A cellular telephone is a variation of the mobile phone system that uses a handset like a cordless telephone. This handset communicates with another handset through a base station. The base station acts as a central road for all users. It receives a signal. And retransmits through the high gain antenna. In the cellular phone system, the entire coverage area is divided into many small cells. These cells are usually hexagonal in shape. A cell is placed next to the cell so that there is no space between two adjacent cells. The number of users depends on the cell number. Diameter i.e. radius is from 10 km to 20 km. Here each letter represents more than one channel but cells of the letter are never used in the same channel. Each cell uses a different frequency. If the number of users in densely populated areas is high, each cell is divided into smaller cells. These smaller cells are called micro cells.