How Mobile Phones Work

Share this article

Mobile phones have become a ubiquitous part of modern life. It is estimated that there are over five billion cell phones currently in use, covering a large portion of the world’s population. However, most people who use mobile phones do not understand how they work. This article demonstrates how a combination of sophisticated radio technology and computer security create the mobile phone systems many take for granted.

The first thing to understand is that underneath the long-distance capabilities, elaborate touch interfaces, and other bells and whistles, modern mobile phones are essentially nothing more than two-way radios. Therefore, to understand how mobile phones work, one must first understand how radio works. 

A radio antenna is a device which turns radio waves into electric currents that can then be processed into sound by a radio receiver. Additionally, it can do the opposite, and convert existing electronic audio signals into transmitted radio waves that other antennas can receive. When a mobile phone transmits audio, it applies an oscillating electric current to the mobile phone antenna. The mobile phone antenna then emits corresponding electromagnetic waves, which are also known as radio waves. To receive calls, the mobile phone antenna intercepts an electromagnetic wave of a particular frequency. Its terminal then receives a minuscule amount of voltage, which is amplified and converted to sound by other components.

Through the process explained above, mobile phone antennas transmit signals to radio towers and receive signals back simultaneously. However, the technology that enabled such sophisticated use of radio signals was developed gradually over many decades.

The closest predecessors of mobile phones were the radios installed in truckers’ vehicles that allowed them to communicate while on the road. Because the radios were so large and heavy, they were impractical for consumer use. These mobile communication systems tended to use one central antenna in each city they serviced. Only a few dozen channels were available on each tower. Therefore, the system wouldn’t work if too many people were trying to use it at once. Also, because the system was only half-duplex, only one party could talk at any given time. This need to be brief and one-way led to some interesting lingo, but it wasn’t very convenient for the average person to use.

Modern mobile phones, in contrast to the portable radio communication systems of old, use cellular networks. Cellular networks are also radio networks, but they are far more sophisticated than the simple local towers that powered old radio communication systems. In a cellular network, the towers are distributed over portions of land called cells. These cells are usually hexagonal in shape, but they can also be square or circular. Each cell of land contains at least one radio tower. 

Each cell is also assigned a number of frequencies which correspond to radio base stations. Other cells can use the same frequencies as long as they are not adjacent. In other words, use of the same frequency must be spaced at least one cell apart. This is done to avoid interference between calls whose signals use the same frequency. This ability to reuse frequencies is the key to the cellular network’s power; far more people can make calls across the network, and over longer distances. Whereas single-transmitter systems cannot reuse the same frequency, cellular networks can use the same frequency in multiple areas for different transmissions, as long as the transmissions are not close enough to cause interference. Because of the cellular approach, conversations can be carried across cells, making it easy to talk to people who are across the country. Additionally, these systems are full-duplex, which means the phone sends and receives a signal at the same time. This makes it possible for people to talk and listen at the same time, and thus to carry on a conversation in the manner to which they are accustomed.

The concept of a cellular network is not limited to mobile phones, but mobile phone networks are an especially sophisticated kind of cellular network. Cellular transmitters and handsets can change frequency under guidance of automated computer systems that find the optimal ranges to avoid interference. They generally have 800 different frequencies available for each cluster of adjacent cells. Because of the nature of wavelengths, lower-frequency waves travel longer without being broken up by atmospheric noise. This principle holds true for mobile phone signals. Lower-frequency clusters are better for long distances, whereas higher-frequency are better for dense areas. Therefore mobile phone signals rural areas tend to use relatively low frequencies, and in urban areas they use high frequencies. 

In cities each cell site typically covers half a mile. In rural areas, they tend to cover about five miles. However, this is not the true limit of modern mobile phone reception. Given circumstances in which there is no interference or blockage, it is sometimes possible to receive a signal from a cell site 25 miles away. Mobile phones also tend to use low power transmitters to avoid interference between calls in compactly arranged cells. Each cell site is connected to telephone switches, which allows for calls to be made from cell phones to the public telephone network.

Many different standards have been established for how mobile phone networks are supposed to communicate and coexist with each other. Currently, the most popular mobile phone communication standards are GSM and CDMA. A new high-speed standard called LTE is being introduced in populous areas.

