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Chapter 1
5G: A Multigenerational Approach
Introduction
Technological change lies at the heart of the mobile communications sector. It seems hard to believe, for example, that the Apple iPhone – the first true smartphone – only arrived in 2007 given that virtually every person in advanced countries now carries one, often in an ostentatious manner, and that using a mobile device to make a voice call seems quaintly old fashioned.
Naturally, rapid technological change is not confined to the mobile sector, but what is unique to it is the pace at which change has occurred during the past three decades. For example, whereas Curwen and Whalley (2008) contained a full chapter on the subject of technology, little more than one page was given over to a preliminary discussion of what was referred to as ‘4G’. Within the space of 2 years, 4G had become a reality and, shortly afterwards, interest began to be expressed in the next technological step forward known as ‘5G’.
The use of the terms 4G and 5G – not to mention their predecessors, 1G, 2G and 3G – results from a tendency to explain technological change as proceeding via a series of ‘generations’ or ‘part-generations’. It should be borne in mind that the divisions between generations are less clear-cut than might be imagined. For example, 4G is now effectively a synonym for long term evolution (LTE) although in practice, as noted below, basic LTE should strictly be described as lying somewhere between 3.75G and 4G with LTE-Advanced (LTE-A) the first technology that meets the agreed specifications for 4G.
Part of the confusion resides in the fact that a mobile technology can also be described in terms of the speed at which data are transferred via either an uplink or a downlink, expressed in megabits per second (Mbps) or gigabits per second (Gbps) (Wisegeek, 2016). Given that it is possible to speed up a technology used in an earlier generation, there is an inevitable overlap between generations once the older technology achieves speeds at least comparable to the lower range of speeds available via the subsequent generation. It must also be borne in mind that in the real world some countries will be introducing one generation at the same point in time when other countries are introducing the next generation.
Broadly speaking, each generation takes 10 years to establish before being overtaken. Thus, 3G lasted roughly from 2000 to 2010 and 4G has so far lasted roughly from 2010 to 2020 as shown in Table 1.1. It accordingly comes as no surprise that 6G is already under discussion with a target launch date of 2030 – see Telecompaper (2020) and conclusion of Chapter 2.
Table 1.1. LTE Network Launches by Region: Nationwide Incumbent Terrestrial Networks.
| Total | Western Europe | Eastern Europe/CIS | Middle East | Asia-Pacific | North America | Latin America a | Africa |
| 2009 | 2 | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| 2010 | 16 | 11 | 2 | 0 | 2 | 1 e | 0 | 0 |
| 2011 | 28 | 11 | 2 | 5 | 4 | 3 | 3 | 0 |
| 2012 | 78 | 27 | 11 | 3 | 16 | 5 | 9 | 7 |
| 2013 | 86 | 30 | 2 c | 8 | 15 | 4 | 19 | 8 |
| 2014 | 80 | 14 b | 6 | 6 | 18 | 1 | 24 | 11 e |
| 2015 | 92 | 19 | 11 d | 5 | 15 | 2 | 23 | 17 |
| 2016 | 89 | 2 | 6 | 8 | 18 | 2 | 26 | 27 |
| 2017 | 46 | 3 | 0 | 1 | 16 | 1 | 8 | 17 |
| 2018 | 38 | 2 | 3 | 2 | 8 | 0 | 6 | 17 |
| 2019 | 16 | 0 | 2 | 0 | 2 | 0 | 2 | 10 f |
| Total | 571 | 121 | 45 | 38 | 114 | 19 | 120 | 114 |
3GPP Releases
There are various ways to produce a timeline for the introduction of 5G, but the main difficulty arises from integrating the role played throughout the process by key bodies such as the Third Generation Partnership Project (3GPP – see www.3gpp.org), which is associated with a series of so-called Releases, and the World Radiocommunication Conference (WRC) which brings together all parties interested in spectrum use every few years.
The 3GPP is a key player in the development of mobile technology although it only covers the development of GSM-based technology (Wikipedia, 2020a).1 3GPP brings together seven telecommunications standard development organisations ‘and provides their members with a stable environment to produce the Reports and Specifications that define 3GPP technologies’ (3GPP, 2020).
3GPP is not a standards body as such but submits its proposals – in this case concerning International Mobile Telecommunication system-2020 (IMT-2020) to the International Telecommunication Union Radiocommunications Sector (ITU-R) (Wikipedia, 2020b). The ITU-R issued the requirements for IMT-2020 in 2015. These are specified in Wikipedia (2020b) in respect of 5G candidate radio access technologies (RATs). A RAT is the underlying physical connection method for a radio-based communication network – a modern smartphone contains RATs in the form of 2G, 3G, 4G and possibly 5G. The non-radio aspects of IMT-2020 are dealt with in ITU-T (Wikipedia, 2020c).
