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- Unified propagation model for Wi-Fi, UMTS and WiMAX planning in mixed scenariosPublication . Varela, Frederico; SebastiĆ£o, Pedro; Correia, Americo; Cercas, Francisco; Rodrigues, AntĆ³nio; Velez, Fernando J.; Robalo, DanielThis paper presents an unified and empirical propagation model to obtain the received power in mixed scenarios, with outdoor and indoor environments, or in a scenario with only one kind of environment, either for an urban, sub-urban or rural scenario, with or without vegetation. This unified model is called the Lisbon University Institute (LUI) one and can be included into planning tools for wireless communication systems. The developed model is suitable for Path Loss prediction in mobile, as well as fixed wireless network systems, e.g., Wireless Fidelity, Universal Mobile Telecommunications System and Worldwide Interoperability for Microwave Access, considering Line-of-Sight or Non-Line-of-Sight propagation conditions.
- Validation of the unified propagation model for Wi-Fi, UMTS and WiMAX planningPublication . Varela, Frederico; SebastiĆ£o, Pedro; Correia, Americo; Cercas, Francisco; Rodrigues, Antonio; Velez, Fernando J.; Robalo, DanielThis paper presents the validation of the unified propagation model, the Lisbon University Institute (LUI) model, which is valid for three wireless technologies: Wireless Fidelity, Universal Mobile Telecommunications System and Worldwide Interoperability for Microwave Access. With this purpose in mind, several experimental trials for those technologies were performed in different scenarios, where mixed environments (outdoor and indoor) were included. This generalized and unified propagation model was tuned by adjusting specific parameters for each different technology, based on the achieved results from the field experiments.
- Planning and Deployment of WiMAX NetworksPublication . SebastiĆ£o, Pedro; Velez, Fernando; Costa, Rui; Robalo, Daniel; Rodrigues, AntĆ³nioIncorporation of measurement based techniques in Worldwide Interoperability for Microwave Access (WiMAX) are required to improve IEEE 802.16 engineering methodologies. Wireless planning methodologies are presented, supported by a planning tool which facilitates the design and implementation of WiMAX networks. Propagation models available for WiMAX still need to be tuned and further validated. By comparing IEEE 802.16-2004 measurement results at 3.5GHz with computed values using the modified Friis and the Stanford University Interim (SUI) models, for a suburban area, we found that the use of the modified Friis equation with a propagation exponent ā¼3 is more appropriate than the use of the SUI model, although, for coverage distances between 275 and 475 m, the SUI-B and mainly SUI-C models may still be used. From the analysis of the carrier-to-noise-plusinterference ratio, it is clear that both noise and interference present a strong limitation to the cellular reuse performance of fixedWiMAX mainly for higher order modulation and codingschemes.With a reuse pattern K = 7, cell throughputs near the maximum are only achieved in the uplink if sub-channelisation is used together with sectorization. The planning tool provides planners with practical and useful information through quick coverage/capacity based procedures, and outputs the number and position of the base stations and an estimation of the total cost of implementation, based on data provided by different equipment manufacturers. WiMAX cellular planning exercises are presented for the zone of CovilhĆ£, Portugal, where Geographic Information Systems are used for representation of rural and sparse urban areas. One of the main conclusions is the strong need to use sector antennas in order to guarantee an adequate coverage, and higher system capacity whilst mitigating interference for several terrain types and environments, including hilly terrain.
