Radio and Network Planning
This 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,
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Radio and Network Planning Fernando J. Velez, Pedro Sebastia˜o, Rui Costa, Daniel Robalo, Cla´udio Comissa´rio, Anto´nio Rodrigues, and A. Hamid Aghvami
Abstract This 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 g = 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 Covilha˜ 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 “best server” cells. The frequency radio resources should be considered as the most valuable resource
F.J. Velez (*) Instituto de Telecomunicac¸o˜es-DEM, Universidade da Beira Interior, Calc¸ada Fonte do Lameiro, 6201-001, Covilha˜, Portugal e-mail: [email protected]
R. Prasad and F.J. Velez, WiMAX Networks, DOI 10.1007/978-90-481-8752-2_8, # Springer ScienceþBusiness Media B.V. 2010
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during 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.
8.1
Introduction
The present context of frequency spectrum management worldwide, as well as the need for making broadband access flexible for users, creates opportunities for the entrance of new operators and offer diversification of innovative access technologies. As Worldwide Interoperability for Microwave Access (WiMAX) enables the support of mobile broadband Internet services in ou
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