Content uploaded by Mouhamad Chehaitly
Author content
All content in this area was uploaded by Mouhamad Chehaitly on Feb 15, 2025
Content may be subject to copyright.
A Study of Lunar Proximity Networks: Scenarios
and Architectures
Mouhamad CHEHAITLY1
mouhamad.chehaitly@uni.lu
Houcine CHOUGRANI1
houcine.chougrani@uni.lu
Sumit KUMAR1,3
sumit.kumar@list.lu
Youssouf DRIF1
youssouf.drif@uni.lu
Jorge QUEROL1
jorge.querol@uni.lu
Stefano PETRI2
stefano.petri@esa.int
Leonardo TURCHI2
leonardo.turchi@ext.esa.int
Symeon CHATZINOTAS1
symeon.chatzinotas@uni.lu
1SnT,University of Luxembourg, Luxembourg.
2European Space Agency, ESA.
3LIST, Luxembourg Institute of Science and Technology, Luxembourg.
Abstract—High data rate, adaptive, inter networked proximity
communications for Space, part of the ESA project PROSPECT,
is focused on selecting the best-fit terrestrial technology for lunar
proximity communications scenarios. This study explores the
concept of lunar proximity networks, which play an essential
role in enabling direct and short-range communication between
devices on the lunar surface. The study is organized to analyze
scenarios where these networks are applicable, the potential
communication architectures, and the technologies that could
be utilized. Furthermore, it includes a trade-off analysis that
focuses on the lunar channel model and technology selection,
followed by simulation results that offer valuable insights into
the performance and feasibility of these networks. The study
ends with recommendations for the design and implementation
of lunar proximity networks, highlighting their pivotal role in
future lunar missions to support the long-term human mission
to the Moon.
Index Terms—3GPP, Wi-Fi, 4G/5G, Proximity Networks,
I. INTRODUCTION
Our closest neighbor in this infinite universe, “Moon,” has
attracted much attention since ancient times. In recent years,
this interest has grown, and several countries are considering
starting to send missions there. To ensure the success of these
missions, it is necessary to have an effective communications
system for mission assets (e.g., delivery of cargo to the surface
of the Moon, lunar robots) that can exchange data and be
controlled and monitored if necessary. Establishing commu-
nication and networking capabilities in lunar environments
involves a deep study of two main challenges: (a) Surface
Coverage and (b) Network Architecture
•Surface Coverage: Ensuring continuous and reliable
communication coverage across the lunar surface, includ-
ing polar regions and potential landing sites, is crucial for
mission success with the impact of delays, latency, and
channel model of the moon.
•Network Architecture: we should design a cohesive
network architecture that integrates lunar surface nodes
(rovers, landers) with orbital assets (satellites, space sta-
tions) and covers all possible scenarios.
On the other hand, we must use technology (by adapting ex-
isting technology or using new technology) under the objective
of ensuring interoperability between the different components
of the lunar network and compatibility with the standards and
protocols of international space agencies. The related work is
rare, but we still have an important one published by The Na-
tional Aeronautics and Space Administration (NASA) in 2023
[1] about using 3GPP (3rd Generation Partnership Project)
Mobile Telecommunications Technology on the Moon. This
work describes the interest of NASA in cooperation with
Nokia to install 4G technology on the moon (principally the
base station). Another important work is about the impact
of the lunar environment on the propagation characteristics
[2]. They found that lunar soil distorts the antenna pattern,
resulting in higher propagation loss and lower signal power
than in free space. A significant drop in signal was due to
the shadow presence of the crater on the moon’s terrain.
Additionally, signal delay could be a problem in a crater
environment.
The paper is organized as follows a trade-off, designing and
demonstrating of an efficient communication system for lunar
mission connectivity based on existing terrestrial technologies
is the objective of the PROSPECT project. In section II,
this paper will define, review, and elaborate on different
Lunar scenarios, use cases, and communication architectures.
