=Paper=
{{Paper
|id=Vol-3382/Paper22
|storemode=property
|title=Reference Models of Satellite Segment Integration for NTN 5G
|pdfUrl=https://ceur-ws.org/Vol-3382/Paper22.pdf
|volume=Vol-3382
|authors=Valery Tikhvinskiy,Yevgeniya Daineko,Altay Aitmagambetov,Aigul Kulakayeva,Bagdat Kozhakhmetova
|dblpUrl=https://dblp.org/rec/conf/dtesi/TikhvinskiyDAKK22
}}
==Reference Models of Satellite Segment Integration for NTN 5G==
https://ceur-ws.org/Vol-3382/Paper22.pdf
Reference Models of Satellite Segment Integration for NTN 5G
Valery Tikhvinskiy1,2, Yevgeniya Daineko1, Altay Aitmagambetov1, Aigul Kulakayeva1, and
Bagdat Kozhakhmetova1
1
International Information Technology University, Manas St. 43/1, Almaty, 050000, Kazakhstan
2
Radio Research and Development Institute, 105064, Moscow, Russia
Abstract
Currently, international communications organizations are carrying out a large amount of
research on the use of satellite communications in the unified telecommunications of a new
generation, related to the 5G and 6G generations.
These studies were initiated by the SaT5G project, which is part of EU Horizon 2020
Research Program (FP-8). The concept of the SaT5G project was to develop cost-effective
"plug and play" solutions for 5G satellite communications, which can enable telecom operators
and service providers to accelerate the deployment of 5G in all geographical regions and at the
same time create new and growing market opportunities for stakeholders in the satellite
communications industry. This article analyzes the research results of several international
organizations for standardization and development of telecommunications as ITU-R, 3GPP,
and ETSI, and their applicability for the construction of satellite segment in the non-terrestrial
network (NTN) in 5G integrated network.
Keywords 1
3GPP; 5G integrated network; ISL; LEO; NTN; reference model
1. Introduction
Reference models of 5G satellite segment proposed in Technical Specifications of 3G Partnerships
Project (3GPP) differ in the following parameters [1-3]:
• satellite grouping orbits used to create a 5G satellite segment;
• type 5G satellite segment access equipment used on board the communication satellite;
• type of signal processing on board the communication satellite;
• type of interfaces and protocols used for inter-satellite communication lines (ISL) of 5G satellite
segment transport network;
• the number of satellite gateways connecting the non-terrestrial network (NTN) in 5G integrated
network with the public access data network.
Reference models of space data processing and transmission systems of the 5G satellite segment can
be created on:
• satellites in low Earth orbit (LEO);
• satellites with medium Earth orbit (MEO);
• satellites with geostationary Earth orbit (GEO);
• satellites in high elliptical orbits (HEO).
Reference models of space data processing and transmission systems can use three payload types on
board of communications satellites:
Proceedings of the 7th International Conference on Digital Technologies in Education, Science and Industry (DTESI 2022), October 20–21,
2022, Almaty, Kazakhstan
EMAIL: vtniir@mail.ru (Valery Tikhvinskiy); y.daineko@iitu.edu.kz (Yevgeniya Daineko); a.aitmagambetov@iitu.edu.kz (Altay
Aitmagambetov); a.kulakayeva@iitu.edu.kz (Aigul Kulakayeva); kozhahmetova.ba@gmail.com (Bagdat Kozhakhmetova)
ORCID: 0000-0002-3443-5171 (Valery Tikhvinskiy); 0000-0001-6581-2622 (Yevgeniya Daineko); 0000-0002-7808-5273 (Altay
Aitmagambetov); 0000-0002-0143-085X (Aigul Kulakayeva); 0000-0002-9566-3629 (Bagdat Kozhakhmetova)
©️ 2022 Copyright for this paper by its authors.
Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
CEUR Workshop Proceedings (CEUR-WS.org)
• Regenerative payload;
• Transparent payload (Bent pipe payload);
• Payload with on-board processing.
Reference models of 5G satellite segment satellite data processing and transmission systems can use
various types of inter-satellite channels (ISL) in the case of using a constellation of satellites (for
example LEO). At the same time, the reference model must necessarily be built using a regenerative
payload on board satellites.
