1,721,020 research outputs found
A Simulator for Creating Drones Networks and Providing Users Connectivity
Full text linkUnmanned aerial vehicles are devices able to perform many different tasks that can help human activity in many processes. One of the most important use regards the possibility of giving wireless connectivity to user in a specific area. These new typologies of networks are called Flying Adhoc Network. Their use benefit all those situations of emergency where the traditional communications may have many issues, due to the specific event. Different types of natural disasters (such as climatological, meteorological, hydrological, geophysical) can result in many deaths and many economic damages. In these situations, drones can provide an additional or complementary access network, supporting web services and multimedia traffic, helping people involved in the rescue. Hence, it is clear that the possibility of using a simulator can result in a huge help to the research community. So, in this work, a Flying Ad-hoc Network simulator is proposed, able to simulate different scenarios with different coverage areas. In particular, emphasis is given to new coverage and human mobility models, in order to support more realistic situations. Some simulations have been led out to show how the simulator works
Evaluation of TCP versions over GEO satellite links
No full textIn this paper an attempt to evaluate the performance of different versions of TCP over satellite link has been performed. The throughput of the protocols has been graphed and considerations have been carried out. The considered protocols can be divided in two main categories: terrestrial protocols and satellite protocols. In the terrestrial category the well performing TCP Sack protocol has been illustrated together with TCP WestWood and his modified version, TCP WestWood+, while in the satellite category Satellite Communication Transport Protocol (SCPS-TP), and Satellite Transmission Protocol (STP) have been shown and compared. The considered protocols have been analyzed on well-known satellite link: GEO satellite link. In particular, a classical GEO satellite link and a single connection between two terminals have been considered
A new threshold switching scheme for a DVB-RCS+M return link in a terrestrian scenario
No full textThe new standard for DVB-RCS includes guidelines for mobile user in the market of aircraft, maritime and terrestrial. The standard suggests the possibility of using, in this scenario, a continuous carrier operation mode in the return channel beside the classical MF-TDMA mode. In this context it can be important a mechanism for switching between these two modalities in order to exploit in a better way the satellite resources. In this paper, after showing the typologies of applications considered in the simulation, a proposal of a novel switching mechanism is presented and the simulation results are reported in order to provide some guidelines to the satellite operators that want to adopt in their satellite system this hybrid mode. © 2012 IEEE
Routing optimization in dynamic networks based on a new entropy metric
No full textA key role in the modern telecommunication networks is played by routing aspects as the great number of works present in literature proves. In particular, in the mobile ad-hoc networks routing is a fundamental aspects because the mobile devices nature and their elevate dynamism. In fact, it is important to have the possibility of finding the minimum overhead for connectivity in the network and, calculate the communication potential through the analysis of different parameters. The focus of this paper is represented by the analysis of the entropy in this type of mobile networks. The entropy gives the possibility of studying and predicting the dynamics of mobile nodes. The knowledge of these aspects can help to optimise some key features of wireless mobile communications, such as nodes stability, channel failures, and routing costs. Many simulation campaigns have been carried out by taking into account the movement of the real nodes, obtaining beneficial results, which confirm the effectiveness of the proposed study
Node Re-Routing and Congestion Reduction Scheme for Wireless Vehicular Networks
No full textRecently, the interest of research is going to be focused on the emerging vehicular ad-hoc networks paradigm. In these networks, vehicles communicate with each other and have the possibility of exploiting a distributed approach, typical of ad-hoc networks, which allow mobile nodes (vehicles) to communicate with each other. Thanks to the different standards for this kind of network, such as DSRC, WAVE/IEEE802.11p, the researchers have the possibility of designing and developing new MAC and routing algorithms, trying to enhance the mobile users experience in the mobile environment. In this paper, the attention is focused on the optimization of traffic flowing in a vehicular environment with vehicle-2-roadside capability. The proposed idea exploits the information that is gathered by road-side units with the main aim of redirecting traffic flows (in terms of vehicles) to less congested roads, with an overall system optimization, also in terms of Carbon Dioxide emissions reduction. A deep campaign of simulations has been carried out to give more effectiveness to our proposal
A new switching scheme for DVB-RCS+M return link in a land based scenario