A trade-off analysis of existing communication technologies
used in Earth-based and their needed adaptation for lunar
environments is present in section III. A simulation of different
scenarios/architectures on MATLAB is presented in section IV.
Finally, we finish this study by selecting the best solutions in
response to the requirements for the Moon Mission.
II. PROXIMITY LUNA R LI NK N ET WORK
Several communication links for lunar communications are
presented in [3]. They propose links between Earth and the
Moon in an up/down direction via spacecraft orbiting the
Moon or elements installed on the Moon’s surface. Focusing
on the proximity communication links between different space
assets on the surface of the Moon, we can distinguish the
following elements:
1. Rovers with Science Instruments
2. Astronauts equipped with communication devices
3. Base Stations/Communication Towers on the surface
The link for proximity communications is characterized by
short-range radio links (distances less than 10 km), bidirec-
tional, fixed, or mobile.
A. Scenarios
In this respect, we defined four groups of scenarios that
correspond to proximity communications and sub-scenarios
depending on the existence of a line of sight (LOS) or not a
line of sight(NLOS) as shown in Figure 1. The classification
of different scenarios with sub-scenarios is presented below:
•Scenario 1: Surface to Surface (S2S): communications
between landed assets.
–Sub-Scenario 1.1: Between the Moon’s outer sur-
faces with LOS which is represented in Figure 1 by
the blue line.
–Sub-Scenario 1.2: Between the Moon’s outer sur-
faces with NLOS which is represented in Figure 1
by the dashed blue line.
–Sub-Scenario 1.3: Surface to Caves/Crater/Pits with
LOS which is represented in Figure 1 by the green
line.
–Sub-Scenario 1.4: Surface to Caves/Crater/Pits with
NLOS which is represented in Figure 1 by the dashed
green line.
•Scenario 2: Caves/Crater/Pits to Caves/Crater/Pits: com-
munications between assets immersed in a crater, cave,
or pit in the lunar surface.
•Scenario 3: Surface-to-Air: communication occurs be-
tween a landed asset and a device flying near the ground,
which is represented in Figure 1 by the red lines.
•Scenario 4: In orbit communications refers to communi-
cation between orbiting assets close to each other (e.g.
astronauts with orbital spacecraft), which is represented
in Figure 1 by the orange lines.
Fig. 1: Global scenario for proximity communications.
B. Communication architectures
Obviously, the scenarios mentioned above will evolve over
time, and as the number of missions increases, the number
of assets on the lunar surface will also increase. Therefore,
different types of architectures can be foreseen due to the
increasing number of nodes and complexity: a) direct point-
to-point communication; b) short-range cluster (≤100 m); c)
long-range cluster (≤10 km); and d) inter-cluster communica-
tions as shown in Figure 2, Figure 3 and Figure 4 respectively.
Three kinds of communications assets or transceivers are
considered:
•Access Point (AP) asset: This kind of asset can act as a
communication hub to aggregate traffic from neighboring
assets; they are mobile and have relatively low resources.
•Base Station (BS) asset: This refers to a communication
tower. These types of assets can aggregate the traffic from
multiple assets and are placed at the center of each cluster.
They are fixed and have high resources.
•Client terminals (CT) or UEs according to the 3gpp
nomenclature: They can either connect to the AP/BS
to enable communications, or they can communicate
directly with each other.
Fig. 2: Short-range cluster communications.
Based on these architectures shown in Figures 2, 3, and 4,
we can define the following types of communication links:
•Short-range direct-point-to-point link: These commu-
nications do not need to be routed via the AP/base station.
From a technological standpoint, client devices can create
an additional dedicated link on top of the AP link (or
the AP link can be disconnected and modified to allow
direct communication). This could be the case of a rover
providing connectivity to another in a crater or astronauts
communicating directly.
•Short-range link: Communications across a coordinated
network architecture are often more efficient than point-
to-point connections and allow for multi-point connec-
tivity. In this situation, the shorter distance between the
terminals and the AP/BS (less than 100m) enables low-
power communication methods.