To counteract unauthorized use of their networks, mobile phone providers have introduced security measures that do not allow a phone to receive and transmit calls without certain valid data. This data is usually stored on small microchips called Subscriber Identity Modules, or SIM cards for short. The data they carry is known as the service-subscriber key. The technical name for this data is the International Mobile Subscriber Identity. This is used to gather information about the mobile country code, the mobile network code, and the mobile station identification number of the phone. It also carries an authentication key. SIM cards are most commonly used in phones that are intended for GSM networks. Many phones built for CDMA networks do not use removable cards, and instead embed the security information permanently in memory. However, “world” phones that can handle both communication protocols include SIM cards.

By sending and receiving radio signals through a vast interconnected network, mobile phones can make calls almost anywhere in developed countries, over distances of thousands of miles. Mobile phones are a wonder of modern technology.

Frequently Asked Questions (FAQs) About How Mobile Phones Work

How Do Mobile Phones Convert Voice into Signals?

Mobile phones convert voice into signals using a process called modulation. When you speak into your phone, the microphone picks up the sound waves and converts them into electrical signals. These signals are then modulated into radio waves by the phone’s transmitter. The radio waves are sent to the nearest cell tower, which then transmits them to the recipient’s phone. The recipient’s phone demodulates the radio waves back into electrical signals, which are then converted back into sound waves by the speaker.

What Role Does a SIM Card Play in a Mobile Phone?

A SIM card, or Subscriber Identity Module, is a small chip that stores information about the mobile phone user. It contains a unique serial number, the International Mobile Subscriber Identity (IMSI), and other user data. The SIM card allows the phone to connect to the mobile network and enables the user to make calls, send messages, and use data services.

How Does a Mobile Phone Connect to the Internet?

Mobile phones connect to the internet using either a Wi-Fi network or a cellular network. When connected to a Wi-Fi network, the phone communicates with a router, which is connected to the internet. When using a cellular network, the phone connects to the internet via the nearest cell tower, which is linked to the internet through a wired network.

How Does a Mobile Phone Use GPS?

GPS, or Global Positioning System, is a satellite-based navigation system that provides location and time information. A mobile phone uses GPS by receiving signals from multiple GPS satellites. The phone calculates its distance from each satellite and uses this information to determine its exact location.

What is the Role of the Operating System in a Mobile Phone?

The operating system (OS) is the software that manages the hardware and software resources of the mobile phone. It provides a user interface, manages files and applications, and controls the phone’s communication functions. The OS also ensures that different applications and processes run smoothly and efficiently.

How Does a Mobile Phone Store Data?

Mobile phones store data in two main ways: internal storage and external storage. Internal storage is built into the phone and is used to store the operating system, applications, and user data. External storage, such as a microSD card, can be added to increase the phone’s storage capacity.

How Does a Mobile Phone Charge Its Battery?

A mobile phone charges its battery using a charger that converts AC power from a wall outlet into DC power. The charger sends this power to the phone’s battery, which stores it as chemical energy. The phone then converts this energy back into electrical energy to power its functions.

How Does a Mobile Phone Use Bluetooth?

Bluetooth is a wireless technology that allows mobile phones to connect to other Bluetooth-enabled devices, such as headphones, speakers, or another phone. The phone and the other device pair and exchange data over a short-range radio frequency.

How Does a Mobile Phone Use NFC?

NFC, or Near Field Communication, is a technology that allows mobile phones to communicate with other NFC-enabled devices over a very short distance. This technology is often used for contactless payments, data transfer, and reading NFC tags.

How Does a Mobile Phone Use Infrared?

Infrared technology in mobile phones is used for short-range communication between devices. It allows data to be transferred wirelessly over short distances, typically a few meters. However, this technology is less common in modern phones, having been largely replaced by Bluetooth and Wi-Fi.

Chris PentagoChris Pentago
View Author

Chris is a web designer, developer and internet marketer experienced in key web technologies and software. He currently works as online exposure consultant at leading mobile phone antenna and network equipment supplier. Chris also has passions for Android and web performance.

