How 4G Technology Functions

You're in an unfamiliar city with a population of 6 million. It's late at night, you're in a sketchy neighborhood, and you urgently need directions to your hotel. No worries. Just pull out your smartphone, which will come to your rescue with detailed, interactive maps.

There's one issue though – your phone's data connection is painfully slow. So slow that you give up on your increasingly frustrating phone and end up purchasing a map from a nearby gas station.

Without a fast data connection, your smartphone seems, well, rather useless. No matter how high-end or advanced your phone is, it still relies on a wireless network to provide the essential data – the lifeblood of everything digital. And the current generation of 3G (third-generation) networks, although fast, often fails to offer a consistent and reliable mobile Internet experience.

What your struggling smartphone truly craves is the kind of broadband (high-speed) Internet connection you use on your home computer. What it needs is mobile broadband. What it needs is 4G. And so does everyone else.

In 2009, for the first time, mobile broadband traffic surpassed that of voice calls [source: Erion]. And by 2020, the demand for data is expected to rise by 33 times [source: 3GPP]. As more and more people purchase mobile devices that consume large amounts of data, networks must keep up with the growing demand.

To achieve this, service providers (known as carriers or operators depending on your region) are pouring significant investments into their infrastructure – the hardware and software that makes cellular communication possible. Estimates suggest they will invest as much as $53 billion in the United States alone, largely to support the expansion of faster networks, often referred to as 4G (fourth-generation) [source: Fool.com].

But what exactly defines 4G networks? And why do they dominate so many loud, bold commercials? What sets them apart from older 2G networks, which were mainly used for voice calls? And how can you distinguish a 4G network from a 3G one?

The answers aren’t always as straightforward as we’d prefer. In many ways, the world of 4G is as confusing as trying to navigate a sprawling metropolis without your collection of online maps.

But don't worry. We'll guide you through the maze of acronyms and marketing jargon, helping you navigate the skyscrapers of technological babble. Along the way, we’ll demonstrate how blazing-fast 4G speeds could usher the mobile internet into a new era.

Wireless' Endless Evolution

Wireless networks are a blend of different, often overlapping technologies. Regardless of the complex acronyms, it always boils down to one thing – wireless networks are essentially radio systems. For more on the basics of cellular technology, check out How Cell Phones Work and How Smartphones Work.

No matter which wireless technology takes the lead in your region, you're part of a global movement – the wireless revolution. There are nearly 6 billion active cellphone subscriptions worldwide [Source: 4G Americas], and mobile phones continue to grow in popularity every day.

To meet the needs of billions of mobile phone users, networks must evolve to support more users and handle higher data loads. Each advancement in network performance or functionality is often labeled (sometimes vaguely) as a new generation.

The early 1G (first-generation) networks, which emerged in the 1980s, were analog and only supported voice calls. In the early 1990s, 2G (second-generation) networks were introduced, enabling basic data services such as text messaging and email.

The rollout of 3G networks began in the early 2000s, bringing mobile internet into the mainstream. With fast connections, you could browse the web and stream audio, though the experience was often frustratingly slow.

Then, consumers began demanding even more robust, web-focused mobile capabilities. Devices with advanced, data-hungry features surged in numbers. Meanwhile, network infrastructures struggled to keep up with the growing demand for data.

3G networks needed an upgrade. It was time for wireless systems to evolve once again, this time to deliver faster mobile broadband. That time has arrived.

These days, the boundaries between network generations are a bit murky. There is no globally accepted definition for what qualifies as 4G.

As a result, networks faster than 3G are often called G, 3.9G, or simply 3G+. However, in their marketing efforts, major carriers, always eager to stand out, label these systems as 4G. Essentially, 4G is just a marketing term, indicating that a network is faster than 3G. That's all.

But 4G comes in various forms of mobile broadband. On the following page, you'll discover how 4G differs from its wireless predecessors and dive deeper into what makes it significantly faster than the original 3G networks.

4G is Fully IP-based

By now, you know that 4G is essentially a sophisticated radio system. The challenge for engineers and programmers is to efficiently pack as much digital data as possible into each radio signal, thereby optimizing the speed and effectiveness of the entire network.

Like 3G, 4G networks are IP-based (Internet Protocol), meaning they use a standard protocol to transmit and receive data in packets. However, unlike 3G, 4G utilizes IP even for voice data. It’s an all-IP standard.

Using these standardized packets, your data can travel through various networks without getting distorted or damaged. To send and receive packets, your phone first communicates with a base station. A base station refers to the tall cell towers equipped with antennas, relaying data between the Internet and your mobile device.

There are numerous methods (called air interfaces) to establish a connection between the base station and your phone. You can explore older air interfaces and their complicated acronyms here in How Cell Phones Work. We’ll cover newer 4G air interfaces later on.