IMT-2020 – which is discussed in more detail in Chapter 2 – specifies a number of key performance indicators. For example, the peak theoretical downlink was specified as a minimum of 20 Gbps – 200 times faster than LTE – and the uplink as a minimum of 10 Gbps while the peak downlink spectral efficiency was set at a minimum of 30 bits/Hz and the uplink at a minimum of 15 bits/Hz. Other indicators included latency, mobility interruption time, reliability, connection density, battery life and coverage (International Telecommunication Union, 2017; Keysight, 2020).
As noted above, 3GPP is particularly associated with a series of Releases – where each Release incorporates hundreds of individual standard documents which undergo a continuous state of revision – that were denoted by dates until 2000 and numbered consecutively starting with Release 4 in 2001 – see https://www.3gpp.org/specifications/67-releases. Release 7 in 2007 was primarily concerned with upgrades to 3G as discussed below (3G Americas, 2007), while those commencing with Release 8 were concerned with the route to 4G and, subsequently the route to 5G (Keysight, 2015).
The most recent Releases that are significant in terms of what follows are Release 14 (end-date June 9, 2017), Release 15 (end-date June 7, 2019), Release 16 (end-date June 19, 2020) and Release 17 (end-date September 17, 2021) – see Chapter 2. Once a Release is ‘frozen’, no further additional functions can be added as the functions are deemed to be ‘stable’.
Harmonisation and the WRC
The edicts of regionally based bodies such as the European Union apply to only 30 or so countries and there are some 225 altogether worldwide, which is where the WRC comes in. Its task is to harmonise the spectrum preferred by the EU, the USA, China, South Korea and so forth – no easy task.
The WRCs are organised by the International Telecommunication Union (ITU) to review and, as necessary, revise the Radio Regulations. These take the form of ‘an international treaty governing the use of the radio-frequency spectrum and the geostationary-satellite and non-geostationary-satellite orbits’. Under the terms of the ITU Constitution, the WRC can, inter alia, revise the Radio Regulations and any associated frequency assignment and allotment plans. The WRC as such has met in 1993, 1995, 1997, 2000, 2003, 2007, 2012, 2015 and 2019 although it met previously under different auspices (Wikipedia, 2020d). Information concerning the WRC can be found at http://www.itu.int/ITU-R/go/wrc/en.
The Early Generations
Technology upgrades are achieved via improved software, hardware or both. An important point is that whereas it is quite cheap and easy to upgrade a technology (largely via software) provided it remains within the same spectrum band, it is relatively expensive to introduce a new technology in a previously unused band because a new set of hardware is required. An intermediate step in terms of cost is to open up a different spectrum band for a technology already in use, the reason being that much less new hardware is needed.
2G was the first digital technology designed primarily to carry voice, whereas 3G – known most commonly either as wide-band code division multiple access (W-CDMA) or universal mobile telecommunications system (UMTS – see Wikipedia, 2020e) – was designed to cope with the transmission of modest amounts of data – modest because transfer speeds were very slow by modern standards. W-CDMA was superseded by high-speed packet access (HSPA – see Wikipedia, 2020f) which had the advantage that it could be upgraded successively either by doubling up the number of channels (dual-carrier) or through the use of multiple input multiple output (MIMO) antennas – see 3G.co.uk (2009) and De Grasse (2016). Adding MIMO to HSPA helped to convert it to HSPA+ which was capable of yet higher speeds, and even these speeds could be doubled through the introduction of 64 QAM (quadrature amplitude modulation) (Radio Electronics, 2016).
It may be helpful to clarify the role of MIMO at this point. MIMO means that antennas at both the tower and end-user device send and receive multiple data streams within one channel. Most smartphones were designed initially to support 2×2 MIMO but towers were upgraded to cope with four data streams – that is, 4×2 MIMO. 4×4 MIMO is common on the latest devices but this can be distinguished from Massive MIMO which is widely viewed as a synonym for at least 16×16 MIMO with 8T8R MIMO – now the common way to describe MIMO where T stands for ‘transmit’ and R stands for ‘receive’ – as an intermediate level (De Grasse, 2016 and see Chapter 2).
In the USA, the 3G technology of choice was cdma 2000 1×EV-DO (evolution-data optimised). This was expected to develop through a sequence of upgrades to what became known as ultra mobile broadband (UMB – Techopedia, 2016), However, as a consequence of the widespread commitment by 1×EV-DO operators to move towards the adoption of LTE during 2008, UMB was effectively abandoned at the year-end.
It is also helpful to refer here to TD-SCDMA – the ‘TD’ refers to time division duplex (TDD) which means that the signal ...