•Long-range link: The AP/BS infrastructure needs to cover
a larger region (up to 10km). In this situation, a lander
might serve as a BS for a network of exploratory rovers.
•Inter-infrastructure link: This link interconnects AP/BSs
from various clusters, establishing a higher-level back-
bone network on the Moon’s surface that may transmit
data between clusters or enable relay to/from Earth.
•Data-relay link: This link is dedicated to connecting
the communication infrastructure to the RS or an Earth
transponder.
Fig. 3: Long-range cluster communications.
Fig. 4: Inter-cluster communication.
Fig. 5: Lunar cave exploration mission and it is matching with
different architectures options.
In Figure 5, we provide an example scenario where a
Lunar cave exploration mission can employ all the architecture
options and links previously mentioned.
In the following sections, we will perform a trade-off
analysis to select the best protocol(s) for Lunar proximity
communication, which will depend on the specific mission re-
quirements, range, data rate requirements, power consumption,
and the impact of the lunar environment on signal propagation.
III. TRA DE -OFF A NALYSIS
Understanding the lunar communication channel is the first
step to designing or selecting an effective proximity network.
The channel characteristics will mainly dictate the selection
of the communication protocol. The Moon’s surface presents
a unique environment with minimal atmosphere, high levels
of radiation, and reflective, irregular terrain.
A. About lunar channel model
The current research [2] includes efforts to simulate the
conditions of the lunar environment. It analyzes the effects of
lunar terrain geometry, signal frequency, antenna location, and
lunar surface material on signal propagation. These key factors
determine the propagation characteristics of lunar wireless
communication systems. Higher antennas result in reduced
path loss, but higher frequencies (i.e., S-band) have better path
loss than lower frequencies (e.g., UHF band) at short range,
but both are worse compared to free space. Based on these
observations, narrower bandwidths (BW) are favored over wide
bandwidths to maintain a favorable connection budget. This
study is supported by recent NASA studies on the Moon [1],
where the authors advised utilizing a bandwidth ≤20 MHz
for LTE.
In addition to signal strength, it is necessary to represent
multi-path phenomena (such as frequency selective fading).
The latter consists of multiple copies of the transmitted signal
that have varied delays and strengths due to the reflection and
diffraction of the radio signal. According to [2], the delay
spread in lunar craters is around 160ns. Larger craters can
result in even more significant delays. A chosen protocol
must be designed to accommodate such a delay, as well as
considerably longer delays in the worst-case scenario.
In the following trade-off analysis, we try to identify useful
protocols and their configurations considering the aforemen-
tioned lunar delay propagation with an additional margin of
100 ns (i.e. 260 ns).
B. Potential Communication Technologies
Investigating potential communication technologies for lu-
nar proximity networks is not an easy mission. The following
technologies stand out as strong candidates due to their specific
advantages and suitability for the lunar environment: Optical
Wireless Communication (OWC), Terrestrial Radio Frequency
(RF) technologies, Light Fidelity (Li-Fi), Millimeter Wave
Communication, Zigbee and Low Power Wide Area Networks
(LPWAN), and Satellite Communication [4].
Each of these technologies offers unique advantages and
trade-offs that must be carefully evaluated in the context of
lunar missions. The choice of technology in this work (As
well as the PROSPECT project) is based on the Consultative
Committee for Space Data Systems - CCSDS Recommended
Standards (known by the Blue Books) [5]. For a lunar
mission, the Blue Book recommends two primary standards:
the IEEE 802.11 (Wi-Fi) standards and the 3GPP standards.
