What is Cellular Systems

A cell corresponds to the covering area of one
transmitter or a small collection of transmitters.
The size of a cell is determined by the transmitter's
power.
The concept of cellular systems is the use of low power
transmitters in order to enable the efficient reuse of the
frequencies.
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Reuse of Frequency

Frequencies used in a cell will be reused several cells
away.
The distance between the cells using the same
frequency must be sufficient to avoid interference.
The frequency reuse will increase considerably the
capacity in number of users.

Cluster

Group of cells.
The number of cells in a cluster must be determined so
that the cluster can be repeated continuously within the
covering area of an operator.
The typical clusters contain 4, 7, 12 or 21 cells.
.
• A cluster is a group of cells
– No channels are reused within a cluster
Clusters
A seven Cell Cluster
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Deciding the cluster size

The smaller the number of cells per cluster is, the bigger
the number of channels per cell will be. The capacity of
each cell will be therefore increased
However a balance must be found in order to avoid the
interference that could occur between neighboring
clusters when small size clusters are opted.
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