Constellations of LEO and MEO satellites can be used to provide services in both the northern and
southern hemispheres. In some cases, the constellation may even provide global coverage, including
polar regions. In the latter case, this requires an appropriate inclination of the orbit, a sufficient number
of generated beams and inter-satellite communication based on ISL transport channels.
Thus, reference models of 5G satellite data processing and transmission systems should take into
account the following features:
1. ISL inter-satellite channels can operate in the radio frequency or optical bands.
2. According to the structure, ISL inter-satellite channels can have a one-hope or over multihop
procedure for transmitting service and space data of the 5G satellite segment in the constellation of
satellites.
3. ISL inter-satellite channels can be built using Integrated Access and Backhaul (IAB) technology
based on the interfaces and protocols of the 3GPP Partner Project used in 5G mobile networks, or
they can use a non-standardized 3GPP structure of interfaces and protocols.
2. Analysis of standardization of the 5G satellite segment by the 3GPP and
ITU-R Partner Project
The process of standardization of the results of work on the use of satellite communications in
unified telecommunications of the new generation is shown in Figure 1 [4-5].
Figure 1: The process of international standardization of satellite communications in unified
telecommunications of the new generation [5]
Carrying out work in the ITU-R Radio Sector. According to ITU-R Resolution 69, the report
M.2460-0 (07/2019) "Key elements for the integration of satellite systems into next-generation access
technologies" was prepared as part of the work related to the 4th Research Commission (RC4 or SG4)
[6].
The ITU-R M.2460-0 (07/2019) report examines the role of satellite systems in Next Generation
Access Technologies (NGAT) or STIN (Satellite Terrestrial Integrated Network) in the terminology of
the 3GPP Partner Project, which will be a highly developed, ubiquitous, seamlessly integrated
heterogeneous "network of networks" or "system of systems" [6].
Both GEO geostationary satellite networks and LEO non-geostationary satellite systems, MEO
provide networking capabilities with NGAT/STIN technology.
In addition to the target study M.2460-0 (07/2019), the ITU-R Sector also prepared two
Recommendations used in the study of the satellite segment of 5G networks to assess the parameters
and capabilities of the radio access equipment used [7,8]:
• Recommendation ITU-R P.681-10, "Data on the propagation of radio waves necessary for the
design of ground-space mobile communication systems" (12/2017).
• Recommendation ITU-R P.618-13, "Propagation data and forecasting methods necessary for
the design of telecommunication systems Earth-space" (12/2017).
2.1. Activities of the target working groups on the Radio Access Network
(RAN) and system Aspects (SA) of the 3GPP Partner Project to create a 5G
satellite segment
Technical Specification Development Groups on non-terrestrial infrastructure of 5G networks (Non-
Terrestrial Networks, NTN) were created by 3GPP in 2017 and are still continuing their work.
According to the definition of 3GPP, satellite part of non-terrestrial networks are understood as
networks or segments of communication networks using on-board or satellite radio-electronic means to
create a relay node with radio transmitting equipment or a base station of a mobile communication
network [1-3].
3GPP classification of Non-Terrestrial Networks is shown in Figure 2.
Figure 2: Classification applied by the 3GPP for non-terrestrial networks
Thus, in addition to satellite communication networks, non-terrestrial networks of 5G integrated
network include communication networks based on high-altitude platforms (HAPS) and
communication networks based on low-flying unmanned aerial vehicles (UAV) platforms.
Table 1 [5] lists all areas of research on the non-terrestrial infrastructure of 5G NTNs, including the
use of a satellite segment of the 5G integrated network, from Release 15 to Release 17 of 3GPP.
As can be seen from Table 1, each working question of 3GPP research is associated with a leading
group (i.e., groups R for RAN aspects and groups S for system aspects), and the date indicates the time
limit at which the research was completed or should be completed. The final work on the Technical
Specifications of the 3GPP Release-17 is scheduled to be completed in the second quarter of 2022.
We will conduct a brief analysis of Technical Reports and Specifications related to NTN (satellite
and platform segment of 5G networks) prepared by 3GPP.
Technical Report TR 38.811 [2] defines deployment scenarios for non-terrestrial (satellite) networks
and corresponding system parameters (for example, architecture, altitude, satellite constellation orbit,
etc.), adapts 3GPP channel models for NTN, describes deployment scenarios, identifies key areas of
impact on NR interface.
