Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 41 for “"Delay Spread"”.
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A statistical ultra wideband indoor channel model and the effects of antenna directivity on multipath delay spread and path loss in ultra wideband indoor channels
… domain statistics of the channel (i.e., mean delay spread and RMS delay spread) are analyzed thoroughly for each antenna combination. Results show that RMS delay spread increases over distance for all three antenna combinations, but at a greater rate when directional antennas are used in the …
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Indoor wide band radio wave propagation measurements and models at 1.3 ghz and 4.0 ghz
… were obtained for mean and maximum excess delay, rms delay spread, time delay jitter, differential delay jitter, and path loss through analyses of impulse response estimates, which were obtained via repetitive 5 ns probing pulses. The effects of frequency, antenna height, topography …
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Antenna effects on indoor wireless channels and a deterministic wide-band propagation model for in-building personal communication systems
… polarization and antenna pattern on multipath delay spread and path loss in indoor obstructed (OBS) wireless channels. A wide-band experiment was performed in a two-floored modern office building at 2.4SGHz in August 1991. Some preliminary results are as follows. Circular polarization cannot …
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Wireless local area radio networks wideband characterisation and measurements at 62.4GHz
… receiver with respect to the base station. With delay spread values ranging from 20 to 70ns the coherence bandwidth remains most of the times below 10MHz. Based on the maximum delay spread of 68ns obtained in a 41m long narrow corridor, a BER of 10" 3 and normalised delay spread of 0.1, the …
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Design and implementation of a methodology to characterize indoor visible light communication channels
… and channel metrics such as path loss, RMS delay spread, coherence bandwidth, and maximum bitrate. Our method accurately estimates path loss, with a measured value of $15$ dB at $30$ cm transceiver distance, consistent with simulation results in the literature. However, our lowest value for …
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Wideband Channel Characterization for MIMO Scenario
… such as capacity, coherence bandwidth, RMS delay spread and maximum delay spread are compared (statistically) to those obtained from the SVA model. The comparisons of the different parameters show the ability of the SVA model to simulate wideband MIMO communication channels.
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Radio Channel Measurements and Modeling for Smart Antenna Array Systems Using a Software Radio Receiver
… under test. Criteria for evaluation include RMS delay spread, excess delay spread, signal envelope fading, antenna diversity gain, and gain achieved through the use of a two-dimensional rake receiver. This research makes contributions to the wireless communications field through analysis, …
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Underwater acoustic communication over Doppler spread channels
… communication channels where the Doppler spread is more severe than the delay spread. An appropriate representation of the linear time- variant channel is introduced, and the wide sense stationary uncorrelated scattering (WSSUS) channel assumption enables characterization in terms of …
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Inter-carrier interference mitigation for underwater acoustic communications
… The underwater acoustic channel has a long delay spread, which makes orthogonal frequency division multiplexing (OFDM) an attractive communication scheme. However, the underwater acoustic channel is highly dynamic, which has the potential to introduce significant inter-carrier interference …
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Estimation and tracking of rapidly time-varying broadband acoustic communication channels
… features: large dimension caused by extensive delay spread; limited number of degrees of freedom (DOF) due to resolvable paths and inter-path correlations; and rapid fluctuations induced by scattering from the moving sea surface. Traditional LS estimation techniques often fail to reconcile the …
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Channel modeling of multilayer diffusion-based molecular nano communication system
… characteristics such as impulse response, time delay, attenuation or the maximum peak, delay spread and capacity were analytically obtained from the mean molecular concentration. In this stage, the multilayer channel is considered as a linear and deterministic channel. For the performance …
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Bit error rate simulation enhancement and outage prediction in mobile communication systems
… and statistical moments of a channel's power delay profile are needed. The studies also indicate that for simulations of channels with large delay spread timing recovery is essential.
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Adaptive and Robust Multi-Gigabit Techniques Based MmWave Massive MU-MIMO Beamforming For 5G Wireless and Mobile Communications Systems. A Road Map for Simple and Robust Beamforming Scheme and Algorithms Based Wideband MmWave Massive MU-MIMO for 5G Wireless and Mobile Communications Systems
… including path loss models and multipath delay spread values. Results are compared to confirm that the received power and delay spread is decreased with increasing frequency. The results were also validated with the measurement findings for 60 GHz. Then several proposed design models of …
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Highly Tunable Integrated Self-Interference Cancellation Techniques for Intelligent Full-duplex Radios
… linearity and the ability to cancel long-delay spread SI. Fabricated in a TSMC 40 nm CMOS process, this chip integrates an EBD with a tuned impedance matching network (Z\textsubscript{Bal}), two broadband complex 5-tap continuous-time FIR-based RF cancellation filters, and a mixed-signal …
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Wideband propagation measurements for personal communication systems
… interference in wideband systems because of delay spread in the channel impulse response. Multipath propagation becomes more pronounced as the wavelength decreases, and at the frequencies around 2GHz assigned for 3rd. generation cellular 'phones and personal communication services, multipath …
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Performance Evaluation of DECT in Different Radio Environments
… and calculated from the recorded power delay profile measurements. Finally, a mean-opinion-score (MOS) rating was performed for National Semiconductor Corporation's implementation of DECT in the indoor, indoor-to- outdoor, and outdoor environments. A comparison is made between the MOS …
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Adaptive DS-CDMA multiuser detection for time variant frequency selective Rayleigh fading channel
… channels. In addition, channel acquisition and delay estimation techniques are developed to combat the uncertainty introduced by the wireless propagation channel. This work emphasizes fast and simple techniques that can meet practical needs for high data rate signal detection. Most existing …
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Measured and Modeled Time and Angle Dispersion Characteristics of the 1.8 GHz Peer-to-Peer Radio Channel
… the receiver to measure over 3500 wideband power-delay profiles (PDPs) of the channel for a peer-to-peer communications system. Rural and urban areas are studied in 22 different transmitter-receiver links. The results are used to characterize the narrowband path loss, mean delay, root-mean-square …
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Analysis of and techniques for adaptive equalization for underwater acoustic communication
… including limited available bandwidth, long delay-spread, time-variability, and Doppler spreading. These difficulties reduce the reliability of the communication system and make high data-rate communication challenging. Adaptive decision feedback equalization is a common method to compensate …
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Analysis of and techniques for adaptive equalization for underwater acoustic communication
… including limited available bandwidth, long delay-spread, time-variability, and Doppler spreading. These difficulties reduce the reliability of the communication system and make high data-rate communication challenging. Adaptive decision feedback equalization is a common method to compensate …
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