IEEE 802.11 IEEE 802.11 refers to a set of standards for
wireless local area networks (WLANs) [7] established by the
Institute of Electrical and Electronics Engineers (IEEE). The
IEEE 802.11 n/ac/ax/ay/ah/be/ad series wireless networks are
suitable for missions with simple requirements and minimal
interoperability requirements. Where these series of standards-
based products allow for extremely simple configuration in
terms of system size and configuration complexity. The
simplicity of the IEEE 802.11 series comes with significantly
reduced capacity and reduced interoperability, but missions
that do not require this capacity and/or interoperability can
operate with the IEEE 802.11 series standards. IEEE802.11ax
remains backward compatible with other legacy WLAN
standards and provides differentiated services such as best
effort, voice, video, and data [6] [7]. It supports outdoor
operations with a higher data rate under good conditions
and extended coverage. IEEE802.11ax has narrower space
subcarrier spacing (SCS), implying longer OFDM symbols
with longer guard intervals (i.e., three CP lengths 0.8, 1.6,
and 3.2us), giving it the advantages of surviving in a severe
multi-path environment [5]. Furthermore, it allows operation
at both 2.4GHz and 5GHz bands, providing more flexibility
in terms of spectrum [8]. For these reasons, the optimal Wi-Fi
version for lunar communication is IEEE802.11ax.
3GPP standard The 3GPP is a collaborative effort that
develops technical standards for mobile telecommunications
and satellite communication and has many releases (Rel). For
the 3GPP standard suggestion is due to the flexibility offered
by the 3GPP standard and its relative maturity and history
of field deployment in public safety applications. The 3GPP
standard includes the modern long-term evolution (LTE) and
new radio (NR) 5th generation (5G) standards. LTE was first
presented in 3GPP Rel-8 and enhanced in later releases up
to Rel-14. From Rel-15 onwards, 3GPP standards become
5G new radio (5G-NR) standards, which are designed
for extremely high data rates and highly mission-critical
reliability at extremely low latencies. The aforementioned
standards allow for longer ranges (up to approximately
70 km) [5], operate over a wide range of frequencies,
and support both indoor/outdoor operations. They are also
designed for a maximum relative motion speed (between base
station and UEs) of 500 km/hr to allow high-speed mobility.
From a waveform standpoint, 5G-NR provides greater radio
configuration freedom than LTE. 5G-NR can operate in
several frequency bands. Furthermore, 5G-NR standards are
designed to provide extremely high data rates and highly
mission-critical reliability while maintaining extremely low
latency. For these reasons, the optimal 3GPP standard for
lunar communication is 5G-NR.
C. Technology Selection
Given these considerations, the lunar channel, and the
requirements, the first conclusion drawn from the foregoing
analysis is that IEEE802.11ax and 5G-NR are the best versions
of the IEEE 802.11 and 3GPP series. Table I summarizes key
performance metrics for IEEE 802.11ax and 5G-NR, including
telemetry capabilities, range, mobility, data rate, configuration
simplicity, infrastructure-level interoperability (for example,
roaming), direct mode, and power consumption.
TABLE I: Main key performance metrics of IEEE 802.11ax and 5G-
NR.
5G-NR is better regarding coverage, supported mobility, and
infrastructure-level interoperability. It should be noted that the
theoretical peak data rate between IEEE802.11ax and 5G is
almost identical, and it was difficult to find references with
accurate information regarding the data rate. However, we
found that 5G-NR, in most cases, has a better achievable data
rate than IEEE 802.11 ax [14]. In general, the performance
of IEEE 802.11ax is compliant with scenarios requiring high
data rate, short range, limited mobility, and scenarios requiring
communication relay to and from devices outside (e.g., devices
under NLOS conditions).
Given 5G-NR’s flexibility and higher performance, we es-
timate that it is the best fit for lunar proximity links. In
general, 5G-NR can handle all lunar proximity scenarios;
however, it has some weaknesses in specific scenarios. For
example, the complexity and cost may not be justifiable for
more straightforward scenarios like short-range coverage.
Finally, in Table II, we provide the score of each protocol
for each scenario defined in the preceding section. The score
is from 1 to 5, with 1 being the worst case and 5 being the
best.
Based on this table and the trade-off analysis performed, we
conclude that the best solution for proximity links is the 5G-
NR network with UEs integrating IEEE802.11ax terminals.
