Link budget analysis for satellite-based narrowband IoT systems

Scientific Conference (2019)

Physical layer security over fading wiretap channels through classic coded transmissions with finite block length and discrete modulation

in Physical Communication (2019)

Theoretical Analysis and Implementation of Effective Receivers for Telecommand Space Links

in 2019 8th International Workshop on Tracking, Telemetry and Command Systems for Space Applications (TTC) (2019)

Deploying Joint Beamforming and Precoding in Multibeam Satellite Networks with Time Variant Traffic

in IEEE Global Conference on Signal and Information Processing (GlobalSIP), Anaheim, California, USA (2018, November)

Resource Allocation Approach for Differential Doppler Reduction in NB-IoT over LEO Satellite

in 9th Advanced Satellite Multimedia Systems Conference (ASMS) and 15th Signal Processing for Space Communications Workshop (SPSC), Berlin, Germany, 10-12 September 2018 (2018)

Internet of things (IoT) over satellite is an attractive system architecture which has been proposed as a key-enabling technology, to extend the coverage in remote areas (e.g. desert, ocean, forest, etc ... [more ▼]

Internet of things (IoT) over satellite is an attractive system architecture which has been proposed as a key-enabling technology, to extend the coverage in remote areas (e.g. desert, ocean, forest, etc), particularly where a terrestrial network is impossible or impractical to reach. One of the most promising technologies that fit the IoT vision of low-power, wide area networks (LPWAN) is the narrowband IoT (NB-IoT). While low earth orbit (LEO) satellites are favourable because of their lower round trip time (RTT) and lower propagation loss in the communication link, they come up with a significantly increased Doppler shift. In our NB-IoT over LEO satellite architecture, we identify the problem of high differential Doppler among channels of different users on Earth, which leads to the performance degradation of our system. In this paper, we propose a resource allocation approach in order to reduce the high values of differential Doppler under the maximum value supported by the standard itself. [less ▲]

Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites

in IEEE Transactions on Vehicular Technology (2018)

Satellite Communication systems are a promising solution to extend and complement terrestrial networks in unserved or under-served areas. This aspect is reflected by recent commercial and standardisation ... [more ▼]

Satellite Communication systems are a promising solution to extend and complement terrestrial networks in unserved or under-served areas. This aspect is reflected by recent commercial and standardisation endeavours. In particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G, Non-Terrestrial Networks aimed at deploying satellite systems either as a stand-alone solution or as an integration to terrestrial networks in mobile broadband and machine-type communication scenarios. However, typical satellite channel impairments, as large path losses, delays, and Doppler shifts, pose severe challenges to the realisation of a satellite-based NR network. In this paper, based on the architecture options currently being discussed in the standardisation fora, we discuss and assess the impact of the satellite channel characteristics on the physical and Medium Access Control layers, both in terms of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB) and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis shows that the main technical challenges are related to the PHY/MAC procedures, in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic Repeat reQuest (HARQ) and, depending on the considered service and architecture, different solutions are proposed. [less ▲]