,CHAPTER 1
What Is 5G?
Abstract
The chapter gives background to 5G mobile communication, describing the earlier generations
and the justification for a new generation. It describes the high-level 5G use cases, eMBB, mMTC,
and URLLC. It also describes the 3GPP process for developing the new 5G/NR radio-access
technology.
KEYW ORDS
5G; NR; 3GPP; eMBB; URLLC; mMTC; machine-type communication
Over the last 40 years, the world has witnessed four generations of mobile communication
(see Fig. 1.1).
The different generations of mobile communication.
FIGURE 1.1
The first generation of mobile communication, emerging around 1980, was based on analog
transmission with the main technologies being AMPS (Advanced Mobile Phone System)
developed within North America, NMT (Nordic Mobile Telephony) jointly developed by the,
at that time, government-controlled public-telephone-network operators of the Nordic
countries, and TACS (Total Access Communication System) used in, for example, the United
Kingdom. The mobile-communication systems based on first-generation technology were
limited to voice services and, for the first time, made mobile telephony accessible to ordinary
people.
The second generation of mobile communication, emerging in the early 1990s, saw the
introduction of digital transmission on the radio link. Although the target service was still
voice, the use of digital transmission allowed for second-generation mobile-communication
systems to also provide limited data services. There were initially several different second-
generation technologies, including GSM (Global System for Mobile communication) jointly
developed by a large number of European countries, D-AMPS (Digital AMPS), PDC
(Personal Digital Cellular) developed and solely used in Japan, and, developed at a
,somewhat later stage, the CDMA-based IS-95 technology. As time went by, GSM spread from
Europe to other parts of the world and eventually came to completely dominate among the
second-generation technologies. Primarily due to the success of GSM, the second-generation
systems also turned mobile telephony from something still being used by only a relatively
small fraction of people to a communication tool being a necessary part of life for a large
majority of the world's population. Even today there are many places in the world where
GSM is the dominating, and in some cases even the only available, technology for mobile
communication, despite the later introduction of both third- and fourth-generation
technologies.
The third generation of mobile communication, often just referred to as 3G, was introduced
in the early 2000. With 3G the true step to high-quality mobile broadband was taken, enabling
fast wireless internet access. This was especially enabled by the 3G evolution known as HSPA
(High Speed Packet Access) [21]. In addition, while earlier mobile-communication
technologies had all been designed for operation in paired spectrum (separate spectrum for
network-to-device and device-to-network links) based on the Frequency-Division
Duplex (FDD), see Chapter 7, 3G also saw the first introduction of mobile communication in
unpaired spectrum based on the china-developed TD-SCDMA technology based on Time
Division Duplex (TDD).
We are now, and have been for several years, in the fourth-generation (4G) era of mobile
communication, represented by the LTE technology [28] LTE has followed in the steps of
HSPA, providing higher efficiency and further enhanced mobile-broadband experience in
terms of higher achievable end-user data rates. This is provided by means of OFDM-based
transmission enabling wider transmission bandwidths and more advanced multi-antenna
technologies. Furthermore, while 3G allowed for mobile communication in unpaired
spectrum by means of a specific radio-access technology (TD-SCDMA), LTE supports both
FDD and TDD operation, that is, operation in both paired and unpaired spectra, within one
common radio-access technology. By means of LTE the world has thus converged into a
single global technology for mobile communication, used by essentially all mobile-network
operators and applicable to both paired and unpaired spectra. As discussed in somewhat
more detail in Chapter 4, the later evolution of LTE has also extended the operation of mobile-
communication networks into unlicensed spectra.
1.1 3GPP and the Standardization of Mobile Communication
Agreeing on multi-national technology specifications and standards has been key to the success
of mobile communication. This has allowed for the deployment and interoperability of devices
and infrastructure of different vendors and enabled devices and subscriptions to operate on a
global basis.
As already mentioned, already the first-generation NMT technology was created on a
multinational basis, allowing for devices and subscription to operate over the national borders
between the Nordic countries. The next step in multi-national specification/standardization of
mobile-communication technology took place when GSM was jointly developed between a large
number of European countries within CEPT, later renamed ETSI (European Telecommunications
, Standards Institute). As a consequence of this, GSM devices and subscriptions were already from
the beginning able to operate over a large number of countries, covering a very large number of
potential users. This large common market had a profound impact on device availability, leading
to an unprecedented number of different device types and substantial reduction in device cost.
