nicipais [Site] [Property] Manaus plan Site VILADA BARRA AEROPORT EDUARDO GOMES JORGE TEIXEIRA TARUMA AGUAS CLARAS #HOUE DE CAXIAS COLONIA DISTRITO CEASA CONDE EDUCANDOS II Figure 2.16 Example of the coverage plot using planning tools Coverage Planning Macro cells Pico cells Micro\cells Figure 2.17 Macro, micro and pico cells drawn as hexagons The coverage estimates given in the dimensioning phase produced only very rough figures, because they were based on the hexagonal model. In practice the cells of a GSM network are completely different from theoretical hexagons, the shape and size being dependent on the surrounding area and also the BTS parameters. Example hexagons are shown in Figure 2.17 and the terms macro, micro and pico cells are explained. In more dense areas smaller cells are used, because the capacity need limits the cells sizes. In this example all the cells are triple sectorised. As a practical example in Figure 2.18 is shows the coverage area of a real GSM cell. The coverage is for a single cell with a sectorised antenna. The first step in coverage planning is to create a preliminary plan based on the calculated number of base stations from the dimensioning phase, which is agreed with the operator. The BTS locations are theoretical in this phase, because they have not been verified in the field. The usage of omni and/or sectorised antennas is part of the planning strategy. Omni cells can be used in rural or other sparsely inhabited areas, where there are not high capacity requirements. As stated before for base stations having sectorised antennas, it is easier to give coverage to precise locations. The next step is to start to find actual base station locations, which is a task of the site acquisition team. To find an optimal BTS location is an essential but complicated task. What makes it complicated are the many practical requirements and especially the transmission that need to be arranged. When the actual BTS location has been found the preliminary location changes and the plan is updated and 