Technical Report TR 38.821 [1] investigated a set of necessary functions/adaptations that ensure the
operation of the NR 5G radio interface in NTN with priority of satellite access to the 5G network.
Related solutions were identified, the performance of the NR 5G radio interface was evaluated in
selected deployment scenarios (access to LEO satellites, access to GEO satellites) through modeling at
the channel and system level, solutions related to NR, levels 2 and 3 of the network system architecture,
as well as solutions for the RAN network architecture and the corresponding interface protocols.
Table 1
Research questions on non-terrestrial infrastructure of 5G networks
Number Working Date of completion
The issue under study
Release group number of the study
Study on NR to support Non-Terrestrial
Release 15 R1 June 2018
Networks
Study on solutions for NR to support Non-
R2 December 2019
Release 16 Terrestrial Networks
S1 Integration of satellite access in 5G June 2018
Study on architecture aspects for using
S2 June 2020
satellite access in 5G
Study on management and orchestration
S5 aspects with integrated satellite June 2020
components in a 5G network
Release 17 Study on NB-IoT/eMTC support for Non-
R1 June 2021
Terrestrial Networks
Integration of satellite components in the
S2 September 2020
5G architecture
Solutions for NR to support Non-Terrestrial
R2 December 2021
Networks
Technical Report TR 22.822 "Research on the use of access to satellite capabilities in 5G. Stage 1"
(Release 16) [3] reviewed the business cases of the satellite segment of the 5G network, the main of
which is the Internet of Things. The report defines the requirements for cross-border connection
scenarios, as well as the main characteristics of the satellite segment of the 5G network: classes of
orbits, geometry of coverage areas and signal delays during propagation, network architecture of the
satellite segment of the 5G network.
In addition, the report examines the continuity of service between the ground-based NGRAN and
the satellite component NG-RAN based on NTN, owned by the same operator or used by agreement
between the operators. The report also identifies service delivery options when considering the
integration of 5G NTN-based access components into a 5G system and, as a result, new services and
requirements (i.e. installations, configurations, maintenance and regulation) are found.
The Technical Specification TS 22.261 "Requirements for servicing new services and new
generation markets" [9] substantiates the requirements for the 5G network to be able to provide services
using the satellite access segment. The specification contains service and operational requirements for
UE subscriber devices, NG-RAN radio access network and 5G Core base network.
Technical Report TR 23.737 [10] defines the areas of influence of satellite integration of non-
terrestrial NTN networks into the 5G system when considering use cases TR 22.822 [3], finds solutions
for adjusting the 5G system for impact areas for three use cases (i.e. roaming between the terrestrial and
NTN 5G segment, between the fixed 5G transport network between NG-RAN based on NTN and 5G
Core, as well as solving problems related to the interaction of the NG-RAN network and the 5G Core
network.
Technical Report TR 28.808 [11] has identified the main key issues related to business roles, service
and network management, as well as 5G network orchestration with integrated satellite components,
and is exploring appropriate solutions. These technical solutions are aimed at minimizing both the
impact and complexity of satellite integration into existing business models, as well as in the
management and orchestration aspects of existing 5G networks.
Thus, the analysis of the main research results of 3GPP and ITU-R on the use of satellite
communications in unified telecommunications of the new generation 5G and 6G showed that their
efforts are aimed at forming flexible reference models of the satellite segment of NTN, allowing the use
of various types of satellites payload based on both implementations of the NR-RAN radio access
network interfaces of 5G networks, as well as other interfaces not standardized by 3GPP.
The main principle of building a new generation of 5G and 6G networks will be the use of an
integrated network architecture that allows the integration of satellite networks to create non-terrestrial
networks as part of an integrated 5G network.
3. Analysis of reference models of the architecture of the satellite segment of
the 5G network
Consider a reference model of a space data processing and transmission system using a transparent
payload and elements of NG-RAN architecture.
This reference model assumes the following features of its implementation (Figure 3.):
• The satellite payload implements frequency conversion and amplification of radio frequency
signals both in the communication line up and in the communication line down. The model, in fact,
corresponds to an analog repeater of satellite signals of previous generations.
• The onboard radio equipment of the satellite repeats the signals transmitted in the NR-G radio
interface from the feeder line (between the NTN gateway and the satellite) to the service line
(between the satellite and the UE) and vice versa.
