Macro cells :-large cells for remote and sparsely populated areas Micro cells:- for densely populated areas Selective cells:-cells with a particular shape and coverage ; for eg. Cells located at the entrances of tunnels where coverage of 360 degrees is not needed Umbrella cells:-covers several micro cells; reduce the number of handovers . Different Types of Cells MACRO-CELL: antenna radiating ‘above’ roofs ---> Wide Coverage (≤ 35 km) EXTENDED-CELL: macro cell with system coverage extension (≤ 120 km) for coasts... MICRO-CELL: Antenna ‘below’ the roofs ---> small coverage Architecture of GSM NW

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. . 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 . Deciding the cluster size The smaller the number of cells per cluster is, the bigger th...

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