Sökning: "directional antenna"

Visar resultat 1 - 5 av 23 avhandlingar innehållade orden directional antenna.

1. 1. On MIMO Systems and Adaptive Arrays for Wireless Communication : Analysis and Practical Aspects

   Författare :Mattias Wennström; Michael A. Jensen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systemteknik; antenna array; calibration; MIMO system; flat fading; non-linear amplifier; switched parasitic antenna; analog beamformer; adaptive antenna testbed; Systemteknik; Systems engineering; Systemteknik; Signal Processing; signalbehandling;

   Sammanfattning : This thesis is concerned with the use of multiple antenna elements in wireless communication over frequency non-selective radio channels. Both measurement results and theoretical analysis are presented. New transmit strategies are derived and compared to existing transmit strategies, such as beamforming and space-time block coding (STBC). LÄS MER

3. 2. Robust Low-Cost Multiple Antenna Processing for V2V Communication

   Författare :Chouaib Bencheikh Lehocine; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Directional antennas; Beamforming; Multiple antennas; Periodic communication; Broadcast V2V communication; Hybrid combining;

   Sammanfattning : Cooperative V2V communication with frequent, periodic broadcast of messages between vehicles is a key enabler of applications that increase traffic safety and traffic efficiency on roads. Such broadcast V2V communication requires an antenna system with omnidirectional coverage, which is difficult to achieve using a single antenna element. LÄS MER

4. 3. Mathematical Models and Algorithms for Wireless Network Design and Optimization

   Författare :Yuan Li; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; max-min flow; directional antenna; optimization; integer programming; cellular backhaul network design; delay minimization; SINR; compatible set;

   Sammanfattning : Optimization techniques always play an important role in designing high-performance wireless systems. This presented thesis studies a selected set of optimization problems for different kinds of wireless networks, making use of mathematical programming techniques to find optimal solutions and of efficient heuristics to find near-optimal solutions. LÄS MER

5. 4. Combating Intersymbol Interference and Cochannel Interference in Wireless Communication Systems

   Författare :Ronnie Gustafsson; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ISI; CCI; wireless systems; beamforming; beam; simulation; fading; equalizer; channel; smart antenna; antenna array; recursive least squares RLS ; adaptive algorithms; blind algorithms;

   Sammanfattning : Over the last decade the world has witnessed explosive growth in the use of wireless mobile communications. Looking around we find users with mobile phones, wireless PDAs, pagers, MP3 players, and wireless headphones to connect to these devices - a small testament of the impact of wireless communications on our daily lives. LÄS MER

7. 5. On the Antenna-Channel Interactions: A Spherical Vector Wave Expansion Approach

   Författare :Andres Alayon Glazunov; Andreas F. Molisch; Michael A. Jensen; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antenna-channel interactions; wireless channels; MIMO; Antennas; propagation; spherical vector waves;

   Sammanfattning : The main focus of this thesis is the analysis of the interactions between antennas and channels where electromagnetic fields play a central role. Our goal has been to devise a general framework to enable a clear separation of the properties of the propagation channel from the influence of the antennas at the same time as it provides a common ground for a joint characterization of their properties. LÄS MER