Sökning: "wireless communications"

Visar resultat 21 - 25 av 269 avhandlingar innehållade orden wireless communications.

1. 21. Behavioral modeling of wireless transmitters for distortion mitigation

   Författare :Ali Soltani Tehrani; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear models; wireless communications.; computational complexity; I Q imbalance; digital predistortion; Volterra series; transmitter; power amplifier; Behavioral modeling;

   Sammanfattning : As the demand for high speed and reliable wireless communication increases, theimportance of having a linear transmitter has enhanced. Distortions created by thetransmitter, such as power amplifier nonlinearity and I/Q imbalance, diminish thefidelity and limit the performance of wireless systems, if left undealt with. LÄS MER

3. 22. The ubiquitous signal processing : Applications to communications, spectral analysis and array processing

   Författare :Erik G. Larsson; Björn Ottersten; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; digital signal processing; array processing; spectral analysis; incomplete data; wireless communications; space-time coding; synthetic aperture radar imaging; signal separation; estimation; detection; Signal processing; Signalbehandling; Signal Processing; Signalbehandling;

   Sammanfattning : This dissertation is concerned with statistical signal processing and its applications. The thesis consists of three parts: I) applications to wireless communications, II) applications to spectral analysis and III) applications to array processing. LÄS MER

4. 23. High-efficiency Power Amplification Techniques for Wireless Transmitters

   Författare :Hossein Mashad Nemati; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; load modulation; LDMOS; supply modulation; GaN HEMT; Power amplifier; wireless communications.; GaAs mHEMT; efficiency;

   Sammanfattning : The low efficiency of existing power amplifiers (PAs) is causing excessive energy consumption in wireless systems. Improving the PA efficiency is therefore of great environmental and economical importance. LÄS MER

5. 24. Mobility and Multi-channel Communications in Low-power Wireless Networks

   Författare :António Gonga; Mikael Johansson; Riku Jäntti; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mobility; Multi-channel communications; Neighbor Discovery; MAC Protocols; Low-power Wireless Networks; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : The prospect of replacing existing fixed networks with cheap, flexible and evenmobile low-power wireless network has been a strong research driver in recent years.However, many challenges still exist: reliability is hampered by unstable and burstycommunication links; the wireless medium is getting congested by an increasingnumber of wireless devices; and life-times are limited due to difficulties in developingefficient duty-cycling mechanisms. LÄS MER

7. 25. Signaling for Optical Intensity Channels

   Författare :Johnny Karout; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lattice codes; mutual information; intensity modulation; noncoherent communications; Direct detection; sphere packing.; infrared communications; free-space optical communications; fiber-optical communications;

   Sammanfattning : With the growing popularity of social media services, e-commerce, and many other internet-based services, we are witnessing a rapid growth in the deployment of data centers and cloud computing platforms. As a result, the telecommunications industry has to continue providing additional network capacity to meet the increasing demand for bandwidth. LÄS MER