Mobile Phone Technologies Explained
When you’re looking at buying a new phone, you might find that there are way too many acronyms to choose from, between CDMA, GSM, LTE, and WiMax, and the list goes on. Instead, it can be easier to focus simply on the differences in these networks as they apply to you directly. The simplest explanation is that the “G” in 4G stands for generation, because 4G is the fourth generation of mobile data technology, as defined by the radio sector of the International Telecommunication Union (ITU-R). LTE stands for “Long Term Evolution” and applies more generally to the idea of improving wireless broadband speeds to meet increasing demand.
What is 3G?
When 3G networks started rolling out, they replaced the 2G system, a network protocol that only allowed the most basic of what we would now call smartphone functionality. Most 2G networks handled phone calls, basic text messaging, and small amounts of data over a protocol called MMS. With the introduction of 3G connectivity, a number of larger data formats became much more accessible, including standard HTML pages, videos, and music. The speeds were still pretty slow, and mostly required pages and data specially formatted for these slower wireless connections. By 2G standards, the new protocol was speedy, but still didn’t come anywhere close to replacing a home broadband connection.
What is 4G?
The ITU-R set standards for 4G connectivity in March of 2008, requiring all services described as 4G to adhere to a set of speed and connection standards. For mobile use, including smartphones and tablets, connection speeds need to have a peak of at least 100 megabits per second, and for more stationary uses such as mobile hotspots, at least 1 gigabit per second.
When these standards were announced, these speeds were unheard of in the practical world, because they were intended as a target for technology developers, a point in the future that marked a significant jump over the current technology. Over time, the systems that power these networks have caught up, not just in the sense that new broadcasting methods have found their way into products, but the previously-established 3G networks have been improved to the point that they can be classified as 4G.
What is LTE?
LTE stands for Long Term Evolution, and isn’t as much a technology as it is the path followed to achieve 4G speeds. As it stands, most of the time when your phone displays the “4G” symbol in the upper right corner, it doesn’t really mean it. When the ITU-R set the minimum speeds for 4G, they were a bit unreachable, despite the amount of money tech manufacturers put into achieving them. In response, the regulating body decided that LTE, the name given to the technology used in pursuit of those standards, could be labeled as 4G if it provided a substantial improvement over the 3G technology. Immediately networks began advertising their connections as 4G LTE, a marketing technique that allowed them to claim next-gen connectivity without having to reach the actual required number first; it would be like the U.S. claiming they had landed on the moon because they got pretty close and the spaceship that got them there was a lot better than the previous ship. It’s not entirely trickery though, despite inconsistent speeds depending on location and network, the difference between 3G and 4G is immediately noticeable.
What is CDMA?
Most mobile phone owners around the world only have to worry about a single carrier technology called the Global System for Mobile Communications, or GSM for short. As its name implies, this standard was developed for, and has been adopted by, almost the entire globe as the way to communicate via cellular calls. But not everyone has jumped on the GSM train. An alternative cellular standard known as Code Division Multiple Access, or CDMA, is used by many carriers around the world. It is most popular in the United States and Russia, but it’s also used in some Asian and African countries, often alongside competing GSM carriers.
CDMA (Code-Division Multiple Access) refers to any of several protocols used in second-generation (2G) and third-generation (3G) wireless communications. As the term implies, CDMA is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth. The technology is used in ultra-high-frequency (UHF) cellular telephone systems in the 800-MHz and 1.9-GHz bands. CDMA consistently provides better capacity for voice and data communications than other commercial mobile technologies, allowing more subscribers to connect at any given time, and it is the common platform on which 3G technologies are built. CDMA is a military technology first used during World War II by English allies to foil German attempts at jamming transmissions. The allies decided to transmit over several frequencies, instead of one, making it difficult for the Germans to pick up the complete signal. Because Qualcomm created communications chips for CDMA technology, it was privy to the classified information. Once the information became public, Qualcomm claimed patents on the technology and became the first to commercialize it.
