Types of Sites
Tower and building-mounted sites are the most common types used by cellular providers. Towers are usually freestanding, such as monopoles and lattice structures, though guyed towers are also common in rural areas. Some are disguised as trees or cacti for aesthetic reasons.
Throughout this website, you’ll find examples and photos of various tower types. Be sure to check out the blog for updates and the latest industry news.
How Wireless Telephone Systems Work
Wireless networks are designed to transmit controlled signals — not the long-range broadcasts used by radio or TV. Each cellular provider is allocated a limited number of frequency channels per geographic area. To maximize efficiency, the service area is divided into smaller “cells,” each covering a radius of roughly one to ten miles depending on terrain and population density.
As a mobile phone moves between cells, the connection is automatically handed off from one tower to another, managed by a Mobile Switching Center (MSC). This process enables frequency re-use, allowing the same frequencies to be used by different users in separate areas without interference.
Communication between the towers and the switching center happens over high-capacity circuits or microwave backhaul links. In the U.S., two main frequency bands are used for cellular communication — 800 MHz and 1900 MHz (PCS). Higher frequencies require more towers for equivalent coverage, so carriers like AT&T, Verizon, and T-Mobile deploy dense site networks in urban areas.
Modern systems use digital technologies such as CDMA (Code Division Multiple Access), GSM (Global System for Mobile Communications), and LTE (Long-Term Evolution). These provide greater capacity, improved security, and better voice quality compared to older analog (AMPS) systems.
Digital systems also make more efficient use of power and spectrum, allowing smaller phones and longer battery life. Today’s networks have evolved far beyond voice-only service to support mobile data, streaming, and IoT connectivity.
Wireless System Definitions
- Backhaul: The connection that links a base station to the Mobile Switching Center (MSC).
- Base Station: A fixed site that communicates with mobile devices within its coverage area.
- COW (Cell on Wheels): A portable tower used during emergencies, events, or network expansion.
- Control Channel: A radio channel for call setup, paging, and system signaling.
- Forward Channel: Transmits data from the base station to the mobile device.
- Handoff: The process of transferring a call between towers as a user moves.
- Mobile Station: Any cellular device that communicates through a base station, such as a phone or modem.
- Mobile Switching Center (MSC): Coordinates routing of calls between base stations and the public network.
- Paging: Broadcasting a brief signal to locate and alert a device.
- Reverse Channel: Transmits data from the mobile device back to the tower.
- Roamer: A subscriber using the network outside their home service area.
- Subscriber: A customer who pays for mobile service.
- Transceiver: A unit capable of both transmitting and receiving radio signals.