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In this paper, we present a thorough characterization of the spatio-temporal communication graph of a large-scale real-world vehicle-based Delay Tolerant Network (DTN). Unlike previous studies which either use synthetic mobility traces or data from small networks (<; 50 nodes), our analysis is based on the mobility patterns of a large scale (~ 1200 nodes) real-world public transport network. In...
Position based routing protocols have lower routing overhead due to exploiting position information of mobile nodes for forwarding data. The performance of location based protocols depends on the precise knowledge of the destination's location. Therefore a location service is a prerequisite, from which a transmitter can find the approximate location of the receiver node. Several location service schemes...
Frequency offset and Doppler effect cause loss of orthogonality in orthogonal frequency division multiplexing (OFDM), which in turn may severely degrade receiver performance. Traditionally, most of the literature dealt with non-varying Doppler effect over OFDM subcarriers. However, in terrestrial ultra-wideband (UWB) OFDM radio frequency (RF) and in high data rate underwater acoustic communication...
In this paper, we propose a mobility model and present its simulation tool to generate realistic mobility traces for mobile ad hoc network. The mobility model is capable of creating realistic node movement pattern in the presence of geographic constraints by exploiting the concepts of anchors. The model dynamically places anchors depending upon the context of the environment through which nodes are...
Computer webcams have been used only for video chats and nowadays almost every internet user has a webcam with his/her computer. Similarly GPRS in mobile phones is often used to surf internet through mobile phones. As security is a big issue for a peaceful life a new technique has been suggested to use webcam and GPRS for visual security purpose. WMS is a new, easy and efficient video surveillance...
The defining characteristic of MANET such as dynamically changing network topology, resource-poor devices and multi-hop nature makes the data transmission very computational. Keeping in view such constraints and complexities, a number of routing protocols have been developed. In this paper, three routing protocols AODV (Ad hoc On demand distance vector), OLSR (Optimized link state routing) and ZRP...
Position based routing has been an attractive area of research due to being scalable and efficient in packet routing in mobile ad-hoc and sensor networks. A source node willing to send a packet to destination uses location service that provides the destination's approximate location. Most of the location service schemes in literature focused only on making the services scalable on location maintenance...
This paper proposes a medium access control (MAC) protocol, termed as CD-MMAC, for wireless networks that utilizes multiple channels and incorporates opportunistic cooperative diversity dynamically to improve its performance. The IEEE 802.11b standard protocol allows the use of multiple channels available at the physical layer but its MAC protocol is designed only for a single channel. The proposed...
In a multi-path channel an orthogonal frequency division multiplexing (OFDM) system is very robust to frequency selective fading, but it is sensitive to the time selective fading of the mobile channel. Time selectivity of the channel causes inter-carrier-interference (ICI) in OFDM, thereby degrading the performance significantly and increasing the computational complexity of the receiver. On the other...
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