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Spectrum handoff scheme with multiple attributes decision making for optimal network selection in cognitive radio networks

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Digital Communications and Networks 2017年第3期3卷 164-175页

作者： Krishan Kumar Arun Prakash rajeev tripathi Department oJ:Electronics and Communication Engineering Motilal Nehru National Institute of Technology Allahabad 211004 India Electronics and Communication Engineering Department National Institute of Technology Hamirpur 177005 India Director Motilal Nehru National Institute of Technology Allahabad 211004 India

It is envisaged that in future Cognitive Radio （CR） networks deployment, multiple radio access networks may coexist. The networks may have different characteristics in terms of multiple attributes. CRs will have choices of selecting the optimal network out of the available networks. Optimal network selection is a challenging task that can be performed by spectrum handoff with Multiple Attribute Decision Making （MADM）. The spectrum handoff decision with MADM provides wider and optimal choice with quality of service. This motivates the development of a spectrum handoff scheme with MADM methods such as simple additive weighting, a technique for order preference by similarity to the ideal solution, a grey relational analysis and a cost function based method, which is the objective of this study. The CR preferences are based on voice, video and data services, called triple play services. The numerical results show that all MADM methods are effective for selecting the optimal network for spectrum handoff with a reduced complexity for the spectrum handoff decision. The paper shows that the proposed spectrum handoff scheme can be effectively implemented to select the optimal network according to triple play services in CR networks.

关键词： Spectrum handoff Cognitive radio SAW TOPSIS GRA Cost function

Analytical Study of Planar Waveguide Sensor With a Metamaterial Guiding Layer

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Photonic Sensors 2017年第4期7卷 377-384页

作者： Anurag UPADHYAY Yogendra Kumar PRAJAPATI rajeev tripathi Department of Electronics and Communication Engineering Motilal Nehru National Institute of Technology Allahabad(U.P.) India

Sensitivities of three-layer and four-layer planar waveguide sensors having metamaterial as guiding layer are analyzed for p-polarization of incident light and compared with existing results. Proposed sensors show improved cover layer sensitivity for each case of the cover layer refractive index. Also, proposed sensors demonstrate improved adlayer sensitivity for different values of adlayer thickness and adlayer refractive indices. It is observed that metamaterial has increased the evanescent field due to the unconventional nature of it, by which values of cover layer sensitivity as well as adlayer sensitivity are enhanced.

关键词： Metamaterials sensitivity three-layer planar waveguides four-layer planar waveguides

Enhancement in QoS for Hybrid Networks Using IEEE 802.11e HCCA with Extended AODV Routing Protocol

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International Journal of Communications, Network and System Sciences 2015年第6期8卷 236-248页

作者： Shalini Singh rajeev tripathi Department of Electronics and Communication Engineering Graphic Era University Dehradun India Department of Electronics and Communication Engineering MN National Institute of Technology Allahabad India

The mobile ad hoc network (MANET) with infrastructure networks (hybrid networks) has several practical uses. The utility of hybrid network is increased in real time applications by providing some suitable quality of service. The quality thresholds are imposed on parameters like end-to-end delay (EED), jitter, packet delivery ratio (PDR) and throughput. This paper utilizes the extended ad hoc on-demand distance vector (AODV) routing protocol for communication between ad hoc network and fixed wired network. This paper also uses the IEEE 802.11e medium access control (MAC) function HCF Controlled Channel Access (HCCA) to support quality of service (QoS) in hybrid network. In this paper two simulation scenarios are analyzed for hybrid networks. The nodes in wireless ad hoc networks are mobile in one scenario and static in the other scenario. Both simulation scenarios are used to compare the performance of extended AODV with HCCA (IEEE 802.11e) and without HCCA (IEEE802.11) for real time voice over IP (VoIP) traffic. The extensive set of simulations results show that the performance of extended AODV with HCCA (IEEE 802.11e) improves QoS in hybrid network and it is unaffected whether the nodes in wireless ad hoc networks are mobile or static.

