Sökning: "Kommunikationssystem"

Visar resultat 1 - 5 av 529 avhandlingar innehållade ordet Kommunikationssystem.

1. 1. Blind Massive MIMO Base Stations : Downlink Transmission and Jamming

   Författare :Marcus Karlsson; Erik G. Larsson; Emil Björnson; Ralf Müller; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Massive MIMO (Multiple-Input--Multiple-Output) is a cellular-network technology in which the base station is equipped with a large number of antennas and aims to serve several different users simultaneously, on the same frequency resource through spatial multiplexing. This is made possible by employing efficient beamforming, based on channel estimates acquired from uplink reference signals, where the base station can transmit the signals in such a way that they add up constructively at the users and destructively elsewhere. LÄS MER

3. 2. On Massive MIMO Base Stations with Low-End Hardware

   Författare :Christopher Mollén; Erik G. Larsson; Thomas Eriksson; Josef Nossek; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; massive MIMO; hardware; ADC; power amplifier; out-of-band radiation; peak-to-average ratio;

   Sammanfattning : Massive MIMO (Multiple-Input Multiple-Output) base stations have proven, both in theory and in practice, to possess many of the qualities that future wireless communication systems will require.  They can provide equally high data rates throughout their coverage area and can concurrently serve multiple low-end handsets without requiring wider spectrum, denser base station deployment or significantly more power than current base stations. LÄS MER

4. 3. Spectrum Sensing Algorithms Based on Second-Order Statistics

   Författare :Erik Axell; Erik G. Larsson; Jan-Åke Larsson; Danyo Danev; Visa Koivunen; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Cognitive radio is a new concept of reusing spectrum in an opportunistic manner. Cognitive radio is motivated by recent measurements of spectrum utilization, showing unused resources in frequency, time and space. Introducing cognitive radios in a primary network inevitably creates increased interference to the primary users. LÄS MER

5. 4. Aspects of Power Allocation in Massive MIMO

   Författare :Hei Victor Cheng; Erik G. Larsson; Daniel Persson; Emil Björnson; Carlo Fischione; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The past decades have seen a rapid growth of mobile data trac, both in terms of connected devices and data rate. To satisfy the ever growing data trac demand in wireless communication systems, the current cellular systems have to be redesigned to increase both spectral eciency and energy eciency. LÄS MER

7. 5. Optimizing Massive MIMO : Precoder Design and Power Allocation

   Författare :Hei Victor Cheng; Erik G. Larsson; Marius Pesavento; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The past decades have seen a rapid growth of mobile data traffic,both in terms of connected devices and data rate. To satisfy the evergrowing data traffic demand in wireless communication systems, thecurrent cellular systems have to be redesigned to increase both spectralefficiency and energy efficiency. LÄS MER