A compact multiband antennas for Long Term Evolution (LTE) applications is a challenge. Both the frequencies of new wireless technologies and new frequency bands must be covered. The lower end of the 0.7- 3.5 GHz band is especially difficult to handle for miniaturized terminal devices. A single layer, line-feed rectangular microstrip patch antenna is small enough for the LTE handsets. Our project proposes size reduction and bandwidth enhancement through adapted feeding techniques. By means of slits the return loss and gain can be optimized with the aid of HFSS (High Frequency Structure Simulator).

Transportation has expanded the scope of human mobility, increasing the distances we cover on a regular basis. The large benefits of transportation have resulted in a huge recent increase in the number of vehicles. This, however, implies an increased number of traffic accidents that cause many fatalities and injuries every year. It also leads to problems like increased delay for commuters, and negative effects on the environment. Not to mention, the money spent in the wasted fuel, as well as the costs of fixing damaged equipment and property. To help in mitigating these problems the vehicles and the road infrastructure should be equipped with intelligent devices that allow them to communicate and collaborate with each other and exchange safety information concerning accidents, road traffic conditions, and weather conditions as well as non-safety information. Recently, this topic termed telematics has gathered considerable interest constituting a lot of work and research all included under the title of Intelligent Transportation System (ITS). The thesis work defines general communication requirements of future telematics applications and investigates various wireless carriers that are important to achieve communication inbetween vehicles and between vehicles and nearby infrastructure. We analyse several future applications related to the ITS field and describe their communication requirements. Based on the communication requirements the applications are grouped into different profiles in order to determine the most suitable carrier for each profile. Disclaimer: This paper reflects only the authors’ views and the European Community (as cofounders of the CVIS, SAFESPOT and PReVENT Sixth Framework Programme projects, through the European Commission DG Information Society and Media) is not liable for any use that may be made of the information contained within.

Streaming applications like multimedia and radar signal processing applications are becoming increasingly compute-intensive. To overcome the computational demands new parallel architectures are emerging.   The programming tools provided with these architectures require low-level programming, which creates a need for a common high-level architecture independent language that can exploit parallelism efficiently. One such language is StreamIt, designed around the notions of streams and stream transformers, which allows efficient mapping to a variety of architectures.   The overall goal of this master’s thesis is to evaluate the StreamIt language from a programmability and portability point of view. An MPD-application has been developed in StreamIt, which is executed on the RAW simulator. Furthermore, a code generator is designed to compile and execute the application on the XPP simulator.   The conclusions drawn are that StreamIt is easy to learn, but hard to use because of its programming paradigm as compared to conventional languages. StreamIt programming involves thinking in terms of streams instead of globally accessed memory. The structure of StreamIt makes it easy to reuse components and modify the application. The construction of the compiler makes it possible to port StreamIt application to various architectures.

Android, a platform for smartphones and mobile devices, is becoming more and more present in the market. Nevertheless, the battery runtime of smartphones is short and strongly influenced by the network usage. Some proposals exist to reduce the energy consumption associated to the network usage and increase the smartphone runtime. But for adjusting them for a real improvement it is required to study the network utilisation triggered by the smartphone applications. With this analysis the applications communication patterns can be obtained and used to predict the network usage and the amount of data expected. In order to gather network statistics of the running applications, a logger application is implemented for the Android platform to log network statistics of running applications. The statistics are analysed on a PC computer to obtain the applications' communication patterns. A number of applications are selected, sorted by the rankings of downloads and type. A detailed analysis of the network usage is presented. This analysis identifies some of their patterns, some application characteristics and groups of applications from the determined network usage. The network usages for applications with similar functionalities are compared and lessons learnt from the analysis are discussed. Finally, some improvements for our logger application and analysis are discussed.

Reproduction de : Thèse de doctorat : Dynamique des fluides : Toulouse, INPT : 2007. / Titre provenant de l'écran-titre. Bibliogr. 71 réf.

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Cooperative driving holds the potential to considerably improve the level of safety and efficiency on our roads. Recent advances in in-vehicle sensing and wireless communication technology have paved the way for the development of cooperative traffic safety applications based on the exchange of data between vehicles (or between vehicles and road side units) over a wireless link. The access to up-to-date status information from surrounding vehicles is vital to most cooperative driving applications. Other applications rely on the fast dissemination of warning messages in case a hazardous event or certain situation is detected. Both message types put high requirements on timeliness and reliability of the underlying communication protocols. The recently adopted European profile of IEEE 802.11p defines two message types,periodic beacons for basic status exchange and event-triggered hazard warnings, both operating at pre-defined send rates and sharing a common control channel. The IEEE 802.11p Medium Access Control (MAC) scheme is a random access protocol that doesnot offer deterministic real-time support, i.e. no guarantee that a packet is granted access to the channel before its deadline can be given. It has been shown that a high number of channel access requests, either due to a high number of communicating vehicles or highdata volumes produced by these vehicles, cannot be supported by the IEEE 802.11p MAC protocol, as it may result in dropped packets and unbounded delays. The goal of the work presented in this thesis has therefore been to enhance IEEE 802.11p without altering the standard such that it better supports the timing and reliability requirements of traffic safety applications and provides context-aware andefficient use of the available communication resources in a vehicular network. The proposed solutions are mapped to the specific demands of a set of cooperative driving scenarios (featuring infrastructure-based and infrastructure-free use cases, densely and sparsely trafficked roads, very high and more relaxed timing requirements) and evaluated either analytically, by computer simulation or by measurements and compared to the results produced by the unaltered IEEE 802.11p standard. As an alternative to the random MAC method of IEEE 802.11p, a centralized solution isproposed for application scenarios where either a road side unit or a suitable dedicated vehicle is present long enough to take the coordinating role. A random access phase forevent-driven data traffic is interleaved with a collision-free phase where timely channel access of periodic delay-sensitive data is scheduled. The ratio of the two phases isdynamically adapted to the current data traffic load and specific application requirements. This centralized MAC solution is mapped on two cooperative driving applications: merge assistance at highway entrances and platooning of trucks. Further,the effect of a context-aware choice of parameters like send rate or priority settings based on a vehicle’s position or role in the safety application is studied with the goal to reduce the overall number of packets in the network or, alternatively, use the available resources more efficiently. Examples include position-based priorities for the merge assistance use case, context-aware send rate adaptation of status updates in anovertaking warning application targeting sparsely-trafficked rural roads and an efficient dissemination strategy for warning messages within a platoon. It can be concluded that IEEE 802.11p as is does not provide sufficient support for the specific timing and reliability requirements imposed by the exchange of safety-criticalreal-time data for cooperative driving applications. While the proper, context-awarechoice of parameters, concerning send rate or priority level, within the limits of the standard, can lead to improved packet inter-arrival rates and reduced end-to-end delays,the added benefits from integrating MAC solutions with real-time support into the standard are obvious and needs to be investigated further.