PreprintPDF Available

Why We Should NOT Talk about 6G

Preprints and early-stage research may not have been peer reviewed yet.

Abstract and Figures

While 5G mobile communication systems are currently in deployment, researchers around the world have already started to discuss 6G technology and funding agencies started their first programs with a 6G label. Although it may seem like a good idea from a historical point of view with returning generations every decade, this contribution will show that there is a great risk of introducing 6G labels at this time. While the reasons to not talk about 6G yet are manifold, some of the more dominant ones are i.) there exists a lack of real technology advancements introduced by a potential 6G system; ii.) the flexibility of the 5G communication system introduced by softwarization concepts, such as in the Internet community, allows for daily updates; and iii.) introducing widespread 6G discussions can have a negative impact on the deployment and evolution of 5G with completely new business cases and customer ecosystems compared to its predecessors. Finally, as we do not believe that 5G is the end of our journey, we will provide an outlook on the future of mobile communication systems, independent of the current mainstream discussion.
Content may be subject to copyright.
1
Why We Should NOT Talk about 6G
Frank H. P. Fitzek and Patrick Seeling
Abstract
While 5G mobile communication systems are currently in deployment, researchers around the world have
already started to discuss 6G technology and funding agencies started their first programs with a 6G label.
Although it may seem like a good idea from a historical point of view with returning generations every decade,
this contribution will show that there is a great risk of introducing 6G labels at this time. While the reasons
to not talk about 6G yet are manifold, some of the more dominant ones are i.)there exists a lack of real
technology advancements introduced by a potential 6G system; ii.)the flexibility of the 5G communication
system introduced by softwarization concepts, such as in the Internet community, allows for daily updates; and
iii.)introducing widespread 6G discissions can have a negative impact on the deployment and evolution of 5G
with completely new business cases and customer ecosystems compared to its predecessors. Finally, as we do
not believe that 5G is the end of our journey, we will provide an outlook on the future of mobile communication
systems, independent of the current mainstream discussion.
Index Terms
5G, 6G, 5G Campus, Tactile Internet, Future Mobile Communications
I. INTRODUCTION – THE EVOLUTION OF MOBILE COMMUNICATION SYSTEMS
Whether there is a clear need for a sixth generation (6G) of mobile communication systems can only
be answered through an initial recognition of the history of mobile communications and the motivations
underpinning the continuous development efforts. Mobile communication systems are commonly categorized in
generations. (We refer to mobile communication systems throughout this contribution with a focus on cellular
mobile communication systems.) So far, a new generation has been introduced in each decade. The first
generation (1G) of mobile communication systems allowed a small group of privileged users to experience
mobile voice services employing purely analog technology [1]. The second generation (2G) democratized these
services for the masses exploiting digital technology. Both generations have been straightforward extensions of
the existing public switched telephone networks (PSTNs) of their times to mobile services. The main services of
2G, following the global system for mobile communications (GSM) definition, were speech services, mobility,
and security. Message and data service implementations were only added to the network afterwards, featuring
F. H. P. Fitzek is with the Centre for Tactile Internet with Human-in-the-Loop and the Deutsche Telekom Chair of Communication
Networks, Technische Universit¨
at Dresden, Dresden, Saxony, Germany, email: frank.fitzek@tu-dresden.de
Patrick Seeling is with the Department of Computer Science at Central Michigan University, Mount Pleasant, MI, USA, email:
patrick.seeling@cmu.edu
Funded by the German Research Foundation (DFG, Deutsche Forschungsgemeinschaft) as part of Germany’s Excellence Strategy –
EXC 2050/1 – Project ID 390696704 – Cluster of Excellence “Centre for Tactile Internet with Human-in-the-Loop” (CeTI) of Technische
Universit¨
at Dresden.
