Cellular systems are networks that enable mobile communication by dividing geographic areas into smaller regions called cells. Each cell has its own base station that connects to a central system, allowing multiple users to share the same frequency without interference. This structure enhances the efficiency and capacity of mobile networks. These systems support various technologies, including 2G, 3G, 4G, and 5G, each offering different data speeds and capabilities. Cellular systems are essential for modern communication, enabling services like voice calls, text messaging, and internet access on mobile devices.