ABSTRACT: The transformative influence of Internet and Communication Technology (ICT) has reshaped society, touching every aspect from the economy to healthcare. As the widespread deployment of 5G continues, there is an ongoing focus on the inception of the sixth generation (6G) of wireless communication systems (WCSs). Anticipated to shape the future of connectivity in the 2030s, 6G aims to deliver unparalleled communication services to meet the demands of hyper-connectivity. While densely populated urban areas have traditionally been the primary beneficiaries of WCS advancements, the vision for 6G transcends city limits. Aligned with the United Nations' sustainability goals for 2030, an important aspect of 6G endeavors to democratize the benefits of ICT, fostering global connectivity sustainably. This talk delves into this particular envisioned landscape of 6G, providing insights into the future of wireless communication and guiding research efforts toward sustainable, inclusive, and high-speed connectivity solutions for the future. Central to this discussion are two emerging technologies: Free Space Optics (FSO) and Non-Terrestrial Networks (NTN). These innovative solutions hold the promise of extending high-speed connectivity beyond urban hubs to underserved regions, fostering digital inclusivity, and contributing to the development of remote areas. Through this exploration, we aim to convey the potential of 6G and its role in shaping a connected, sustainable future for all. BIO: Mohamed-Slim Alouini, was born in Tunis, Tunisia. He earned his Ph.D. from the California Institute of Technology (Caltech) in 1998 before serving as a faculty member at the University of Minnesota and later at Texas A&M University in Qatar. In 2009, he became a founding faculty member at King Abdullah University of Science and Technology (KAUST), where he currently is the Al-Khawarizmi Distinguished Professor of Electrical and Computer Engineering and where he holds the UNESCO Chair on Education to Connect the Unconnected. Prof. Alouini is a Fellow of the IEEE and OPTICA and his research interests encompass a wide array of research topics in wireless and satellite communications. He is currently particularly focusing on addressing the technical challenges associated with information and communication technologies (ICT) in underserved regions and is deeply committed to bridging the digital divide by tackling issues related to the uneven distribution, access to, and utilization of ICT in rural, low-income, disaster-prone, and hard-to-reach areas.

1. What Should 6G Be ?
Mohamed-Slim Alouini
Communication Theory Lab. @ KAUST
http://ctl.kaust.edu.sa 1

2. 2
6G is Coming
V2X E-Health XR
Super eMBB
AI
Industrial IoT
S. Dang, O. Amin, B. Shihada, & M. –S. Alouini, “What Should 6G Be?”, Nature Electronics, January 2020

3. Power Consumption Concern
• Massive antenna arrays and
beamforming
• mmWave band
5G use case
• Densification of 5G sites
• Massive connection of IoT devices
• Power consumption of 5G equipment in some
bands is up 3 times of 4G with the same
configuration.
• The number of sites is expected to be 2 to 3
times that of the 4G era in order to achieve 4G
equivalent coverage.
Power consumption of frequency evolution
C. L. I., S. Han, and S. Bian, “Energy-efficient 5G for a greener future”, Nature Electronics, April 2020.
Huawei White Paper, “5G telecom power target network,” 5th Global ICT Energy Efficiency Summit,
https://carrier.huawei.com/~/media/CNBGV2/download/products/network-energy/5G-Telecom-Energy-Target-Network-White-Paper.pdf

4. EMF Radiation Concern
• Concern on electromagnetic field exposure
– Potential health risks associated with the extra RF emissions from 5G base stations
L. Chiaraviglio, A. Elzanaty, and M.-S. Alouini, “Health risks associated with 5G exposure: A view from the communications engineering perspective ”, IEEE Open Journal of
Communication Society, 2021. Available on Arxiv: https://arxiv.org/pdf/2006.00944.pdf
© Xavier Pita | KAUST

5. 5
The Global Connectivity Divide
World Wide BS Distribution
LTE (4G)
We are suffering from serious gaps in global internet connectivity.
E. Yaacoub and M.-S. Alouini, “A Key 6G Challenge and Opportunity - Connecting the Base of the
Pyramid: A Survey on Rural Connectivity,” Proceedings of IEEE, April 2020. Available on Arxiv.