No full textThe standard for DVB-RCS+M includes important guidelines for better exploiting the satellite resource in the return channel. An important suggestion is the possibility of using a continuous carrier operation mode in the return channel beyond the classical MF-TDMA mode. In order to realize it a mechanism for switching between these two modalities has to be used. In this paper, after showing the typologies of applications considered in the simulation, a proposal of a novel switching mechanism is presented and the simulation results are reported in order to provide some guidelines to the satellite operators that want to adopt in their satellite system this hybrid mode. © 2012 IEEE
A Novel per degradation model for VANETs
No full textIn this work, we present a new channel modeling approach for vehicular networks, where there are frequent topology changes due to a high grade of mobility. The Markov-based trace analysis is used to analyze packet error rate degradation dynamics in relation to both Doppler shift and signal to noise ratio. After the model definition, we applied an additional polynomial regression to remove dependence on boundary parameters. Differing from existing works, our idea takes into account the stochastic behavior of wireless links, in spite of most of the existing closed forms. We considered MATLAB for evaluation of the proposed model. We also propose numerical results as a possible application of our study
A simulator for drones and Fanet management supporting multimedia traffic under human mobility
Full text linkIn this paper a simulator for the management of a team of Unmanned Aerial Vehicles (UAVs) and drones has been proposed. This new network is known as Fly Ad-Hoc Network (FANET), and it is a particular type of Mobile Ad-Hoc Network (MANET) but with some specific aspects that allow to provide new services in future generation networks. One of the possible applications is emergency situations or scenario where drones can provide an additional or complementary access networks supporting web services and multimedia traffic. In this paper a simulator for FANET deploying has been proposed providing the possibility to simulate different scenarios with different coverage areas. New coverage model has been included in the features and also interesting human mobility model to support more realistic users mobility. Moreover, additional modules for traffic pattern generation have been implemented to create scenario where mobile users can activate multimedia calls and traffic on FANET. Some simulations have been led out to show how the simulator works
Bio-inspired routing over FANET in emergency situations to support multimedia traffic
No full textA QoS routing to select the best paths among Drones supporting incoming calls and multimedia traffic in emergency or critical situations is proposed. In situations where drones' teams are requested to cover areas where mobile users can need to communicate under the absence of network infrastructure, a self-organized on-the fly network becomes an essential goal. Cooperating with a critical network infrastructure, deploying a QoS aware path selection strategy supporting QoS requests and multimedia traffic such as VoIP and Video traffic can become a key issue to face. In this paper, a bio-inspired strategy to maintain the drones' network topology in a ligthway manner is proposed. Two metrics considered in a joint unified metric are proposed in order to balance traffic load and, at the same time, select the shortest routes. A comparison with an enhanced Link-State (LS) routing has been performed where the minimum hop count metric has been considered together to a LS routing with maximum available bandwidth metric. Performance evaluation has been evaluated in terms of control overhead, number or admitted calls, average bandwidth utilization
Prediction and QoS Enhancement in New Generation Cellular Networks with Mobile Hosts: A Survey on Different Protocols and Conventional/Unconventional Approaches
No full textNowadays, interest in mobile communications is growing rapidly due to the high level of device development, which permits the achievement of good objectives in terms of quality of service (QoS) for user satisfaction during active data flows. The increasing mobile client populations use different mobile devices to access the wireless medium and many applications are being developed to satisfy eager client requirements. Independently on the considered architecture (WLAN, UMTS, LTE, etc.), mobility represents a great advantage for user comfort, but it needs to be managed in an adequate manner in order to avoid service disruptions or unacceptable degradation of the perceived quality. In this paper, the concept of cell-mobility prediction is considered and we show how the analysis of user behavior, in terms of mobility, can be exploited to enhance QoS levels in current communications among mobile hosts and base stations (coverage cells, in general). This paper surveys different unconventional approaches and protocols, showing how it is possible to consider in-advance bandwidth reservations to achieve service continuity, avoiding call droppings during active sessions. First, we present the importance of in-advance reserving in wireless cellular networks, then we discuss the existing protocols and approaches for determining the most suitable future cells
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