Frequency
range
Channel
bandwidth,
MHz
Carrier
spacing
of
OFDM-
symbol,
kHz
Modulation
type
Power
level
accuracy,
dB
FR1
5, 10, 15,20,
25, 30, 40,
50, 60, 70,
80, 90, 100
15, 30, 60
QPSK,
16QAM,
64QAM,
256QAM
±2
FR2
50, 100, 200,
400
60, 120
QPSK,
16QAM,
64QAM,
256QAM
±2
B. Prototyping tools
A prototype of 5G base station can be made on the basis of
various modules and tools for fast prototyping. Base station
types 1-O and 2-O cannot be implemented on fast prototyping
tools due to their design features. Since BS types 1-O and 2-O
should consist of a single module that combines the transceiver
part and the DAA (digital antenna array), the only possibility is
to design and implement software without a real hardware
device due to the lack of systems in the market that combine
the transceiver module and the DAAs.
Base stations type 1-C could be implemented by the means
of fast prototyping since they are BSs of modular structure.
Currently there are a large number of USRP models on the
market for fast prototyping systems which operate in the FR1
range (e.g. Ettus Research, National Instruments) [6]. It is also
possible to implement a base station based on prototyping
platforms, such as Analog Devices modules [7].
Similarly it is possible to implement BS type 1-H using
fast prototyping tools. An example of such an implementation
is the MIMO system at the University of Bristol [8]. For signal
processing, the PXI module is used as a network core, which
can be connected to an external Internet network. USRP
modules act as transceivers, which are integrated into a single
block through a switching device. A composite antenna is
connected to the USRP modules.
The options for implementing base stations, based on the
allocated frequency bands for subscribers are described further.
For prototyping BS operating in bands up to 40 MHz the
following devices can be used: USRP-2940, USRP-2942,
USRP-2943, USRP-2950, USRP-2952, USRP-2953 by
National Instruments and transceiver modules ADRV9009,
AD6688, AD9364 by Analog Devices.
For bands up to 100 MHz the following devices can be
used: USRP-2940, USRP-2942, USRP-2943, USRP-2944,
USRP-2950, USRP-2952, USRP-2953, USRP-2954, USRP-
2974 by National Instruments and transceiver modules
ADRV9009, AD6688 from Analog Devices.
IV. 5G
BS
P
ROTOTYPING
E
XPERIENCE
The development of the BS prototype is carried out on the
National Instruments MIMO system. The main parameters
used to select the USRP block for prototyping the 5G mobile
communication system are the ability to work in the selected
frequency range, bandwidth, order of latency values and the
number of supported devices. Comparative characteristics of
some NI devices are presented in Table 4.
The analysis of the data in Table 4 allows to conclude that
the USRP RIO provide the best of the required characteristics
including the bandwidth, the latency, the minimum number of
devices. For the further work USRP-2943R was selected [9].
MIMO system includes the following equipment: PXI
Chassis PXIe-1085, PXI Controller PXIe-8135, 8Gb RAM
Upgrade, PXI FPGA Module PXIe-7976, PXI Synchronization
Module PXIe-6674T, 8-Channel Clock Distribution Accessory
CDA-2990, PXI Bus Extension Module PXIe-8384, Switch
Device for PCI Express CPS-8910 [10-16]. The final structure
of NI equipment testbed is shown in Fig.1.
Fig. 1. BS prototyping equipment.
TABLE IV.
P
ROGRAMMABLE
T
RANSIEVER
D
EVICES
P
ARAMETERS
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