6. Sustainability Development Goals (SDGs)
• In 2016, the United Nations (UN) released 17 Sustainability Development Goals
(SDGs) for the 2030 Agenda

7. SDGs & 6G
• The UN SDGs should drive the evolution of
6G
• 6G should target:
–Improved Energy Efficiency
–No Bad Effects on Environment & Human Health
–Digital Inclusion
–More Security and Privacy
–Resilience, Robustness, and Dependability

8. 8
Bridging Connectivity Divide
• Cooperation
needed to bring
reliable internet to
those without it
Poor infrastructure
Shortage of healthcare
Low quality of education
for schooling
Social Barriers
E. Yaacoub and M.-S. Alouini, “A Key 6G Challenge and Opportunity - Connecting the Base of the Pyramid: A
Survey on Rural Connectivity,” Proceedings of IEEE, April 2020. Available at https://arxiv.org/abs/1906.11541

9. 9
From Smart Cities to Smart Living
Smart Grid
Smart Transportation
Environmental Protection
Water Distribution
Smart Healthcare
Smart Village
Smart Home
Virtual Education
Remote Healthcare
Nature Friendly
SMART LIVING
RURAL
URBAN High Speed
Backhaul
SMART EVERYWHERE
Equal and Eco-Friendly
Quality of Life
High Data Rate
URLLC
E. Yaacoub and M.-S. Alouini, “Efficient Front-haul and Back-haul Connectivity for IoT

10. Resilience with On-Demand Pop-up Networks
10
Disaster
Emergency
Concert
Sport Event
Scientific
Mission
Military
Mission
• M. Matracia, N. Saeed, M. Kishk, and M. -S. Alouini, " Post-disaster communications: Enabling technologies, architectures, and open challenges ", IEEE Open Journal of Communication
Society, Vol. 3, No. , pp. 1177 - 1205, July 2022.
• F. Alqurashi, A. Trichili, N. Saeed, B. Ooi, and M. -S. Alouini, "Maritime communications: A survey on enabling technologies, opportunities, and challenges ", IEEE
Internet of Things Journal, Vol. 10, No. 4, pp. 3525-3547, February 2023.

11. Post-Disaster Communications Set-Up
M. Matracia, M. Kishk, and M.-S. Alouini, “On the Topological Aspects of UAV-Assisted Post-Disaster Wireless
Communication Networks”, IEEE Comm Magazine, 2022

12. Post-Disaster Communications Results
(𝑎) (𝑏)
Simulation results considering terrestrial base station uniformly distributed over the ground plane and a
number 𝑛𝐴 of (𝑎) drones and (𝑏) HAPS

13. 13
Climate Monitoring Using
Internet of X-Things
[1] N. Saeed, A. Celik, T. Al-Naffouri, and M. -S. Alouini, "Underwater optical wireless communications, networking, and localization: A survey", Elsevier Adhoc
Networks, 2019.
[2] N. Saeed, T. Al-Naffouri, and M. -S. Alouini, "Towards the Internet of underground things: A systematic survey", IEEE Communications Surveys and Tutorials, 2019.
[3] N. Saeed, A. Elzanaty, H. Almorad, H. Dahrouj, T. Y. Al-Naffouri, M -S. Alouini, "CubeSat communications: Recent advances and future challenges", IEEE Com
Surveys and Tutorials 2020

14. 14
Backhaul Challenge

15. 15
Global Connectivity Holy Grail
“A telephone subscriber here may call up and talk to any other subscriber
on the Globe. An inexpensive receiver, not bigger than a watch, will enable
him to listen anywhere, on land or sea, to a speech delivered or music
played in some other place, however distant.”
― Nikola Tesla 1919
Quality
of
Experience
(High
Data
Rate
+
Low
Latency)
Cost per User in Remote Low Population Density Areas
Global Connectivity
Holy Grail
Optic Fiber Cables
Microwave
Wireless Links
Classic
GEO Satellite
Low
High
High

16. 16
Existing TV Infrastructure
• TV White Space (TVWS)
– Reusing TVWS unless harming TV channels
by interference
– VHF/UHF Band (i.e. 470~700 MHz )
– Ultra-wide coverage
TV Tower
A. El Falou and M. -S. Alouini, "Enhancement of Rural Connectivity by Recycling TV Towers with Massive MIMO Techniques",
IEEE Communication Magazine 2023.

