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Summary: This paper presents the design, testing, and validation of a ultra‐wideband (UWB) wireless solution to replace wired intra‐spacecraft communications with wireless communications. The system requirements are provided in the framework of the Eu:CROPIS mission and the wired intra‐spacecraft communication system is replaced with a two‐segment wireless network. As such, distinct sets of UWB gateways and nodes are prototyped to interface with the on‐board entities and properly handle the data transmission in the resulting spacecraft and payload wireless networks. To accomplish these tasks, a custom radio module integrated into the prototypes was designed to provide the appropriate UWB RF front‐end and run a custom‐built communication stack. The viability of the solution was tested in laboratory conditions. For the test scenarios, sensor data are acquired in the payload network and forwarded as SpaceWire packets over the spacecraft network. Experimental test results indicate the suitability of the proposed solution in terms of delay and data integrity for implementing intra‐spacecraft wireless communications. [ABSTRACT FROM AUTHOR]

HF frequency band, lying within 1.6-30 MHz, is very important from data communications point of view and is unique in its property that it is refracted by the ionosphere. The main advantage of HF communications is their ability to enable data transmission over very long distances using ionospheric propagation paths without any preexisting infrastructure, making them suitable for many applications. This paper presents a detailed study regarding the modeling of a low latitudes and moderate conditions channel and its integration in an end-to-end system using the software environment VSS from National Instruments in co-simulation with MATLAB. This channel model considers that the channel fading is characterized by a Rayleigh distribution, which assumes that the magnitude of a signal passing through a communications channel will vary randomly. The ionospheric channel model is simulated through the MATLAB block, using the specific parameters of the low latitudes and moderate conditions channel, according to the Recommendation ITU-R F.1487. The simulation results illustrate the received signal attenuation level at the receiver after its propagation through the modeled ionospheric HF channel. [ABSTRACT FROM AUTHOR]

The scope of this paper is to provide a method to determine the variation of the TEC of the Ionosphere by means of GPS received signals. The solution makes use of dual carrier phase and pseudo-range measurements from a terrestrial receiver, stored in specific RINEX files. The implemented algorithm processes the data and provides the variation of TEC and TEC gradient. For a considered period of time, the TEC variation indicates the behavior of the Ionosphere allowing a better modeling of the radio channel. [ABSTRACT FROM AUTHOR]

In wireless communication systems the resource management needs to integrate adaptive techniques to the varying network conditions, due to the eventual dramatic changes that may occur in the link quality. Therefore, it may be desirable to support adaptable resource management techniques that are able to find their decisions in the network configuration information or in the source application description. Accordingly, the paper identifies, explores and proposes adaptive techniques for resource management so as to enhance the transmission quality on wireless systems either through a feedback channel or by making use of the network virtualization concept. Setting up dependencies between the application requests and the radio channel conditions, a feedback loop adaptively configures modulation and coding schemes, calibrates multi-antenna system, controls power per beam allocation or invokes a linear precoding. Finally, when the application requests exceed the network capacity, by the network virtualization process the adaptive potential of the application parameters can be employed, either through source fragmentation or source code adaptation. [ABSTRACT FROM AUTHOR]