I am working with ArcGIS. In some areas of the map labels are shown twice or three times for the same name and the same area. I want to have one single label for each area.
You should use the Maplex Label Engine (Customize --> Arcmap options --> Data View).
Then you can go to the Labels tab on your layer with labels, click Placement Properties. From there you can manage a number of different things, I can really recommend clicking around for a bit and see what you can do.
What you are looking for is in the Label density tab.
You can even decide how far away two labels has to be in order to be considered as duplicates.