March 5, 2020 DRAFT
arXiv:2003.02079v1 [cs.NI] 4 Mar 2020
2
limited data rates and capacities [2]. With the introduction of the third generation (3G), an extension of mobile
communication systems to the Internet was targeted. Even though the first realizations, such as i-mode in Japan
or the wireless application protocol (WAP) in Europe, had been great failures, the fourth generation (4G) finally
enabled the mobile Internet for users with great success [3]. The introduction of a new generation was always
motivated by and aligned with changes in the underpinning technical details. While 1G was based purely on
analog technology, the digital era was introduced with 2G. Furthermore, 2G in Europe was based on time
division multiple access (TDMA), while code division multiple access (CDMA) was deployed in the USA and
other countries alongside TDMA. With 3G, CDMA was introduced as a global standard, significantly unifying
the formerly divided technology landscape. Finally, 4G uses orthogonal division multiple access (OFDM). With
that, each generation could have been identified by the predominant access scheme. All generations so far
have in common that they targeted the consumer market’s main demands over time: to enable voice services
and mobility in the beginning (starting in the 1980s) up to video streaming and social networking towards the
end (the 2010s). Nevertheless, each generation has its entitlement in a technical development stage. The fifth
generation (5G) is different [4], as i.)it continues to use OFDM as it provides technical benefits over other
access technologies and there are simply no novel access technologies left, ii.)its standardization efforts from
the beginning onward did not just follow a philosophy of pure capacity increases but already addressed new
technical parameters, such as latency, resilience, heterogeneity, or energy, iii.)it already has a strong impact
on the overall network architecture rather than focusing on a new air interface with some radio access network
(RAN) elements, and iv.)the target use cases are mainly in the domain of machine control rather than the
consumer market, a major shift with respect to prior generations.
As illustrated in Figure 1, the initial four generations have been addressing the wireless domain with some
additional RAN elements. 5G will follow this approach on the wireless side, but is strongly engaged with
the wired domain. One evidence for that is the large number of bilateral meetings from the 3rd Generation
Partnership Project (3GPP) and the Internet Engineering Task Force (IETF) to define 5G technologies. These
meetings are embossed by a cultural clash where one side is dominated by hardware while the other is dominated
by software. While the generations on the mobile communication system side are a result of changing hardware
in the time frame of one decade, the Internet domain is realized by software and allows for daily updates. Once
the two worlds are truly merged in an holistic manner in the future, software will play a dominant role, while
specialized hardware is needed only for special tasks, such as energy efficient computing or energy efficient
and secure radio front-ends with antennas.
5G is a highly disruptive communication system, as can already be derived from only some of the main
differences to its predecessors, as highlighted in the following.
Low Latency as a Service:
Besides pure data rate, 5G also targets low latency communications. This enables communication for
time-critical scenarios. In other words, 5G combines control and communication theory. While the
predecessors target the consumer market for communication needs of humans, 5G is mainly targeting
machine-type communications. Even though 5G is currently introduced as a bit pipe, with upcoming
releases 16 and onward, the new service area will be the target. Therefore, 5G is able to become
the communication network for a broad variety of use cases, such as transportation, Industry 4.0,
March 5, 2020 DRAFT
3
4G3G2G1G
SOFTWARE
HARDWARE
wireless world wired world
5G
10y 1d
5G
SOFTWARE
5G
HARDWARE HARDWARE
Fig. 1. Evolution of mobile communication generations.
Agriculture 4.0, construction, health care, or the upcoming Tactile Internet. The Tactile Internet has
the most severe latency requirements with 1ms end-to-end delay including the embedded system,
the wireless link, and the computing within the wired network. As given in [5], the most challenging
entity for low latency are network functions realized in software.
Softwarization:
5G is not just an agnostic bit pipe as the generations before. This is achieved by the concept of
softwarization. While its predecessors came in the form of dedicated hardware, 5G is mainly based
on generic hardware with software solutions. Different concepts, such as software defined radio
(SDR), software defined networks (SDN), and network function virtualization (NFV), enable network
operators to keep operational expenses (OPEX) as well as capital expenses (CAPEX) low. Additionally,
softwarization enables network operators to dynamically reorganise their networks for different current
and future use cases. New concepts such as mobile edge cloud and network slicing are only possible
due to the introduction of the softwarization concept.
5G as Campus Solutions:
Due to the last point, the realization of so-called 5G campus solutions is now possible. In some
countries, industry or government entities can apply for 5G frequencies for a given local area. A
5G campus solution operates in an isolated geographic area and provides localized services. Mobility
support is not needed in this application scenario, but ultra-low latency communication is.
These three main differentiators of 5G with respect to prior generations already highlight how it completely
differs from its predecessors. It is the first generation to target machine-type communications, even though
the support of multimedia services is still an option. 5G will support different technical parameters such as
March 5, 2020 DRAFT
4
low latency, security, heterogeneity, and more. More importantly, the replacement of specialized hardware with
generic hardware in combination with dedicated software solutions is such a fundamental change, that it will
have long-term implications for the future of communication networks.
Based on the paradigm shift towards network as a software solution, the architecture of 5G will be extended
by campus solutions. Those campus solutions do not necessarily support mobility in the cellular WAN context,
but rather offer mobility in the LAN context, which is more nomadic. While earlier generations defined
communication as a transport of bits leading to the end-to-end paradigm of communication, with 5G we
enter a new definition where communication is defined as transport, storage, and computing of bits within the
network. The disruptive nature of 5G is that it elevates the network from data to information.