17. 17
Recycling TV Towers with Massive
MIMO Techniques
• Observations:
❑ A large part of the considered area is not covered
by any 3G BS.
❑ Legacy BSs are located in some places with high
population densities.
❑ 4G BSs are not available in the considered area.
❑ Some TV towers are available in the considered
area
A. El Falou and M. -S. Alouini, "Enhancement of Rural Connectivity by Recycling TV Towers with Massive MIMO Techniques",
IEEE Communication Magazine 2023.
• Observations:
❑ Only 9,000 persons out of the total population
of 200, 000 is covered (4.5%)
❑ 19,500 more persons can be covered (14.25%)
❑ Number of covered persons can be increased
to 30,000 (19.5%)

18. Tethered Balloons/Airships/Aerostats
18
T. Staedter, “Soaring ‘Super Towers’ Aim to Bring Mobile Broadband to Rural Areas,” IEEE. Spectrum, April 2018.
B.E.Y. Belmekki and M.-S. Alouini, “Unleashing the Potential of Tethered Networked Flying Platforms: Prospects,
Challenges, and Applications,” IEEE Open Journal of Vehicular Technology, 2022.

19. 19
High Altitude Platform Stations (HAPS)
balloon
Flight equipment
Mobile network provider
AQUILA
LOON
“Tower-in-the-air”
• Solar-powered swarm of HAPs in the backbone network at
a height of 18-28 km
Z. Lou, B. Belmekki, and M. -S. Alouini, "HAPS in the non-terrestrial network nexus: Prospective architectures and
performance insights ", IEEE Wireless Communication Magazine, 2024.

20. [3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.
High Altitude Platform Stations (HAPS)
1
[2] Z. Lou, B. E. Y. Belmekki, and M. -S. Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
[1] S. Javed, M.-S. Alouini, and Z. Ding, "“An interdisciplinary approach to optimal communication and flight operation of high-altitude long-endurance platforms”, IEEE TAES., 2023.
UNESCO Chair
on Education
to Connect the Unconnected
Fixed-Wing Airship Balloon

21. [3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.
High Altitude Platform Stations (HAPS)
2
[2] Z. Lou, B. E. Y. Belmekki, and M. -S. Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
[1] S. Javed, M.-S. Alouini, and Z. Ding, "“An interdisciplinary approach to optimal communication and flight operation of high-altitude long-endurance platforms”, IEEE TAES., 2023.
UNESCO Chair
on Education
to Connect the Unconnected
Endurance Energy Payload Steering Cost
Lift
2 Months
6 Months
4-6 Months
Solar
Hydrogen
Solar
Helium
Solar Helium
50-150 Kg
200-400 Kg
25-50 Kg
Precise
Control
Moderate
Control
Wind
Dependent
Aerodynamic
Aerostatic
Aerostatic
Moderate
to High
Moderate to High
Low
To Moderate
Please note that the cost categories - high, moderate, and low - represent relative comparisons among HAPS platforms, rather than in comparison to other communication infrastructures.
Fixed-Wing
Airship
Balloon

22. [3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.
HAPS with other Telecommunication Solutions
3
Environment: Urban/Suburban Environment: Ubiquitous Environment: Rural/Deep Rural
Coverage Radius: 10-50 km
Tower Mast
HAPS
LEO Satellite
17-23 km
25 m
160 km
Coverage Radius: 500 km
[2] Z. Lou, B. E. Y. Belmekki, and M. -S. Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
[1] S. Javed, M.-S. Alouini, and Z. Ding, "“An interdisciplinary approach to optimal communication and flight operation of high-altitude long-endurance platforms”, IEEE TAES., 2023.
UNESCO Chair
on Education
to Connect the Unconnected
Coverage Radius: 100 m-10 km
Altitude:
Altitude:
Altitude:

23. HAPS with other Telecommunication Solutions
4
Environment: Urban/Suburban Environment: Urban Environment: Suburban Environment: Ubiquitous Environment: Rural/Deep Rural
Tower Mast
UAV
Tethered Blimp
HAPS
LEO Satellite
17-23 km
1-2 km
150 m
25 m
160 km
UNESCO Chair
on Education
to Connect the Unconnected
Coverage Radius: 10-50 km Coverage Radius: 500 km
Coverage Radius: 100 m-10 km Coverage Radius: 5-10 km
Coverage Radius: 500 m-4 km
[3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.
[2] Z. Lou, B. E. Y. Belmekki, and M. -S. Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
[1] S. Javed, M.-S. Alouini, and Z. Ding, "“An interdisciplinary approach to optimal communication and flight operation of high-altitude long-endurance platforms”, IEEE TAES., 2023.

