Capacity and Frequency Re-use

It is the number of frequencies in a cell that determines the cell’s capacity.
However, a cellular network can overcome this constraint and maximize the number of subscribers that it can service by using frequency re-use.
Each company with a license to operate a mobile network is allocated a limited number of frequencies.
Depending on the traffic load and the availability of frequencies, a cell may have one or more frequencies allocated to it.
It is important when allocating frequencies that interference is avoided.
Frequency re-use means that two radio channels within the same network can use exactly the same pair of frequencies, provided that there is a sufficient geographical distance.
The tighter frequency re-use plan, the greater the capacity potential of the networkInterference can be caused by a variety of factors.
A common factor is the use of similar frequencies close to each other. The higher interference, the lower call quality.
To provide coverage to all the subscribers, frequencies must be reused many times at different geographical locations in order to provide a network with sufficient capacity.
The same frequencies can not be re-used in neighboring cells as they would interfere with each other so special patterns of frequency usage are determined during the planning of the network.

These frequency re-use patterns ensure that any frequencies being re-used are located at a sufficient distance apart to ensure that there is little interference between them.
The term “frequency re-use distance” is used to describe the distance between two identical frequencies in a re-use pattern.
The lower frequency re-use distance, the more capacity will be available in the network.