- Radio and Network PlanningPublication . Velez, Fernando J.; SebastiĆ£o, Pedro; Costa, Rui; Robalo, Daniel; ComissĆ”rio, ClĆ”udio; Rodrigues, AntĆ³nio; Aghvami, A. HamidThis chapter starts by presenting the Stanford University Interim (SUI) and modified Friis propagation models. Although the SUI model is being recommended for WiMAX, the comparison between the model and experimental results show that, in our environment, at 3.5 GHz, the modified Friis model with gama = 3 fits better the measurement values. From the analyses of the signal-to-noise-plusinterference ratio, SNIR, interference-to-noise ratio and reuse pattern, it is found that both noise and interference present a strong limitation to the performance of fixed WiMAX, mainly for higher order modulation and coding schemes (MCSs). In general terms, the use of sectorization in fixed WiMAX enables to reduce the reuse pattern while considering sub-channelisation allows for improvement on the coverage. The reduction of the reuse pattern directly corresponds to an increase in the system capacity but the improvement in the coverage range (through subchannelisation) can also allow for an improvement in UL system capacity, as adaptive MCS are used. Two different approaches are considered for graphical cellular planning, and the district of CovilhaĖ is considered as a case study. On the one hand, one considered a GIS based WiMAX planning tool conceived by considering coverage issues, frequency reuse, and the impact of the different classes of service. On the other, WinpropTM is used as it distinguishes among different MCS in the graphical presentation of the results. Both tools consider the information coming from the digital terrain profile. The GIS functionalities allow for appropriately adjusting azimuth and tilt of antennas. This cellular planning exercises confirm the results of theoretical analysis, where different crowns are achieved for the coverage with each MCS (corresponding to a given range of values for SNIR), for the maximum physical throughput, and for the ābest serverā cells. The frequency radio resources should be considered as the most valuable resourceduring the planning of wireless broadband access networks. As a rule, spectral efficiency needs to be optimized by using several advanced techniques, corresponding to an optimization from the cost-benefit point of view.
- WLAN planning tool: a techno-economic perspectivePublication . SebastiĆ£o, Pedro; TomĆ©, Ricardo; Velez, Fernando J.; Grilo, AntĆ³nio; Cercas, Francisco; Robalo, Daniel; Rodrigues, AntĆ³nio; Varela, Frederico F.A simple wireless local area network (WLAN) planning tool was developed to optimize the position and number of access points (APs), as well as the total cost of the required equipment, according to different WLAN suppliers, in indoor and outdoor environments. This planning tool can be distinguished in two mains scopes: technical (defining the number and position of APs) and economic (generating a budget according to all planned equipment and its suppliers). The proposed planning tool enables manual and automatic planning modes. It only needs some inputs, like the digital format of the floor plan, the obstacle types and their positions, the areas to be covered, the userās most probable position and the applications used by them. The propagation model used in this tool was validated using experimental results for some scenarios. In the manual mode, the APs positions are defined by the network designer. The output of the tool is the received power or the throughput, depending on the chosen option. However, in the automatic mode the tool defines the AP position and minimizes the total amount of APs in a given area. For the implementation of the latter mode, two hot spots position planning algorithms were developed and implemented; they depend on the values of the received power or throughput, while guaranteeing the total coverage or service supply for all users, respectively. This tool also provides an estimation of the budget for the required implementation, and can avoid several days of tedious site-survey work. Except for the lowest distances, experimental values for the received power generally agree with the DP model for the range of distances considered, from the terminal station to the AP, both for outdoor and indoor environments. The differences near the AP are due to different antenna radiation patterns between the tool (omnidirectional isotropic) and the experimental setup (dipole antenna). In the indoor paths, the slight differences between the results of two floors may be due to the interaction of the direct ray with the floor direction itself.
- Planning of an IEEE 802.16e Network for Emergency and Safety ServicesPublication . Velez, Fernando JosĆ©; Caravalho, Vitor; Santos, Dany; Marcos, Rui P.; Costa, Rui; SebastiĆ£o, Pedro; Rodrigues, AntĆ³nioAn overlaid Wimax cellular structure is proposed for emergency and safety services, with micro-cells covering urban hotspots over a macro-cellular structure. In the region of Beira Interior the process of cellular planning has to account for carrier-to-noise-interference ratio. Sectorisation is used in order to reduce reuse patterns and increase system capacity, while cell overlay is proposed to overcome coverage problems in large towns and cities. Geographic Information Systems tools are considered for Line-of-Sight discovery, and ~75% of LoS coverage is guaranteed in the city of CovilhĆ£. The point-to-point component is also being incorporated in the planning tool. By comparing the 3.5GHz and the 5.8GHz bands one concludes that it is possible to use lower values of the antenna gains in the first case.
