What do the terms 1G, 2G, 3G, 4G and 5G really mean?

Mobile networks have now been around for 40 years and we see a new generation of mobile networks nearly every ten years. The first commercial mobile network was launched around 1980 and since then there have been many technologies that have played their part in shaping the mobile communication industry. As a result, there is an abundance of terminologies, acronyms and abbreviations that represent the different technologies within the last 40 years. This post dives into the definitions of all the different generations of mobile networks including 1G, 2G, 3G 4G and 5G.

What 1G, 2G, 3G 4G and 5G stand for?

1G, 2G, 3G, 4G and 5G represent the five generations of mobile networks where G stands for ‘Generation’ and the numbers 1, 2, 3, 4 and 5 represent the generation number. Since the early 1980s, we see a new generation of mobile networks almost every ten years. Each generation of mobile networks has a set of requirements that are fulfilled by the cellular technologies that enable the generation. Examples of cellular technologies include AMPS, GSM, UMTS, CDMA2000 and LTE etc.

GenerationMeaningCellular Technologies
1GFirst Generation of mobile networksAMPS, NMT, TACS, C-Netz
2GSecond Generation of mobile networksGSM, D-AMPS, IS-95
3GThird Generation of mobile networksUMTS, CDMA2000
4GFourth Generation of mobile networksLTE
5GFifth Generation of mobile networksNR

The different generations of mobile networks

1G, 2G, 3G, 4G and 5G – Details

The first generation of mobile networks used analogue technologies to deliver mobile communications services. Later, with technological developments and constant demand for new services, we moved into the secure world of digital communications. Analogue mobile systems were based on a technique called FDMA (Frequency Division Multiple Access). Separate frequency bands were used to transmit and receive communication wirelessly. The frequency bands were then divided into multiple sub-frequencies or channels to enable communication between the base station and the mobile phone. Unlike digital systems, analogue communications systems do not have encryption capabilities which makes them susceptible to security issues. The continuous nature of the radio signal also makes the analogue systems more prone to noise.

The digital era of mobile communications started with the second generation of mobile networks or 2G. The technology standards that enabled 2G followed two tracks. The first track used a combination of FDMA and TDMA (Time Division Multiple Access), while the second track used the CDMA technology (Code Division Multiple Access). 2G networks have relatively higher bandwidths as compared to earlier technologies. Starting with 2G, all mobile networks have used digital communications.

Let’s now dig a bit deeper to get a general understanding of the different generations of mobile networks and the technologies that enable them. If you are a student or professional, you may find it useful to also check out the links in this post to the relevant network technologies for further information. Alternatively, you may find the new edition of Mobile Communications Made Easy a bit quicker with all the information summarised properly in one place.

1G – First Generation

1G stands for the first generation of mobile networks which were designed to provide basic voice calling services to customers. 1G networks started in the 1980s and were introduced in different parts of the world through a range of analogue cellular technologies. These cellular technologies included AMPS (Advanced Mobile Phone System), NMT (Nordisk MobilTelefoni or Nordic Mobile Telephone), TACS (Total Access Communications System) and C-Netz (Funktelefonnetz-C or Radio Telephone Network C). AMPS was primarily used in the US and some Asian countries whereas NMT in the Nordic/Scandinavian region, TACS mainly in the UK, and C-Netz in Germany. The 1G networks were based on the FDMA- Frequency Division Multiple Access technology. AMPS was later upgraded to its digital version D-AMPS which was a key second-generation technology. You can learn more about AMPS and D-AMPS in our dedicated post.

2G – Second Generation

2G stands for the second generation of mobile networks which replaced the earlier 1G networks. These networks enabled highly secure voice calls, text messages (SMS), and limited mobile data services. 2G networks started in the 1990s and were deployed in different parts of the world through various digital technologies. The most widely used technology standard for the second generation of mobile networks is Global System for Mobile Communications (GSM). Digital Advanced Mobile Phone System (D-AMPS) and Interim Standard 95 (IS-95) are the other technologies that were used for launching second-generation mobile networks (2G).

The second generation of mobile networks employed two new access technologies; Time Division Multiple Access – TDMA and Code Division Multiple Access – CDMA. Access technologies are used by the radio part of a mobile network to connect mobile phones to the mobile network wirelessly through radio waves. The original GSM and D-AMPS networks were circuit-switched and not designed to provide efficient data services.