关键词： MANET HCCA Extended AODV Hybrid Network Quality of Service

Simulation &Performance Evaluation of QoS Routing Protocol for Adhoc Networks Using Directional Communication

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International Journal of Communications, Network and System Sciences 2012年第12期5卷 825-833页

作者： Arvind Kumar rajeev tripathi Department of Electronics and Communication Engineering Motilal Nehru National Institute of Technology Allahabad India

A wireless ad-hoc network is a self-organized wireless network without fixed or backbone infrastructure. All nodes have routing capability and use peer-to-peer packet transmission or forward packets to other node using multi hop communication. Now days mobile ad-hoc networks are being used for different applications and traffics, so it require quality of service (QoS) support in routing protocol. In this paper, a modified QoS routing protocol using directional antenna has been proposed. High and normal priority can be assigned based on type of traffic. All the nodes in the path used by high priority flow are reserved as high priority flow for that flow and normal priority flow will avoid the paths used by high priority flows. If no disjoint paths are available, there may be two possibilities: Normal priority flows are blocked and other is, normal priority flows are allow using the coupled path with high priority flow. Blocking the normal priority flow, QoS routing protocol improves the performance of high priority flow. This concept may be use in emergency communication. Simulation results show that by assigning the priorities to flows, performance of high priority flows are improved and it will further improved by blocking the normal priority flow.

关键词： Ad-hoc Networks Directional Antenna Routing Protocol QoS Routing Protocols

QoS Bandwidth Estimation Scheme for Delay Sensitive Applications in MANETs

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Communications and Network 2013年第1期5卷 1-8页

作者： Surjeet Arun Parkash rajeev tripathi Electronics & Communication Department Motilal Nehru National Institute of Technology Allahabad India

For last few years, MobileAd hoc Networks (MANETs) have attracted a great interest in case of wireless and multimedia technologies. Infrastructure less nature of MANETs makes Quality of Service (QoS) provisioning very challenging and important research aspect. To find a QoS constrained route from source to destination, we should be able to effectively determine the available resources throughout the route. The routing protocol is the most integral part of any type of QoS provisioning. It has to decide which route is able to fulfill the requirement of the desired QoS for specified application. In this paper, modification has been proposed in the existing MANET protocols to get the information about total path bandwidth for delay sensitive applications. It uses modified technique for bandwidth estimation and for route maintenance. The proposed protocol is implemented and simulated using NS-2 simulator. Results of our implementation show that there is much improvement in overheads without any impact on overall end-to-end throughput.

关键词： AODV MANETs NS-2 QoS

Bandwidth Constrained Priority-Based Routing Algorithm for Mobile Ad Hoc Networks

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International Journal of Communications, Network and System Sciences 2014年第5期7卷 141-150页

作者： Surjeet Arun Parkash rajeev tripathi Electronics & Communication Engineering Department Motilal Nehru National Institute of Technology (MNNIT) Allahabad India

A Mobile Ad hoc NETwork (MANET) is a dynamically formed self-configured network by an autonomous system of mobile nodes connected by wireless links. With the advancements of wireless technology, the necessity of Quality of Service (QoS) is increasing rapidly. Developing QoS constraint routing protocol for MANETs is still a challenging task. As the nodes are free to move randomly, most routing protocols for MANETs are susceptible to node mobility. As routing protocol has to decide which route is able to fulfill the requirement of the desired QoS, routing is the most important part to accomplish the specified application with desired QoS metrics. This paper is based on design of such a kind of proposed MANET algorithm that will estimate the available bandwidth throughout the path by assigning priority. Based on available bandwidth, packets are transferred from source to destination of the applications in queue based on priority. The proposed algorithm is implemented and simulated using NS-2 simulator. Results of our approach show that new protocol can significantly reduce overheads and decrease overall end-to-end delay.