We won’t overwhelm you with every acronym, but common 3G interfaces include CDMA2000, HSPA, 3G LTE, EV-DO Revision B, DO Advanced, and Mobile WiMAX, to name just a few. Each of these interfaces transfers data in distinct ways via radio waves within a specific spectrum. You can quickly review those earlier technologies here.

At present, 4G systems aren’t fully all-IP, as there’s still considerable overlap with 3G and even 2G networks across various regions worldwide. However, as 4G infrastructure develops further, the all-IP data delivery system will become fully realized.

The concept of IP-based wireless is just one element that defines 4G. On the following page, you’ll discover that several other factors come together to create the perfect recipe for 4G performance.

The Complete 4G Formula

4G isn’t a revolutionary breakthrough; it’s an evolutionary leap that significantly enhances the 3G Internet experience. Compared to 3G networks, 4G offers several distinct advantages.

The speed boost is likely the most important factor for you. With 3G, smartphones typically reach download speeds up to around 2Mbps (megabits per second). In contrast, 4G can push those speeds into overdrive, ranging from 3 to 5Mbps; that’s about the same speed many home computers get with cable modems or DSL.

4G speeds have the potential to go even higher, but for now, forget about those 100Mbps speeds that are often hyped online. Those are theoretical numbers and won’t be seen in everyday usage anytime soon.

Mark Murphy, innovation lead at Erion, points out that beyond just speed, 4G brings additional features that distinguish it from earlier network generations.

4G offers higher capacity, meaning it can accommodate more users simultaneously. It also provides faster data rates, improving multimedia functions like video calls and YouTube streaming. A 3G tower can support around 60 to 100 users, delivering fast and reliable service. However, a 4G LTE (Long Term Evolution) tower can serve 300 to 400 users without sacrificing quality.

Additionally, 4G features reduced latency. With less delay, commands are processed more quickly, which is particularly useful for fast-paced online gaming or remotely controlling vehicles and robots. For a network to qualify as real-time, latency should be 50ms (milliseconds) or less; 4G LTE has latency between 20 to 40ms. This low latency also eliminates lag or echo in voice calls.

4G is much more spectrum-efficient compared to 3G. Imagine the radio spectrum as a pipe with a fixed diameter; only a limited amount of data can flow through that pipe at any given time. 4G, however, utilizes smart coding techniques that significantly boost the amount of data traveling through the spectrum. Ultimately, it achieves a higher data transfer rate per hertz than 3G.

What exactly makes 4G so much faster and more efficient? Keep reading, and you'll discover the key factors that power 4G’s remarkable performance.

The Role of the Air Interface

You probably haven’t given much thought to the language your phone uses. That ‘language’ is known as the air interface, a standardized communication protocol that your mobile device relies on to interact with a base station.

If you've ever watched a smartphone ad (yes, go ahead and groan), you've likely encountered terms like 4G LTE, WiMAX (Worldwide Interoperability for Microwave Access), HSPA+ (High Speed Packet Access), and others. While these air interface names vary, they all share one key function – managing network traffic and signaling when devices should transmit and receive data. Their difference lies in how they execute this function.

The WiMAX system is somewhat akin to the WiFi protocol found in homes and offices. However, it's gradually being phased out as carriers favor other interfaces like LTE and HSPA+.

With LTE, devices can transmit and receive at the same time, thanks to the use of different frequencies for each task. LTE relies on OFDM (orthogonal frequency division multiplexing), which splits a signal into multiple parallel data streams that travel over various radio sub-channels. These streams are reassembled by processors on the receiving end.

LTE (and HSPA+) also uses a technique called MIMO (multiple input multiple output), which utilizes several antennas and transmitters at both the phone and base station to allow for simultaneous uploading and downloading of data.

HSPA+ is compatible with older 3G systems, but LTE is not. However, HSPA+ isn't seen as the future of mobile networks. Instead, it's a way to extend the life of existing infrastructure.

LTE is here to stay for the foreseeable future. Named long-term evolution, LTE networks are designed to provide carriers with a technology they can rely on for an extended period, avoiding the need to spend large amounts of money on infrastructure upgrades every few years. It's seen as a solid long-term choice because it’s easier to scale for higher capacity and performance.

Currently, pure 4G LTE networks are still quite rare. Most networks today are a mix of 3G, 4G, and even 2G technologies and air interfaces. In many locations, 2G, 3G, and 4G signals overlap. You can explore this coverage with interactive maps on OpenSignalMaps. Because of this overlap, even phones marketed as 4G typically come equipped with 3G chips to connect to both 3G and 3G+ networks.

Hold onto your phone – on the next page, you’ll discover why both your phone and network are getting faster and becoming remarkably intelligent.

The Living, Breathing Network

4G LTE overcomes many of the limitations of 3G and introduces a host of mind-blowing features. Be warned – if you found the "Terminator" or "Matrix" movies unsettling, you might want to skip ahead to the next section.

