Nortel Networks DCT1900 User Manual
Technical Product Manual - DCT1900
Config-DCT1900/R8/mw
3-1
© 2000-2005
C
HAPTER
3
Base Station Planning
The major task in configuring a DCT1900 system is defining the number of Base Stations required
to cover an area to a satisfactory level. This Chapter describes how a Base Station plan can be
made in order to gain full area coverage. Chapter 5, Paragraph 5.2 explains how traffic
requirements additionally influence the number of Base Stations.
to cover an area to a satisfactory level. This Chapter describes how a Base Station plan can be
made in order to gain full area coverage. Chapter 5, Paragraph 5.2 explains how traffic
requirements additionally influence the number of Base Stations.
Another aspect of Base Station configuration is powering of Base Stations. The various ways of
distributing power to the Base Stations and the requirements on the power supply are described in
Chapter 4.
distributing power to the Base Stations and the requirements on the power supply are described in
Chapter 4.
3.1
Introduction
The radio environment or the cell that is covered by a Base Station is not a spherical shape as
often suggested in drawings. If a snapshot could be taken of the cell, it would become clear that its
shape is more of a cloud form. The momentary size and shape vary depending on the material of
which 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 these
unpredictable conditions it is not possible to give any hard rules for calculating the number of Base
Stations in a given situation.
often suggested in drawings. If a snapshot could be taken of the cell, it would become clear that its
shape is more of a cloud form. The momentary size and shape vary depending on the material of
which 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 these
unpredictable conditions it is not possible to give any hard rules for calculating the number of Base
Stations in a given situation.
Base Station planning is not very difficult. However, size, architecture and the structure of
buildings and their influence on the RF field pattern cannot be foreseen. The quickest and simplest
way to do the Base Station Plan is by measuring. During a site survey, an average cell size can be
determined, 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.
buildings and their influence on the RF field pattern cannot be foreseen. The quickest and simplest
way to do the Base Station Plan is by measuring. During a site survey, an average cell size can be
determined, 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 placement
of Base Stations is being planned. Paragraph 3.6 explains how a site survey can be done.
of Base Stations is being planned. Paragraph 3.6 explains how a site survey can be done.
3.2
Total Area Coverage
z
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 is
enough free space for radio signals to travel.
enough 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 the
effective coverage area, except of course when a parking area, for example, has to be
covered.
effective coverage area, except of course when a parking area, for example, has to be
covered.
z
Base Stations may partially cover the floors immediately above and below as well. The useful
range through floors and ceiling varies between a 0 and 26 ft. (2 floors) radius; see Figure 3–1.
range through floors and ceiling varies between a 0 and 26 ft. (2 floors) radius; see Figure 3–1.
3.3
Absorption and Reflection
z
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 in
different ways.
different ways.
z
Metal walls and large metal cabinet rows reflect all signals, resulting in greatly reduced
coverage behind these areas.
coverage behind these areas.