24. 5G Trial using HAPS
5
UNESCO Chair
on Education
to Connect the Unconnected
[3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.
5G User
HAPS
Ground Backhaul Internet
Access Router
Antennas

25. Distance from
the Cell Center
6.5 Km
5G Trial using HAPS
6
UNESCO Chair
on Education
to Connect the Unconnected
[3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.

26. 5G Trial using HAPS
7
UNESCO Chair
on Education
to Connect the Unconnected
90 Mbps
Internet Speed
1/6th
Bandwidth
High
Signal Quality
450 Km2
Large Coverage
Uniform Coverage
Cell Coverage
High
Signal Quality
High speed internet
Mobility
Superior
Vs. Cellular Tower
High
Aerial Coverage
High
Maritime Coverage
6 Km
Outside Cell
4K Streaming
Multimedia
Disruptive
Technologies
Inclusion
and Equity
Future Transportation
Systems
Blue
Economy
[3] B.E.Y. Belmekki, A. J. Aljohani, S. A. Althubaity, A. Al Harthi, K. Bean, A. Aijaz, and M.-S Alouini, "Cellular Network From the Sky: Toward People-Centered Smart Communities", IEEE OJCS, 2024.

27. HAPS-Relayed Cell-Free Networks
8
UNESCO Chair
on Education
to Connect the Unconnected
[2] Z. Lou, B.E.Y. Belmekki, and M.-S Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
User
LEO Satellite
HAPS
Access Point
Central Processing Unit Binomial Point Process
Binomial Point Process
550 km
Altitude:
Altitude:
20 km
Radius: 50 km
Coverage
Probability
=
P(SINR
≥
Threshold)
mmWave
Carrier Frequency: 28 GHz
Bandwidth: 100 MHz
Need HAPS
Increase HAPS
Constant Satellites
Constant HAPS
Increase Satellites
Poisson Point Process
Density:1 user /km2
simultaneously
transmitting
Active users: 1/10th

28. HAPS-Based Adhoc Networks
9
UNESCO Chair
on Education
to Connect the Unconnected
[2] Z. Lou, B.E.Y. Belmekki, and M.-S Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
HAPS
Altitude:
20 km
Radius: 20 km
RF
Carrier Frequency: 2 GHz
Bandwidth: 40 MHz
Poisson Point Process
Binomial Point Process
Altitude:
50 m
UAV
Tree OLoS -20dB path loss LoS
P(LOS) =exp(-0.08. Distance)

29. HAPS-Based IAB Architectures
10
UNESCO Chair
on Education
to Connect the Unconnected
[2] Z. Lou, B.E.Y. Belmekki, and M.-S Alouini, "HAPS in the Non-Terrestrial Network Nexus: Prospective Architectures and Performance Insights", IEEE Wireless Communications, 2023.
• Donor: Macro Base Station
Aggregate Uplink: 16.5 Gbps
• Layer 1: HAPS
Aggregate Uplink: 3.8 Gbps
• Layer 2: HAPS
Aggregate Uplink: 1.6 Gbps
• Layer 3: HAPS
Aggregate Uplink: 0.5 Gbps
Layer 1: 4 HAPS
Macro Base Station
Layer 2: 8 HAPS
Layer 3: 16 HAPS
Downlink
Channel
Capacity
[Mbps]
Y-axis
[km]
X-axis [km]

30. •Remote coverage
•Earth observation
•Relay/Backhaul Solution
•Weather predictions
•Catastrophe management
•Flash crowds
•Monitoring and surveillance
•Connecting the unconnected
Truly mobile network
Scaling capability
Better LOS links
Remote coverage including
maritime/aviation
Economical for sparse regions
UW coverage (~60km-400km)
Resilient to natural disasters
30
Motivation Behind Solar-Powered HAPS
Low-delay characteristics
No special UE requirement
Favorable channels
Almost stationary positions
Higher area throughput
Reusability/Maintenance
Quick deployment
Seamless merger
•Green communications
•Ubiquitous connection
•Resilient operations
•Flexible deployment
•Easy maintenance
•Remedy to architectural
problems General
Benefits
Benefits
over
Satellite
Commun.
Benefits
over
Terrestrial
Commun.
Use Cases
Terrestrial
Network
Low-Altitude
Platform Stations
(LAPS)
High-Altitude
Platform Stations
(HAPS)
LEO
Satellites
6G
Vision
<400m
~1000km
~18-24km