• The satellite radio interface (SRI) on the feeder line is NR-Uu. In other words, the satellite does
not terminate the communication line from the subscriber terminal for the NR-Uu physical interface.
• The NTN GW gateway supports all the necessary functions for forwarding the NR-Uu interface
signal to the public data network via the gNB base station of the 5G network on the ground.
• The gNB base station of the 5G network interacts with the 5G Core reference network via the
NG logical interface and further via the N6 interface with the public data network.
• Various satellites with transparent payloads can be connected via the NTN GW gateway to the
same gNB base station of the 5G network on earth.
NG-RAN
UE gNB 5G CN
Data
NR Uu NG N6 Network
NTN
Gateway
Remote Radio Unit
Figure 3: Reference model when using transparent LEO payload for NG-RAN radio interface
The reference model architecture for the satellite segment of 5G integrated network and the
transparent payload on the LEO satellite, implementing the NG Uu physical interface standardized by
3GPP in the service and feeder channels is shown in Figure 4. This figure also shows user data streams
(session PDUs) and service data streams that provide QoS through the Radio Bearers radio channel
management service and formed tunnels in the User Plane (UP) for NG-U logical interface. The
connection of UE to the 5G network via the RAN is carried out on the basis of the technical requirements
of 3GPP. The UP protocol stack is shown in Figure 5.
Figure 5 the sign shows HF processing of incoming and outgoing signals and
frequency switching.
As can be seen from Figure 4. User data is transmitted between the UE subscriber terminal of the
5G network and the 5G Core reference network, in accordance with the algorithms for 5G protocols,
but through the NTN GW ground gateway without changing the structure of the 5G protocols.
The control plane (CP) protocol stack for the 5G satellite segment reference network with transparent
payload is shown in Figure 6.
NTN 5GC
Satellite
Gateway
PDU sessions
Radio Bearers NG-U Tunnels
QoS Flows
QoS Flows
UPF
Transponders &
Frequency
UE Switching NR Uu gNB NG
NR Uu
Figure 4: Architecture of a 5G reference network with a physical NR Uu interface and a LEO satellite
with a transparent payload
Figure 5: Protocol stack in the user plane for the reference network of the 5G satellite segment with
a transparent payload
Satellite NTN
UE 5GC: AMF
Gateway
NAS NAS
gNB
RRC RRC NGAP NGAP
PDCP PDCP SCTP SCTP
RLC RLC IP IP
MAC MAC L2 L2
PHY PHY L1 L1
NR-Uu NR-Uu NG-C
Figure 6: Protocol stack in the CP for a reference model of a 5G satellite segment network with a
transparent payload
Figure 6 shows HF processing of incoming and outgoing signals and frequency
switching.
Analysis of the UP and CP protocol stacks for the 5G satellite segment with a transparent payload
shows that there is no need to modify the NG-RAN architecture to support satellite access when using
a transparent payload. The timers of the NR-Uu physical radio interface between UE and LEO satellite
may have to be expanded, compared to 5G terrestrial network, in order to cope with the long signal
delay in the feeder line and service line. In the context of the LEO scenario with inter-satellite lines ISL,
the delay in question should include at least the delay of SRI logical interface feeder line between the
NTN GW gateway and LEO satellite and in one or more ISL lines.
The CP and UP protocols terminate on the Ground in the public data network (DN). As for CP, this
reference model does not create any special problems in its use, except for the need to adapt to a much
longer signal transit time back and forth over the physical radio interface of the Uu. This problem can
be solved by implementing a reference model. Analysis of User Plane for the reference model shows
that, with the exception of problems with signal delay due to a longer receive-transmit time for packets
in the UP, UP protocol itself does not require changes. However, a longer delay on the physical Uu
interface will require more buffering for UP packets in the gNB base station of the 5G network.
4. Reference model of a system for processing and transmitting space data
using a regenerative payload for the LEO constellation of satellites
This reference model assumes the following features of its implementation (Figure 7):
• LEO satellite constellation is used to provide continuous customer service.
• On board the LEO communication satellite, the payload of the communication satellite
implements the regeneration of signals received from Earth via the NR-Uu physical radio interface.
