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

Mobile networks have matured over the last two decades from a data speed perspective, but they continue to evolve to enable many new use cases for people and IoT (Internet of Things) devices. Today, the 4G and 5G use the same technologies worldwide; however, it wasn’t the case before the fourth generation of mobile networks. The first generation of mobile networks is now obsolete, but we still have 2G, 3G, 4G and 5G networks active in most parts of the world.

1G, 2G, 3G, 4G and 5G are the five generations of mobile networks where G stands for Generation, and the number denotes the generation number. 5G is the latest generation, whereas 1G networks are now obsolete. The cellular technologies GSM, UMTS, LTE and NR enable 2G, 3G, 4G and 5G, respectively.

TermStands forLaunch Year
1GFirst Generation1979
2GSecond Generation1991
3GThird Generation2001
4GFourth Generation2009
5GFifth Generation2019
—What 1G, 2G, 3G, 4G and 5G mean and when they were launched—

We live in an era of mobile communications where we have four different generations of mobile networks that provide us with cellular services. The first generation of mobile networks was introduced in most parts of the world in the early 1980s. Digital mobile networks replaced the first generation in 1991-92, but some of the technologies that replaced the 1G networks are still around even after thirty years.

1G, 2G, 3G, 4G and 5G are the generations of mobile networks

There have been five generations of mobile networks so far. 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 have seen a new generation of mobile networks nearly every ten (10) years.

Each generation of mobile networks (e.g. 2G) has a set of requirements fulfilled by the relevant cellular technologies (e.g. GSM). Examples of cellular technologies include AMPS, GSM, UMTS, CDMA2000, LTE, etc.

Mobile networks started their journey in a very decentralised way, and different regions, e.g. Nordic, US, UK, Germany, Japan etc., followed their own preferred technologies for launching local cellular services.

As mobile networks became an integral part of our lives, the technologies started to mature with the aim to allow customers to enjoy the same experience abroad as they would in their home country.

GenerationTechnology standardRadio access technology
1G – First GenerationAMPS, NMT, TACS, J-TACS, C-NetzFDMA
2G – Second GenerationGSM, D-AMPS, IS-95Combination of TDMA & FDMA, and Narrowband CDMA
3G – Third GenerationUMTS (WCDMA) and CDMA2000Wideband CDMA and Narrowband CDMA
4G – Fourth GenerationLTE (Long Term Evolution)OFDMA and SC-FDMA
5G – Fifth GenerationNR (New Radio)OFDMA
—Technologies used by 1G, 2G, 3G, 4G and 5G—

Multiple technologies are required for 1G, 2G, 3G, 4G and 5G

The first-generation mobile networks (1G) used analogue technologies: AMPS, NMT, TACS, J-TACS and C-Netz. The following generations were digital and used GSM, D-AMPS and IS-95 for second-generation (2G), CDMA2000 and UMTS for third (3G), LTE for fourth (4G) and NR for the fifth generation (5G).

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 FDMA technology. FDMA stands for Frequency Division Multiple Access and uses separate frequency bands to transmit and receive communication wirelessly. The frequency bands are then divided into multiple sub-frequencies, also known as channels, to enable communication between the mobile network and the mobile phone.

Analogue networks do not have encryption capabilities, making them susceptible to security issues. The continuous nature of the radio signal also makes the analogue systems more prone to noise.

The mobile networks started their digital era in the early 1990s to overcome the challenges that analogue networks could not address. This digital journey started with the second generation of mobile networks, also known as 2G. The technology standards that enabled the second generation of mobile networks (2G) followed two major tracks.

The first track used a combination of FDMA (Frequency Division Multiple Access) and TDMA (Time Division Multiple Access). The other track employed the CDMA technology (Code Division Multiple Access) for the first time in mobile communications. More about 2G and later generations can be found in the following sections, but have a look at the table below for a summary of the technologies used for various generations of mobile networks.

Summary of 1G, 2G, 3G, 4G and 5G network technologies

We also have an ebook that captures the different generations of mobile networks in an easy to follow way. If you want to get the book, follow this link to Mobile Communications Made Easy or click on the picture of the book below.

1G – First Generation

1G stands for the first generation of mobile networks that were designed to provide basic voice calling services. 1G networks started in the early 1980s and were introduced in different parts of the world through various FDMA-based analogue technologies, including AMPS, NMT, TACS, J-TACS and C-Netz.

First-generation (1G) 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 was deployed in the Nordic/Scandinavian region, TACS mainly in the UK, and C-Netz in Germany.

While Japan was the first country in the world to launch a commercial cellular network in 1979, it later adopted a variant of AMPS called J-TACS (Japanese Total Access Communication System). For clarity, the TACS technology in the UK was also a variant of AMPS. 1G networks were based on the Frequency Division Multiple Access technology (FDMA).

I have written a dedicated post on analogue and digital cellular networks that provides further details on the first generation of mobile networks. The AMPS technology was later upgraded to its digital version, D-AMPS, a key second-generation technology which you can learn about in this dedicated post on AMPS vs D-AMPS.

2G – Second Generation

2G stands for the second generation of mobile networks that initially offered voice calls, text messages and limited mobile internet. 2G networks started in the early 1990s and were introduced in different parts of the world through various digital technologies, including GSM, D-AMPS and IS-95.

The second-generation (2G) mobile networks are digital, and they replaced the first-generation (1G) networks. 2G 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, TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access). Access technologies are part of the mobile radio network that allows a mobile phone to connect 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 a second-generation enhancement and 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 GPRS originally introduced. These nodes are part of the mobile core network and are called SGSN (Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node).