Despite these revolutionary changes, it is highly likely that 5G will face immense problems in the beginning
of its deployment phase. Classic services, such as video streaming, voice calls, etc., are part of the general
update of capabilities from 4G to 5G – but focusing on their contribution to business success might be more
than disappointing. This should not surprise, as the superiority of 5G lies in low latency communications, which
will become part of implementation rollouts with the standard release 16 and onward. Once the implmentations
find their way into associated use cases, the business side of the success story of 5G will start as well.
II. TH E ATOM –AHOLISTIC VIEW ON 5G
In this section, we briefly discuss the 5G landscape from a holistic viewpoint by employing the 5G Atom.
Figure 2 illustrates this view, which deviates from the massiveness in the International Mobile Telecommuni-
cations (IMT) vision [6] of massive IoT, massive multimedia, and massive low latency, by following 5G use
cases defining higher layers, up to novel applications.
Through-
put
Massive
Resilience
Network
Coding
Network
Slicing
Multi-Path
Mobile
Edge
Cloud
Com-
pressed
Sensing
Machine
learning
SDN
NFV
SDR
Content
Delivery
Networks
novelty
Block
Chaining
5G
Latency
Security
Hetero-
geneity
Air
Interface
Energy
concepts
technologies
requirements
Mesh
U
C
U
CU
C
U
C
U
C
!%$
Fig. 2. The 5G Atom – A holistic view of 5G use cases, requirements, technologies, concepts, and novel applications.
The massive use cases identified in IMT-2020 are part of the initial wave of 5G use cases, but they do not
account for all of them. One can readily separate the use cases by their focus of communication, whereby the
March 5, 2020 DRAFT
5
machine-to-machine communication will be expressed in roll-outs in connected autonomous cars, Industry 4.0,
Agriculture 4.0, energy grids, as well as construction, health care, or education – in what is heavily marketed
today as the Internet of Things (IoT). In contrast to these, human-machine-type communications that are
summarized as the Tactile Internet [7] will feature ultra-reliable low latency communications (URLLC) [8]
enabling human-machine collaborations across all sectors of industry and in mixed realities. The Tactile Internet
has the potential to usher in a new paradigm shift from a network of information to a network of skills [9]
with a focus on layer 8 of the network.
A readily notable technical requirement resulting from these different use cases is the handling of increased
heterogeneity of communication types and challenges when considering different communication actors and
device types. For example, connecting massive numbers of IoT devices in the billions requires new approaches
to data handling and storage. Additionally, 5G networks need to feature security as well as resilience, not just
with respect to adverse actors threatening the network, privacy concerns, or interference. Maintaining quality of
service (QoS) levels to higher degrees than before for at least a slice of the network is of utmost importance as use
cases feature control loops that are comprised of machines as well as humans, with potentially dire consequences
as results of service degradation. For example, URLLC requires significant reductions of the latency present in
today’s networks down to a millisecond, while simultaneously bounding delay variations (jitter). As the case
with all prior generations, increases of throughput are common requests in use case evolutions. Some of these
move from today’s dominant multimedia streaming services to fully immersive experience streaming services
requiring significantly more data. With such a broad landscape of devices and use cases, energy consumption
is an additional factor, e.g., to reduce battery depletion rates and required maintenance for devices in the field.
The following concept layer in Figure 2 highlights approaches to resolve these often diametrically opposed
technical requirements. The 5G new radio air interface will significantly reduce latency, offer higher throughput,
and enable massive numbers of securely connected devices. In addition, new concepts that offer extensions of
the 5G network through meshed networks as well as multi-path communications can aid significantly to realize
the technical requirements as part of a softwarized solution. In addition to networking-centric approaches, the
softwarization inherent in 5G also is tied to new approaches to managing the network, such as focusing on
information rather than just data, and to dynamically allocate the network resources (including computation and
storage) through network slicing. This approach enables an ability to dynamically move these resources at the
network’s edge, as mobile edge cloud (MEC).
These solutions make heavy use of softwarization technologies across the 5G network by employing software-
defined radio (SDR), software-defined networking (SDN), network function virtualization (NFV), and service
function chaining (SFC). Jointly, these technologies allow a dynamic allocation of all resources within a
5G network and their logical combination. This makes the common computing resources (communication,
computation, and storage) flexible and versatile to perform flexible service composition.
