Product manual

Configuration directions, Base station planning
Technical Product Manual - DCT1800-GAP
TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C
© 2006
9
Chapter 3 Base station planning
The major task in configuring a DCT1800-GAP system is defining the number of base stations required
to cover an area to a satisfactory level. This chapter describes how a base station planning can be
made in order to gain full area coverage. For additional information about base station planning, refer
to chapter
4. Chapter 6 explains how traffic requirements additionally influence the number of base
stations.
Another aspect of base station configuration is the powering of bases. The various ways of power
distribution to the base stations and the requirements on the power supply are described in chapter
5 for BS330 and BS340 type base stations.
3.1 Introduction
The radio environment or the cell that is covered by a base station is not of a spherical shape as often
suggested in figures. If a snapshot could be taken of its form, it would become clear that its shape is
much more irregular. The momentary size and shape are dependant on the material of which walls
and floors are made, the position and material of furniture, machines, air-conditioning and the position
of the base station in such an environment. Because of these unpredictable conditions it is not possible
to give any hard rules on calculating the number of base stations in a given situation.
It is not to say that base station planning is very difficult, on the contrary, but size, architecture and
structure of buildings and their influence on the field pattern cannot be foreseen. The quickest and
simplest way is therefore measuring. During a so-called site survey, an average cell size can be
determined, with help of a site survey tool. This forms the basis of a base station planning. Then
experience will very soon be the best guide to make base station plans.
The guide-lines listed below, will help in getting a better view on the local situation when base stations
are being planned. Paragraph
3.6 explains how a site survey can be done.
3.2 Total area coverage
• The in-house cell size in offices may be in a range of 10 - 30 metre radius; see figure 3. The cell
size in exhibition halls or production halls may go up to 200 metre radius when there is enough
free space for radio signals to travel.
• The cell size out-doors in free space may be up to 300 m radius.
• Base stations should not be placed near the outer walls of the building as this reduces the effective
covered area, except of course when e.g. a parking area has to be covered.
• Base stations may partially cover the floors immediately above and below as well. The useful
range through floors and ceiling varies between 0 and 8 m (2 floors) radius; see figure
3.
3.3 Absorption and reflection
• The cell size is very dependant on the material of which walls, ceilings and floors are made.
• Plain, light or reinforced concrete, wood and plaster all absorb and pass radio waves in different
ways.
• Metal walls and large metal cabinet rows reflect all signals, resulting in a greatly reduced coverage
behind these areas.