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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Multiple-Input Multiple-Output Systems for Spinning Vehicles

Petersen, Samuel 10 1900 (has links)
ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / This paper investigates the performance of a multiple-input multiple-output (MIMO) digital communication system, when the transmitter is located on a spinning vehicle. In particular, a 2x2 MIMO system is used, with Alamouti coding at the transmitter. Both Rayleigh and Rayleigh plus line-of-sight, or Rician, models combined with a deterministic model to simulate the channel. The spinning of the transmitting vehicle, relative to the stationary receive antennas, modulates the signal, and complicates the decoding and channel parameter estimation processes. The simulated system bit error rate is the primary performance metric used. The Alamouti channel code is shown to perform better than the maximal ratio receiver combining (MRRC) and single receiver (2x1) system in some circumstances and performs similarly to the MRRC in the broadside case.
2

PERFORMANCE STUDY OF ENHANCED FQPSK AND CONSTRAINED ENVELOPE MODULATION TECHNIQUES

Borah, Deva K., Horan, Stephen 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / This paper investigates the spectral properties and the bit error rate (BER) performance of enhanced FQPSK (EFQPSK) and constrained envelope modulation (CEM) techniques. Both the techniques are found to provide good spectral efficiencies. The EFQPSK signals are found to generate spectral lines for unbalanced data. An analytical spectral study for the spectral lines is presented. While the performance of CEM techniques has been presented in [6] for an ideal nonlinear amplifier, we present results for more realistic amplifiers with AM/AM and AM/PM effects. It is shown that such an amplifier generates spectral regrowth and a predistorter is required to reduce the adverse effects. A BER performance study with/without channel coding is also presented for the two techniques.
3

Modular Field Programmable Gate Array Implementation of a MIMO Transmitter

Shekhar, Richa 10 1900 (has links)
ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / Multiple-Input Multiple-Output (MIMO) systems have at least two transmitting antennas, each generating unique signals. However some applications may require three, four, or more transmitting devices to achieve the desired system performance. This paper describes the design of a scalable MIMO transmitter, based on field programmable gate array (FPGA) technology. Each module contains a FPGA, and associated digital-to-analog converters, I/Q modulators, and RF amplifiers needed to power one of the MIMO transmitters. The system was designed to handle up to a 10 Mbps data rate, and transmit signals in the unlicensed 2.4 GHz ISM band.
4

BINARY GMSK: CHARACTERISTICS AND PERFORMANCE

Tsai, Kuang, Lui, Gee L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Gaussian Minimum Shift Keying (GMSK) is a form of Continuous Phase Modulation (CPM) whose spectral occupancy can be easily tailored to the available channel bandwidth by a suitable choice of signal parameters. The constant envelope of the GMSK signal enables it to corporate with saturated power amplifier without the spectral re-growth problem. This paper provides a quantitative synopsis of binary GMSK signals in terms of their bandwidth occupancy and coherent demodulation performance. A detailed account of how to demodulate such signals using the Viterbi Algorithm (VA) is given, along with analytical power spectral density (PSD) and computer simulated bit-error-rate (BER) results for various signal BT products. The effect of adjacent channel interference (ACI) is also quantified. Ideal synchronization for both symbol time and carrier phase is assumed.
5

FLEXIBLE ALL-DIGITAL RECEIVER FOR BANDWIDTH EFFICIENT MODULATIONS

Gray, Andrew, Srinivasan, Meera, Simon, Marvin, Yan, Tsun-Yee 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / An all-digital high data rate parallel receiver architecture developed jointly by Goddard Space Flight Center and the Jet Propulsion Laboratory is pre- sented. This receiver utilizes only a small number of high speed components along with a majority of lower speed components operating in a parallel fre- quency domain structure implementable in CMOS, and can process over 600 Mbps with numerous varieties of QPSK modulation, including those incorpo- rating precise pulse shaping for bandwidth eÆcient modulation. Performance results for this receiver for bandwidth eÆcient QPSK modulation schemes such as square-root raised cosine pulse shaped QPSK and Feher’s patented QPSK are presented, demonstrating the great degree of exibility and high performance of the receiver architecture.
6

Optimised radio over fibre links for next generation radio access networks

Abbood, Abdul Nasser Abdul Jabbar January 2018 (has links)
Optical fibre has become the dominant theme of transmission in long haul, high data rate communication systems due to its tremendous bandwidth and low loss. Radio over Fibre (RoF) technology facilitates the seamless integration between wireless and optical communication systems and found to be the most promising solution to meet the exponential bandwidth demands expected for the upcoming years. However, the main bit-rate/distance limitation in RoF systems is the chromatic dispersion. In this thesis, the two generations of RoF technologies, namely Analogue RoF (ARoF) and Digital RoF (DRoF) are investigated. The overall aim of this research is to optimise the optical bandwidth utilisation of these two approaches for a typical transmission of the fronthaul link proposed in the next generation Centralised Radio Access Network (C-RAN). Consequently, a number of physical layer design scenarios for the optimised transmission of the Radio Frequency (RF) signals over a Standards Single Mode Fibre (SSMF) are demonstrated. Firstly, for an ARoF transmission, where the analogue RF signals are transported over SSMF using an optical carrier, a bidirectional link transmitting four Downlink/Uplink channels in a chromatic dispersion limited scenario is designed. Simulation results have shown a clear constellation diagram of a 2.5 Gb/s RF signal transmission over 120 km fibre length. Secondly, a DRoF system with reduced optical bandwidth occupancy is proposed. This system employs an optical Duobinary transmission to the digitised RF signal at the transmitter side to reduce its spectrum and to address the chromatic dispersion effect, simultaneously. Simulation results demonstrate the capability of the proposed system to maintain high-quality transmission of the digitised signals over 70 km of fibre distance without dispersion compensation requirements. Finally, an advanced DRoF transmission link based on integrating digital Optical Single Sideband (OSSB) transmission with Duobinary encoding scheme is designed. Simulation results have clearly verified system's robustness against transmission impairments and have better performances in terms of the obtained BER and EVM with respect to the 3GPP standardised values. Moreover, the results show that both transmission distance and power budget are furtherly improved in comparison with two other digital transmission scenarios.

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