Browsing NTNU Open by Author "Ekman, Torbjörn"

Now showing items 1-10 of 10

    • Cluster Based MIMO Radio Channel Modeling 

      Li, Xin (Doctoral theses at NTNU;2020:379, Doctoral thesis, 2020)
      Modeling of wireless channels is perhaps the most complex task in implementing a wireless communication system because wireless channels change over time, vary with frequency and space. That is, the transmit signal with ...

    • Design of a practical and compact mm-wave MIMO system with optimized capacity and phased arrays 

      Cella, Tommaso; Orten, Pål; Ekman, Torbjörn (Journal article; Peer reviewed, 2014)
      In this paper we evaluate the feasibility of short range outdoor mm-wave MIMO links in the 70 GHz portion of the E-band (71–76 GHz). We use phased arrays in order to strongly reduce the impact of the multipath components, ...

    • Effective Channel Hardening in an Indoor Multiband Scenario 

      Ghiaasi, Golsa; Abraham, Jens; Eide, Egil; Ekman, Torbjörn (Journal article; Peer reviewed, 2019)
      We evaluate channel hardening for a large scale antenna system by means of indoor channel measurements over four frequency bands, 1.472 GHz, 2.6 GHz, 3.82 GHz and 4.16 GHz. NTNU’s Reconfgurable Radio Network Platform has ...

    • In-orbit Interference Measurements and Analysis in the VDES-band with the NorSat-2 Satellite 

      Quintana Díaz, Gara; Birkeland, Roger; Løge, Lars; Andersen, Even; Bolstad, Anton; Ekman, Torbjörn (Peer reviewed; Journal article, 2022)
      Maritime activity in the Arctic is increasing, triggering a need for better communication infrastructure. With limited terrestrial infrastructure available, satellite services are essential for distributing maritime safety ...

    • In-orbit measurements and analysis of radio interference in the UHF amateur radio band from the LUME-1 satellite 

      Quintana Díaz, Gara; Ekman, Torbjörn; Lago Agra, José Miguel; Hurtado de Mendoza, Diego; González Muíño, Alberto; Agelet, Fernando Aguado (Journal article; Peer reviewed, 2021)

    • Increasing sum-rate in large-scale cognitive radio networks by centralized power and spectrum allocation 

      Vijayandran, Luxmiram; Byun, Sang-Soon; Øien, Geir Egil; Ekman, Torbjörn (Journal article; Peer reviewed, 2012)
      We revisit the widely investigated problem of maximizing the centralized sum-rate capacity in a cognitive radio network. We consider an interference-limited multi-user multi-channel environment, with a transmit sum-power ...

    • Methods for Finite Massive MIMO Analysis 

      Abraham, Jens (Doctoral thesis, 2022)
      Massive MIMO is a core technology for 5G cellular networks, that matured from a concept to commercial implementations over the last decade. It uses large-scale antenna systems to provide unprecedented access to the spatial ...

    • A Multi-purpose Software Defined Radio Payload for the HYPSO-2 Satellite 

      Birkeland, Roger; Quintana Díaz, Gara; Honoré-Livermore, Evelyn; Ekman, Torbjörn; Agelet, Fernando Aguado; Johansen, Tor Arne (Peer reviewed; Journal article, 2022)
      Recent developments in flexible Software Defined Radio (SDR) platforms provide researchers with a framework for small satellite missions that combine several parallel objectives. A part of the mission for the HYPer-spectral ...

    • Satellite uplink interference measurements in the 437 MHz UHF amateur radio band onboard LUME-1 

      Quintana Diaz, Gara; Ekman, Torbjörn; Camanzo, Alejandro; Birkeland, Roger; Lago, José Miguel; Muíño, Alberto González; Aguado, Fernando (Peer reviewed; Journal article, 2023)
      Satellite operators struggle to communicate with their satellites over Europe in the UHF amateur band (430–440 MHz) due to high power in-orbit interference. Statistical characterisation of the interference beyond average ...

    • Statistics of the Effective Massive MIMO Channel in Correlated Rician Fading 

      Abraham, Jens; Ramírez-Espinosa, Pablo; Ekman, Torbjörn (Peer reviewed; Journal article, 2022)
      Massive multiple-input multiple-output base stations use multiple spatial diversity branches, which are often assumed to be uncorrelated in theoretical work. Correlated branches are seldom considered since they are ...