• The NR-Uu interface is used in the service channel - the channel between the UE subscriber
terminal of the 5G network and the LEO satellite on which a fully functional gNB base station is
implemented in the form of a regenerative payload through which access to the data transmission
network is organized.
• The satellite radio interface (SRI) is implemented on the feeder channel - the channel between
the NTN GW gateway and the LEO satellite on top of which the NG over SRI (Satellite Radio
Interface) standardized 3GPP is organized.
• The transport channel between NTN GW and the satellite is based on the SRI interface, from
the NTN GW gateway to the 5G Core network, the logical interface NG standardized by 3GPP is
used.
• The 5G Core network interacts via the N6 logical interface with the public data network.
NG-RAN
UE gNB 5G CN
Data
NR Uu NG N6
Network
NG over SRI
Xn NTN
(over ISL) Gateway
UE
5G CN
Data
NR Uu N6
Network
gNB NG over SRI
NTN
Gateway
Figure 7: Reference model when using the regenerative payload of the LEO satellite constellation
Inter-satellite interaction in the LEO constellation of satellites is implemented on the basis of the Xn
over SSL logical interface used in the 5G terrestrial mobile network [4]. Considering that when using a
regenerative payload, a gNB base station is deployed on board the satellite, it can be used as an
integrated access and transit IAB (Integrated Access and Backhaul) node in the transport network [13]
connecting the LEO satellites constellation of 5G network.
Standardization of IAB technology began in 2017 and was adopted in3GPP TS 38.401 [4] in 2020
as part of Release 16. IAB technology will support a very flexible deployment of the satellite segment
of the 5G network, allowing the onboard nodes (gNB base stations) of NG RAN to function as repeaters
for other LEO satellite constellation network nodes, in addition to their functioning as a regular gNB
access node for ground UE. The LEO satellite constellation transport network will contain usual IAB
nodes and an IAB donor. A regular IAB node is an NG-RAN node that supports wireless access for UE
and wirelessly transmits access traffic [14-15]. The IAN donor is NG-RAN node, which provides an
interface between the UE and 5G Core network and the functionality of a wireless repeater of ISL
connections for conventional IAB nodes.
From the scheme of the reference model in Figure 7 [1] it can be seen that the UE subscriber terminal,
serviced by the gNB base station on board the satellite, can access the 5G Core network via ISL inter-
satellite communication lines via the Xn over ISM logical interface, which LEO satellites are connected
to the constellation. gNB base stations on board different constellation satellites can be connected via
NG over SRI and Xn over ISM logical interfaces to the same 5G Core reference network on Earth. If
more than one gNB base station is placed on the LEO satellite, the same SPI logical interface will
transport the aggregate user data via the NG logical interface.
The architecture for the reference model of the satellite segment of the 5G network with a
regenerative payload on the LEO satellite implementing the gNB base station on board the
communication satellite is shown in Figure 8.
Satellite NTN Gateway 5GC
PDU sessions
Radio Bearers NG-U Tunnels
QoS Flows
QoS Flows SRI
UPF
NG
UE NR Uu gNB
SRI
Figure 8: Architecture for the reference model of the satellite segment of the 5G network with a
regenerative payload on the LEO satellite
Figure 8 also shows user data streams (session PDUs) and service data streams that provide QoS
through the Radio Bearers radio channel management service, as well as formed tunnels in the user
plane for the NG-U logical interface in the service channel and for the NG over SRI logical interface in
the feeder channel connecting the satellite to the NTN GW ground gateway.
The protocol stack of the UP for the PDU session in the reference model of the satellite segment of
the 5G network with a regenerative payload is shown in Figure 9 [1].
Figure 9 shows by the note that the protocol stack of the SRI satellite radio interface is used
to transport data (PDU sessions) in User plane between the LEO satellite and the NTN gateway. PDU
session data is transported via GTP-U tunnels, as usual, between the 5G Core reference network and
the gNB base station located on the satellite, but through the NTN GW gateway.
The CP control plane protocol stack for the 5G satellite segment reference network with transparent
payload is shown in Figure 10 [1].
Figure 10 by the note shows the protocol layer stack on the SPI logical interface between the
LEO satellite and the ground gateway of the NTN GW network. It can also be seen that the data of the
NG-AP protocol is transported over the SCTP protocol between the gNB base station located on the
LEO satellite and the 5G Core reference network, as usual, through the NTN gateway. Control plane
data using the NAS protocol is also transmitted via the NG-AP protocol between 5G Core and the
onboard gNB base station via the NTN GW gateway.
