Sökning: "Base station antennas"

Visar resultat 6 - 10 av 56 avhandlingar innehållade orden Base station antennas.

  1. 6. Mobile cellular communications with base station antenna arrays

    Författare :Per Zetterberg; KTH; []
    Nyckelord :;

    Sammanfattning : This thesis deals with the problem of increasing thespectrum efflciency of cellular systems by the use of antennaarray base stations. The focus of the thesis is on downlinktransmission in frequency division duplex systems. i.e. LÄS MER

  3. 7. Moment Method Analysis of Antennas on Cylindrical Structures by Using G2DMULT and Design of Hat Fed Reflector Antennas

    Författare :Jian Yang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; G2DMULT; reflector antenna; paraboloid; dipole; base station antenna; screw heads; vertex plate; self impedance; G1DMULT; ring-shaped phase center; radiation efficiency; FDTD; cylindrical structures; V2D; ring-focus; moment method;

    Sammanfattning : This thesis deals with two aspects of research interest: moment method analysis of antennas on cylindrical structures by using G2DMULT, and design of hat fed reflector antennas. Both of them are two-dimensional (2D) structure problems, one being cylindrical and the other rotationally symmetric. LÄS MER

  4. 8. Scheduling and Base-Station Cooperation in MIMO Downlink Systems

    Författare :Nima Seifi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Multiple input multiple output (MIMO) techniques have been shown to improvethe capacity and link reliability of wireless communication without a need to extrapower and bandwidth. In multi-user (MU) MIMO networks, a linear increaseof sum capacity in the number of transmit antennas can be achieved by usinglinear precoding combined with efficient scheduling algorithms. LÄS MER

  5. 9. 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

  7. 10. Wireless Communication with Medical Implants: Antennas and Propagation

    Författare :Anders J Johansson; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; medical implant communication; electromagnetic propagation; biomedical telemetry; antennas in matter; MICS; Electronics; Elektronik;

    Sammanfattning : With the increased sophistication of medical implants, there is a growing need for flexible high-speed communication with the implant from outside the body. Today the communication is done by an inductive link between the implant and an external coil at a low carrier frequency. LÄS MER