Discussion
Share this article
Read Next
Leveraging Progressive Web Apps (PWAs) for Enhanced Mobile User Engagement
Leveraging Progressive Web Apps (PWAs) for Enhanced Mobile User Engagement
SitePoint Sponsors
10 Artificial Intelligence APIs for Developers
10 Artificial Intelligence APIs for Developers
SitePoint Sponsors
The Ultimate Guide to Navigating SQL Server With SQLCMD
The Ultimate Guide to Navigating SQL Server With SQLCMD
Nisarg Upadhyay
Retrieval-augmented Generation: Revolution or Overpromise?
Retrieval-augmented Generation: Revolution or Overpromise?
Kateryna ReshetiloOlexandr Moklyak
How to Deploy Apache Airflow on Vultr Using Anaconda
How to Deploy Apache Airflow on Vultr Using Anaconda
Vultr
Cloud Native: How Ampere Is Improving Nightly Arm64 Builds
Cloud Native: How Ampere Is Improving Nightly Arm64 Builds
Dave NearyAaron Williams
How to Create Content in WordPress with AI
How to Create Content in WordPress with AI
Çağdaş Dağ
A Beginner’s Guide to Setting Up a Project in Laravel
A Beginner’s Guide to Setting Up a Project in Laravel
Claudio Ribeiro
Enhancing DevSecOps Workflows with Generative AI: A Comprehensive Guide
Enhancing DevSecOps Workflows with Generative AI: A Comprehensive Guide
Gitlab
Creating Fluid Typography with the CSS clamp() Function
Creating Fluid Typography with the CSS clamp() Function
Daine Mawer
Comparing Full Stack and Headless CMS Platforms
Comparing Full Stack and Headless CMS Platforms
Vultr
7 Easy Ways to Make a Magento 2 Website Faster
7 Easy Ways to Make a Magento 2 Website Faster
Konstantin Gerasimov
Powerful React Form Builders to Consider in 2024
Powerful React Form Builders to Consider in 2024
Femi Akinyemi
Quick Tip: How to Animate Text Gradients and Patterns in CSS
Quick Tip: How to Animate Text Gradients and Patterns in CSS
Ralph Mason
Sending Email Using Node.js
Sending Email Using Node.js
Craig Buckler
Creating a Navbar in React
Creating a Navbar in React
Vidura Senevirathne
A Complete Guide to CSS Logical Properties, with Cheat Sheet
A Complete Guide to CSS Logical Properties, with Cheat Sheet
Ralph Mason
Using JSON Web Tokens with Node.js
Using JSON Web Tokens with Node.js
Lakindu Hewawasam
How to Build a Simple Web Server with Node.js
How to Build a Simple Web Server with Node.js
Chameera Dulanga
Building a Digital Fortress: How to Strengthen DNS Against DDoS Attacks?
Building a Digital Fortress: How to Strengthen DNS Against DDoS Attacks?
Beloslava Petrova
Crafting Interactive Scatter Plots with Plotly
Crafting Interactive Scatter Plots with Plotly
Binara Prabhanga
GenAI: How to Reduce Cost with Prompt Compression Techniques
GenAI: How to Reduce Cost with Prompt Compression Techniques
Suvoraj Biswas
How to Use jQuery’s ajax() Function for Asynchronous HTTP Requests
How to Use jQuery’s ajax() Function for Asynchronous HTTP Requests
Aurelio De RosaMaria Antonietta Perna
Quick Tip: How to Align Column Rows with CSS Subgrid
Quick Tip: How to Align Column Rows with CSS Subgrid
Ralph Mason
15 Top Web Design Tools & Resources To Try in 2024
15 Top Web Design Tools & Resources To Try in 2024
SitePoint Sponsors
7 Simple Rules for Better Data Visualization
7 Simple Rules for Better Data Visualization
Mariia Merkulova
Cloudways Autonomous: Fully-Managed Scalable WordPress Hosting
Cloudways Autonomous: Fully-Managed Scalable WordPress Hosting
SitePoint Team
Best Programming Language for AI
Best Programming Language for AI
Lucero del Alba
Quick Tip: How to Add Gradient Effects and Patterns to Text
Quick Tip: How to Add Gradient Effects and Patterns to Text
Ralph Mason
Logging Made Easy: A Beginner’s Guide to Winston in Node.js
Logging Made Easy: A Beginner’s Guide to Winston in Node.js
Vultr
How to Optimize Website Content for Featured Snippets
How to Optimize Website Content for Featured Snippets
Dipen Visavadiya
Psychology and UX: Decoding the Science Behind User Clicks
Psychology and UX: Decoding the Science Behind User Clicks