GSM networks added an enhancement called General Packet Radio Service (GPRS) that introduced new network nodes in the GSM architecture to provide efficient mobile data (internet) services. GPRS is often referred to as 2.5G as it paved the way for the 3G data services that later utilised the same network nodes that were originally introduced by GPRS. These network nodes are SGSN (Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node) which you can learn more about in this post. Another enhancement EDGE – Enhanced Data for Global Evolution was launched after GPRS and before the 3G networks to improve the peak download speeds from 171.2 kbps (with GPRS) to 384 kbps (with EDGE). More details on the difference between GPRS and EDGE in our dedicated post.

Another key technology of the 2G era is IS-95 commercially known as cdmaOne. IS-95 was the first-ever CDMA-based mobile network and was designed to support mobile data also. There have been two versions of IS-95: IS-95 A and IS-95 B. IS-95 A can support peak download data rates of up to 14.4 kbps. IS-95 B can improve these rates to up to 115 kbps. IS-95 is also important because it is the technology that evolved to CDMA2000 for the 3G cellular services. We have a dedicated post on IS-95 vs CDMA2000 which can help you understand the difference between these two technologies.

3G – Third Generation

3G in mobile communications stands for the third generation of mobile networks. There have been two key 3G migration tracks which were both based on the CDMA technology (Code Division Multiple Access). The first track was UMTS for migrating GSM networks to 3G while the other track was CDMA2000 for IS-95 and D-AMPS.

UMTS stands for Universal Mobile Telecommunication Systems which is based on the Wideband Code Division Multiple Acces – WCDMA technology. It offers peak download speeds of up to 2 Mbps and average data rates of up to 384 kbps. We have a dedicated post on 3G UMTS with details of the technology, frequencies, bandwidths and more. UMTS is also the underlying technology that HSPA – High-Speed Packet Access networks are built upon. HSPA can offer peak downlink and uplink speeds of up to 14.4 Mbps and 5.76 Mbps respectively. UMTS was introduced as part of the 3GPP Release 1999 which later saw enhancements in the form of HSDPA (High-Speed Downlink Packet Access), HSUPA (High-Speed Uplink Packet Access) and Evolved High-Speed Packet Access (HSPA+) to provide data rate improvements. HSPA+ can offer data rates of up to 42 Mbps in the downlink and 11.5 Mbps in the uplink.

The other track CDMA2000 was mainly for IS-95 and for D-AMPS. CDMA2000 can support peak data rates of up to 153 kbps in the downlink and the uplink. The data rates in CDMA2000 networks were later enhanced through EVDO (EVolution Data Optimized). EVDO can offer maximum download speeds of up to 14.7 Mbps and maximum upload speeds of up to 5.4 Mbps. 

4G – Fourth Generation

4G stands for the fourth generation of mobile networks. It is enabled by a technology called LTE which stands for Long Term Evolution (of mobile networks). LTE is the 4G migration path for key 3G technologies including UMTS as well as CDMA2000. Even though another technology WiMAX (Worldwide Interoperability for Microwave Access) is also capable of fulfilling the 4G requirements, LTE has been the primary technology for worldwide 4G deployments.

LTE networks are packet-based unlike the earlier 2G and 3G networks that were both circuit and packet-switched. The voice and SMS part in LTE can be enabled by a technology Voice over LTE (VoLTE), which is packet-based. LTE networks however have a circuit-switched fallback which means if the device or the base station does not support VoLTE, the LTE network can facilitate voice calls and SMS over 2G or 3G networks also. LTE can offer peak downlink data rates of up to 300 Mbps and lower latencies compared to 3G networks. From a customer use case viewpoint, 4G LTE networks can offer reliable mobile broadband services due to the average speeds they can enable. LTE on your mobile phone can also work as a mobile hotspot to provide a backup for your home broadband.

After the launch of LTE, some enhancements were introduced in the form of LTE Advanced (LTE-A) and LTE Advanced Pro. LTE-Advanced and LTE-Advanced Pro are shown on the mobile phone screen as LTE+ and can support maximum theoretical speeds of up to 1 Gbps and 3Gbps, respectively. The average 4G LTE speeds are considerably lower than these peak speeds. On average, 4G LTE Advanced networks can offer download speeds of around 65 Mbps based on some speed tests we carried out in the UK. Have a look at this post where we documented the results of the 4G LTE data speed tests.

