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Fading channel is a communication channel that experiences different interference and fading due to multi-path signal propagation. The fading channel is designed by the finite impulse response filter with the time-varying impulse characteristic. The realisation of this filtr is based on the TDL (Tapped Delay Line) model, which simulate signal delay and signal attenuation in each branch. The aim of this thesis is to create the VHDL design of selected fading channel simulator and its description for hardware implementation into the FPGA.

When teaching discriminations, many researchers and practitioners recommend presenting multiple examples of both the correct and incorrect stimuli. To test this suggestion, we compared two procedures for presenting multiple examples. In one, multiple examples across trials (ME, Across), one correct (S+) and one incorrect (S-) stimulus were presented each trial; examples then changed across trials. In another procedure, multiple examples within trials (ME, Within), three stimuli (either 2 S+'s and 1 S-, or 1 S+ and 2 S-'s) were presented each trial; examples again changed across trials. Two experiments were conducted to test these procedures. The first procedure used a non-fading program to teach discrimination; the second used a fading procedure. In the first experiment, we taught 10 persons to identify words under these two procedures. The former procedure was superior in acquisition; the latter procedure, however, was better under generalization for most participants. In the second experiment, we presented the two procedures within a fading paradigm. The results replicated those in Experiment 1: ME, Across was better for acquisition, but ME, Within was better for generalization. Results were discussed and follow-up studies suggested.

By endowing the base station with hundreds of antennas and relying on spatial multiplexing, massive multiple-input-multiple-output (MIMO) allows impressive advantages in many fronts. To reduce this promising technology to reality, thorough performance analysis has to be conducted. Along this line, this work is focused on the convenient high-dimensionality of massive MIMO’s corresponding model. Indeed, the large number of antennas allows us to harness asymptotic results from Random Matrix Theory to provide accurate approximations of the main performance metrics. The derivations yield simple closed-form expressions that can be easily interpreted and manipulated in contrast to their alternative random equivalents. Accordingly, in this dissertation, we investigate and optimize the performance of massive MIMO in different contexts. First, we explore the spectral efficiency of massive MIMO in large-scale multi-tier heterogeneous networks that aim at network densification. This latter is epitomized by the joint implementation of massive MIMO and small cells to reap their benefits. Our interest is on the design of coordinated beamforming that mitigates cross-tier interference. Thus, we propose a regularized SLNR-based precoding in which the regularization factor is used to allow better resilience to channel estimation errors. Second, we move to studying massive MIMO under Line-of-Sight (LoS) propagation conditions. To this end, we carry out an analysis of the uplink (UL) of a massive MIMO system with per-user channel correlation and Rician factor. We start by analyzing conventional processing schemes such as LMMSE and MRC under training-based imperfect-channel-estimates, and then, propose a statistical combining technique that is more suitable in LoS-prevailing environments. Finally, we look into the interplay between LoS and the fundamental limitation of massive MIMO systems, namely, pilot contamination. We propose to analyze and compare the performance using single-cell and multi-cell detection methods. In this regard, the single-cell schemes are shown to produce higher SEs as the LoS strengthens, yet remain hindered by LoS-induced interference and pilot contamination. In contrast, for multi-cell combining, we analytically demonstrate that M-MMSE outperforms both single-cell detectors by generating a capacity that scales linearly with the number of antennas, and is further enhanced with LoS.

In this study, we examined the effect of peer-implemented script fading procedures on the frequency of independent statements of play by children with autism spectrum disorder (ASD) in a classroom setting. The target children included five 5-year-old individuals with ASD with the ability to speak in three- to five-word phrases but did not initiate play with peers. We trained typically developing peers, ages 5 to 6, on how to implement procedures, prompt correct responses, systematically fade scripts, and interact with the target children. We used a script-fading intervention, including auditory scripts that prompted initiation of play with peers. We conducted sessions in an open area of a classroom using a preferred toy set and two additional toy sets for generalization. Following training, we found that peers implemented procedures with fidelity and target participants showed an increase in independent statements of play, both scripted and unscripted.

