Technical Product Manual - DCT1900Configuration Directions, Base Station PlanningConfig-DCT1900/R8/mw 3-1© 2000-2005CHAPTER 3Base Station PlanningThe major task in configuring a DCT1900 system is defining the number of Base Stations requiredto cover an area to a satisfactory level. This Chapter describes how a Base Station plan can bemade in order to gain full area coverage. Chapter 5, Paragraph 5.2 explains how trafficrequirements additionally influence the number of Base Stations.Another aspect of Base Station configuration is powering of Base Stations. The various ways ofdistributing power to the Base Stations and the requirements on the power supply are described inChapter 4.3.1 IntroductionThe radio environment or the cell that is covered by a Base Station is not a spherical shape asoften suggested in drawings. If a snapshot could be taken of the cell, it would become clear that itsshape is more of a cloud form. The momentary size and shape vary depending on the material ofwhich walls and floors are made of, the position and material of furniture, machines, air–conditioning and the position of the Base Station in such an environment. Because of theseunpredictable conditions it is not possible to give any hard rules for calculating the number of BaseStations in a given situation.Base Station planning is not very difficult. However, size, architecture and the structure ofbuildings and their influence on the RF field pattern cannot be foreseen. The quickest and simplestway to do the Base Station Plan is by measuring. During a site survey, an average cell size can bedetermined, with the help of a Site Survey Tool. This forms the basis of Base Station planning.Experience is the best guide in making a Base Station plan.The guide–lines listed below will help give a better view on the local situation when the placementof Base Stations is being planned. Paragraph 3.6 explains how a site survey can be done.3.2 Total Area Coveragez The in–house cell size in offices may be in a range of 30-200 ft. radius; see Figure 3–1.z The cell size in exhibition halls or production halls may go up to a 660 ft. radius when there isenough free space for radio signals to travel.z The cell size outdoors in free space may be up to 1000+ ft. radius.z Base Stations should not be placed near the outer walls of the building as this reduces theeffective coverage area, except of course when a parking area, for example, has to becovered.z Base Stations may partially cover the floors immediately above and below as well. The usefulrange through floors and ceiling varies between a 0 and 26 ft. (2 floors) radius; see Figure 3–1.3.3 Absorption and Reflectionz The cell size depends on the materials used in walls, ceilings and floors.z Plain, light or reinforced concrete, wood and plaster all absorb and pass radio waves indifferent ways.z Metal walls and large metal cabinet rows reflect all signals, resulting in greatly reducedcoverage behind these areas.