While outdated 1G and 2G networks seem primitive by today's standards, 4G networks are far more sophisticated, almost like intelligent machines. They're designed to handle unexpected surges in demand, such as when a traffic jam occurs. When thousands of people are stuck in traffic, they often turn to their phones, causing a sharp spike in data usage in that area.

In contrast to 3G networks, which struggle in these situations, 4G systems are much more advanced. With their self-organizing and self-configuring features, they can adjust in real time, ensuring that more people get faster service. Additionally, 4G systems have self-healing abilities, meaning that even in power outages or equipment failures, the system can reroute traffic through other towers until repairs are made.

What’s truly remarkable is that these workarounds occur automatically, without the need for human intervention. According to Wojtek Felendzer, technical solutions marketing manager at Nokia Siemens Networks, these systems are some of the largest machines ever built by humanity, spanning continents and oceans. And now, they're becoming smart enough to repair themselves.

Despite all these advancements, 4G isn’t exactly a revolutionary breakthrough. As Felendzer puts it, "People in this industry sometimes say that nothing new has been invented in the past 100 years." Rather, 4G represents a new way of combining existing technologies with more powerful processing capabilities. Take your smartphone as an example—many of today's phones are powered by dual-core processors, a level of computing power that was unimaginable just a few years ago.

If you’ve ever worried about a tech takeover, it might be time to consider hiding out in the wilderness. But for now, keep reading to see how a different kind of battle is unfolding—one between the network operators.

The Mobile Broadband Battlefield

Everywhere you turn, you can’t avoid the bold, fast-paced advertisements for both smartphones and wireless broadband. In this high-stakes, competitive market, service providers are eager to attract new customers. To stand out, they focus on building networks that are faster, with the widest possible coverage in terms of both geography and population.

To create these expansive networks, carriers need access to spectrum. Aside from the funds required for infrastructure, spectrum is the most essential resource for carriers. In business terms, it’s referred to as a constraining resource—a critical element for success.

Spectrum refers to the range of radio frequencies that government bodies auction to wireless carriers. Since there’s a finite amount of spectrum available in any given area, carriers compete fiercely to secure their share. Those who gain access to this precious resource can provide superior coverage to their customers, which in turn allows them to attract more subscribers and generate higher revenue.

Spectrum comes with a hefty price tag. For instance, AT&T spent nearly $2 billion to acquire a 700 MHz block of spectrum to expand its 4G network, covering approximately 300 million people in the U.S. [source: Apple Insider].

In the past, older technologies required carriers to have a continuous block of spectrum to provide service. However, advanced air interfaces like LTE can work across multiple frequencies, such as 700 MHz, 900 MHz, 1.7 GHz, 2.1 GHz, and many more. That said, not all frequencies perform equally well.

Lower frequencies, like 700 MHz, are the most valuable because they behave like a thick fog, easily penetrating obstacles such as buildings. On the other hand, higher frequencies require line-of-sight and are more susceptible to interference from objects and other disturbances. This is why carriers favor lower frequencies to deliver more reliable and faster service.

Once a carrier secures its spectrum, the next step is upgrading parts of its network, one segment at a time. It’s typically not the cell towers you see along highways or on tall buildings that get replaced. Instead, engineers focus on updating routers and servers, upgrading them to newer versions that can easily scale up as more capacity is needed in the future.

The future is always top of mind for wireless professionals. Keep reading to explore what lies ahead in the world of cell communications, extending beyond today’s ultra-fast 4G networks.

The Evolution and Impact of 4G

"Widespread 4G will radically change the game," says Richard Karpinksi, senior mobility analyst at Yankee Group. "It will influence sectors like business, education, retail, and much more." However, Karpinksi cautions users to temper their expectations regarding 4G speeds. He points out, "When a network gets overloaded with users, its speed naturally decreases." That's why he believes that if mobile users are able to achieve download speeds of 10 to 20Mbps in the coming years, it will be considered a notable achievement.

While streaming HD video might not be feasible for a while, 4G will allow smooth video calls, YouTube videos, and other media—if you're willing to pay the premium. 4G data plans will be costlier than their 3G counterparts, and users may encounter data caps that could limit their experience.

As a result, carriers will provide more on-demand quality of service upgrades. Imagine being at the mall, waiting for your kids, while trying to watch a football game on your phone. You've hit your data limit, and the network is slow due to congestion. You can authorize a one-time charge to upgrade your service temporarily, boosting your speed so you can watch the game live.

Naturally, this is all assuming your battery is still going strong. Because 4G signals are less widespread than 3G, phones consume more energy searching for 4G connections, which could mean you don't even get a full day's use. On top of that, smartphones are becoming more powerful, and these additional features quickly drain batteries. These devices will need significant upgrades to match their advanced capabilities.

The Internet continues to expand both virtually and in the hardware and software supporting it. Wherever you are, the rollout of faster, more robust 4G networks is inevitable, marking the dawn of a new era in mobile internet access. For tech enthusiasts, this means exciting times ahead as the reach of wireless technologies grows—the Internet and the world will soon be more accessible than ever.