=Paper=
{{Paper
|id=Vol-2746/paper10
|storemode=property
|title=Analysis of Facing Developers Problems of Modern Telecommunication Technologies
|pdfUrl=https://ceur-ws.org/Vol-2746/paper10.pdf
|volume=Vol-2746
|authors=Ruslan Politanskyi,Andrij Veryga,Mariya Vistak
|dblpUrl=https://dblp.org/rec/conf/cpits/PolitanskyiVV20
}}
==Analysis of Facing Developers Problems of Modern Telecommunication Technologies==
https://ceur-ws.org/Vol-2746/paper10.pdf
Analysis of Facing Developers Problems
of Modern Telecommunication Technologies
Ruslan Politanskyi1[0000-0003-0015-7123], Andrij Veryga1[0000-0002-2616-3057],
and Mariya Vistak2[0000-0001-5192-4017]
1 Yuriy Fedkovych Chernivtsi National University, Ukraine
2 Danylo Halytsky Lviv National Medical University, Ukraine
r.politansky@chnu.edu.ua
Abstract. The development of modern telecommunication technologies is
accompanied by a significant amount of theoretical research. We can identify
three most important areas that precede the introduction of new technologies in
specific solutions made by the largest manufacturers of modern
telecommunications equipment: (1) research in signal theory; (2) research of
routing algorithms; (3) convergence of telecommunication technologies. We
briefly analyze all three areas, indicating the main trends and problems of further
development of information and communication technologies.
Keywords: Telecommunication, Signal Theory, Routing Algorithms, Internet of
Things.
1 Introduction
The development of mobile communication began in the early ’80s of the last century.
Currently, it is possible to identify 5 generations based on fundamentally different
access technologies for subscribers and base stations. These are AMPS technology
using analog signals, GSM and UMTS technology, and at least LTE and 5G technology,
which are transnational corporate technologies. The use of LTE and 5G technologies
has made it possible to unify data transmission standards in mobile networks and the
Internet. The rapid growth of traffic transmitted by mobile networks has led to an
increase in such transmission system performance as the maximum data rate and the
density of the number of connected devices. The ability to provide the characteristics
of each new standard was achieved both by moving to higher frequency bands with
more channels in each band and by improving the technology of modulation and
encoding of digital data. A significant increase in transmission rate without increasing
the total power consumption resulted in the transition from code division multiplexing
(CDMA) in GSM and UMTS technologies to orthogonal frequency division
multiplexing (OFDM) in LTE and 5G technologies.
Copyright © 2020 for this paper by its authors.
Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0)
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2 Research in Signal Theory
Increasing the data rates declared in the 5G standard requires the development of
directional phase antennas, the development of new data routing standards that enable
the implementation of point-to-point connections, as well as the development of new
technologies for free frequency band search [1], to efficiently use bandwidth and
prevention of collisions of users using fixed frequency bands [2].
Fig. 1. Development of mobile communication technologies.
The growing demand for the number of devices that can simultaneously transmit
information within one cell, causes a significant increase in the problem of inter-
channel interference. Solving the problems of inter-symbol (ISI) and inter-channel
interference (ICI) requires solving the problem of protection against interference that
has the properties of non-stationary random processes. The importance of this problem
is noted in the classic work of the famous engineer of telecommunication systems B.
Sklar [3], who divided wireless channels into three groups as for statistical properties
of noise acting in the channel:
Channel with additive white Gaussian noise.
Relays channel.
Channel with a high probability of a bit error.
The methods of prevention of white Gaussian noise which is present in most wireless
channels are widely used and are well known. The most common of these are
correlation detection and digital filtering methods based on discrete Fourier transform
algorithms and the use of a matched filter with a transient response determined by the
waveform that forms the channel symbol.
To prevent non-stationary noises, which both include inter-symbol and inter-channel
interference, several adaptive methods are applied based on:
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The transverse line filters.
The equalizer with feedback.
The Viterbi equalizer.
B. Sklar also noted that most traditional methods of removing channel interference are
ineffective against little-scaled fading. This fact is greatly enhanced with increasing
frequency of signals, as this significantly increases the number of possible paths of
propagation. Such characteristic as the number of simultaneously connected end-point
devices also becomes significantly non-stationary, as the maximum possible number of
simultaneously connected subscribers significantly increases in new types of networks
(5G standard) [2].
The current state of development of digital signal filtering is a fairly effective means
of combating stationary interference, which in most cases can be modeled by white
Gaussian noise. From a theoretical point of view, the possibility of such approximation
is a consequence of the central limit theorem. Another non-stationary type of
interference is conventionally divided into two groups: pulses-shape noise present in
the channel and more regular types of interference acting both in time and frequency
domain (Fig. 2).
Fig. 2. Types of noise and methods of combating them.
Based on the data on the search for new modulation methods that can be used in the 4G
and 5G standards [2], we can conclude that many new solutions are based on the use of
non-orthogonal signals [4].
