227 research outputs found
Spiking Neural Networks for Detecting Satellite-Based Internet-of-Things Signals
With the rapid growth of IoT networks, ubiquitous coverage is becoming
increasingly necessary. Low Earth Orbit (LEO) satellite constellations for IoT
have been proposed to provide coverage to regions where terrestrial systems
cannot. However, LEO constellations for uplink communications are severely
limited by the high density of user devices, which causes a high level of
co-channel interference. This research presents a novel framework that utilizes
spiking neural networks (SNNs) to detect IoT signals in the presence of uplink
interference. The key advantage of SNNs is the extremely low power consumption
relative to traditional deep learning (DL) networks. The performance of the
spiking-based neural network detectors is compared against state-of-the-art DL
networks and the conventional matched filter detector. Results indicate that
both DL and SNN-based receivers surpass the matched filter detector in
interference-heavy scenarios, owing to their capacity to effectively
distinguish target signals amidst co-channel interference. Moreover, our work
highlights the ultra-low power consumption of SNNs compared to other DL methods
for signal detection. The strong detection performance and low power
consumption of SNNs make them particularly suitable for onboard signal
detection in IoT LEO satellites, especially in high interference conditions
LoRa-based Over-the-Air Computing for Sat-IoT
Satellite Internet of Things (Sat-IoT) is a novel framework in which
satellites integrate sensing, communication and computing capabilities to carry
out task-oriented communications. In this paper we propose to use the Long
Range (LoRa) modulation for the purpose of estimation in a Sat-IoT scenario.
Then we realize that the collisions generated by LoRa can be harnessed in an
Over-the-Air Computing (AirComp) framework. Specifically, we propose to use
LoRa for Type-based Multiple Access (TBMA), a semantic-aware scheme in which
communication resources are assigned to different parameters, not users. Our
experimental results show that LoRa-TBMA is suitable as a massive access
scheme, provides large gains in terms of mean squared error (MSE) and saves
scarce satellite communication resources (i.e., power, latency and bandwidth)
with respect to orthogonal multiple access schemes. We also analyze the
satellite scenarios that could take advantage of the LoRa-TBMA scheme. In
summary, that angular modulations, which are very useful in satellite
communications, can also benefit from AirComp.Comment: Paper accepted in 2023 European Signal Processing Conference
(EUSIPCO
A COMPREHENSIVE REVIEW OF INTERNET OF THINGS WAVEFORMS FOR A DOD LOW EARTH ORBIT CUBESAT MESH NETWORK
The Department of Defense (DOD) requires the military to provide command and control during missions in locations where terrestrial communications infrastructure is unreliable or unavailable, which results in a high reliance on satellite communications (SATCOM). This is problematic because they use and consume more digital data in the operational environment. The DOD has several forms of data capable of meeting Internet of Things (IoT) transmission parameters that could be diversified onto an IoT network. This research assesses the potential for an IoT satellite constellation in Low Earth Orbit to provide an alternative, space-based communication platform to military units while offering increased overall SATCOM capacity and resiliency. This research explores alternative IoT waveforms and compatible transceivers in place of LoRaWAN for the NPS CENETIX Ortbial-1 CubeSat. The study uses a descriptive comparative research approach to simultaneously assess several variables. Five alternative waveformsâSigfox, NB-IoT, LTE-M, Wi-sun, and Ingenuâare evaluated. NB-IoT, LTE-M, and Ingenu meet the threshold to be feasible alternatives to replace the LoRaWAN waveform in the Orbital-1 CubeSat. Six potential IoT transceivers are assessed as replacements. Two transceivers for the NB-IoT and LTE-M IoT waveforms and one transceiver from U-blox for the Ingenu waveform are assessed as compliant.Lieutenant, United States NavyApproved for public release. Distribution is unlimited
Quasisynchronous LoRa for LEO nanosatellite communications
Perfect synchronization in LoRa communications between Low Earth Orbit (LEO) satellites and ground base stations is still challenging, despite the potential use of atomic clocks in LEO satellites, which offer high precision. Even by incorporating atomic clocks in LEO satellites, their inherent precision can be leveraged to enhance the overall synchronization process, perfect synchronization is infeasible due to a combination of factors such as signal propagation delay, Doppler effects, clock drift and atmospheric effects. These challenges require the development of advanced synchronization techniques and algorithms to mitigate their effects and ensure reliable communication from / to LEO satellites. However, maintaining acceptable levels of synchronization rather than striving for perfection, quasisynchronous (QS) communication can be adopted which maintains communication reliability, improves resource utilization, reduces power consumption, and ensures scalability as more devices join the communication. Overall, QS communication offers a practical, adaptive, and robust solution that enables LEO satellite communications to support the growing demands of IoT applications and global connectivity. In our investigation, we explore different chip waveforms such as rectangular and raised cosine. Furthermore, for the first time, we study the Symbol Error Rate (SER) performance of QS LoRa communication, for different spreading factors (SF), over Additive White Gaussian Noise (AWGN) channels.IEEE Communications Societ
Integrated Satellite-terrestrial networks for IoT: LoRaWAN as a Flying Gateway
When the Internet of Things (IoT) was introduced, it causes an immense change in
human life. Recently, different IoT emerging use cases, which will involve an even higher
number of connected devices aimed at collecting and sending data with different purposes
and over different application scenarios, such as smart city, smart factory, and smart
agriculture. In some cases, the terrestrial infrastructure is not enough to guarantee the
typical performance indicators due to its design and intrinsic limitations. Coverage is
an example, where the terrestrial infrastructure is not able to cover certain areas such
as remote and rural areas. Flying technologies, such as communication satellites and
Unmanned Aerial Vehicles (UAVs), can contribute to overcome the limitations of the
terrestrial infrastructure, offering wider coverage, higher resilience and availability, and
improving user\u2019s Quality of Experience (QoE). IoT can benefit from the UAVs and satellite
integration in many ways, also beyond the coverage extension and the increase of the
available bandwidth that these objects can offer. This thesis proposes the integration
of both IoT and UAVs to guarantee the increased coverage in hard to reach and out of
coverage areas. Its core focus addresses the development of the IoT flying gateway and
data mule and testing both approaches to show their feasibility.