31. 31
Stratospheric Solar-Powered HAPS
S. Javed, M.-S. Alouini, and Z. Ding, “An interdisciplinary approach to optimal communication and flight operation of high-altitude long-
endurance platforms,” IEEE Trans. Aerosp. Electron. Syst., vol. 59, no. 6, pp. 8327–8341, Dec. 2023.
North Position
East Position
Altitude
(Aircraft)
Latitude
Longitude
(WGS84)
Solar Angles:
Azimuth
Elevation
Julian Day
Solar Flux
Rotation
Angles:
Heading, Pitch,
& bank angles
Angle of Attack
and
Inertial Flight
Angle
Lift Force
Equivalent
Airspeed and
Air density
True Airspeed
Aircraft Angles
and weight
Earth Radius
Drift Force
Thrust/
Propulsion
power
Input Power
Output Power
Transmission
Power for DL
NOMA
Corrected for
circular trajectory
Pyproj
Reda Algorithm
using Pysolar
Inertial Frame to
Body Frame
Transformation
Lookup
Tables
Lookup
Tables
Battery
Storage
Day Time
Day Time
Night Time
Solar Flux Measurement
Aerodynamics
Available Power
Power Consumption
T
D
W
L
T
D
W
L
d/2
C
W
Lv L
�
(a) (b)
r=100km
d=6km
h=24km
d=6km
h=18km
r=100km
Station keeping
flight pattern:
Dwell mode
Station keeping
flight pattern:
Charge mode
Gateway Gateway
Steady Horizontal Flight Steady Circular Flight

32. 32
Methodology
Day Time Operation Night Time Operation
Power State Abundant Solar Energy
High Power Budget
Absence of Solar Energy
Limited Power Budget
Flight State Optimal Flight Dwell Flight
Battery Status Charging Discharging
Objective Function Maximize Sum Rate Minimize Propulsion Power
Optimization Parameters Aircraft Altitude
Aircraft True Airspeed
DL NOMA - Users Power Allocation
Aircraft Altitude
Aircraft True Airspeed
Constrained Optimization Constrained by user ordering, power budget
and boundary limits
Boundary Constraints
Throughput Maximum possible data rate Minimum threshold rate
Services All communications services Priority/mandatory
Coupled with the aim of self-sustainable flight while ensuring QoS communications to DL NOMA Users

33. 33
Solar Powered HAPS: Performance Analysis
Available solar energy at different latitudes
Night Time: Minimum propulsion power requirement with joint
design of aerodynamic parameters for existing HAPS prototypes
Day Time: Link and mean user spectral
efficiency with NOMA vs OFDMA
Flux variation at different altitudes in Stratosphere
Duration of Daylight Hours throughout the year
Day Time: Sum rate for different user target
rates NOMA vs OFDMA

34. 34
HAPS System Design and Parameter Optimization
S. Javed and M.-S. Alouini, “System Design and Parameter Optimization for Remote Coverage from NOMA-based
High-Altitude Platform Stations (HAPS)”, submitted in IEEE Trans. Wireless. Commun., Feb. 2024.
User
Distribution
• Based on Point Poisson Process (PPP)
• Distribution in the coverage area
User
Grouping
• Based on Geometric Disk Cover (GDC) algorithm
• Finds the minimum number of spot beams and
their locations.
User
Association
• Based on Greedy Algorithm (GA)
• Identifies the serving beam for group of users.
• Single beam association for user fairness
and interference mitigation.
Beam
Optimization
• Minimum enclosing circle (MEC) problem.
• Employment of the efficient Welzl’s algorithm.
• Optimal beam locations with minimal beamwidth
D
i
r
e
c
t
i
o
n
a
l
B
e
a
m
Station keeping
flight pattern
d
H
�
Coverage Area
�
�
�
�
Group m
Group m1 Group m2
�
�

35. 35
HAPS System Design: Performance Analysis
Average sumrate of users with NOMA vs OMA Average and worst case outage performance of ground users Average energy efficiency of HAPS Downlink transmission