An effective means of combating interference owing to pulse-shape noise is the use
of redundancy codes which is a usual practice. More complex types of interference are
inter-channel and inter-symbol interference. The cause of inter-symbol interference is
the overlap of signals transmitting neighboring channel symbols in the time domain due
to multipath signal propagation. There are two reasons for the overlap of signals in the
frequency domain: the finite duration of the signals, and the blurring of the signals due
to the Doppler effect. In present, it seems that the most potentially effective method for
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elimination of inter-symbol and inter-channel interference is the use of broadband
signals. These channel symbols could be both orthogonal and non-orthogonal. Thus,
the task of finding complex signals with a high base, which was a classic among
specialists in the field of telecommunications, becomes relevant again. This is the well-
known optimization problem of signal modeling which consists of determining signals
having a given spectrum width in conditions of limited signal duration.
The use of signals with some special shape could be effective against both inter-
symbol (ISI) and inter-channel interference (ICI), while traditional signals, like OFDM,
usually prevents only one of them.
Moreover, the transition to a high-quality spectrum area and the increase in the
number of users will be designed with this problem in mind. Finally, the number of
signal propagation paths increases due to the decrease in pulse duration, which leads to
an increase in the power of the interference due to the inter-symbol interference.
Increasing the number of users leads to a greater variety of this value during this time,
not only increasing the power of migration barriers, but also fundamentally changing
the statistical properties of a random process that uses migration barriers, and it
becomes significantly non-stationary, which may be a major factor.
In this case, the traditional methods of redundancy coding and the use of optimal
filtering are not more effective, because they are designed for known statistical
characteristics of the channels, which in the case of non-stationary interference is very
difficult to establish. Therefore, the methods of adaptive filtering are also becoming
less suitable, because they are designed to be able to some extent to predict the
characteristics of the channels over some time. This problem was appointed before
providing modern communications by B. Sclar [3], who emphasized that in the case of
deviation of the characteristics of the channel first from Rayleigh, and then from
Gaussian, any traditional methods of noise control lose their effectiveness. And the fact
that this problem can be solved by using complex broadband signals, say modern
developers of 5G technologies [2].
We conducted a comparative analysis of the most common modern signals and
modulation methods and so far little known, which are under development. The results
of this analysis are shown in Table 1, where the most important in our opinion
characteristics of signals and modulation methods are indicated: orthogonality of
carriers, method of protection against interference of both types, presence of direct and
inverse Fourier transforms in signals present in signal processing.
Table 1 shows the characteristics of the following signals and modulation methods:
OFDM (Orthogonal Frequency Division Multiplexing), FBMC (Filter-Bank
MultiCarrier), GFDM (Generalized Frequency Division Multiplexing), BFDM
(Biorthogonal Frequency Division Multiplexing), TFP (Time-Frequency Packing).
Also, we add a chaotic carrier as it is potentially the most suitable for preventing both
ISI and ICI.
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Table 1. Characteristics of complex signals and modulation methods
Method Orthogonality
Protection from ISI Protection from ICI DFT IDFT
of modulation of subcarriers
OFDM + Cyclic prefix Guard band + +
Additional coefficient between the FFT
FBMC – + +
coefficient (overlapping factor)
Adding a CP between all subcarriers in the
GFDM – frequency domain and they become to be not – –
contiguous
The same as in OFDM and filters with
BFDM + different characteristics in transmitter and + +
receiver sides
The use of an optimal receiver in the
assumption that controlled interference
TFP +
between contiguous signals in the time domain
has the Gaussian white noise statistics
Almost uniform
Narrow time domain spectrum in the
correlation. Ability to frequency domain.
Chaotic apply the phenomenon Ability to apply the
–
carriers of the synchronous phenomenon of the
response of systems synchronous response
with dynamic chaos of systems with
dynamic chaos
3 Research of Routing Algorithms
The increase in integrated characteristics of telecommunication networks the volume
of traffic, data transfer speed, and the total number of end-point devices has led to a
significant complication of both the network structure and transport layer algorithms.
Also, the development of telecommunications technologies has led to the possibility of
new telecommunications services (cloud computing, mobile services, Internet of
Things, Tactile Internet, Internet of All) and the merging of networks into a single
global system. As a result of the above trends, technology convergence is becoming
increasingly important, as it makes it possible to get rid of inconsistencies in platforms
developed by different vendors and at the same time prevent the undesirable
monopolization of the telecommunications technology market.
Therefore, as in the case of research of new methods of formation of channel signals
caused by fundamentally new characteristics of channels, the importance of finding
new methods of the simulation of the distribution of traffic at the transport level of the
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network is growing again. From the theoretical point search and researches of
algorithms of transport-level for networks with a time-variable structure (Fig. 3)
become more important.
Fig. 3. Transport layer methods and algorithms.
Methods of modeling networks with a static structure and constant speed of request
processing have been used since the emergence of networks with a packet type of
information transmission. These methods used well-developed theories of queuing
systems, Markov chains, methods of diacoptics, the theory of graphs with unchanged
structure. But such methods are no more possibly applicable to networks with complex
especially changeable topologies, which take place in modern mobile networks. This is
evidenced by at least a comparison of one of the most common results for networks of
both types: the average number of nodes connected directly with each other for
achieving the best network bandwidth: for networks with a static structure there are
only three such nodes, and form networks with variable structure, this statement needs
to be proved.