UE Satellite NTN Gateway 5GC
UPF
PDU PDU
gNB
UPF
SDAP SDAP GTP-U GTP-U
PDCP PDCP UDP UDP
RLC RLC IP IP IP IP
N11
Protocol Protocol
Layers Layers
MAC MAC of the SRI of the SRI L2 L2
NR PHY NR PHY L1 L1
NR-Uu NG-U
Figure 9: Protocol stack in the user plane for the reference network of the 5G satellite segment with
regenerative payload
UE Satellite NTN Gateway 5GC
AMF SMF
NAS-SM NAS-SM relay NAS-SM
gNB
NAS-MM NAS-MM
RRC RRC NG-AP NG-AP
PDCP PDCP SCTP SCTP
N11 N11 N6
RLC RLC IP IP IP IP
Protocol Protocol
layers of the layers of the
MAC MAC L2 L2
SRI SRI
NR PHY NR PHY L1 L1
NR-Uu NG-C
Figure 10: Protocol stack in the SR control plane for a reference model of a 5G satellite segment
network with a regenerative payload
The NG application protocol timers between the LEO satellite and the AMF module of 5G Core
network may have to be expanded to compensate for the long delay in the feeder line. In the reference
model for a constellation of LEO satellites with ISL transport links, the delay in question should cover
the delay at least. in the SRI logical interface feeder line between the NTN GW gateway and the LEO
satellite and in one or more ISL inter-satellite communication lines.
There are several options for transforming and implementing NG RAN architecture in the
architecture of satellite segment in 5G integrated network. It depends on whether the satellite uses a
payload with Bent-pipe technology (with transparent satellite transponders-repeaters without
information processing on board) or a payload with signal processing on board.
Figure 11 (a-d) [16] shows the architecture of the 5G satellite segment, which is planned to be based
on technology with transparent satellite transponders-repeaters without on-board information
processing (Bent-pipe) without placing gNB or its elements on board satellites and in which only
amplification and frequency conversion of signals is carried out on board the satellite while maintaining
the type of 5G signal modulation used.
Radio interface Radio interface
5G (NR) 5G (NR)
Frequency 1 Frequency 2 DNN data
gNB 5GC
UE Transmission Network
Repeater
(Bent-pipe) Gateway
(HUB)
a) Retransmission of radio interface signals NR.
NR Radio interface Radio interface
5G (NR) 5G (NR)
Frequency 1 Frequency 2 DNN data
gNB 5GC
UE UE Relay Transmission Network
Repeater
(Bent-pipe) Gateway
(HUB)
b) Retransmission of signals of the NR radio interface of the UE Relay subscriber device.
Interfaces Interfaces
NR N2, N3 N2, N3
N2, DNN data
gNB Frequency 1 Frequency 2 5GC N6
N3 Transmission Network
UE Repeater
Satellite network (Bent-pipe) Gateway
terminal equipment (HUB)
c) Retransmission of signals of interfaces N1, N2.
NR Interface F1 Interface F1
gNB-
Frequency 1 Frequency 2 gNB- N2, DNN data
CU 5GC
CU N3 Transmission Network
UE Repeater
Satellite network (Bent-pipe) Gateway
terminal equipment (HUB)
d) Relay of F1 interface signals.
Non-3GPP radio Non-3GPP radio
interface interface
Frequency 1 Frequency 2 DNN data
N3IWF 5GC
Transmission Network
UE Repeater
Satellite network (Bent-pipe) Gateway
terminal equipment (HUB)
e) Retransmission of non-3GPP interface signals.
Figure 11 a-d: 5G satellite segment architecture based on Bent-pipe technology [16]
Figure 12 shows the architecture of the 5G satellite segment, which is planned to be based on a
regenerative payload with 5G signal processing technology on board (On-Board Processing), which
implies the placement of all or part of the gNB base station equipment on board the satellite.