36. 36
Satellite Constellations Backhaul
Geostationary Earth Orbit (GEO) Satellite
• Fixed position in the sky at ~35,000 km
• Relatively large delay
• ViaSat 1, 2, 3
Medium Earth Orbit (MEO) Satellite
• 2,000~35,000 km
• Position and tracking
• O3B, SES Networks
Low Earth Orbit (LEO) Satellite
• 160~2,000 km
• Hand-Over
• OneWeb, Starlink,
Lightspeed, Kuiper, Curvanet
Manufacturing Cost Down => Mass Production

37. 37
Integrated
Space-Air-Ground Networks
Global Connectivity
Satellite Communication
UAV Communication
Digital Divide: Rural Connectivity
Low Altitude Platform
Mega-Constellation
High Altitude Platform

38. 38
To Be Ready for Emerging and Future
Transportation Systems
[1] G. Pan and M. -S. Alouini, “Flying car transportation systems: Advances, techniques, and challenges“, IEEE Access 2021.
[2] N. Saeed, T. Y. Al-Naffouri, M -S. Alouini, “Wireless communications for flying cars", Frontiers in Communications and Networking 2021.

39. 39
Integrated
Space-Air-Ground Networks
Global Connectivity
Satellite Communication
UAV Communication
Digital Divide: Rural Connectivity
Low Altitude Platform
Mega-Constellation
High Altitude Platform

40. 40
Towards the Underwater Internet of Things
Using Multi-Level Communication Networks

41. About 71% of Earth is
covered with water.
Great potential to explore!
Scientific Data Collection
Oceanography, Marine biology
Underwater Exploration
Resource Exploration, Geology
Underwater Monitoring
Oil/gas Field and Disaster Control
Military Use
Growing Need for High Data Rate and Real Time Transmission

42. 42
Motivation
● The underwater Internet of Things (UIoT) device in a deep sea can not be
covered by a single layer network.
K-tier Network
• Underwater network
promotes the development
of UIoT and underwater
applications
• A multilevel acoustic
communication network is
proposed to enhance the
coverage probability in
underwater
From the Sea Surface to the Deep Sea
J. Xu, M. Kishk and M. –S. Alouini, "Coverage Enhancement of Underwater Internet of Things Using Multi-Level Acoustic
Communication Networks," in IEEE Internet of Things Journal, 2022

43. 43
Motivation From Space to the Sea Surface
An aerial relay station is needed to provide connection to the sea
surface station, and then connect the underwater network.
sea surface station
Aerial station
Base station
Deep Sea Large Scale

44. 44
Space-Air-Ground-Sea Network
● The offshore end-users are unconnected in a large-scale ocean application
scenarios.
Integrated Network
• Only onshore station:
CA is too small, 50 km away
from shoreline can be covered.
• Only satellite:
CP is always at low level, but
the CA is big enough.
• Only aerial station:
CP is lower than onshore station
near to shoreline;
CA is smaller than satellite
within a large-scale oceans
CA: coverage area, CP: coverage probability
Figure 5. System model of the SIGSINs.

45. Distances between SS and Relays
Satellite
Onshore
station
Tethered
balloon
HAP
Poisson
distribution
Surface
station x
y
z
𝑋ℎ𝑎𝑝
ℎ𝑡𝑏
𝑋𝑠𝑠
ℎℎ𝑎𝑝
ℎ𝑜𝑠
Coastline
ℎ𝑠𝑠
➢ The coastline denotes the y-axis.
➢ The x-axis is perpendicular to the coastline.
➢ The z-axis is perpendicular to sea level.
The x coordinates of OS and TB, 𝑥𝑜𝑠,
𝑥𝑡𝑏, are 0.
𝑥ℎ𝑎𝑝 is the distance between the HAP
and the coastline.
On the y-axis, SS, OS, TB, and HAP are
modeled as one-dimensional Poisson
Point Processes (1DPPPs) with given
densities 𝛾𝑠𝑠, 𝛾𝑡𝑏, 𝛾ℎ𝑎𝑝.
The heights of SS, OS, TB, and HAP are
noted as ℎ𝑠𝑠, ℎ𝑜𝑠, ℎ𝑡𝑏, ℎℎ𝑎𝑝, and all of
them are known.