In addition, 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). EDGE is also a second-generation enhancement and is referred to as 2.75G because it bridged the gap between GPRS and 3G UMTS. We have a dedicated post on GPRS, EGPRS and EDGE that you may check out for more information.

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 also designed to support mobile data. 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 stands for the third generation of mobile networks that offer voice, text and data services. The technologies that enable 3G are UMTS and CDMA2000 which are based on the CDMA technology. UMTS is the 3G technology for GSM, and CDMA2000 is the 3G technology for IS-95.

There have been two 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, and the other track was CDMA2000 for IS-95 and D-AMPS.

UMTS, which represents the first track, stands for Universal Mobile Telecommunication System. It employs Wideband Code Division Multiple Access (WCDMA) for its air interface to offer peak download data rates of up to 2 Mbps. The average data rate with UMTS is around 384 kbps.

We have a dedicated post on 3G UMTS that dives deeper into the technical aspects, including frequencies, bandwidths and more. High-Speed Packet Access (HSPA) networks are built upon the UMTS technology. 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 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 top upload speeds of up to 5.4 Mbps. 

4G – Fourth Generation

4G stands for the fourth generation of mobile networks that are data-only networks enabled by the LTE technology. 4G networks use packet-switching to offer IP-based voice calls and text messages in addition to high-speed mobile data. LTE is the 4G technology for both UMTS and CDMA2000.

4G is enabled by the LTE technology, which stands for Long Term Evolution (of mobile networks). LTE is the 4G migration path for key 3G technologies, including UMTS and CDMA2000. Even though another technology WiMAX (Worldwide Interoperability for Microwave Access), can also fulfil the 4G requirements, LTE has been the primary technology for worldwide 4G deployments.

LTE networks are fully packet-switched and do not have a circuit-switched part. A packet-based technology Voice over LTE (VoLTE), is responsible for enabling voice calls and text messaging in 4G LTE networks. However, LTE networks have a 2G/3G circuit-switched fallback, which allows them to facilitate voice calls and SMS over 2G or 3G networks if the VoLTE capability is not supported by the phone or your mobile operator.

LTE can offer peak downlink data rates of up to 300 Mbps and lower latencies than3G 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 an internet 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 the peak speeds. On average, 4G LTE Advanced networks can offer download speeds of around 65 Mbps.

LTE uses Orthogonal Frequency Division Multiple Access – OFDMA for radio access, which is highly efficient than earlier radio access technologies. OFDMA supports a highly efficient modulation technique, QAM – Quadrature Amplitude Modulation, which generates higher data rates to utilise the available frequency better. You may also check out our post on LTE and LTE+ symbols on your phone for a general understanding of 4G LTE 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 created for beginners.

5G – Fifth Generation

5G stands for the fifth generation of mobile networks that are data-only and offer average download speeds of around 150 to 200 Mbps. It is the latest generation of mobile networks enabled by the New Radio technology (NR). 5G networks can offer latencies as low as one millisecond.

The 5G New Radio (NR) technology is based on Orthogonal Frequency Division Multiple Access (OFDMA), just like LTE. However, it is different from the earlier generations of mobile networks as it can cater to a wide variety of use cases by leveraging its in-built flexibility. It can also operate in various frequency bands, including high and low frequencies.

The higher frequency bands for 5G have limited coverage but very low latency (less than one millisecond), 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 critical pillars of 5G.

As per the laws of physics, lower frequency bands have higher latency but much better coverage. Therefore, mass deployment of 5G in the wider geographical areas can benefit from the lower frequency bands. On the other hand, the higher frequency bands have lower latency. Hence, they are ideal for providing communications for real-time applications like self-driving cars, manufacturing, virtual reality (VR), and other IoT (Internet of Things) services. Like the IP-based voice calling capability in LTE networks (VoLTE), 5G networks have VoNR or Voice over NR, also known as Voice over 5G (Vo5G).

Is 5G a lot faster than 4G LTE?

Compared to 4G, 5G can offer much higher data rates on average. While the peak download speed of 5G is over 10 Gbps, the average speeds are around 150 Mbps to 200 Mbps. Currently, most 5G deployments are non-stand-alone (NSA) that use a combination of 4G and 5G networks to deliver 5G services.

From a technology viewpoint, 5G can offer peak speeds of up to 10 Gbps compared to LTE-Advanced Pro, which can enable peak speeds of 3 Gbps. So on average, 5G is arguably ten times better than 4G LTE. It is important to note 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 LTE-Advanced and LTE-Advanced Pro deployments. 5GNR networks are still new and are likely to see enhancements over the next few years, just like LTE networks did. At the moment, most 5G deployments are non-stand-alone (5G NSA), which means they are not complete or end-to-end 5G deployments.

5G non-standalone is when the 5G technology is enabled by a combination of 4G and 5G networks. If you want to find out exactly what average speeds to expect from 4G and 5G networks, check out our dedicated posts on average 4G speeds and average 5G speeds to see real-life speed tests results.

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

The main difference between 4G LTE and 5G NR is that the maximum bandwidth in 5G is higher than in 4G LTE networks. As a result, 5G NR networks can accommodate higher data rates than 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 150-200 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 our dedicated post to understand the overall difference between 4G LTE, LTE Advanced and 5G networks.

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 extra support, especially when preparing for a new job, studying a new topic, or 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 you 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 the product overview and product roadmap.

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