关键词： AODV MANETs NS-2 QoS Routing

Fast Converging Generalized Turbo Decoding Scheme with Enhanced Throughput for Mobile Radio

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Communications and Network 2013年第1期5卷 9-15页

作者： Ashok Kumar Shankhwar Sachin Sharma rajeev tripathi Arun Prakash Ashutosh Singh Electronics and Communication Engineering Department Motilal Nehru National Institute of Technology Allahabad India Electronics Engineering Department Harcourt Butler Technological Institute Kanpur India

The use of turbo codes enhances the data transmission efficiency and optimizes the performance of a communication system over wireless fading channels. In this paper, we present a brief overview of the various components of the turbo coding scheme, analyze the complexities of the most popular turbo decoding algorithms, and discuss the various implementation methods of the maximum a posteriori (MAP) algorithm. The paper considers the well-known log-MAP decoding algorithm by a linear approximation of the correction function used by the max* operator. We propose a generalized decoding scheme that optimizes the existing MAP algorithm for faster convergence and better throughput on the basis of varying channel conditions. The proposed scheme of decoding reduces complexity and enhances the throughput with only a negligible loss in BER performance.

关键词： Log-MAP Decoding Mobile Radio Turbo Decoder UMTS Wireless

Performance Evaluation of Adaptive Modulation Based MC-CDMA System

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Wireless Engineering and Technology 2013年第1期4卷 54-58页

作者： Iftekhar Alam Vikas Srivastva Arun Prakash rajeev tripathi A. K. Shankhwar ECED MNNIT Allahabad India Electronics Engineering HBTI Kanpur India Wireless Communication and Computing IIIT Allahabad India

In today’s scenario mobile phones are not used only for messaging and talking, now we use mobiles also to access internet. For that we need higher data rates. Mobiles use wireless communication channel, which is very fast varying channel. To increase the data rate we have to utilize the full channel based on the channel condition. For that we have to estimate the channel condition and based on that we have to vary the data rate so that our communication system performance parameters (bit error rate, throughput) do not change beyond the accepted level. To increase the data rate we are also using the multi-carrier CDMA system in conjunction with the above described adaptive modulation. Adaptive modulation, in conjunction with MC-CDMA transmission system is very assuring way to increase data rate. In current scenario demand of very high data rates up to 100 Mbits/s may be achieved with this scheme. In this paper, adaptive modulation based M-ary QAM, M-PSK and M-ary CPM systems applied to a MC-CDMA system in Rayleigh fading channel environment have been investigated and BER performances of all these digital modulation schemes have been compared.

关键词： Adaptive Modulation CDMA Digital Modulation MC-CDMA OFDM

A Mathematical Study on Three Layered Oscillatory Blood Flow Through Stenosed Arteries

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Journal of Bionic Engineering 2012年第1期9卷 119-131页

作者： Dharmendra tripathi Department of Mathematics Indian Institute of Technology Ropar Punjab-140001 India

A mathematical model is constructed to examine the characteristics of three layered blood flow through the oscillatory cylindrical tube （stenosed arteries）. The proposed model basically consists three layers of blood （viscous fluids with different viscosities） named as core layer （red blood cells）, intermediate layer （platelets/white blood cells） and peripheral layer （plasma）. The analysis was restricted to propagation of small-amplitude harmonic waves, generated due to blood flow whose wave length is larger compared to the radius of the arterial segment. The impacts of viscosity of fluid in peripheral layer and intermediate layer on the interfaces, average flow rate, mechanical efficiency, trapping and reflux are discussed with the help of numerical and computational results. This model is the generalized form of the preceding models. On the basis of present discussion, it is found that the size of intermediate and peripheral layers reduces in expanded region and enhances in contracted region with the increasing viscosity of fluid in peripheral layer, whereas, opposite effect is observed for viscosity of fluid in intermediate layer. Final conclusion is that the average flow rate and mechanical efficiency increase with the increasing viscosity of fluid in both layers, however, the effects of the viscosity of fluid in both layers on trapping and reflux are opposite to each other.

关键词： mathematical model three layered oscillatory blood flow stenosed arteries mechanical efficiency trapping reflux