46. Channel Model
To make full use of the SAGSIN and achieve the best coverage probability, SS will
connect to the strongest relay among the nearest relay of four different tiers (OSs, TBs,
HAPs, and SATs).
Target SS
Tagged OS
𝐷𝑜𝑠
𝐷𝑜𝑠,𝑖
Interfering 𝐼𝑜𝑠,𝑖
J. Xu, M. A. Kishk and M. –S. Alouini, "Space-Aerial-Ground-Sea Integrated Networks: Modeling and
Coverage Analysis”, IEEE Trans on Wireless Com, 2023.

47. Performance of Individual Relay Stations
Only relay on onshore station Only relay on tethered balloon
Only relay on HAPS Only relay on satellite
The maximum
cover range:
50 km
The maximum
cover range:
200 km The cover
range is very
good: 1000 km
CP is good
CP is not bad
CP is not bad
CP is not bad
The maximum
cover range:
50 km

48. Integrated Network Performance
Relay on OS
Relay on HAP
Relay on SAT
J. Xu, M. A. Kishk, and M. –S. Alouini, "Space-Aerial-Ground-Sea Integrated Networks: Modeling and Coverage
Analysis”, IEEE Trans on Wireless Com, 2023.

49. 49
A Light in Digital Darkness

50. Spectrum
• RF spectrum typically refers to the full frequency range from 3 KHz to 30 GHz.
• RF spectrum is a national resource that is typically considered as an exclusive
property of the state.
• RF spectrum usage is regulated and optimized
• RF spectrum is allocated into different bands and is typically used for
– Radio and TV broadcasting
– Government (defense and public safety) and industry
– Commercial services to the public (voice and data)
RF IR VL UV X-ray γ-ray
HF VHF UHF SHF EHF
Wavelength [m]
10 10-1 10-3 10-5 10-7 10-9 10-11 10-13
107 109 1011 1013 1015 1017 1019 1021 1023
Frequency [Hz]
300 GHz 300 THz 30 PHz 30 EHz
750 nm 350 nm 10 nm
50

51. FSO Communication
Autonomous
Drone
Wireless
Fronthaul
Last Mile
Solutions
Primary
Building
Mobile FSO
Benefits
• Unlicensed and unbounded spectrum
• Cost-effective
• Narrow beam-widths (Energy efficient,
immune to interference and secure)
• Behind windows
• Fast turn-around time
• Suitable for brown-field
Challenges
• Additive noise and background radiation
• Atmospheric path loss and attenuation
• Atmospheric Turbulences
• Alignment and tracking
Campus/Event
Connectivity
Temporary
Events
Applications
• Initially used for secure military and in space
• Last mile solution
• Optical fiber back-up
• High data rate temporary links
• Wireless Fronthaul/Backhaul in celluar network
Narrow beam connects two optical wireless
transceivers in LOS.
[1] M. Esmail, A. Raghed, H. Fathallah, and M. -S. Alouini, "Investigation and demonstration of high speed full-optical hybrid FSO/fiber
communication system under light and storm condition", IEEE Photonics Journal, Vol. 9, No. 1, February 2017.
[2] M. -A. Lahmeri, M. Kishk, and M. -S. Alouini, "Stochastic geometry-based analysis of airborne base stations with Laser-powered
UAVs," IEEE Communication Letters, Vol. 24, No. 1, pp. 173-177, January 2020.
[3] A. Trichili, M. Cox, B. S. Ooi, and M.-S. Alouini, , ‘’Roadmap to free space optics,’ Journal of Optical Society of America B, 2020
51

52. 52
A Light in Digital Darkness
• Key issues in RF satellite/HAPS backhaul systems
– Bandwidth limitation of conventional RF solutions
– Interference with terrestrial RF networks
• FSO feeder is an attractive alternative for future very
high throughput (VHT) satellite/HAPS systems without
spectrum regulation.
Ground Air Space
© Mynaric

53. 53
Hybrid VHT Satellite with Site Diversity
Conceptual Design for hybrid RF
(Ka band) and optical feeder
OGS
Weather
Conditions
OGS
RF service region
Site diversity to avoid the
atmospheric effect
RF GS
Satellite
RF GS
E. Zedini, A. Kammoun, and M. –S. Alouini, “Performance of multibeam very high throughput satellite
systems based on FSO feeder links with HPA nonlinearity, IEEE Trans. On Wireless Communications, 2020

54. 54
AtmosphericTurbulence

55. c
Transmitter Receiver
Propagation through turbulent atmosphere:
Main reasons: Random variations in temperature and pressure leading to
random variation in the refractive index structure.
Eddies
Atmospheric Turbulence
55
 
