How Does a Mobile Network Work?

The Complex Telecommunications Web

Cellphone Tower - Image © Wikimedia Commons.

Mobile networks have become the backbone of telecommunications in recent years, with the widespread adoption of cell phones, tablets, and other mobile devices. The technologies that power the networks continue to evolve and advance along with the equipment consumers use to connect with them.

A Web of Connected Cells

Mobile networks are also known as cellular networks. They're made up of "cells" that connect to one another and to telephone switches or exchanges.

These cells are areas of land that are typically hexagonal, have at least one transceiver, and use various radio frequencies. These transceivers are the cell towers that have become ubiquitous in our electronically connected world. They connect to each other to hand off packets of signals—data, voice, and text—ultimately bringing these signals to mobile devices such as phones and tablets that act as receivers. Providers use each others' towers in many areas, creating a complex web that offers the widest possible network coverage to subscribers. 

Frequencies

The frequencies of mobile networks can be used by many network subscribers at the same time. Cell tower sites and mobile devices manipulate the frequencies so that they can use low-power transmitters to supply their services with the least possible interference.

Leading Mobile Network Providers

Cellular service providers in the U.S. are many, ranging from small, regional companies to large, well-known players in the telecommunications field.

These include Verizon Wireless, AT&T, T-Mobile, US Cellular, and Sprint.

Types of Mobile Networks

Different types of mobile technologies are used to provide mobile network services to users. The large service providers vary as to which they use, so mobile devices typically are built to use the technology of the intended carrier.

GSM phones don't work on CDMA networks, and vice versa.

The most commonly used radio systems are GSM (Global System for Mobile Communication) and CDMA (Code Division Multiple Access). As of September 2017, Verizon, Sprint, and US Cellular use CDMA. AT&T, T-Mobile, and most other providers around the world use GSM, making it the most widely used mobile network technology. LTE (Long-Term Evolution) is based on GSM and offers greater network capacity and speed.

Which Are Better: GSM or CDMA Mobile Networks?

Signal reception, call quality, and speed depend on many factors. The user's location, service provider, and equipment all play a role. GSM and CDMA don't differ much on quality, but the way they work does.

From a consumer standpoint, GSM is more convenient because a GSM phone carries all the customer's data on a removable SIM card; to change phones, the customer simply swaps the SIM card into the new GSM phone, and it connects to the provider's GSM network. A GSM network must accept any GSM-compliant phone, leaving consumers quite a bit of freedom over their choices in equipment.

CDMA phones, on the other hand, aren't as easily swapped around. Carriers identify subscribers based on "whitelists," not SIM cards, and only approved phones are allowed on their networks.

Some CDMA phones do have SIM cards, but these are for the purpose of connecting to LTE networks or for flexibility when the phone is used outside of the U.S. GSM wasn't available in the mid 1990s when some networks switched from analog to digital, so they locked into CDMA—at the time, the most advanced mobile network technology.