The developed services can readily be altered to reflect changing use cases as well as new use cases providing
network operators with long-term flexibility as well. The outer layer application examples in Figure 2 that
will likely become part of these future services include block chains, machine learning, network coding, and
compressed sensing. While a detailed discussion of these are out of scope here, we note that all of these have
been extensively researched in conjunction with networked applications. It is therefore foreseeable that they
March 5, 2020 DRAFT
6
will become part of future service offerings – or not, as the flexibility offered by the softwarized network can
readily support others not even considered yet.
III. MYT HBUSTING 6G
After the introduction of 5G, in this section, we present several theses which question the necessity of a 6G
technology.
A. Nothing New in 6G
Currently, there is nothing to little novelty proposed for 6G that can not be adopted or realized in 5G networks
and its evolution plan. Often new frequencies, such as terahertz frequencies, are labeled as 6G. But the 5G
evolution foresees already higher frequencies up to 60 GHz and to include even higher frequencies would not
require a new generation. Even a change of hardware or software components is not necessarily leading to a
new generation – 2G already supported channel bundling (software) and novel modulation schemes (hardware).
Some research labs are even proposing artificial intelligence or mobile edge cloud as a 6G feature, but this
has been already introduced in 5G. Oftentimes, lower latencies than promised in 5G are also referred to when
discussing 6G. Some researchers claim that higher data rates are needed to achieve this goal, others rely on
a novel medium access protocol in their claims. In general, the data rates of 5G are already so high that the
propagation delay increases in importance when compared to the relative delay, as [10] have shown for simple
M/M/1 queues. In conclusion, there is little in individual technologies that would require a new generation.
General evolution steps as well as disruptive ideas can be realized with software changes within 5G networks,
as introduced beforehand.
B. The Internet Has No Generation, Why Mobile Networks?
Given the evolutionary changes in the roll-outs of cellular network generations to date, a common thread
is the combination of typically specialized hardware combined with specialized and provider- or operator-
based services targeting cellular end-systems used by humans. This development increased capacities on the
network side to support mobile Internet based over-the-top (OTT) services at the end-units (e.g., smartphones for
media consumption). The fixation on continuously evolving services for individual human customers meant that
architectural changes were required to fully enable Internet-based services following the end-to-end paradigm.
At the same time as mobile communication network operators switched out generations of different custom
hardware and software solutions moving from 3G to 4G, the smartphones they were connecting to the Inter-
net were already softwarized. The software-oriented approach inherent to common smartphones enables the
continuous addition of new features based on a common set of hardware components via software updates.
Throughout the history of the Internet, the closest notion of generational change can be seen in the versions
of protocols, predominantly the migration from IPv4 to IPv6. The reason that the sunset of IPv4 takes so
long is also based on hardware legacy. Nevertheless, researchers in standardization groups such as IETF would
never use the term generation as software enables agile testing and implementation. The overall nature of
“Everything over IP and IP over Everything” abstracts or even virtualizes the underlying complexity for upper
layer protocols. In turn, changes can be made on all layers above IP as needed in a fluid fashion.The softwarized
March 5, 2020 DRAFT
7
nature of even a significant portion of the core network components means that within reason, new features can
now be added via system software upgrades on general-purpose hardware and no longer require full system
hardware swaps, i.e., a new generation.
As the network role is elevated from data to information, it becomes clear that only individual components
need changes over time, as 5G already contains the built-in flexibility of softwarization of the network. Thus, it
is difficult to justify individual component tweaks to modify network capabilities to be labeled as a generational
change. Indeed, intuitive examples such as replacing an older general-purpose server in a rack with a more
powerful could increase the in-network computation speed (e.g., to support more services offered through a MEC
or in a nomadic 5G campus container), but hardly qualify as a new generation. Similarly, significantly changing
TCP’s congestion algorithm did not result in new protocol versions despite significant performance changes. The
network softwarization of 5G enables continuous, fluid change that reduces the need for generational changes.
C. 5G Engaged Vertical Players – 6G Scares Them Away
5G was very successful to engage vertical players even before the start of the technology itself. While 3G
failed in identifying possible markets and 4G took over the promise of 3G, 5G breaks new grounds for a
wide range of heterogeneous markets. Some markets such as agriculture or construction happily engaged with
the 5G technology. Other market segments such as connected cars or Industry 4.0 had alternatives such as
IEEE 802.11p or field busses. It took, and still takes, some effort to explain the advantages of 5G over existing
solutions. This was successful for most use cases and is ongoing for others. The upcoming discussions of the
6G technology creates some nervousness among the management in industry. When considered by merit and
potential, there should be a Fear Of Missing Out (FOMO), but these discussions more likely begin to create
a Fear Of Joining In (FOJI). Some might think that 5G is already an old technology and 6G is the holy grail
now. This has the potential to destroy the momentum 5G has. Distracting the industry from 5G could lead
to a decreased market adoption. Subsequently, this would put both network operators and network equipment
suppliers in great financial distress. Without the revenues earned from 5G, a new generation, possibly 6G, would
not even see the light of day.