 
2
2
2
E
1
E
I
I
I
 = −
Scintillation index:

56. ccc
Wavefront
Sensor
Receiver
Wavefront
Corrector
Control
System
PBS
Mirror
Beacon
Corrected
information beam
Telescope
Distorted wavefronts
Polx
Poly
Wavefront corrector can be based on:
• A liquid crystal display (slow)
• An array of deformable mirrors (fast)
Principle of Adaptive Optics
56

57. ccc
• Post-compensation
AO post-
compensation
Adaptive Optics Schemes
• Pre-compensation
Pure beam distorted beam corrected beam
AO post-
compensation
Pure beam pre-distorted beam
nearly pure
beam
Requires a beacon Gaussian beam from the transmitter.
Requires a beacon Gaussian beam from the receiver. 57

58. 58
Outage Probability Performance

59. 59
Closed-Forms for the Outage Probability
Gamma-Gamma Turbulence Model
• Imbalanced vibrations
• Balanced vibrations
Y. Ata and M.-S. Alouini, “HAPS based FSO links performance analysis and improvement with adaptive optics correction,” IEEE Trans. on
Wireless Com, 2023.

60. 60
Closed-Forms for the Outage Probability
Lognormal Turbulence Model
Y. Ata and M.-S. Alouini, “Performance of Integrated Ground-Air-Space FSO networks in Various Turbulent Environments,” IEEE Photonics
Journal, 2022.

61. 61
Uplink, Downlink, Horizontal Link Comparison
Y. Ata and M.-S. Alouini, “ HAPS based FSO links performance analysis and improvement with adaptive optics correction,” IEEE Trans. On
Wireless Com., 2023.

62. 62
Hybrid SAG-FSO/RF
Satellite Communication Systems

63. 63
FSO for Sat-Com
• FSO can achieve Terabits/s data rate in
GEO-equivalent turbulent channel.
• Pointing errors, induced by beam-wander
and misalignment, affect FSO-link
reliability.
• FSO transmission is susceptible to
atmospheric turbulence, beam
divergence, free-space loss, and weather
conditions, such as clouds, fog, and haze.

64. 64
Space-Air-Ground (SAG) FSO Network
• Introduce a HAPS with FSO relaying
capability to create a SAG FSO network.
• Reduce beam-wandering effect with two
short hops and achieve a gain of 4 dB.
• Ground-to-HAP hop experiences similar
amount of turbulence as direct link.
R. Swaminathan, S. Sharma, N. Vishwakarma, and A. Madhukumar, “HAPS-based relaying for integrated space-air-
ground networks with hybrid FSO/RF communication: A performance analysis,” IEEE Transactions on Aerospace
and Electronic Systems, 2021

65. 65
System under Consideration
• R. Zaghloul, H. –C. Yang, T. Rakia, and M. -S. Alouini, “Space-Air-Ground FSO Networks for High-Throughput Satellite Communications", IEEE
Communication Magazine, 2022
• Y. Ata and M. -S. Alouini, “Performance of Integrated Ground-Air-Space FSO Networks in Various Turbulent Environments", IEEE Photonics
Journal 2022.

66. 66
Comparison Direct vs. Relayed Transmission

67. 67
Conclusion
• World’s dependence on air and space networks is growing at a fast paste for land, sea, and air end-user
terminals deployed in rural, post-disaster, aeronautical/maritime, or urban offloading broadband
communication scenarios
• An opportunity for FSO communication technology to capitalize on its unique advantages to enter this
expected mass market demands
• Emerging schemes for (i) adaptive optics, (ii) integrated space-air-ground networks, (iii) site and/or RF back-
up diversity, (iv) practical low-cost PAT systems, (v) optical waveform design, and (vi) in-house space
qualification for standard electronic/photonics to enable our global, reliable, and affordable broadband
connectivity holy grail objective.

68. Thank You
ctl.kaust.edu.sa
Nikola Tesla
(10 July 1856 – 7 January 1943)
“A telephone subscriber here may call
up and talk to any other subscriber on
the globe. An inexpensive receiver, not
bigger than a watch, will enable him to
listen anywhere, on land or sea, to a
speech delivered or music played in
some other place, however distant.”
― Nikola Tesla 1919