- Planning and Deployment of WiMAX and Wi-Fi Networks for Health Sciences EducationPublication . SebastiĆ£o, Pedro; Velez, Fernando J.; Costa, Rui; Robalo, Daniel; ComissĆ”rio, ClĆ”udio; Rodrigues, AntĆ³nioOptimal planning for the integration of WiMAX (Worldwide Interoperability for Microwave Access) and Wi-Fi (Wireless Fidelity) technologies enables real technical conditions to make a hybrid Wi-Fi/WiMAX network available at the Health Sciences Faculty of University of Beira Interior, supporting nomadic applications like videoconference, voice over IP and communication of high resolution video/image. A simple wireless planning tool is designed and used in this optimal planning, which facilitates the design and implementation of Wi-Fi and WiMAX networks in indoor and outdoor environments. The tool gives useful information through quick coverage/capacity based procedures, as the output is the number and position of the APs (access points)/BSs (base stations) or an estimation of the total cost of implementation, based on data provided by different manufacturers. While planning methodologies are already stable for Wi-Fi, and propagation models have already been widely validated, the propagation models available for WiMAX still need to be tuned, which motivates the need to carry out propagation measurements. For IEEE 802.16-2004 networks operating at 3.5 GHz, by comparing the measurement results with the ones obtained using the modified Friis and the SUI (Stanford University Interim) models, it was concluded that, for a suburban area of CovilhĆ£, Portugal, the use of the modified Friis model with a propagation exponent ~3 is more appropriate than the use of the SUI one, although for coverage distances between 275 and 475 m the SUI model (SUI-B and mainly SUI-C) may still be used. WiMAX cellular planning exercises are presented for the zone of CovilhĆ£. Carrier-to-noise-plus-interference issues are discussed, and Geographic Information Systems are applied to determine the existence of line-of-sight in rural and sparse urban areas. One of the main conclusions arising from this work is the strong need of using sectorial antennas to guarantee an adequate coverage and interference mitigation for several terrain types and environments, including hilly terrain.
- Hybrid WiMAX and Wi-Fi networks for the support of b-Learning and TelemedicinePublication . Costa, Rui; Velez, Fernando JosĆ©; Robalo, Daniel LuĆs Silveira; Marques, Marco; ComissĆ”rio, ClĆ”udio; Riscado, JosĆ©; Cavaleiro, Victor; SebastiĆ£o, Pedro; Rodrigues, AntĆ³niohis paper addresses the deployment of hybrid WiMAX and Wi-Fi networks for the support of always best connected telemedicine and health sciences education applications. The available services include a LMS (Learning Management System) and several structured functionalities for b-Learning. For the support of these services, fixed and wireless LANs have been deployed, as well as an experimental point-to-multipoint IEEE 802.16-2004 network covering part of the city of CovilhĆ£. The FCS (Health Sciences Faculty) Campus as well as the tutorial rooms of the Faculty spread at the different Hospitals of the region of Beira Interior, Portugal, are benefiting from WLAN coverage, whose backhaul is supported by WiMAX point-to-point links with relays. Field trials results were compared with the ones arising from the WiMAX radio links design, and very similar results were achieved. Service quality was guaranteed by adjusting QoS parameters.
- Cellular Planning of an IEEE 802.16 Wireless Metropolitan Area NetworkPublication . Velez, Fernando JosĆ©; Carvalho, Vitor; Santos, Dany; Marcos, Rui P.; Costa, Rui; SebastiĆ£o, Pedro; TomĆ©, Ricardo; Rodrigues, AntĆ³nioThis work intends to develop a WiMax (Worldwide Interoperability for Microwave Access) point-to-multipoint wireless network that includes all the district of CovilhĆ£, and particularly the urban area of the city in detail, with the objective to guarantee a point-to-multipoint connection from the Health Science Faculty of the University of Beira Interior (HSF/UBI) / Hospital PĆŖro da CovilhĆ£ to all urban area of the centre of the city. The cellular planning of this WiMax mobile network was done having in account aspects related with the carrier-to-noise ratio and carrier-to-interference ratio, concluding that is necessary to consider a cellular structure with coverage distances of 3 km and sectorisation is needed to create a high capacity wireless network in the urban area of CovilhĆ£. Because this zone is very hilly, the choice of the location for base stations is essential; one used the potentialities of the GIS (Geographic Information Systems) tools to optimize the line of sight coverage and, simultaneously, reduce the propagation exponent. A new mobile IP architecture for Wi-Fi/WiMax interoperability is being conceived, developed and implemented based in Media Independent Handover.
- User capacity based planning tool for Wi-Fi and WiMAX networksPublication . SebastiĆ£o, Pedro; Velez, Fernando; TomĆ©, Ricardo; Costa, Rui; Robalo, Daniel; Grilo, AntĆ³nio; Rodrigues, AntĆ³nio; 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 CovilhĆ£ is presented. There is a need of using sectorial antennas to guarantee an adequate coverage and interference mitigation.