D. Only Even Numbered Generations Are a Success
In several keynotes about 5G and 6G, the speakers claim that only even numbered generations are a success.
Such statements are not only ridiculous but also technically wrong. These statements are based on the difficulties
3G had in the beginning of its introduction, while 2G and 4G were a success story from the beginning. However,
this argumentation has several flaws. The first generation 1G was undoubtedly a success even if not available
for the masses. Furthermore, the problem with such a statement is the statistical confidence one can achieve
with only five samples. Finally, if the statement were true, we should just use even numbered generations from
the beginning.
E. The Use Case, Stupid
Making a numbers-only argument additionally obfuscates a significant shortcoming in the overall interplay
of 5G and 4G with respect to use cases. Through complete softwarization of the network, components can be
March 5, 2020 DRAFT
8
TABLE I
MINIMUM REQUIREMENTS (IN TERMS OF GENERATIONS AND USE CASES)FOR HUMAN-AND MACHINE-TYPE COMMUNICATIONS.
Mobility target Human Machine
Mobile 3G/4G for browsing 5G for cars, drones (for both mobility is needed), energy grids (coverage is
needed), also for the Tactile Internet
4G/5G for over-the-top services
5G for the Tactile Internet
Nomadic/stationary WiFi 5G campus, OpenRAN, also for the Tactile Internet
5G, also for the Tactile Internet
changed dynamically and without a need to call for a new number. It is noteworthy to consider the scenarios
for which these last two generations were designed: mobile Internet user-centered in 4G (over-the-top media
consumption by humans) and expanding with (mobile) mission-critical with ultra-low latency in 5G (massive
machine-type communications, including the Tactile Internet). Some use cases for 5G, such as the outlined 5G
campus, offer the seamless integration of solutions into a locally managed 5G solution, but no mobility. Jointly,
these cases cover the currently imaginable scenarios for implementation fairly well, as listed in Table I.
Differently put, there are no current new scenarios that are not already covered through 5G or with a potential
incorporation of non-cellular approaches. The remaining generational updates could be attributed to radio access
network upgrades. While additional arguments could be made that increased radio access network capabilities
would yield better front-end latency characteristics, the question is how much is enough for use cases? As usual
when moving into business considerations, one also needs to carefully consider the diminishing rates of return
for increased resource expenditures. Realizing higher throughput to reduce transmission delays (assuming that
propagation delays cannot be influenced in the near future, e.g., with quantum networking), higher frequency
bands are needed. As a direct downside, this requires significant attenuation handling and will reduce the current
small cell sizes for going beyond mmWave bands even further, which might impose the need for a significant
and cost-prohibitive increase in the number of cells needed for sufficient coverage.
IV. SO, WH AT IS THE FUTURE OF MOBILE COMMUNICATION NETWO RK S?
While we advocate against the 6G label for the moment, we still believe in fundamental changes in future
communication systems. As illustrated in Figure 3, the first (cellular) mobile communication systems leading
to 4G target humans and their mobility. Beginning with 5G, the focus shifts to being able to support commu-
nications with and between machines in real-time. As the 5G standard continues to evolve jointly with applied
use cases, its evolution will continue with future releases 16, 17, .. . , simultaneously incorporating additional
features for deployments.
In contrast to the common prior focus on use cases incorporating mobility, 5G represents a turning point for
the support of stationary, localized communications. Similar to prior generations, 5G will continue to support
the mobility of humans as well as machines, such as cars or drones. The URLLC components of 5G can even be
seen as one enabler for future mobility scenarios with connected autonomous cars. Mobility could also refer to
the scope of information needs, which can readily go beyond single-cell sizes when considering the organization
of large, distributed deployments, such as the energy grid. While information mobility support is highly needed
March 5, 2020 DRAFT
9
for these types of use cases, the emergence of human-machine co-habitation for the future of work and life
represents a new scenario. Here, URLLC will support the Tactile Internet-based and localized cooperation of
humans and robots within their similarly networked but transparently operating local environment.
4G 5G Future
humans
machines
mobility
nomadic
2G 3G
human-machine
co-habitation
Fig. 3. The evolution of mobile communication systems in generations and the disruptive change in future systems.
In these localized scenarios, mobility is just needed in a nomadic context common to WiFi networks, e.g.,
as provided by EduRoam for academic users that move between campuses, and the focus will be on URLLC.
