieved via the robust sensing technique to sense the unused spectrum in an opportunistic manner. In this paper, we propose multiple energy detectors (MED) utilising adaptive double-threshold (ADT) for spectrum sensing. In the present framework of CR networks, each CR node is equipped with MED and each energy detector with single antenna. Numerical results show that it improves detection performance at very low signal-to-noise ratio (SNR), and overcomes sensing failure problem. Further, the scheme was analysed in conjunction with cooperative spectrum sensing (CSS), where each CR users employ selection combining (SC) scheme to take global decision by MED with adaptive double-threshold (MED_ADT). It is further found that this arrangement improves detection performance around 6.3% as compared to hierarchical with quantisation method at –10 dB SNR, u...

Cooperative spectrum sensing in multiple energy detectors based cognitive radio networks using adaptive double-threshold scheme

Cognitive radio is an enabling technology to solve the spectrum scarcity problem in wireless communication. This is based on the concept of opportunistic spectrum access. Spectrum sensing is one of the most important functions in cognitive radio (CR) implementation. In this paper, we propose a multiple energy detectors (MED) based scheme with improved detection performance at low SNR. We consider a framework of CR networks in which each CR node is equipped with MEDs and each energy detector with single antenna. An analytical model is developed for performance evaluation in terms of probability of false alarm Pf, and probability of detection Pd. Numerical results obtained in Rayleigh fading channel show that the proposed scheme performs better as compared to conventional energy detector (ED).

/pdf/multiple-energy-detectors-based-spectrum-sensing-for-297zfealpi.pdf

Multiple Energy Detectors based Spectrum Sensing for Cognitive Radio Networks

Mobile Ad Hoc Network (MANET) consists of dynamic topology as nodes in the network are mobile, and connected via wireless links. Nodes within the cluster communicate directly. However, nodes communicate outside the cluster through a centralized node that is called a Cluster Head Gateway (CHG) [1]. As the number of nodes increases complexity of MANET increases in various issues. Ad hoc wireless network is a dynamic multi-hop network, which is established by a group of mobile nodes on a shared wireless channel. The shared medium and the multi-hop nature of the wireless ad hoc networks pose fundamental challenges to the design of an effective resource allocation algorithm to maximize the aggregated utility of flows, maintaining basic fairness among the multiple flows. An elected Cluster Head Gateway (CHG) is assigned for communication with all other clusters. The centralized Cluster Head Gateway can become a bottleneck and possibly cause a lower connectivity for the clustering system. In this paper we propose a mechanism in which communication outside the cluster is distributed through separate Cluster Head Gateways. We will discuss how the averaged connectivity for the clustering system increases considerably. We also show that the increase in overall connectivity is by the increase/add Cluster Head Gateways. Additionally, the routing reliability to outside the cluster is increased since routes to different clusters use distinct Cluster Head Gateways. Finally, this paper conducts simulation experiments in the conditions where we using Multiple CHG to the nodes within a network.

Cluster Head Gateway approach using in Integrated Mobile Ad hoc Network

/pdf/multiple-energy-detectors-based-spectrum-sensing-for-5edi71g6s3.pdf

Multiple Energy Detectors Based Spectrum Sensing for Cognitive Radio Networks

Unhindered security accomplishment in WSNs has always been threating task. Due to its compelling and tangled nature a lot of research work is going on all around the globe. Out of the various key topics Broadcasting from sink node to other sensor nodes has been the most sophisticated matter which is still untapped. A base station frequently broadcasts messages such as network query, time synchronization, multi-hop routing etc. The basic problem in such communication is source authentication because of untrusted receivers and unreliable communication environment. Therefore a unique topology is in demand. Keeping this theme in mind our proposed paper has come-up with such unique topology and an algorithm which can help sink node not only for broadcasting but also for multicasting and unicasting. Thus helps in improving security to a greater level.

/pdf/bmu-routing-algorithm-through-smart-role-of-intermediate-40rw6e0jkd.pdf

BMU Routing Algorithm through Smart Role of Intermediate Nodes in WSNs

This paper presents double stage energy detectors for spectrum sensing (SS). The first stage carries fixed threshold (FT) based energy detector (ED), and the second stage carries adaptive double threshold (ADT) based ED. Numerical analysis has been carried out on the basis of results obtained and shows that proposed scheme outperforms the cyclostationary based sensing method and adaptive SS by 12.9% and 15% at -- 8 dB signal-to-noise ratio (SNR), respectively. It also shows that the proposed scheme takes shorter detection time period than cyclostationary detection and adaptive SS scheme in the order of 5 ms and 0.8 ms at - 20 dB SNR , respectively.

Ashish Bagwari

Papers

Multiple Energy Detectors based Spectrum Sensing for Cognitive Radio Networks

Cluster Head Gateway approach using in Integrated Mobile Ad hoc Network

Multiple Energy Detectors Based Spectrum Sensing for Cognitive Radio Networks

BMU Routing Algorithm through Smart Role of Intermediate Nodes in WSNs

Double Stage Energy Detectors for Sensing Spectrum in Cognitive Radio Networks