Tanya Kumari
Build a Full-stack App with Node.js and htmx
Build a Full-stack App with Node.js and htmx
James Hibbard
Digital Transformation with AI: The Benefits and Challenges
Digital Transformation with AI: The Benefits and Challenges
Priyanka Prajapat
Quick Tip: Creating a Date Picker in React
Quick Tip: Creating a Date Picker in React
Dianne Pena
How to Create Interactive Animations Using React Spring
How to Create Interactive Animations Using React Spring
Yemi Ojedapo
10 Reasons to Love Google Docs
10 Reasons to Love Google Docs
Joshua KrausZain Zaidi
How to Use Magento 2 for International Ecommerce Success
How to Use Magento 2 for International Ecommerce Success
Mitul Patel
5 Exciting New JavaScript Features in 2024
5 Exciting New JavaScript Features in 2024
Olivia GibsonDarren Jones
Tools and Strategies for Efficient Web Project Management
Tools and Strategies for Efficient Web Project Management
Juliet Ofoegbu
Choosing the Best WordPress CRM Plugin for Your Business
Choosing the Best WordPress CRM Plugin for Your Business
Neve Wilkinson
ChatGPT Plugins for Marketing Success
ChatGPT Plugins for Marketing Success
Neil Jordan
Managing Static Files in Django: A Comprehensive Guide
Managing Static Files in Django: A Comprehensive Guide
Kabaki Antony
The Ultimate Guide to Choosing the Best React Website Builder
The Ultimate Guide to Choosing the Best React Website Builder
Dianne Pena
Exploring the Creative Power of CSS Filters and Blending
Exploring the Creative Power of CSS Filters and Blending
Joan Ayebola
How to Use WebSockets in Node.js to Create Real-time Apps
How to Use WebSockets in Node.js to Create Real-time Apps
Craig Buckler
Best Node.js Framework Choices for Modern App Development
Best Node.js Framework Choices for Modern App Development
Dianne Pena
SaaS Boilerplates: What They Are, And 10 of the Best
SaaS Boilerplates: What They Are, And 10 of the Best
Zain Zaidi
Understanding Cookies and Sessions in React
Understanding Cookies and Sessions in React
Blessing Ene Anyebe
Enhanced Internationalization (i18n) in Next.js 14
Enhanced Internationalization (i18n) in Next.js 14
Emmanuel Onyeyaforo
Essential React Native Performance Tips and Tricks
Essential React Native Performance Tips and Tricks
Shaik Mukthahar
How to Use Server-sent Events in Node.js
How to Use Server-sent Events in Node.js
Craig Buckler
Five Simple Ways to Boost a WooCommerce Site’s Performance
Five Simple Ways to Boost a WooCommerce Site’s Performance
Palash Ghosh
Elevate Your Online Store with Top WooCommerce Plugins
Elevate Your Online Store with Top WooCommerce Plugins
Dianne Pena
Unleash Your Website’s Potential: Top 5 SEO Tools of 2024
Unleash Your Website’s Potential: Top 5 SEO Tools of 2024
Dianne Pena
How to Build a Chat Interface using Gradio & Vultr Cloud GPU
How to Build a Chat Interface using Gradio & Vultr Cloud GPU
Vultr
Enhance Your React Apps with ShadCn Utilities and Components
Enhance Your React Apps with ShadCn Utilities and Components
David Jaja
10 Best Create React App Alternatives for Different Use Cases
10 Best Create React App Alternatives for Different Use Cases
Zain Zaidi
Control Lazy Load, Infinite Scroll and Animations in React
Control Lazy Load, Infinite Scroll and Animations in React
Blessing Ene Anyebe
Building a Research Assistant Tool with AI and JavaScript
Building a Research Assistant Tool with AI and JavaScript
Mahmud Adeleye
Understanding React useEffect
Understanding React useEffect
Dianne Pena
Web Design Trends to Watch in 2024
Web Design Trends to Watch in 2024
Juliet Ofoegbu
Building a 3D Card Flip Animation with CSS Houdini
Building a 3D Card Flip Animation with CSS Houdini
Fred Zugs
How to Use ChatGPT in an Unavailable Country
How to Use ChatGPT in an Unavailable Country
Dianne Pena
An Introduction to Node.js Multithreading
An Introduction to Node.js Multithreading
Craig Buckler
How to Boost WordPress Security and Protect Your SEO Ranking
