13,822 research outputs found

    Optimisation of Mobile Communication Networks - OMCO NET

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    The mini conference “Optimisation of Mobile Communication Networks” focuses on advanced methods for search and optimisation applied to wireless communication networks. It is sponsored by Research & Enterprise Fund Southampton Solent University. The conference strives to widen knowledge on advanced search methods capable of optimisation of wireless communications networks. The aim is to provide a forum for exchange of recent knowledge, new ideas and trends in this progressive and challenging area. The conference will popularise new successful approaches on resolving hard tasks such as minimisation of transmit power, cooperative and optimal routing

    Vehicular Inter-Networking via Named Data

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    In this paper we apply the Named Data Networking, a newly proposed Internet architecture, to networking vehicles on the run. Our initial design, dubbed V-NDN, illustrates NDN's promising potential in providing a unifying architecture that enables networking among all computing devices independent from whether they are connected through wired infrastructure, ad hoc, or intermittent DTN. This paper describes the prototype implementation of V-NDN and its preliminary performance assessment

    Mobile ad hoc networks for intelligent systems

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    Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. Mobile ad hoc networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. They do not rely on specialized routers for path discovery and traffic routing. Research on ad hoc networks has been extensively investigated in the past few years and related work has focused on many of the layers of the communications architecture. This research intends to investigate applications of MANET for intelligent systems, including intelligent transportation system (ITS), sensor network and mobile intelligent robot network, and propose some approaches to topology management, link layer multiple access and routing algorithms. Their performance is evaluated by theoretical analysis and off-the-shelf simulation tools. Most current research on ad hoc networks assumes the availability of IEEE 802.11. However, the RTS/CTS protocol of 802.11 still leads to packet collision which in turn decreases the network throughput and lifetime. For sensor networks, sensors are mostly battery operated. Hence, resolving packet collision may improve network lifetime by saving valuable power. Using space and network diversity combination, this work proposes a new packet separation approach to packet collision caused by masked nodes. Inter-vehicle communication is a key component of ITS and it is also called vehicular ad hoc network. VANET has many features different from regular MANETs in terms of mobility, network size and connectivity. Given rapid topology changes and network partitioning, this work studies how to organize the numerous vehicular nodes and establish message paths between any pair of vehicular nodes if they are not apart too far away. In urban areas, the inter-vehicle communication has different requirements and constraints than highway environments. The proposed position-based routing strategy for VANETs utilizes the traffic pattern in city environments. Packets are forwarded based on traffic lights timing sequence and the moving direction of relaying vehicles. A multicast protocol is also introduced to visualize the real time road traffic with customized scale. Only vehicles related to a source node\u27s planned trajectory will reply the query packet. The visualized real time traffic information therefore helps the driver make better decision in route planning when traffic congestion happens. Nowadays robots become more and more powerful and intelligent. They can take part in operations in a cooperative manner which makes distributed control necessary. Ad hoc robot communication network is still fresh field for researchers working on networking technology. This work investigates some key issues in robot ad hoc network and evaluate the challenges while establishing robot ad hoc networks

    An overview of VANET vehicular networks

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    Today, with the development of intercity and metropolitan roadways and with various cars moving in various directions, there is a greater need than ever for a network to coordinate commutes. Nowadays, people spend a lot of time in their vehicles. Smart automobiles have developed to make that time safer, more effective, more fun, pollution-free, and affordable. However, maintaining the optimum use of resources and addressing rising needs continues to be a challenge given the popularity of vehicle users and the growing diversity of requests for various services. As a result, VANET will require modernized working practices in the future. Modern intelligent transportation management and driver assistance systems are created using cutting-edge communication technology. Vehicular Ad-hoc networks promise to increase transportation effectiveness, accident prevention, and pedestrian comfort by allowing automobiles and road infrastructure to communicate entertainment and traffic information. By constructing thorough frameworks, workflow patterns, and update procedures, including block-chain, artificial intelligence, and SDN (Software Defined Networking), this paper addresses VANET-related technologies, future advances, and related challenges. An overview of the VANET upgrade solution is given in this document in order to handle potential future problems

    Vehicle to vehicle (V2V) wireless communications

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    This work focuses on the vehicle-to-vehicle (V2V) communication, its current challenges, future perspective and possible improvement.V2V communication is characterized by the dynamic environment, high mobility, nonpredective scenario, propagation effects, and also communicating antenna's positions. This peculiarity of V2V wireless communication makes channel modelling and the vehicular propagation quite challenging. In this work, firstly we studied the present context of V2V communication also known as Vehicular Ad-hoc Netwok (VANET) including ongoing researches and studies particularly related to Dedicated Short Range Communication (DSRC), specifically designed for automotive uses with corresponding set of protocols and standards. Secondly, we focused on communication models and improvement of these models to make them more suitable, reliable and efficient for the V2V environment. As specifies the standard, OFDM is used in V2V communication, Adaptable OFDM transceiver was designed. Some parameters as performance analytics are used to compare the improvement with the actual situation. For the enhancement of physical layer of V2V communication, this work is focused in the study of MIMO channel instead of SISO. In the designed transceiver both SISO and MIMO were implemented and studied successfully

