Browsing by Issue Date, starting with "2007-05"
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- Application of Wireless Sensor Networks to the AutomobilePublication . Tavares, Jorge; Velez, Fernando José; Ferro, João MiguelSome applications of Wireless sensor networks (WSNs) to the automobile are identified, and the use of MICAz motes operating at 2.4GHz is considered together with TinyOS support. These WSNs are being conceived in order to measure, process and supply to the user diverse types of information during an automobile journey. Examples are acceleration and fuel consumption, identification of incorrect tire pressure, verification of illumination, and evaluation of the vital signals of the driver. A survey on WSNs concepts is presented, and the wireless sensor network itself (transmitter/receiver/control board) is developed. Aspects of the definition of the architecture and the choice/implementation of the protocols are identified. Security aspects are also addressed, and solutions are proposed.
- Application of Wireless Sensor Networks to the AutomobilePublication . Tavares, Jorge; Velez, Fernando José; Ferro, João MiguelSome applications of Wireless sensor networks (WSNs) to the automobile are identified, and the use of MICAz motes operating at 2.4GHz is considered together with TinyOS support. These WSNs are being conceived in order to measure, process and supply to the user diverse types of information during an automobile journey. Examples are acceleration and fuel consumption, identification of incorrect tire pressure, verification of illumination, and evaluation of the vital signals of the driver. A survey on WSNs concepts is presented, and the wireless sensor network itself (transmitter/receiver/control board) is developed. Aspects of the definition of the architecture and the choice/implementation of the protocols are identified. Security aspects are also addressed.
- Design and Implementation of IEEE 802.16 Radio Links with RelaysPublication . Marques, Marco; Ambrósio, João; Reis, Carlos; Gouveia, David; Robalo, Daniel; Velez, Fernando José; Costa, Rui; Riscado, JoséThis paper addresses aspects of design and planning of a Wireless network WiMAX (IEEE 802.16) to establish a point-to-point, PTP, link from the Health Sciences Faculty of University of Beira Interior (FCS/UBI) to Hospital Sousa Martins (Guarda), and also presents a field trial where we tested point-to-point links with pre-WiMAX equipment. The design of the link had into consideration the carrier to noise ratio, C/N, and the minimum carrier to noise ratio with fading, C/Nmin_fad. The use of two relays is needed to guarantee LoS conditions. The use of BreezeNET B equipment from Alvarion was assumed. From the dimensioning process, it was verified that with γ = 2, for the second clause, the three types of modulations can be used. Field trials results were compared with the theoretical model, and very similar conclusions were achieved.
- Event-based Tele-Traffic Simulation of Mobile Communication Systems Beyond 3GPublication . Juárez Valero, Jesús M.; Paulo, Rui R.; Velez, Fernando J.By considering the deployment scenarios and teletraffic parameters from the Vehicular scenario of SEACORN, a simulator was produced to extract conclusions about blocking and handover failure probabilities in Enhanced UMTS. Simulations, which consider the burstiness of traffic, were performed for different cases, from single- to multi-service situations, and from absence to presence of mobility. The simulator allows for extracting conclusions about the validation of the Bernoulli-Poisson-Pascal model for the computation of the ON/OFF blocking probability, the ratio between the number of call rejected at the beginning of an ON period and the total number of bursts generated during a session. As the theoretical and the simulation results agree, the validation was achieved, and there is an almost perfect concordance between theoretical and simulation values when the average sojourn time in cells is equal to the average holding time. In the multi-service case, the behaviour is not exactly the same but a coherent trend is achieved.
- User capacity based planning tool for Wi-Fi and WiMAX networksPublication . Sebastião, Pedro; Velez, Fernando; Tomé, Ricardo; Costa, Rui; Robalo, Daniel; Grilo, António; Rodrigues, António; Cercas, FranciscoA simple wireless planning tool (WPT) is proposed, which facilitates the design and implementation of wireless fidelity (Wi-Fi), and worldwide microwave access (WiMAX) networks in indoor and outdoor environments. The tool gives to professional planners practical and useful information through quick procedures as the output is the number and position of the access points (APs), or an estimation of the total cost of implementation, based on data provided by different equipment manufacturers. It uses innovative algorithms for computing the best position of each AP. Carrier-to-noise and carrier-tointerference issues are discussed in detail, and a practical deployment of a single WiMAX cell in Covilhã is presented. There is a need of using sectorial antennas to guarantee an adequate coverage and interference mitigation.