LTE is based on Orthogonal Frequency Division Multiple Access – OFDMA, which is highly efficient compared to earlier radio access technologies. OFDMA also supports a modulation technique QAM – Quadrature Amplitude Modulation which is capable of generating higher data rates to make better use of the available bandwidth. You can also check out our post What is the meaning of LTE for a general understanding of 4G LTE networks and to learn what it means for you as a customer. If you are new to mobile communications and trying to build a quick understanding of mobile networks and how the industry works, check out this slide deck which has been created for beginners.

5G – Fifth Generation

5G stands for the fifth generation of mobile networks and it is the latest cellular generation so far. It is enabled by a technology called New Radio (NR) which is based on OFDMA. 5G is different from the earlier generations of mobile networks as it can cater to a vast variety of use cases by leveraging its in-built flexibility. 5G is very quick and is capable of supporting a large number of devices that can help digitise many industries. It can also operate in various frequency bands including high as well as low frequencies. The higher frequency bands for 5G have limited coverage but very low latency (less than 1 millisecond) which is suitable for real-time services. The use cases for 5G are categorised into three main classes: enhanced mobile broadband (eMBB), massive Machine Type Communication (mMTC) and ultra-reliable low latency communications (uRLLC). We have a dedicated post on eMBB, mMTC and uRLLC which can help you understand these three key pillars of 5G.

Lower frequency bands, as per the laws of physics, have higher latency but much better coverage. Therefore, mass deployment of 5G in the wider regions can benefit from the lower frequency bands. On the other hand, the higher frequency bands have lower latency and are therefore ideal for providing communications for real-time applications like self-driving cars, manufacturing, virtual reality (VR) and other IoT (Internet of Things) services. Check out our dedicated post to learn what 5G means to you as a customer.

Compared to 4G LTE networks, 5G NR can offer much higher data rates on average. While the peak downlink speed of 5G is over 10 Gbps, the average speeds of 150 Mbps are not uncommon. At the moment, most 5G deployments are non-stand-alone (NSA), which means they are not full 5G deployments. 5G non-standalone is when the 5G technology is enabled by using a combination of 4G and 5G networks. As a customer of 5G, I have been using 5G NSA for the last six months and the experience has been good. If you are considering 5G as your home internet service, then you can check out this post that documents my personal experience of using 5G non-standalone. You can also check out this post for the average 5G speeds that I have seen so far with my 5G SIM and router combination.

What is the difference between 4G and 5G networks?

The main difference between 4G LTE and 5G NR is that the maximum bandwidth in 5G is a lot higher than 4G LTE networks. As a result, 5G NR networks can accommodate a lot higher data rates compared to 4G LTE. The average download speed with LTE-Advanced is around 65 Mbps (UK- Berkshire) whereas the average download speed with 5G NR is around 130-150 Mbps. Important to note that the 5G networks are still in their infancy and most deployments are non-standalone so far. Have a look at this post to understand the key differences between 4G and 5G.

Is 5G that much better than 4G?

From a technology viewpoint, 5G can offer peak speeds of up to 10 Gbps compared to LTE-Advanced Pro that can enable peak speeds of 3 Gbps. On average 5G is arguably ten times better than 4G LTE. Important to note though that it all depends on your mobile operator as to how much capacity they allocate, which configurations they use etc. Also, 4G LTE networks are mature now with the launch of LTE-Advanced and LTE-Advanced Pro a few years back. 5GNR networks are still new and are likely to see enhancements over the next few years just like LTE networks did.

1G to 5G explained in 8 minutes

Here are some helpful downloads

Thank you for reading this post, I hope it helped you in developing a better understanding of cellular networks. Sometimes, we need some extra support especially when preparing for a new job, or studying a new topic, or maybe just buying a new phone. Whatever you are trying to do, here are some downloads that can help you:

Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy which explains the network nodes e.g. BTS, MSC, GGSN etc.

Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and the challenges considering how quickly the industry evolves. The bigger picture comes from experience which is why I’ve carefully put together a few slides to get you started in no time. So if work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on product overview and product roadmap.

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