A cellular network is a radio network made up of a number of radio cells (or just cells) each served by at least one fixed-location transceiver known as a cell site or base station. These cells cover different land areas to provide radio coverage over a wider area than the area of one cell, so that a variable number of portable transceivers can be used in any one cell and moved through more than one cell during transmission.

Cellular networks offer a number of advantages over alternative solutions:

1. Increased capacity

2. Reduced power usage

3. Larger coverage area

4. Reduced interference from other signals

A macrocell is a cell in a mobile phone network that provides radio coverage served by a power cellular base station (tower). Generally, macrocells provide coverage larger than microcell. The antennas for macrocells are mounted on ground-based masts, rooftops and other existing structures, at a height that provides a clear view over the surrounding buildings and terrain.  Macrocell base stations have power outputs of typically tens of watts. The term macrocell is used to describe the widest range of cell sizes. Macrocells are found in rural areas or along highways. Over a smaller cell area, a microcell is used in a densely populated urban area.

Each frequency range has a band designator and each range of frequencies behaves differently and performs different functions. The frequency spectrum is shared by civil, government, and military users of all nations according to International Telecommunications Union (ITU) radio regulations.

For communications purposes, the usable frequency spectrum now extends from about 3Hz to about 300GHz. There are also some experiments at about 100THz where research on laser communications is taking place but we won’t discuss this now. This range from 3Hz to 300GHz has been split into regions.