Individuals with autism often display rote and repetitive responding across behavioral topographies. One area that is often affected is the individual’s verbal repertoire. In an attempt to build and expand verbal repertoires, script and script fading procedures have often been implemented to teach individuals new and varied verbal behavior. Script training and fading procedures have also been used specifically to remediate deficits in an individual’s mand repertoire. Researchers have examined the effects of script training and fading procedures on the variability within an individual’s mand repertoire. This line of research is of great importance since a lack of variability in mands can limit an individual’s access to desired and/or needed items as well as social interactions. In the present study, we implemented simultaneous script training and fading procedures to increase the variability of mands used by three preschool-aged children (one male and two females) diagnosed with autism. We implemented these procedures in an attempt to promote mand variability using antecedent only procedures and to teach variability explicitly in our script training and fading preparation. It was also our goal to address some of the limitations that arose in the previously conducted mand variability studies, namely, the suppression of the default mand frame. At the conclusion of the study, and following procedural modifications, all three participants demonstrated an increase in variability of mand frames. This increase was observed following the inclusion of extinction procedures and following low levels of variability while using antecedent-only procedures. Participants in this study demonstrated an average of one mand frame following antecedent-only procedures and this increased to an average of three mand frames following the inclusion of extinction procedures. The combination of the antecedent procedures and extinction further increased variability across participants. The need for the extinction condition led to many limitations in this study including the limitations analyzed in the simultaneous script training and fading procedures.

No description available.

This thesis takes the reader through an overview of issues pertinent to Local Multi-point Distribution Services (LMDS). The reader will first learn what LMDS is and then review the system architectures that are made available for LMDS technologies. After summarizing the basics of LMDS, we will compare it with some competing technologies. The reader will then be guided through the aspects of millimeter (mm) wave radio link design. This should be a good lead into the experiment section, since it is suspected that the reader would want to be aware of what design techniques are involved in mm-wave radio link design and what issues may pose potential problems and how they may be mitigated. Of the potential problems posed in the mm-wave radio link design section, one will be further investigated experimentally. This is the investigation of the effect of vegetation on the magnitude, phase and error vector magnitude (EVM) performance of an LMDS channel. The motivation for this experiment came from the review earlier work, which showed an unexpected relationship between carrier to noise ratio (C/N) and bit error rate BER. / Master of Science

<p> A self-synchronized echo ranging system with optimum utilization of signal estimation and detection strategies has been designed and simulated. A binary convolution code has been utilized to modulate the transmitter signal. The random medium is modelled by a vector sum of a fixed and a random component; the medium fading process has a Rician distribution density. A channel estimator has been derived using a maximum a posteriori probability criterion. The estimator is an adaptive processor whereby the variance of the medium fading process is recomputed during each updating cycle. The estimator attempts to provide a coherent input to the correlator. An optimum processor for the signalling described is an ordered serial estimator-correlator combination. It is conjectured that the estimator offers an improvement in signal processing gain of approximately 5 dB over and above the non-optimized system. Accompanying this is an improvement in peak-to -sidelobe ratio and in false alarm probability. A 3 bit (8 level) quantized system is conjectured to be a 'good' trade-off between degradation in system performance and simplification in system implementation.</p> / Thesis / Master of Engineering (MEngr)

Multiple-in multiple-out (MIMO) is a wireless communication technique where antenna arrays, at the receiver and transmitter, utilize signal multipath propagation to increase data throughput capacity. The unique benefits MIMO provides have over the last 20 years led to the steady increase in usage in both Wi-Fi and mobile networks. Predicting the performance of an antenna array designed for MIMO is more difficult than predicting the performance of a single antenna. This is due to the increased performance deriving from the processed combination of information from each antenna element. To determine the increased benefits that additional antenna elements can provide to a wireless system, the statistical correlation between the signals received from all antenna element needs to be evaluated. This correlation is expressed with the correlation coefficient $\rho$. The correlation coefficient may be estimated from the far field radiation pattern measured in an anechoic chamber, or measured from the statistically isotropic and homogeneous radiation environment provided by a reverberation chamber. However, Blanch, et al. 2003, proposed a much simpler method to estimate the correlation coefficient using a Vector Network Analyzer (VNA) to measure scattering parameters (S-parameters) while assuming perfect antenna efficiency. In 2005 Hallbjörner proposed a modified version of the estimation including the effect of antenna efficiency. This project aimed to measure and compare the results from the two types of chamber tests along with the two S-parameter based approximation methods mentioned. To accomplish this, three different antenna arrays, with four elements each with varying efficiency and mutual coupling, were designed and manufactured. The antenna arrays were then measured in an anechoic chamber, in a reverberation chamber, and had their S-parameters determined with a VNA. From the measurements it was found that the results from both types of chamber tests agree well, indicating that both tests are viable methods of signal correlation estimation. The S-parameter method proposed by Blanch was found to be inaccurate for the antennas tested, likely due to low radiation efficiencies. However, the approximation method proposed by Hallbjörner produced better results, but requires the efficiencies of the antennas which is generally not simple to determine. In conclusion it is found that S-parameter measurements, which are commonly used by the wireless industry, do not provide valid estimates of the MIMO performance of antenna arrays unless they are complemented with measurements of antenna efficiency. / <p></p><p></p><p></p>