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Visar resultat 1 - 5 av 45 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Pulse Shape Adaptation and Channel Estimation in Generalised Frequency Division Multiplexing Systems

   Författare :Jinfeng Du; Svante Signell; Ben Slimane; Arne Svenssons; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; OFDM; GFDM; OQAM; pulse shaping; adaptation; channel estimation; Electronics; Elektronik;

   Sammanfattning : Orthogonal Frequency Division Multiplexing (OFDM) is well known as an efficient technology for wireless communications and is widely used in many of the current and upcoming wireless and wireline communication standards. However, it has some intrinsic drawbacks, e.g. LÄS MER

3. 2. Diversity and Interference Aspects in the Downlink of Code Division Multiple Access Systems

   Författare :Anders Persson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; orthogonal frequency division multiplexing; multi-carrier modulation; Rayleigh-fading channels; code division multiple access; frequency-selective channels; multiple access interference; diversity;

   Sammanfattning : This thesis consists of six included papers and technical reports, plus an introduction. The topic studied is interference and diversity aspects in code division multiple access (CDMA) systems for mobile cellular communications. The focus in the papers is on the downlink - the communication link from the base station to the mobile terminal. LÄS MER

4. 3. Massive Multi-Antenna Communications with Low-Resolution Data Converters

   Författare :Sven Jacobsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; orthogonal frequency-division multiplexing; channel estimation; quantization; linear precoding; convex optimization; nonlinear precoding; linear combing; hardware impairments; analog-to-digital converter; beamforming; Massive multi-user multiple-input multiple-output; digital-to-analog converter;

   Sammanfattning : Massive multi-user (MU) multiple-input multiple-output (MIMO) will be a core technology in future cellular communication systems. In massive MU-MIMO systems, the number of antennas at the base station (BS) is scaled up by several orders of magnitude compared to traditional multi-antenna systems with the goals of enabling large gains in capacity and energy efficiency. LÄS MER

5. 4. Nonlinearity in Broadband Wireless Communication Systems

   Författare :Ali Behravan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; baseband predistortion; single carrier modulation; orthogonal frequency division multiplexing OFDM ; bandpass nonlinearity; multicarrier modulation; nonlinearity distortion; high power amplifier; RF predistortion; peak to average power ratio PAPR ; baseband nonlinearity;

   Sammanfattning : In the implementation of a digital communication system, there often exist imperfections that are not considered in the primary design. One such imperfection is the nonlinearity of the front-end devices. LÄS MER

7. 5. On Receiver Algorithms for OFDM Systems

   Författare :Florent Munier; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; quantisation; multicarrier modulation; Intercarrier Interference ICI ; Phase noise; Wiener process; orthogonal frequency division multiplexing OFDM ; estimation; fading channels; channel estimation; iterative decoding.;

   Sammanfattning : This thesis addresses the problem of designing a receiver for an Orthogonal FrequencyDivisionMultiplexing (OFDM)communication system operating over fading channels, taking into account the effects of hardware imperfections. We discuss solutions for efficiently estimating the parameters of a channel model and for compensating oscillator phase noise and analog to digital converter (ADC) quantisation errors at the receiver. LÄS MER