5G will always be superior over WiFi (i.e., the IEEE 802.11 WLAN standard range) products, even WiFi6,
when it comes to dedicated latency requirements. WiFi’s core philosophy of “listen before talk” clashes with
deterministic latencies. Similarly, potential enhancements to WiFi protocols still require CSMA to operate in the
general ISM bands, see, e.g., [11], which will continue to result in a no-guarantee upper timing bound unsuitable
for mission-critical application scenarios requiring URLLC. Nevertheless, the cost efficiency of WiFi networks
that maintain their ISM band reliance is still remarkable and readily serves as a target for future communication
systems. This future might well be in the combination of the strengths of the two aforementioned technologies,
namely 5G and WiFi6.
Subsequently, it is highly likely that we will witness two main trends, namely the evolution of 5G technologies
and the rise of a new communication system that is not categorized in a generation. This new communication
system will target specific use cases that do not need mobility support and national coverage to a large extent.
Here we see Industry 4.0 or human–machine interaction as possible use cases. This can be seen as a low cost
variant of the 5G campus idea, where the wireless technology is realized by OpenRAN solutions.
The flexibility of OpenRAN in combination with network slicing ideas of the core network will enable
ultra-low latency communications that is also resilient against hostile agents. For example, adverse activities
could include denial of service through extensive jamming of individual cells or modifying the data exchanged.
The latter case is particularly interesting in the context of URLLC, as sophisticated mitigation techniques
might readily impact the ability to remain at the ultra-low latency level, e.g., as required for the 1 ms round-
March 5, 2020 DRAFT
10
trip (including all sensing, computing, and actuating next to network transport) deadlines imposed by the
Tactile Internet. In the context of collaborative robotics in Industry 4.0 use cases, one result could be that
adversaries become enabled to tamper with the actual payload without detection, e.g., through knowledge of
the actual information content, for an individual robot’s control and cause undetectable extensive damage. One
opportunity that OpenRAN offers with software-defined radios is to change the underlying MAC protocols at a
high frequency. (We note that this is not the same approach as security through obfuscation, which is commonly
considered harmful, but a new approach to security enabled by softwarization.) A similar trend to enable the
lower latency bounds imposed by use cases is the need to move computation from the cloud to the edge of
the network. Here, significant computational resources will need to be dynamically allocated and re-partitioned
based on use cases. Again, this can only be realized through softwarization. Further latency reductions for actual
use cases that take the shift to information-based mobile communications into account will, in turn, more likely
be based on commodity hardware upgrades at the network edge and algorithmic improvements in software,
as ultra-low latency dependent services will not be able to leave an operator’s network. Even more stringent
latency requirements could be realized in 5G campus offerings with the possibility of significant embedded
computational resources at its center (if an individual single cell) or edge (in general).
Considering the combination of flexible, commodity hardware paired with fully softwarized access and core
networks as well as OpenRAN for the last hop, it becomes clear that 5G generates the ability for network
operators to offer everything as a service (*aaS). For example, general latency as a service can be realized
through flexible resource slicing on the network and computation side. Upgraded, guaranteed latencies can be
provided through software-based OpenRAN changes that implement a bus-based polling protocol of subscribed
stations, resulting in upper latency bounds. Storage, in-network computation, resource pooling, and, ultimately,
services as a service (SaaS) all become enabled through elevation of the network to an information level, where
an interplay of wireless access technologies could be orchestrated through 5G.
V. CONCLUSION
In this article, we made a case for future mobile communication network research needs. Research and
development must focus on the evolutionary advancement of the 5G roadmap. This roadmap provides many
improvements in the areas of spectrum usage, integration of IETF software solutions for the mobile edge cloud,
network slicing, and artificial intelligence. In parallel, there will be a disruptive evolution in the architectures of
future mobile communications systems, targeting very specific applications, such as human–machine cooperation
and Industry 4.0. The envisioned mobile radio systems will no longer be cellular and will only provide local
coverage. The latter will allow low latency applications, novel security concepts, and extremely low cost. This
approach could be seen as a symbiosis of the existing 5G campus solutions and WiFi6. Nevertheless, we have
also argued in this article that the use of the 6G label is not only counterproductive, but it also is not even
technically motivated. Using 6G is counterproductive where new markets have just been opened up by 5G. The
players in these new markets could be very nervous about investing in 5G, when new technology may soon be
available. For example, the mere use of the term 6G may prevent the 5G market from fully developing. From
a technical point of view, there is little reason to talk about a further generation in mobile communications
because with 5G we leave the area of hardware behind us and now mostly realize everything in software.
March 5, 2020 DRAFT
11
Thus, mobile communication systems are reaching the status that the Internet community has held for decades:
continuous evolution and improvement through software. Nowadays, the 6G term is more a marketing tool that
might end up in a 6G label without technical needs.
