BS with 5G physical layer parameters based on National
Instruments testbed was demonstrated.
Keywords—5G; base station; fast prototyping; physical layer
I. I
NTRODUCTION
In accordance with the concept of development of
International Mobile Telecommunications (IMT) for 2020 and
beyond, a significant increase in mobile traffic is expected due
to factors such as an increase in the share of HD/UHD video
broadcasts, a rapid growth in the number of user devices and an
increase in mobile application traffic. Further development of
mobile communication systems will require the introduction of
new affordable devices with high user-grade quality of
services, or quality of experience (QoE) and high quality of
service (QoS). This causes the necessity of the development of
innovative technical solutions in this area. The key parameters
characterizing the capabilities of modern mobile
communication systems include:
• peak data transfer rate (for one user in ideal conditions,
Gbit/s);
• data transfer rate through the user interface (for a single
user in the entire coverage area, Gbit/s);
• latency (time to transfer the packet from transmitter to
receiver, ms);
• mobility (maximum speed for which a given quality of
service can be achieved, km/h);
• connection density (the number of connected and
accessible devices per area unit, km
2
);
• energy efficiency (amount of information transmitted
per unit of energy consumption, bit/J);
• spectrum efficiency (average data transmission rate in a
cell, bps/Hz);
• area traffic capacity (total capacity in a geographic area,
Mbps/m
2
).
Among the requirements for the fifth-generation (5G)
enhanced mobile broadband communications such as high-
speed network parameters, mobility, spectral and energy
efficiency are the most significant. At the same time, along
with the challenges arising from the implementation of the
physical layer of devices of the fifth generation, including the
use of new frequency bands, there are some difficulties
connected to the development of algorithms and software for
5G systems.
At the moment, there is a tendency to develop and
implement pilot 5G projects using the existing infrastructure
and deploy 5G over LTE or LTE Advanced Pro networks,
inserting changes to the physical and data link layers. At the
moment frequency bands FR1 450 MHz – 6000 MHz and FR2
24250 MHz – 52600 MHz are defined for 5G systems, and
each of the given band is also divided into sub-bands. The
lower FR1 band is used more intensively in 5G projects,
however, the implementation of the physical layer even in this
band have certain difficulties due to the shift in the
implementation of communication devices functions from the
hardware to the software part. The development of algorithms
and software that implement the basic functions of the base
station (BS) require fast prototyping tools. The methods
obtained can then be used on various facilities that meet the
requirements of 5G. The working out of new approaches to
achieve the desired characteristics of 5G communication
system with the use of rapid prototyping allows making a fast
transition to the software design. The successful experience of
prototyping, described in [1, 2, etc.] allows to conclude that the
use of software and hardware tools for fast prototyping will
speed up the development of key nodes of the 5G
communication systems.
In June 2018, 3GPP Group made publicly available Release
15, which describes the first phase of development of the fifth-
generation mobile communication networks [3]. In particular, a
list of basic requirements for base stations of a new generation
of mobile communications has been presented. The analysis of
these requirements shows that the creation of 5G BS in the near
future is possible. First of all, such an implementation is
available on National Instruments fast prototyping tools in the
frequency range FR1. In this case, parallel development of the
software and algorithmic basis of 5G devices should be
1565
accompanied by the development of the perspective hardware
of the device to ensure the possibility of mass production of
microchips.
II. B
ASE
S
TATION
T
YPES
3GPP Release 15 describes several types of the fifth
generation base stations depending on how they are
implemented. It should be mentioned that in this release there
is no BS classification according to the usage scenario,
however, the presented BS types are divided into classes
according to the size of the service area. The BS types and their
main features are described below.
A. BS type1-С
Base station type 1-C is a distributed structure in both the
transmitting and receiving parts. BS type 1-С is similar in its
structure with distributed base stations used in 4th generation
of mobile communication. It includes as well as 4G BS a
separate remote antenna module and a transceiver module
located in a telecommunication BS-cabinet. Additional
modules can also be used between the BS cabinet and the
antenna module: a filter and a power amplifier. The use of
these modules depends on the size of the area where the type 1-
C base station will operate.
The required parameters of the base station type 1-C are
presented in Table 1. They should be achieved at the output of
the transceiver module (BS cabinet) in the absence of a power
amplifier and filter and at the antenna connector in the presence
of a power amplifier and filter [4]. Thus, the presence of these
two elements should not have an impact on the signal level in
the radio channel.
B. BS type 1-H
The base station type 1-H architecture is adapted to the use
of MIMO system. It has an array of transceivers (transceiver
unit array, TRXUA), each of which connects through its
channel to a composite antenna array, which has at its input a
radio distribution network (RDN) module. The number of
transmission modules is determined at the system design stage
depending on what type of MIMO is needed to be
implemented. The characteristics of the BS type 1-H presented
in Table 1 should be determined at the input of the composite
antenna.
Base stations type 1-C and 1-H should operate in the
frequency band FR1. BS classes of both types depend on the
coverage area and are allocated according to the minimum
coupling loss. Macrocells are considered for the Wide Area and
Medium Range classes, and picocells for the Local Area class.
Note that sensitivity power level in Table 1 corresponds to
channel bandwidth 20, 25, 30, 40 or 50 MHz with sub-carrier
spacing equal to 15 kHz.
According to the requirements [4] a spectrum allocation
where a BS operates can either be contiguous or non-
contiguous. For BS operation in non-contiguous spectrum,
some requirements apply both at the BS RF bandwidth edges
and inside the sub-block gaps. For each such requirement, it is
stated how the limits apply relative to the Base Station RF
bandwidth edges and the sub-block edges respectively.
TABLE I.
BS
T
YPES
1-C
AND
1-H
P
ARAMETRES
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