Owners of CDMA phones don’t need to worry about SIM cards, but this is more a curse than a blessing. CDMA phones bake in compatibility restrictions that are difficult to get around, while GSM owners can simply take out their SIM and replace it with one from another carrier. Most CDMA networks do not allow the use of a phone originally purchased from another carrier even if the phone is otherwise technically compatible. This is an important restriction to remember when going with a CDMA network.
What is WiMax?
WiMax is one of the hottest Broadband technologies around today. WiMax systems are expected to deliver Broadband access services to residential and enterprise customers in an economical way. Looslely, WiMax is a standardized wireless version of Ethernet intended primarily as an alternative to wire technologies (such as Cable Modems, DSL and T1/E1 links) to provide broadband access to customer premises. WiMAX would operate similar to WiFi, but at higher speeds over greater distances and for a greater number of users. WiMAX has the ability to provide service even in areas that are difficult for wired infrastructure to reach and the ability to overcome the physical limitations of traditional wired infrastructure. WiMax is an Acronym for Worldwide Interoperability for Microwave access.
What about the Speed?
So the real question is, can you feel a difference between 4G and LTE networks? Is the speed of loading a page or downloading an app on your handheld a lot faster if you have LTE technology built in? Probably not. While the difference between slower 3G networks and new 4G or LTE networks is certainly noticeably faster, most of the 4G and “true 4G” networks have upload and download speeds that are almost identical. For now, LTE is the fastest connection available for wireless networks.
Creating 4G connectivity requires two components: a network that can support the necessary speeds, and a device that is able to connect to that network and download information at high enough speed. Just because a phone has 4G LTE connectivity inside doesn’t mean you can get the speeds you want, in the same way that buying a car that can drive 200 MPH doesn’t mean you can go that fast on a 55 MPH freeway. Before carriers were able to truly offer LTE speeds in major areas, they were selling phones that had the capabilities they would need to reach the desired speeds, and afterwards started rolling out the service on a limited scale. Now that LTE service is fairly widespread, this isn’t as much of a problem, but if you don’t live in a major metropolitan area it’s worth checking to make sure you actually need LTE service where you live and work. With the rise in popularity, it’s uncommon for a provider to charge less if you aren’t utilizing the LTE speeds on a regular basis, but you can save money by picking up an older generation smartphone with only 3G or 4G connectivity.
Packet-switching and circuit-switching
No matter what the data is or how fast it’s being transferred, it needs to be packaged and sent so that other points on the network can interpret it. Older networks use circuit-switching technology, a term that refers to the method of communicating. In a circuit-switching system, a connection is established directly to the target through the network, and the entirety of the connection, whether it’s a phone call or a file transfer, happens through that connection. The advantages of a circuit-switched network include a faster connection time, and less chance of the connection dropping. Newer networks take advantage of packet-switching technology, a modern protocol that takes advantage of the much larger number of connected points across the globe. In a packet-switching network, your information is broken up into small chunks which are then sent to your destination over whatever path is currently the most efficient. If a node drops out of your connection in the circuit-switching networks, you’ll have to reconnect, but in a packet-switching network the next packet will simply hunt for a different path.
A lot of the technology used to create 4G speeds doesn’t have anything to do with voice communication. Because voice networks still use circuit-switching technology, it became necessary to reconcile the difference between older and newer network structures. A few different methods have been enacted that deal with the issue, and most carriers chose to deploy one of two options that preserved their control over the minutes used. They do this by either allowing the phone to fall back to circuit-switching standards when used to make or receive a call, or by using packet-switching communication for data and circuit-switching for voice at the same time. The third option is to simply run the voice audio as data over the new LTE networks, a method that most companies have avoided, most likely because it takes away their power to easily charge for voice minutes. Voice over LTE is basically what happens already when you make a Skype call or a Facetime Audio connection to another user, with higher-resolution audio and faster connection speeds.