The first approach for the integration of IoT and UAV results in the implementing of
LoRa flying gateway with the aim of increasing the IoT communication protocols\u2019
coverage area to reach remote and rural areas. This flying gateway examines the
feasibility for extending the coverage in a remote area and transmitting the data to the IoT cloud in real-time. Moreover, it considers the presence of a satellite between the
gateway and the final destination for areas with no Internet connectivity and
communication means such as WiFi, Ethernet, 4G, or LTE. The experimental results
have shown that deploying a LoRa gateway on board a flying drone is an ideal option
for the extension of the IoT network coverage in rural and remote areas.
The second approach for the integration of the aforementioned technologies is the
deployment of IoT data mule concept for LoRa networks. The difference here is the
storage of the data on board of the gateway and not transmitting the data to the IoT
cloud in real time. The aim of this approach is to receive the data from the LoRa
sensors installed in a remote area, store them in the gateway up until this flying
gateway is connected to the Internet. The experimental results have shown the
feasibility of our flying data mule in terms of signal quality, data delivery, power
consumption and gateway status.
The third approach considers the security aspect in LoRa networks. The possible
physical attacks that can be performed on any LoRa device can be performed once its
location is revealed. Position estimation was carried out using one of the LoRa signal
features: RSSI. The values of RSSI are fed to the Trilateration localization algorithm to
estimate the device\u2019s position. Different outdoor tests were done with and without the
drone, and the results have shown that RSSI is a low cost option for position estimation
that can result in a slight error due to different environmental conditions that affect
the signal quality.
In conclusion, by adopting both IoT technology and UAV, this thesis advances the
development of flying LoRa gateway and LoRa data mule for the aim of increasing the
coverage of LoRa networks to reach rural and remote areas. Moreover, this research
could be considered as the first step towards the development of high quality and
performance LoRa flying gateway to be tested and used in massive LoRa IoT networks
in rural and remote areas
UAV Command and Control, Navigation and Surveillance: A Review of Potential 5G and Satellite Systems
Drones, unmanned aerial vehicles (UAVs), or unmanned aerial systems (UAS) are
expected to be an important component of 5G/beyond 5G (B5G) communications.
This includes their use within cellular architectures (5G UAVs), in which they
can facilitate both wireless broadcast and point-to-point transmissions,
usually using small UAS (sUAS). Allowing UAS to operate within airspace along
with commercial, cargo, and other piloted aircraft will likely require
dedicated and protected aviation spectrum at least in the near term, while
regulatory authorities adapt to their use. The command and control (C2), or
control and non-payload communications (CNPC) link provides safety critical
information for the control of the UAV both in terrestrial-based line of sight
(LOS) conditions and in satellite communication links for so-called beyond LOS
(BLOS) conditions. In this paper, we provide an overview of these CNPC links as
they may be used in 5G and satellite systems by describing basic concepts and
challenges. We review new entrant technologies that might be used for UAV C2 as
well as for payload communication, such as millimeter wave (mmWave) systems,
and also review navigation and surveillance challenges. A brief discussion of
UAV-to-UAV communication and hardware issues are also provided.Comment: 10 pages, 5 figures, IEEE aerospace conferenc
Emulating the Doppler-Shift for LoRa based Low Earth Orbit Satellite Communication
This project investigates the adverse effects of the Doppler Shift on a LoRa waveform transmitted from a Low Earth Orbit Satellite or LEOSAT. This work is on behalf of Project OWL, who will use these results to justify further investment into developing a LEOSAT for their communication network. Part of the project is to design a test setup to replicate the Doppler Shift in the lab. The Doppler shift replication setup distorts the transmitted waveform, similar to how the signal gets distorted if sent from a LEOSAT. The test setup will comprise both software and hardware control, wherein software, the user provides a center frequency of transmission, LEOSAT orbital altitude, and maximum range of signal transmission. Once given test parameters, the software will calculate the Doppler shift as the satellite travels overhead, then send information to hardware that modulates the output of one of Project OWLâs radios to apply the Doppler shift to a transmission. The software will monitor another radio receiver, and determine if communication is theoretically possible from a LEOSAT to one of their radios
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