For networks with variable structure, other methods of theoretical research are used:
graph theory with fuzzy logic of connection between pairs of nodes, tensor models of
fully loaded networks [5], Kerner’s theory of three-phase traffic flow [6], modeling of
networks with variable topology (the content approach) [7].
According to the tensor model, a transport network can be described as an oriented
graph, with given sets of vertices V and arcs E. Each arc corresponds to a real
information transmission channel, and each vertex is a transport node of the network.
The set of all nodes is divided into two subsets: the set S, which generates flows, and
the set D, which absorbs them. The tensor model can be the basis of multithreaded
routing (MPTCP), which allows data to be transmitted on several routes simultaneously
for one connection.
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4 Methods and Algorithms of Convergence of Data
Transmission Technologies
One of the main trends in the convergence of technologies for storage, processing, and
transmission of information. The consequence of convergence is the achievement in
three main areas: cloud technology, information transmission channels, and the
manufacture of electronic devices of the final link of the information transmission
system.
To date, the convergence of info-communication networks has led to the emergence
of three main concepts: virtualization of network functions (Network Function
Virtualization), cloud computing (Cloud Computing), and software-controlled
networks (Software Defined Network).
The increase in integrated indicators of telecommunication networks the volume of
traffic, data transfer speed, and the total number of subscribers has led to a significant
complication of both the network structure and transport layer algorithms. Also, the
development of telecommunications technologies has led to the possibility of new
telecommunications services (cloud computing, mobile services, the Internet of Things,
tactile Internet, Internet of All) and the merging of networks into a single global system.
The increase in the number of mobile devices connected to the Internet (the Internet
of Things) has led to intensive research in the field of mobile cloud computing (MCC).
This area includes several important technologies used in MCC, namely [8]:
The strategy of unloading traffic from cellular networks to other available wireless
access technologies (for example, Wi-Fi).
Migration of services and data caching.
The most common convergence technology is network virtualization. The essence of
this concept is that many isolated logical networks with significantly different
addressing algorithms and mechanisms for redirecting information flows have the same
physical equipment. This is achieved by developing more flexible software and by
duplicating network equipment components. This technology makes it possible to avoid
the use of programmable hardware, such as FPGAs or network processors.
There is a clear analogy between network virtualization and computer hardware
virtualization. Computer virtualization provides hardware abstraction and hardware
distribution between different operating systems, and everything looks as if each
operating system has its hardware. Thanks to virtualization in computer technology, it
becomes possible to install software platforms from different manufacturers on a
hardware platform manufactured by the world’s most famous brands, thus realizing the
“many-to-many” relationship (Fig. 4).
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Fig. 4. Scheme of computer technology virtualization.
Thus the many-to-many relationship between software and hardware vendors is
realized through virtualization of network functions.
A specific mechanism that provides virtualization is different sets of instructions for
different hardware platforms implemented in one software shell. The purpose of the
virtualization of network functions as well as the virtualization of computer hardware
is also the convergence (convergence) of different hardware and software platforms.
By analogy with computer hardware, network software should also include a level of
hardware abstraction.
Virtualization of network functions means the division of five different resources:
Bandwidth.
Topologies.
Traffic.
CPU resources.
Redirection tables.
Due to this, Cloud Computing technology becomes possible to use instead of corporate
networks. Cloud Computing technology has become an advanced technology in the
design of info-communication networks, and today it is used to build their info-
communication structure by such giants of the IT industry as Google, Amazon, Axios
System, Salesforce, Microsoft, Yahoo, Zoho. Three of them share a significant share of
the info-communication services market by providing services in almost 40
geographical regions, competing with the Chinese telecommunications giant Huawei.
5 Conclusions
The main directions of theoretical researches directed on the search of new technologies
of data transmission taking into account growth of volume of traffic and speed of data
transfer and convergence of all existing telecommunication network technologies are
considered in the work. It is concluded that an important area of research at the physical
level is the search for new channel broadband signals that are resistant to both inter-
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symbol and inter-channel interference. At the transport level, the main search for data
routing methods takes into account the convergence of networks, which results in the
transition from the most common Ethernet protocol, which is based on the 7-layer OSI
model, to a simplified 3-layer SDN network.
Despite its great practical importance, the implementation of software-controlled
networks is a major science-intensive problem, which confirms, in particular, that much
of the current SDN standards have been developed at Stanford University.
To date, active research is being carried out to find new convergent technologies that
ensure the effective use of the latest advances in the processing of information-carrying
signals—fully optical networks that do not use optoelectronic and electro-optical
transformations [9]. The all-optical network is a promising technology for FN, which
is also associated with the rapid development of optical technologies. This optical
packet and integrated network (OPCInet) offers a variety of services that increase
functional flexibility along with energy efficiency with high switching speed in the
SDN packet system in the metro/core network.
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