The latter is helpful for scenarios where multi-hop commu-
nication (i.e., multiple relays) is required or where a single
relay is used for short ranges. Based on this vision, this 5G-
NR network will be composed of Large or small BS, UEs
with embedded Wi-Fi (IEEE802.11ax), 5G repeaters if needed
(long-range NLOS conditions), and a network subsystem (5G
core network).
IV. SIMULATION RESULTS
To study the performance of the proposed lunar proximity
network architectures under various scenarios, we have done
many simulations under several scenarios. The simulations
considered factors such as carrier frequency, system band-
width, transmit power for the UE and the gNB, the antenna
gain, noise figure, sub-carrier spacing, MIMO configuration,
and propagation channel with desired delay spread and duplex
mode as shown in Table III.
TABLE II: Lunar proximity scenarios vs best technology.
TABLE III: 5G-NR simulation parameters for data rate evaluation.
Firstly, we evaluated the effective UL/DL throughput for
different distances between the UE and gNB. The simulations
are done as follows in two cases:
•1 UE: 1 UE placed at the desired distance (i.e., 100m,
2 km, and 10 km) from the gNB. Bandwidth BW value
5MHz or 20 MHz. Delay spread value. 260ns or 1µs
•Multiple UEs: Multiple UEs placed at the desired distance
from the gNB. Two distributions are used for the UEs
placement: (1) all the UEs at the edge and (2) non-
uniform placements where most UEs are close to the
edge. The other steps are the same as the 1-UE.
The obtained results 1-UE case are shown in Table IV.a
and Table IV.b. Table IV.a gives the results of gNB with a
0dBi and Tx power of 50dBm, except for the case of 100m,
where the Tx power was 30dBm. Table IV provides results of a
gNB with 10dBi antenna gain and 40dBm Tx power. We can
see that the obtained throughput depends on distance/delay
spread/BW /antenna type. In the case of 2km coverage, the
best UL (resp. DL) throughput for UE at the edge (i.e. 2km)
is around 87 Mbps (resp. 123Mbps), while for 10km, it is
12Mbps (resp. 46Mbps). The DL throughput is better than the
UL one due to the higher power of the base station compared
to the UE one.
TABLE IV: 5G-NR effective throughput vs. coverage range for 1-UE
with two different delay spreads (with 0 or 10 dBi gNB antenna gain,
Figure a or b respectively).
For the multi-UEs case, the obtained DL results are shown
in Figure 6. One can see that the obtained DL throughput
values are approximately stable when shifting from 1-UE to
multi-UEs.
First, for the UEs at the edge, one can see the degradation of
the throughput when shifting from 1-UE to multi-UEs. In the
case of 2-km coverage, about 18%of throughput decrease is
observed for BW = 5MHz, while 30%for BW = 20 MHz. On
the other hand, in the case of 10-km coverage, the degradation
is about 70%and 50%for BW of 5 MHz and 20 MHz,
respectively. This degradation is mainly due to the scheduler’s
presence. Note that the scheduler will practically give the same
resources between UEs in this situation since they have all
Fig. 6: a. Obtained throughput with All UEs at the edge (2km
coverage); b.Obtained throughput with all UEs at the edge (10km
coverage); c.Obtained throughput with All UEs with non-uniform
distribution (2km coverage); d.Obtained throughput with all UEs with
non-uniform distribution (10km coverage)
the same conditions, and consequently, the throughput per UE
is the same. For the UEs with non-uniform distribution, one
can see that the system throughput in case of multi-UEs is
not necessarily worse compared to 1-UE, and even when it is
worst, the gap is smaller (about 21%) compared to the previous
case (all UEs at the edge). This comes from the fact that UEs
that are not at the edge will have better SNR and consequently
better throughput assuming the same resource as well as due
to the proportional fairness scheduler that aims to maximize
the system throughput.