REFERENCES
[1] R. H. Frenkiel, “Creating cellular: A history of the AMPS project (1971–1983) [History of communications],IEEE Communications
Magazine, vol. 48, no. 9, pp. 14–24, September 2010. [Online]. Available: https://doi.org/10.1109/MCOM.2010.5560579
[2] T. S. Rappaport, A. Annamalai, R. M. Buehrer, and W. H. Tranter, “Wireless communications: Past events and a future perspective,
IEEE Communications Magazine, vol. 40, no. 5, pp. 148–161, May 2002.
[3] B. A. Bjerke, “Lte-advanced and the evolution of lte deployments,IEEE Wireless Communications, vol. 18, no. 5, pp. 4–5, October
2011.
[4] M. Shafi, A. F. Molisch, P. J. Smith, T. Haustein, P. Zhu, P. De Silva, F. Tufvesson, A. Benjebbour, and G. Wunder, “5g: A tutorial
overview of standards, trials, challenges, deployment, and practice,IEEE Journal on Selected Areas in Communications, vol. 35,
no. 6, pp. 1201–1221, June 2017.
[5] Z. Xiang, F. Gabriel, E. Urbano, G. T. Nguyen, M. Reisslein, and F. H. P. Fitzek, “Reducing latency in virtual machines enabling
Tactile Internet for human–machine co-working,IEEE Journal on Selected Areas in Communications, vol. 37, no. 5, pp. 1098–1116,
May 2019.
[6] Radiocommunication Sector of International Telecommunication Union, “IMT vision – Framework and overall objectives of the future
development of IMT for 2020 and beyond,” Sep. 2015.
[7] G. P. Fettweis, “The tactile internet: Applications and challenges,” IEEE Vehicular Technology Magazine, vol. 9, no. 1, pp. 64–70,
March 2014.
[8] H. Chen, R. Abbas, P. Cheng, M. Shirvanimoghaddam, W. Hardjawana, W. Bao, Y. Li, and B. Vucetic, “Ultra-reliable low latency
cellular networks: Use cases, challenges and approaches,” IEEE Communications Magazine, vol. 56, no. 12, pp. 119–125, December
2018.
[9] Cluster of Excellence at TU Dresden, Centre for Tactile Internet with Human-in-the-Loop, 2019 (accessed March 3, 2020), http:
//ceti.one.
[10] D. P. Bertsekas and R. G. Gallager, Data Networks, 2nd ed. Prentice Hall, 7 1992.
[11] ETSI, “ETSI EN 300 328 v2.2.2 (2019-07): Harmonised Standard for Access to Radio Spectrum,” July 2019.
March 5, 2020 DRAFT
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Software Defined Networking (SDN) and Network Function Virtualization (NFV) processed in Multi-access Edge Computing (MEC) cloud systems have been proposed as critical paradigms for achieving the low latency requirements of the tactile Internet. While Virtual Network Functions (VNFs) allow greater flexibility compared to hardware based solutions, the VNF abstraction also introduces additional packet processing delays. In this paper, we investigate the practical feasibility of NFV with respect to the tactile Internet latency requirements. We develop, implement, and evaluate Chain bAsed Low latency VNF ImplemeNtation (CALVIN), a low-latency management framework for distributed Service Function Chains (SFCs). CALVIN classifies VNFs into elementary, basic, and advanced VNFs. CALVIN implements elementary and basic VNFs in the kernel space, while advanced VNFs are implemented in the user space. Throughout, CALVIN employs a distributed mapping with one VNF per Virtual Machine (VM) in a MEC system. Moreover, CALVIN avoids the metadata structure processing and batch processing of packets in the conventional Linux networking stack so as to achieve short per-packet latencies. Our rigorous measurements on off-the-shelf conventional networking and computing hardware demonstrate that CALVIN achieves round-trip times from a MEC ingress point via two elementary forwarding VNFs (one in kernel space and one in user space) and a MEC server to a MEC egress point on the order of 0.32 ms. Our measurements also indicate that MEC network coding and encryption are feasible for small 256 byte packets with an MEC latency budget of 0.35 ms; whereas, large 1400 byte packets can complete the network coding, but not the encryption within the 0.35 ms.
Article
Full-text available
The fifth-generation cellular mobile networks are expected to support mission critical ultra-reliable low latency communication (uRLLC) services in addition to the enhanced mobile broadband applications. This article first introduces three emerging mission critical applications of uRLLC and identifies their requirements on end-to-end latency and reliability. We then investigate the various sources of end-to-end delay of current wireless networks by taking the 4G Long Term Evolution (LTE) as an example. Subsequently, we propose and evaluate several techniques to reduce the end-to-end latency from the perspectives of error control coding, signal processing, and radio resource management. We also briefly discuss other network design approaches with the potential for further latency reduction.
