3 research outputs found
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
Inter-Plane Inter-Satellite Connectivity in LEO Constellations: Beam Switching vs. Beam Steering
Low Earth orbit (LEO) satellite constellations rely on inter-satellite links (ISLs) to provide global connectivity. However, one significant challenge is to establish and maintain inter-plane ISLs, which support communication between different orbital planes. This is due to the fast movement of the infrastructure and to the limited computation and communication capabilities on the satellites. In this paper, we make use of antenna arrays with either Butler matrix beam switching networks or digital beam steering to establish the inter-plane ISLs in a LEO satellite constellation. Furthermore, we present a greedy matching algorithm to establish inter-plane ISLs with the objective of maximizing the sum of rates. This is achieved by sequentially selecting the pairs, switching or pointing the beams and, finally, setting the data rates. Our results show that, by selecting an update period of 30 seconds for the matching, reliable communication can be achieved throughout the constellation, where the impact of interference in the rates is less than 0.7 % when compared to orthogonal links, even for relatively small antenna arrays. Furthermore, doubling the number of antenna elements increases the rates by around one order of magnitude.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Cross Layer Optimization of Wireless Control Links in the Software-Defined LEO Satellite Network
The low earth orbit (LEO) satellite network can benefit from software-defined networking (SDN) by lightening forwarding devices and improving service diversity. In order to apply SDN into the network, however, reliable SDN control links should be associated from satellite gateways to satellites, with the wireless and mobile properties of the network taken into account. Since these characteristics affect both control link association and gateway power allocation, we define a new cross layer SDN control link problem. To the best of our knowledge, this is the first attempt to explore the cross layer control link problem for the software-defined satellite network. A logically centralized SDN control framework constrained by maximum total power is introduced to enhance gateway power efficiency for control link setup. Based on the power control analysis of the problem, a power-efficient control link algorithm is developed, which establishes low latency control links with reduced power consumption. Along with the sensitivity analysis of the proposed control link algorithm, numerical results demonstrate low latency and high reliability of control links established by the algorithm, ultimately suggesting the feasibility, both technical and economical, of the software-defined LEO satellite network. © 2019 BMJ Publishing Group. All rights reserved.1