V. CONCLUSION
To ensure the success of future lunar missions, we should
have efficient communication between habitats, astronauts,
and autonomous systems. By analyzing various scenarios and
communication architectures, this study has highlighted the
importance of selecting robust, high data rate, and low-power
technologies suited to the Moon’s unique environment. The
trade-off analysis and discussion results suggest that a hybrid
network architecture, leveraging IEEE802.11 and 3GPP proto-
cols technologies, provides an optimal solution for supporting
diverse lunar activities. A 5G network with UEs embedding
IEEE 802.11ax terminals appears to be the best system for
Lunar proximity links.IEEE 802.11ax is useful for deploying
mesh networks (via direct mode) to connect terminals that are
out of coverage (e.g., Lunar cave/pit). Also, when terminals
that are out of coverage or in NLOS conditions are far from
the other UEs, 5G repeaters are needed.
VI. ACK NOWLEDGMENT
This work has been supported by the European Space
Agency (ESA) funded under Contract No. ESAAO/1−
10931/21/NL/F E named ”High data rate, adaptive, internet
worked proximity communications for Space (PROSPECT).”
Please note that the views of the authors of this paper do not
necessarily reflect the views of ESA.
This study has provided a comprehensive analysis of lunar
proximity networks, several areas remain open for future
exploration. In our current/future work, we want to study and
continue to develop lunar networks that can survive the ex-
treme lunar environment (e.g., radiation, extreme temperature
fluctuations). In other words, developing lunar networks with
long-term survivability and maintenance capability.
REFERENCES
[1] Edwards, B.,et al. (2023, March). 3GPP mobile telecommunications
technology on the Moon. In 2023 IEEE Aerospace Conference (pp.
1-12). IEEE.
[2] Hwu, S., Upanavage, M., &Sham, C. (2008, June). Lunar surface prop-
agation modeling and effects on communications. In 26th international
communications satellite systems conference (ICSSC).
[3] Cosby, M., et al. (2022). The future lunar communications architecture.
Washington, DC USA: the Interagency Operations Advisory Group
(Lunar Communications Architecture Working Group).
[4] Yost, B., &Weston, S. (2024). State-of-the-art small spacecraft technol-
ogy (No. NASA/TP-20240001462).
[5] CCSDS, Recommendation for Space Data System Standards - SPACE-
CRAFT ONBOARD INTERFACE SERVICES HIGH DATA RATE
3GPP AND WI-FI LOCAL AREA COMMUNICATIONS, Blue Book,
February 2022.
[6] Khorov, E.,,et al. (2018). A tutorial on IEEE 802.11 ax high efficiency
WLANs. IEEE Communications Surveys &Tutorials, 21(1), 197-216.
[7] Bellalta, B. (2016). IEEE 802.11 ax: High-efficiency WLANs. IEEE
wireless communications, 23(1), 38-46.
[8] Aruba, White paper - 802.11AX, 2018. [Online]. Available:
https://www.arubanetworks.com/assets/wp/WP 802.11AX.pdf.
[9] EnGenius 802.11ax 2x2 Dual-Band Managed Outdoor Wireless Ac-
cess Point EWS850-FIT: Solwise Ltd. (n.d.). [Online]. Available:
https://www.solwise.co.uk/EL-EWS850-FIT
[10] Orange, Extreme 5G coverage, April 2019.[Online]. Available: hellofu-
ture.orange.com
[11] O. Aboul-Magd, P802.11ax. IEEE-SA, 2014. [Online]. Available:
development.standards.ieee.org/get-file/P802.11ax.pdf.
[12] Intel, intel 2020. [Online]. Available: www.intel.com/∼/resources/wifi-6.
[13] Qualcomm, Everything you need to know about 5G.[Online]. Available:
www.qualcomm.com/5g/what-is-5g
[14] Maldonado, R.,et al.(2021). Comparing Wi-Fi 6 and 5G downlink
performance for industrial IoT. IEEE Access, 9, 86928-86937.
[15] Giordano, P.,,et al.(2021, October). Moonlight navigation service-how to
land on peaks of eternal light. In Proceedings of the 72nd International
Astronautical Congress (IAC), Dubai, United Arab Emirates (pp. 25-29).
