Firmware de seleção de célula para redes 5G não-terrestres

The integration of satellite technology in 5G will enable networks to become more ubiquitous and reliable, extending coverage to previously underserved areas and making the network more resilient to natural catastrophes. The nonterrestrial networks (NTN) are expected to co-exist with the current terrestrial infrastructures, sharing much of the same requirements. This in turn will allow the User Equipment to connect to both, opening up new use cases and possibilities. The intent of this dissertation is to design a firmware that prepares these devices to take advantage of this new paradigm. This firmware implements an extended, radio access and backhaul-aware cell selection scheme, that chooses either to connect to terrestrial or non-terrestrial cells. The selection is based on metrics, such as, the latency and packet loss of the link, in addition to the traditional signal strength indicators. Testing the solution required deploying an end-to-end 5G network which includes not only a gNodeB (gNB) capable of simulating the propagation delay induced by long distances but also a terrestrial node. This deployment uses the OpenAirInterface (OAI) 5G software stack. With the use of this testbench, the implemented firmware was tested against key network degradation scenarios. These scenarios include, for example, the total failure of the terrestrial gNB and the steady increase of latency. The results show that this use of the firmware might help upkeep the quality of service for the User Equipment using it.A integração de tecnologias satélite nas redes 5G vai permitir que estas se tornem mais seguras e omnipresentes, estendendo a cobertura de forma a abranger áreas remotas e tornando estas redes mais resilientes contra catástrofes naturais. É expectado que as redes não-terrestres venham a coexistir com as atuais redes terrestres, partilhando os mesmos requisitos. Por sua vez isto vai permitir que os terminais se conectem a ambos, abrindo assim novas possibilidades e casos de uso. Com esta dissertação pretende-se projetar um firmware que prepare estes dispositivos para tomar partido deste novo paradigma. Este firmware funciona como uma versão estendida, ciente do backhaul, do esquema de cell selection, de forma a que este possa decidir entre conectar cells terrestres ou não terrestres. Esta decisão é informada por métricas como a latência e a perda de pacotes da ligação, além dos indicadores de força de sinal tradicionais. Para a validação desta solução foi necessário a instalação de uma rede 5G end-to-end que incluísse tanto um gNodeB (gNB) capaz de simular atraso de propagação induzido pelas longas distâncias, tal como um nó terrestre. Esta instalação usa o OpenAirInterface (OAI), uma implementação da stack 5G. Usando esta testbench, a implementação do firmware projetado foi testada face a cenários de degradação da rede. Estes incluem, por exemplo, a falha total do gNB terrestre ou um aumento crescente da latência. Os resultados obtidos mostram que o uso deste firmware poderá ajudar a manter a qualidade de serviço de um terminal que o utilize.Mestrado em Engenharia de Computadores e Telemátic

Operations for parallel satellite support

In the early preparation phase for the upcoming robotic dual-satellite DLR mission several technical and operational challenges presented themselves. The mission itself shall produce advanced scientific findings for the on-orbit servicing missions. One of the satellites includes a sophisticated robotic arm with automated as well as manual operation modes. Very restrictive robotic payload requirements with respect to ground station visibilities as well as the quality of the data link became a main driver for the ground data system design. The real-time control and feedback of the robotic arm represents the particular challenge. Analysis of these requirements as well as technical and operational solutions will be presented, whereas some results are based on the successful ROKVISS mission. The usage of a dual-uplink antenna is discussed with regard to parallel operations of two satellites, here again, with already existing results provided by operations of the TanDEM-X mission. The design of the ground communication network as well as possible solutions allowing parallel robotic and housekeeping operations is shown. Results of this mission analysis and preparation are not only valuable for particular robotic, but for all dual-satellite, high data rate or realtime communication missions

Customer premise service study for 30/20 GHz satellite system

Satellite systems in which the space segment operates in the 30/20 GHz frequency band are defined and compared as to their potential for providing various types of communications services to customer premises and the economic and technical feasibility of doing so. Technical tasks performed include: market postulation, definition of the ground segment, definition of the space segment, definition of the integrated satellite system, service costs for satellite systems, sensitivity analysis, and critical technology. Based on an analysis of market data, a sufficiently large market for services is projected so as to make the system economically viable. A large market, and hence a high capacity satellite system, is found to be necessary to minimize service costs, i.e., economy of scale is found to hold. The wide bandwidth expected to be available in the 30/20 GHz band, along with frequency reuse which further increases the effective system bandwidth, makes possible the high capacity system. Extensive ground networking is required in most systems to both connect users into the system and to interconnect Earth stations to provide spatial diversity. Earth station spatial diversity is found to be a cost effective means of compensating the large fading encountered in the 30/20 GHz operating band

Chapter Tactical Communications for Cooperative SAR Robot Missions

This chapter describes how the ICARUS communications (COM) team defined, developed and implemented an integrated wireless communication system to ensure an interoperable and dependable networking capability for both human and robotic search and rescue field teams and crisis managers. It starts explaining the analysis of the requirements and the context of the project, the existing solutions and the design of the ICARUS communication system to fulfil all the project needs. Next, it addresses the implementation process of the required networking capabilities, and finally, it explains how the ICARUS communication system and associated tools have been integrated in the overall mission systems and have been validated to provide reliable communications for real‐time information sharing during search and rescue operations in hostile conditions

Tactical Communications for Cooperative SAR Robot Missions

This chapter describes how the ICARUS communications (COM) team defined, developed and implemented an integrated wireless communication system to ensure an interoperable and dependable networking capability for both human and robotic search and rescue field teams and crisis managers. It starts explaining the analysis of the requirements and the context of the project, the existing solutions and the design of the ICARUS communication system to fulfil all the project needs. Next, it addresses the implementation process of the required networking capabilities, and finally, it explains how the ICARUS communication system and associated tools have been integrated in the overall mission systems and have been validated to provide reliable communications for real‐time information sharing during search and rescue operations in hostile conditions

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications