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

The mobile communications industry is full of acronyms and abbreviations, and we often come across terminologies like 2G, 3G, 4G and 5G. People who are closer to the industry may be more familiar with these terminologies but others may find all this a little bit daunting. The mobile networks that we know today have evolved continuously since their inception nearly 40 years ago. Let’s have a quick look at this evolution to understand what these terminologies really mean for us.

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, almost every ten years, we have seen a new generation of mobile networks.

The table below summarises this concept and gives an overview of the technologies employed by 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 bandwidth as compared to earlier technologies. Starting with 2G, all mobile networks have used digital communications. Let’s now have a quick look at all the generations of mobile networks and the technologies used for enabling them.

1G

1G stands for the first generation of mobile networks which were built to provide basic voice services to customers. 1G networks started in the 1980s and were introduced in different parts of the world through various analogue technologies. The 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).

2G

2G stands for the second generation of mobile networks which replaced the earlier 1G networks. These networks enabled highly secure voice and text messaging services as well as limited 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). Voice calling and text messaging are the key services that the 2G networks enabled. Even today, you can get basic GSM mobile phones if all you are looking for is a phone that allows you to make/receive calls and text messages. You can find one from Easyfone that does the job perfectly as a basic phone and is available on Amazon’s website here and Amazon UK’s website here.

The second generation of mobile networks introduced two new access technologies; TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access). For clarity, the access technology is what connects the mobile phone to the mobile network by sending and receiving signals wirelessly through the air interface. The original GSM and D-AMPS networks were not really equipped for data services. General Packet Radio Service (GPRS) and Enhanced Data for Global Evolution (EDGE) were introduced in the GSM networks to provide mobile data services. GPRS and EDGE are also referred to as 2.5G and 2.75G respectively. You can learn more about GSM networks in our dedicated post here and about D-AMPS in this post.

The first-ever CDMA based mobile communications technology IS-95 was introduced in 1995 that also supported mobile data. There have been two versions of IS-95 which are IS-95 A and IS-95 B. IS-95 A can support peak data rates of up to 14.4 kbps. IS-95 B can improve these rates to up to 115 kbps. More about IS-95 in our dedicated post on this topic here.

3G

3G in mobile communications refers to the third generation of mobile networks. There have been two key tracks for 3G and they were both based on the CDMA technology. The first track was Universal Mobile Telecommunications Systems (UMTS) and the other was CDMA2000. UMTS was used for migrating GSM networks to 3G and CDMA2000 was the 3G technology for IS-95 and D-AMPS. UMTS employs WCDMA (Wideband CDMA) for the access part and offers peak downlink speeds of up to 2 Mbps. The UMTS networks saw data rate enhancements through a technology called High-Speed Packet Access (HSPA). HSPA can offer peak downlink and uplink speeds of up to 14.4 Mbps and 5.76 Mbps respectively. Later, another enhancement Evolved High-Speed Packet Access (HSPA+) was introduced, which can provide data rates of up to 42 Mbps in the downlink and 11.5 Mbps in the uplink. You can learn more about HSPA in our dedicated post on the topic by clicking here. If you are looking for a good technical reference on the evolution of 3G networks including HSPA, we would recommend ‘3G Evolution: HSPA and LTE for Mobile Broadband’. You can find this book on Amazon’s website here and on Amazon UK’s website here.

CDMA2000 can support peak data rates of up to 153 kbps in the downlink as well as 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. You can check out this post for more information on the EVDO technology.

4G

4G stands for the fourth generation of mobile networks. 4G was enabled by a new technology called LTE which stands for Long Term Evolution (of mobile networks). LTE is the 4G migration path for key 3G technologies including Universal Mobile Telecommunication System (UMTS) and CDMA2000. Another technology WiMax (Worldwide Interoperability for Microwave Access) can also provide a 4G upgrade path but LTE has been the primary technology used worldwide for 4G deployments. LTE is much more efficient than the earlier 3G technologies, and it also reduces the latency in data transfer. 

After the launch of LTE, some enhancements were introduced in the form of LTE Advanced (LTE-A) and LTE Pro. LTE can support peak speeds of up to 300 Mbps in the downlink, while LTE-A and LTE-Pro can support maximum speeds of up to 1 Gbps and 3Gbps respectively. The average 4G speeds are considerably lower than the peak speeds (around 17 Mbps with LTE and 66 Mbps with LTE Advanced) which you can find out more about in this post. Due to the speeds it offers, 4G is a perfect choice as a mobile broadband service also. As a customer, if you have a 4G router or a spare 4G tablet, you can get a data-only SIM and create your own WiFi coverage in your home. There is a one resonably-priced 4G LTE router from TP-Link which you can find on Amazon’s website here and on Amazon UK’s website here.

You can also learn more about LTE in our dedicated post on that topic by clicking here. If you are looking for an in-depth technical reference on LTE, we would recommend LTE-Advanced: A Practical Systems Approach to Understanding 3GPP LTE Releases 10 and 11 Radio Access Technologies. You can find this book on Amazon’s website here and on Amazon UK’s website here.

5G

5G stands for the fifth generation of mobile networks and it uses a technology called New Radio or NR. 5G is fundamentally different from the earlier mobile technologies and the true demand for it is yet to be seen. It is a lot more than just high-speed mobile internet service. The majority of its use cases are very futuristic and yet to come. 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.

In terms of the data rates, 5G can offer peak speeds of over 10 Gbps in the downlink with a latency of as low as 1 millisecond. The average speeds you get with 5G are considerably lower but still around 150 Mbps (in the UK 2019/20). Have a look at this post for more information on the average 5G speeds and device and SIM considerations. On average, 5G phones are more expensive than the 4G phones at the moment, and anything around £1000 is not unusual. However, we have found two good 5G phones that are reasonably priced. One of them is OnePlusNord which ticks all the main boxes and available on OnePlus’ website here. The other one is Samsung Galaxy A51 5G which you can find on Amazon’s website here and on Amazon UK’s website here.

Lower frequency bands, as per the laws of physics, have higher latency but much better coverage. Mass deployment of 5G in the wider regions, therefore, can benefit from the lower frequency bands. The higher frequency bands have lower latency and therefore ideal for providing communications for self-driving cars, manufacturing, virtual reality (VR) and other IoT (Internet of Things) services. If you are looking for a technical reference on 5G NR, we would recommend ‘5G NR: The Next Generation Wireless Access Technology’. You can find this book on Amazon’s website here and on Amazon UK’s website here

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