Radio interface
5G (NR) Interface F1
Frequency 1 Frequency 2 gNB- N2, DNN data
5GC
UE gNB- CU N3 Transmission Network
DU
Gateway
(HUB)
NR Radio interface
5G (NR) Interface F1
Frequency 1 Frequency 2 gNB- N2, DNN data
5GC N6
UE UE Relay gNB- CU N3 Transmission Network
DU
Gateway
(HUB)
Figure 12: 5G satellite segment architecture based on On-Board Processing technology [16]
As shown in Figure 12, the architecture of the 5G satellite segment can use a ground relay (relay)
node UE relay, which can amplify the signal of the UE subscriber devices before sending it on board.
Mobile subscriber devices of the 5G satellite segment UE are represented by both wearable subscriber
terminals and other mobile devices installed on cars, ships, airplanes, and so on. Currently, the
capabilities of wearable subscriber terminals are limited to the use of L- and S-band bands, however,
research is continuing to support subscriber terminals in higher frequency bands.
5. Conclusion
The analysis carried out by authors showed that the reference models of systems for processing and
transmitting space data of satellite segment in 5G integrated network, which is part of 5G non-terrestrial
networks, are divided according to the following parameters:
• orbits of the satellite grouping used to create the 5G satellite segment;
• type of equipment, interfaces and access protocols of the 5G satellite segment used on board
the communication satellite (3GPP and non –3GPP);
• type of signal processing on board a communication satellite (direct relay, regenerative
processing, processor processing);
• type of SRI interfaces and protocols used for inter-satellite communication lines ILC of 5G
satellite segment transport network;
• the number of satellite gateways connecting 5G NTN network to the public data network.
In addition, the analysis performed in the article showed that 3GPP standardized several reference
models which can use for systems development for processing and transmitting space data in the
satellite segment of 5G integrated network, namely:
Reference model with transparent payload and satellite-repeater for NR-RAN interface;
Reference model with regenerative payload and distributed 5G gNB base station infrastructure for
NR-RAN interface;
Reference model with regenerative payload and centralized infrastructure of 5G gNB base station
on board for NR-RAN interfaces;
Reference model of LEO satellite constellation with 5G gNB distributed infrastructure on board for
regional and global coverage;
Reference model of LEO satellites constellation for 5G satellite network segment with centralized
infrastructure of gNB base stations on board for regional and global coverage.
6. Acknowledgements
This research was funded by the Science Committee of the Ministry of Education and Science of the
Republic of Kazakhstan (grant no. AP08857146).
7. References
[1] 3GPP TR 38.821, Solutions for NR to support non-terrestrial networks (NTN), Release 16, Jan.
2020. URL: https://www.3gpp.org/.
[2] 3GPP TR 38.811, Study on New Radio (NR) to support non terrestrial networks, Release 15, Oct.
2019. URL: https://www.3gpp.org/.
[3] 3GPP TR 22.822, Study on using Satellite Access in 5G, Release 16, Jun. 2018.
[4] 3GPP TS 38.401. NG-RAN; Architecture description. URL: https://5g-ppp.eu/sat5g/.
[5] ITU-R Report ITU-R М.2460-0 Key elements for integration of satellite systems into Next
Generation Access Technologies (07/2019).
[6] ITU-R Recommendation P.681-10: Propagation data required for the design systems in the land
mobile-satellite service (12/2017).
[7] ITU-R Recommendation P.618-13: Propagation data and prediction methods required for the
design of Earth-space telecommunication systems (12/2017).
[8] 3GPP TS 22.261, Service requirements for the 5G system, Release 17, Mar. 2020. URL:
https://www.3gpp.org/.
[9] 3GPP TR 23.737, Study on architecture aspects for using satellite access in 5G, Release 17, Dec.
2019. URL: https://www.3gpp.org/.
[10] 3GPP TR 28.808, Study on management and orchestration aspects with integrated satellite
components in a 5G network, Release 16, Jun. 2020. URL: https://www.3gpp.org/.
[11] 3GPP TR 36.763, Study on Narrow-Band Internet of Things (NB-IoT) / enhanced Machine Type
Communication (eMTC) support for Non-Terrestrial Networks (NTN), created for Rel. 17. URL:
https://www.3gpp.org/.
[12] 3GPP TR 38.874, NR, Study on Integrated Access and Backhaul, Release 16, Oct. 2018. URL:
https://www.3gpp.org/.
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Networks and Fixed Service in the 6425–7125 MHz Band with Monte Carlo Simulation Analysis,
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