However, the final step to true global standardization of mobile communication came with the
specification of the 3G technologies, especially WCDMA. Work on 3G technology was initially also
carried out on a regional basis, that is, separately within Europe (ETSI), North America (TIA,
T1P1), Japan (ARIB), etc. However, the success of GSM had shown the importance of a large
technology footprint, especially in terms of device availability and cost. It also become clear that
although work was carried out separately within the different regional standard organizations,
there were many similarities in the underlying technology being pursued. This was especially
true for Europe and Japan which were both developing different but very similar flavors
of wideband CDMA (WCDMA) technology.
As a consequence, in 1998, the different regional standardization organizations came together
and jointly created the Third-Generation Partnership Project (3GPP) with the task of finalizing
the development of 3G technology based on WCDMA. A parallel organization (3GPP2) was
somewhat later created with the task of developing an alternative 3G technology, cdma2000, as
an evolution of second-generation IS-95. For a number of years, the two organizations (3GPP and
3GPP2) with their respective 3G technologies (WCDMA and cdma2000) existed in parallel.
However, over time 3GPP came to completely dominate and has, despite its name, continued into
the development of 4G (LTE, and 5G) technologies. Today, 3GPP is the only significant
organization developing technical specifications for mobile communication.
1.2 The Next Generation—5G/NR
Discussions on fifth-generation (5G) mobile communication began around 2012. In many
discussions, the term 5G is used to refer to specific new 5G radio-access technology. However,
5G is also often used in a much wider context, not just referring to a specific radio-access
technology but rather to a wide range of new services envisioned to be enabled by future mobile
communication.
1.2.1 THE 5G USE CASES
In the context of 5G, one is often talking about three distinctive classes of use cases: enhanced
mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable and
low-latency communication (URLLC) (see also Fig. 1.2).
• eMBB corresponds to a more or less straightforward evolution of the mobile-
broadband services of today, enabling even larger data volumes and further
enhanced user experience, for example, by supporting even higher end-user data
rates.
• mMTC corresponds to services that are characterized by a massive number of
devices, for example, remote sensors, actuators, and monitoring of various
equipment. Key requirements for such services include very low device cost and
very low device energy consumption, allowing for very long device battery life of
up to at least several years. Typically, each device consumes and generates only a
relatively small amount of data, that is, support for high data rates is of less
importance.
What Is 5G?
Abstract
The chapter gives background to 5G mobile communication, describing the earlier generations
and the justification for a new generation. It describes the high-level 5G use cases, eMBB, mMTC,
and URLLC. It also describes the 3GPP process for developing the new 5G/NR radio-access
technology.
KEYW ORDS
5G; NR; 3GPP; eMBB; URLLC; mMTC; machine-type communication
Over the last 40 years, the world has witnessed four generations of mobile communication
(see Fig. 1.1).
The different generations of mobile communication.
FIGURE 1.1
The first generation of mobile communication, emerging around 1980, was based on analog
transmission with the main technologies being AMPS (Advanced Mobile Phone System)
developed within North America, NMT (Nordic Mobile Telephony) jointly developed by the,
at that time, government-controlled public-telephone-network operators of the Nordic
countries, and TACS (Total Access Communication System) used in, for example, the United
Kingdom. The mobile-communication systems based on first-generation technology were
limited to voice services and, for the first time, made mobile telephony accessible to ordinary
people.
The second generation of mobile communication, emerging in the early 1990s, saw the
introduction of digital transmission on the radio link. Although the target service was still
voice, the use of digital transmission allowed for second-generation mobile-communication
systems to also provide limited data services. There were initially several different second-
generation technologies, including GSM (Global System for Mobile communication) jointly
developed by a large number of European countries, D-AMPS (Digital AMPS), PDC
(Personal Digital Cellular) developed and solely used in Japan, and, developed at a
,somewhat later stage, the CDMA-based IS-95 technology. As time went by, GSM spread from
Europe to other parts of the world and eventually came to completely dominate among the
second-generation technologies. Primarily due to the success of GSM, the second-generation
systems also turned mobile telephony from something still being used by only a relatively
small fraction of people to a communication tool being a necessary part of life for a large
majority of the world's population. Even today there are many places in the world where
GSM is the dominating, and in some cases even the only available, technology for mobile
communication, despite the later introduction of both third- and fourth-generation
technologies.