How to Boost WordPress Security and Protect Your SEO Ranking
Jaya Iyer
Understanding How ChatGPT Maintains Context
Understanding How ChatGPT Maintains Context
Dianne Pena
Building Interactive Data Visualizations with D3.js and React
Building Interactive Data Visualizations with D3.js and React
Oluwabusayo Jacobs
JavaScript vs Python: Which One Should You Learn First?
JavaScript vs Python: Which One Should You Learn First?
Olivia GibsonDarren Jones
13 Best Books, Courses and Communities for Learning React
13 Best Books, Courses and Communities for Learning React
Zain Zaidi
5 jQuery.each() Function Examples
5 jQuery.each() Function Examples
Florian RapplJames Hibbard
Implementing User Authentication in React Apps with Appwrite
Implementing User Authentication in React Apps with Appwrite
Yemi Ojedapo
AI-Powered Search Engine With Milvus Vector Database on Vultr
AI-Powered Search Engine With Milvus Vector Database on Vultr
Vultr
Understanding Signals in Django
Understanding Signals in Django
Kabaki Antony
Why React Icons May Be the Only Icon Library You Need
Why React Icons May Be the Only Icon Library You Need
Zain Zaidi
View Transitions in Astro
View Transitions in Astro
Tamas Piros
Getting Started with Content Collections in Astro
Getting Started with Content Collections in Astro
Tamas Piros
What Does the Java Virtual Machine Do All Day?
What Does the Java Virtual Machine Do All Day?
Peter Kessler
Become a Freelance Web Developer on Fiverr: Ultimate Guide
Become a Freelance Web Developer on Fiverr: Ultimate Guide
Mayank Singh
Layouts in Astro
Layouts in Astro
Tamas Piros
.NET 8: Blazor Render Modes Explained
.NET 8: Blazor Render Modes Explained
Peter De Tender
Mastering Node CSV
Mastering Node CSV
Dianne Pena
A Beginner’s Guide to SvelteKit
A Beginner’s Guide to SvelteKit
Erik KückelheimSimon Holthausen
Brighten Up Your Astro Site with KwesForms and Rive
Brighten Up Your Astro Site with KwesForms and Rive
Paul Scanlon
Which Programming Language Should I Learn First in 2024?
Which Programming Language Should I Learn First in 2024?
Joel Falconer
Managing PHP Versions with Laravel Herd
Managing PHP Versions with Laravel Herd
Dianne Pena
Accelerating the Cloud: The Final Steps
Accelerating the Cloud: The Final Steps
Dave Neary
An Alphebetized List of MIME Types
An Alphebetized List of MIME Types
Dianne Pena
The Best PHP Frameworks for 2024
The Best PHP Frameworks for 2024
Claudio Ribeiro
11 Best WordPress Themes for Developers & Designers in 2024
11 Best WordPress Themes for Developers & Designers in 2024
SitePoint Sponsors
Top 10 Best WordPress AI Plugins of 2024
Top 10 Best WordPress AI Plugins of 2024
Dianne Pena
20+ Tools for Node.js Development in 2024
20+ Tools for Node.js Development in 2024
Dianne Pena
The Best Figma Plugins to Enhance Your Design Workflow in 2024
The Best Figma Plugins to Enhance Your Design Workflow in 2024
Dianne Pena
Harnessing the Power of Zenserp for Advanced Search Engine Parsing
Harnessing the Power of Zenserp for Advanced Search Engine Parsing
Christopher Collins
Build Your Own AI Tools in Python Using the OpenAI API
Build Your Own AI Tools in Python Using the OpenAI API
Zain Zaidi
The Best React Chart Libraries for Data Visualization in 2024
The Best React Chart Libraries for Data Visualization in 2024
Dianne Pena
7 Free AI Logo Generators to Get Started
7 Free AI Logo Generators to Get Started
Zain Zaidi
Turn Your Vue App into an Offline-ready Progressive Web App
Turn Your Vue App into an Offline-ready Progressive Web App
Imran Alam
Clean Architecture: Theming with Tailwind and CSS Variables
Clean Architecture: Theming with Tailwind and CSS Variables
Emmanuel Onyeyaforo
How to Analyze Large Text Datasets with LangChain and Python
How to Analyze Large Text Datasets with LangChain and Python
Matt Nikonorov
Get the freshest news and resources for developers, designers and digital creators in your inbox each week
Loading form