Sandeep Dhariwal

Performance Evaluation of Mobile Ad Hoc Networks with Reactive and Proactive Routing Protocols and Mobility Models

Mobile Ad hoc Network is a collection of wireless mobile nodes dynamically forming a temporary network without the aid of any established infrastructure or centralized administration. Routing protocols in mobile ad hoc network helps node to send and receive packets. In this paper we are doing study of AODV, DSR (Reactive), and OLSR, DSDV, TORA (Proactive) protocols based on various mobility models [3] such as RPGM, CMM and RWP . In this paper we evaluate performance of five types of routing protocols (AODV, DSR, OLSR, DSDV and TORA) based on packet delivery ratio, average end to end delay, routing overhead and throughput. In this paper we will analyze and compare the performance of reactive and proactive routing protocols under different mobility models using NS-2 simulator in the area of 700 x 700 m 2 .

Modeling transport properties of single-wall carbon nanotube between metal and graphene electrodes

In this article, transport properties of a single-wall carbon nanotube having chirality (4, 0), connected to copper, gold and graphene electrodes, have been investigated. Electronic structures have been analyzed using the density functional theory calculator. Transport properties of the devices formed by interfacing of single-wall carbon nanotube and electrodes are computed using the nonequilibrium Green’s functional method coupled with density functional theory approach. Contact effects due to metal–carbon nanotube interface have significant impact on transport properties of charge carriers. Therefore, transport properties have been critically analyzed with the help of transmission spectra, differential conductance and conductance plots and I–V characteristics. From these results, it has been concluded that formulation of the electrode material is not the single-factor responsible for creating conduction problems. Along with the electrode material, interface position of metal–carbon nanotube configuration and heterostructure contacts are also responsible in influencing transport phenomenon. In this way, varying the contact geometry is found to play an important role in integrated circuit interconnect technologies for exploring the transport properties. Gold is best among all three simulated contact electrodes, and for low-power applications, graphene can be next choice over an applied bias range of −1 to +1 V. Atomistix software tool has been used to analyze transport properties of interconnect models.

Analysis of TCP Performance over Mobile Ad Hoc Networks with Varying Speed

Transmission Control Protocol (TCP) is a connection oriented protocol for reliable end-to-end data delivery over IP networks. TCP is unable to distinguish between packet losses induced by network congestion and wireless packet losses. TCP assume every packet loss or delay due to congestion. Wireless Mobile Ad-hoc networks offer challenges to TCP congestion control mechanism because mobile Ad-hoc networks encounter several types of losses or delays that are unrelated to congestion such as high BER, delays due to reordering of packets. Several approaches have been proposed to deal with this issue that can be categorized to either end system based or network assisted. This paper will present such approaches & their characteristics. Moreover the paper points out comparison of the performance of different routing protocols with varying speed & maximum packets size. Evaluation of the performance of different TCP variants over different routing protocols has also been performed.