The third generation of mobile communication, often just referred to as 3G, was introduced
in the early 2000. With 3G the true step to high-quality mobile broadband was taken, enabling
fast wireless internet access. This was especially enabled by the 3G evolution known as HSPA
(High Speed Packet Access) [21]. In addition, while earlier mobile-communication
technologies had all been designed for operation in paired spectrum (separate spectrum for
network-to-device and device-to-network links) based on the Frequency-Division
Duplex (FDD), see Chapter 7, 3G also saw the first introduction of mobile communication in
unpaired spectrum based on the china-developed TD-SCDMA technology based on Time
Division Duplex (TDD).
We are now, and have been for several years, in the fourth-generation (4G) era of mobile
communication, represented by the LTE technology [28] LTE has followed in the steps of
HSPA, providing higher efficiency and further enhanced mobile-broadband experience in
terms of higher achievable end-user data rates. This is provided by means of OFDM-based
transmission enabling wider transmission bandwidths and more advanced multi-antenna
technologies. Furthermore, while 3G allowed for mobile communication in unpaired
spectrum by means of a specific radio-access technology (TD-SCDMA), LTE supports both
FDD and TDD operation, that is, operation in both paired and unpaired spectra, within one
common radio-access technology. By means of LTE the world has thus converged into a
single global technology for mobile communication, used by essentially all mobile-network
operators and applicable to both paired and unpaired spectra. As discussed in somewhat
more detail in Chapter 4, the later evolution of LTE has also extended the operation of mobile-
communication networks into unlicensed spectra.
1.1 3GPP and the Standardization of Mobile Communication
Agreeing on multi-national technology specifications and standards has been key to the success
of mobile communication. This has allowed for the deployment and interoperability of devices
and infrastructure of different vendors and enabled devices and subscriptions to operate on a
global basis.
As already mentioned, already the first-generation NMT technology was created on a
multinational basis, allowing for devices and subscription to operate over the national borders
between the Nordic countries. The next step in multi-national specification/standardization of
mobile-communication technology took place when GSM was jointly developed between a large
number of European countries within CEPT, later renamed ETSI (European Telecommunications
, Standards Institute). As a consequence of this, GSM devices and subscriptions were already from
the beginning able to operate over a large number of countries, covering a very large number of
potential users. This large common market had a profound impact on device availability, leading
to an unprecedented number of different device types and substantial reduction in device cost.
However, the final step to true global standardization of mobile communication came with the
specification of the 3G technologies, especially WCDMA. Work on 3G technology was initially also
carried out on a regional basis, that is, separately within Europe (ETSI), North America (TIA,
T1P1), Japan (ARIB), etc. However, the success of GSM had shown the importance of a large
technology footprint, especially in terms of device availability and cost. It also become clear that
although work was carried out separately within the different regional standard organizations,
there were many similarities in the underlying technology being pursued. This was especially
true for Europe and Japan which were both developing different but very similar flavors
of wideband CDMA (WCDMA) technology.
As a consequence, in 1998, the different regional standardization organizations came together
and jointly created the Third-Generation Partnership Project (3GPP) with the task of finalizing
the development of 3G technology based on WCDMA. A parallel organization (3GPP2) was
somewhat later created with the task of developing an alternative 3G technology, cdma2000, as
an evolution of second-generation IS-95. For a number of years, the two organizations (3GPP and
3GPP2) with their respective 3G technologies (WCDMA and cdma2000) existed in parallel.
However, over time 3GPP came to completely dominate and has, despite its name, continued into
the development of 4G (LTE, and 5G) technologies. Today, 3GPP is the only significant
organization developing technical specifications for mobile communication.
1.2 The Next Generation—5G/NR
Discussions on fifth-generation (5G) mobile communication began around 2012. In many
discussions, the term 5G is used to refer to specific new 5G radio-access technology. However,
5G is also often used in a much wider context, not just referring to a specific radio-access
technology but rather to a wide range of new services envisioned to be enabled by future mobile
communication.
1.2.1 THE 5G USE CASES
In the context of 5G, one is often talking about three distinctive classes of use cases: enhanced
mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable and
low-latency communication (URLLC) (see also Fig. 1.2).
• eMBB corresponds to a more or less straightforward evolution of the mobile-
broadband services of today, enabling even larger data volumes and further
enhanced user experience, for example, by supporting even higher end-user data
rates.
• mMTC corresponds to services that are characterized by a massive number of
devices, for example, remote sensors, actuators, and monitoring of various
equipment. Key requirements for such services include very low device cost and
very low device energy consumption, allowing for very long device battery life of
up to at least several years. Typically, each device consumes and generates only a
relatively small amount of data, that is, support for high data rates is of less
importance.