    Dealing with mobility: Understanding access anytime, anywhere

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    The rapid and accelerating move towards the adoption and use of mobile technologies has increasingly provided people and organisations with the ability to work away from the office and on the move. The new ways of working afforded by these technologies are often characterised in terms of access to information and people ‘anytime, anywhere’. This paper presents a study of mobile workers that highlights different facets of access to remote people and information, and different facets of anytime, anywhere. Four key factors in mobile work are identified from the study: the role of planning, working in ‘dead time’, accessing remote technological and informational resources, and monitoring the activities of remote colleagues. By reflecting on these issues, we can better understand the role of technology and artefact use in mobile work and identify the opportunities for the development of appropriate technological solutions to support mobile workers

    Measurement Based Channel Characterization and Modeling for Vehicle-to-Vehicle Communications

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    Vehicle-to-Vehicle (V2V) communication is a challenging but fast growing technology that has potential to enhance traffic safety and efficiency. It can also provide environmental benefits in terms of reduced fuel consumption. The effectiveness and reliability of these applications highly depends on the quality of the V2V communication link, which rely upon the properties of the propagation channel. Therefore, understanding the properties of the propagation channel becomes extremely important. This thesis aims to fill some gaps of knowledge in V2V channel research by addressing four different topics. The first topic is channel characterization of some important safety critical scenarios (papers I and II). Second, is the accuracy or validation study of existing channel models for these safety critical scenarios (papers III and IV). Third, is about channel modeling (paper V) and, the fourth topic is the impact of antenna placement on vehicles and the possible diversity gains. This thesis consists of an introduction and six papers: Paper I presents a double directional analysis of vehicular channels based on channel measurement data. Using SAGE, a high-resolution algorithm for parameter estimation, we estimate channel parameters to identify underlying propagation mechanisms. It is found that, single-bounce reflections from static objects are dominating propagation mechanisms in the absence of line-of-sight (LOS). Directional spread is observed to be high, which encourages the use of diversity-based methods. Paper II presents results for V2V channel characterization based on channel measurements conducted for merging lanes on highway, and four-way street intersection scenarios. It is found that the merging lane scenario has the worst propagation condition due to lack of scatterers. Signal reception is possible only with the present LOS component given that the antenna has a good gain in the direction of LOS. Thus designing an antenna that has an omni-directional gain, or using multiple antennas that radiate towards different directions become more important for such safety critical scenarios. Paper III presents the results of an accuracy study of a deterministic ray tracing channel model for vehicle-to-vehicle (V2V) communication, that is compared against channel measurement data. It is found that the results from measurement and simulation show a good agreement especially in LOS situations where as in NLOS situations the simulations are accurate as far as existing physical phenomena of wave propagation are captured by the implemented algorithm. Paper IV presents the results of a validation study of a stochastic NLOS pathloss and fading model named VirtualSource11p for V2V communication in urban street intersections. The reference model is validated with the help of independent channel measurement data. It is found that the model is flexible and fits well to most of the measurements with a few exceptions, and we propose minor modifications to the model for increased accuracy. Paper V presents a shadow fading model targeting system simulations based on channel measurements. The model parameters are extracted from measurement data, which is separated into three categories; line-of-sight (LOS), LOS obstructed by vehicles (OLOS), and LOS blocked by buildings (NLOS), with the help of video information recorded during the measurements. It is found that vehicles obstructing the LOS induce an additional attenuation in the received signal power. The results from system level vehicular ad hoc network (VANET) simulations are also presented, showing that the LOS obstruction affects the packet reception probability and this can not be ignored. Paper VI investigates the impact of antenna placement based on channel measurements performed with four omni-directional antennas mounted on the roof, bumper, windscreen and left-side mirror of the transmitter and receiver cars. We use diversity combining methods to evaluate the performance differences for all possible single-input single-output (SIMO), multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) link combinations. This investigation suggests that a pair of antennas with complementary properties, e.g., a roof mounted antenna together with a bumper antenna is a good solution for obtaining the best reception performance, in most of the propagation environments. In summary, this thesis describes the channel behavior for safety-critical scenarios by statistical means and models it so that the system performance can be assessed in a realistic manner. In addition to that the influence of different antenna arrangements has also been studied to exploit the spatial diversity and to mitigate the shadowing effects. The presented work can thus enable more efficient design of future V2V communication systems
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