Article
There is considerable pressure to define the key requirements of 5G, develop 5G standards, and perform technology trials as quickly as possible. Normally, these activities are best done in series but there is a desire to complete these tasks in parallel so that commercial deployments of 5G can begin by 2020. 5G will not be an incremental improvement over its predecessors; it aims to be a revolutionary leap forward in terms of data rates, latency, massive connectivity, network reliability and energy efficiency. These capabilities are targeted at realising high speed connectivity, the internet of things, augmented virtual reality, the tactile internet, etc. The requirements of 5G are expected to be met by utilising large bandwidths available in mm-wave bands, increasing spatial degrees of freedom via large antenna arrays and 3D MIMO, network densification and new waveforms that provide scalability and flexibility to meet the varying demands of 5G services. Unlike the one size fits all 4G core network, the 5G core network must be flexible and adaptable and is expected to simultaneously provide optimised support for the diverse 5G use case categories. In this paper, we provide an overview of 5G research, standardization trials and deployment challenges. Due to the enormous scope of 5G systems, it is necessary to provide some direction in a tutorial article and in this overview the focus is largely user-centric, rather than devicecentric. In addition to surveying the state-of-play in the area, we identify leading technologies, evaluating their strengths and weaknesses, and outline the key challenges ahead, with research test-beds delivering promising performance but pre-commercial trials lagging behind the desired 5G targets.
Article
Wireless communications today enables us to connect devices and people for an unprecedented exchange of multimedia and data content. The data rates of wireless communications continue to increase, mainly driven by innovation in electronics. Once the latency of communication systems becomes low enough to enable a round-trip delay from terminals through the network back to terminals of approximately 1 ms, an overlooked breakthrough?human tactile to visual feedback control?will change how humans communicate around the world. Using these controls, wireless communications can be the platform for enabling the control and direction of real and virtual objects in many situations of our life. Almost no area of the economy will be left untouched, as this new technology will change health care, mobility, education, manufacturing, smart grids, and much more. The Tactile Internet will become a driver for economic growth and innovation and will help bring a new level of sophistication to societies.
Article
The fourth generation (4G) wireless technology known as Long Term Evolution (LTE) allows cellular operators to use new and wider spectrum and complements third generation (3G) networks with higher user data rates, lower latency, and a flat Internet Protocol (IP)-based network architecture. The LTE standard was first published in March 2009 as part of the Third Generation Partnership Project (3GPP) Release 8 specifications. The specifications have been in development since 2005 when 3GPP defined LTE requirements and performance goals to significantly improve on the 3GPP Release 6 standard, which was at that point the state of the art. Achieving those goals required an evolution of both the air interface and the network architecture, now known as Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and Evolved Packet Core (EPC), respectively. The very first commercial LTE networks were deployed on a limited scale in Scandinavia at the end of 2009, and currently, large-scale deployments are taking place in several regions, including North America, Europe, and Asia.
Article
The article following, written by one of the lead engineers in the project, describes the development of AMPS, the first cellular telephone system in the United States. As noted, the project ran for over 12 years and required the services of a "vast number" of engineers at AT&T's Bell Labs. The hundreds of millions of people currently using cellphones, smart phones, and all the other mobile wireless equipment available in the United States, as well as everywhere else in the world, often take these devices and the infrastructure behind them for granted. Until the cellular concept was recognized, it wasn 't clear that many mobile phones could simultaneously share the same channels in a local area. With the cellular concept agreed on, problems such as tracking of cell phones and handoff from cell to cell had to be resolved. Computerized base stations had to be designed and tested. A myriad other important development and design issues and problems had to be resolved. Dick Frenkiel very clearly describes the various engineering problems that had to be solved, step by step, sometimes quite painstakingly. He gives credit to the many teams of Bell engineers who worked on this project. He also points out policy issues involving the FCC that had to be resolved. Competition for scarce radio spectral space was fierce. Competing engineering companies and telephone operators had to be assuaged. In the meantime, I urge you to read on through this exciting description of the genesis of cellular telephony in the United States.
ETSI EN 300 328 v2.2.2 (2019-07): Harmonised Standard for Access to Radio Spectrum
  • Etsi
ETSI, "ETSI EN 300 328 v2.2.2 (2019-07): Harmonised Standard for Access to Radio Spectrum," July 2019. March 5, 2020 DRAFT