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 25 for “"Channel Impulse Response"”.
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Channel Impulse Response and Its Relationship to Bit Error Rate at 28 GHz
… it is necessary to find the most useable channel at the site as quickly as possible. In addition to 28GHz radio links, the system also has a built-in channel sounder that measures and captures the channel impulse response of the current channel. Until now, there has been limited research …
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An information theoretic study of reduced-complexity receivers for intersymbol interference channels
… additive Gaussian intersymbol interference channel typically grows exponentially with the duration of the channel impulse response. Consequently, practical sub-optimal receivers are often designed as though the channel impulse response were shorter than it is. While previous studies on the …
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Bit error rate simulation of a CDMA system for personal communications
… capture the complexities of the mobile radio channel needed to accurately predict the performance of complex system designs. This thesis presents a novel simulation technique in which a CDMA system is modeled by software, but the channel impulse response model is derived from actual …
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The Applicability of the Tap-Delay Line Channel Model to Ultra Wideband
… bandwidth of UWB signals, we need to revisit UWB channel modeling. Specifically we need to verify whether or not the traditional tap-line delay channel model is still applicable to UWB. One essential task involved in channel modeling is deconvolving the channel impulse response from the …
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A channel subspace post-filtering approach to adaptive equalization
… type of wireless communications in which the channel is highly dynamic and the amount of ISI due to multipath is relatively large. In the underwater acoustic channel, associated with each of the deterministic propagation paths are macro-multipath fluctuations which depend on large scale …
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A Scaleable FIR Filter Implementation Using 32-bit Floating-Point Complex Arithmetic on a FPGA Base Custom Computing Platform
This thesis presents a linear phase finite impulse response filter implementation developed on a custom computing platform called WILDFORCE. The work has been motivated by ways to off-load intensive computing tasks to hardware for indoor communications channel modeling. The design entails complex …
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Sum-rate optimal network beamforming and power allocation for single-carrier asynchronous bidirectional relay network
… signal they convey. As a result, the end-to-end channel is not amenable to a frequency flat model, rather a multi-path channel model with multiple taps appears to be more appropriate. Such a multi-path model for the end-to-end channel raises the issue of inter-symbol-interference (ISI) at the two …
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Bit error rate simulation enhancement and outage prediction in mobile communication systems
… Internally generated two-ray Rayleigh fading channel models as well as imported spatially varying complex channel impulse responses can be utilized in simulations. Implementation of receiver timing jitter and timing recovery models, as well as modifications of the channel generation (two-ray …
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Design and implementation of a methodology to characterize indoor visible light communication channels
Understanding the channel behavior in communication systems is important for ensuring reliable and robust connectivity. This is also true for Visible Light Communication systems in different environments and scenarios. In this work, we develop an adaptable, simple, and reliable method to quantify, …
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Towards location-awareness in next generation wireless networks : a new approach based on channel state information
… by establishing a new approach relying on channel state information (CSI) measurements. In particular, we design an efficient joint message-passing (MP) localization algorithm, which consists of two layers: the transformation layer and the estimation layer. The transformation layer extracts …
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Wideband propagation measurements for personal communication systems
The propagation channel is a vital but invisible part of any wireless communications system. As wavelengths get shorter, multipath effects become more pronounced, causing small scale fading in narrowband channels, and inter-symbol interference in wideband systems because of delay spread in the …
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Performance Evaluation of DECT in Different Radio Environments
… the performance of DECT in different channel conditions. DECT is simulated using the Signal Processing WorkSystem (SPW) software in different channels including the additive white Gaussian noise (AWGN) channel, the flat faded Rayleigh channel, the frequency selective faded Rayleigh …
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A novel OFDM Blind Equalizer: Analysis and Implementation
… is implemented at the receiver to estimate the channel impulse response. This estimate can be fed back to the transmitter via a feedback channel, which can in turn help generate a sub-optimal transmission solution for the current situation. In this thesis, a link adaptation method is proposed …
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Characterization and Evaluation of Non-Line-of-Sight Paths for Fixed Broadband Wireless Communications
Channel impulse responses collected on the Virginia Tech campus show combinations of specular multipath and diffuse scattering at LMDS frequencies. An algorithm is presented that estimates link performance based on the channel impulse response. Presented and analyzed are representative impulse …
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Microwave multipath resolution in microcellular channels
… objective of this research is to compare radio channel impulse response measurements with site-specific radio wave propagation prediction techniques. A wide band spread spectrum measurement system was developed, and desirable measurement locations were selected on the Virginia Tech campus. These …
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A Study of Rough Surface Scattering Phenomena in the LMDS Band (28 GHz)
… Virginia Tech campus. The sounder collected the channel impulse response analog waveform, sampled, digitized and reconstructed it. The stored data were used to produce the power delay profile and other channel parameters. In particular, we collected scattered and reflected data regarding the …
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CPM Equalization to Compensate for ISI due to Band Limiting Channels
… attractive modulation schemes in band limited channels. However, as the data rates keep increasing, the spectral width of the CPM signal increases beyond the channel bandwidth and performance becomes constrained by the intersymbol interference (ISI) that results from band-limiting filters. We …
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Ultra-wideband Small Scale Channel Modeling and its Application to Receiver Design
… of topics related to the analysis of indoor UWB channels for communications and to system level design issues for UWB receivers. Measurement based UWB small scale modeling and characterization efforts as well as UWB communications system analysis and simulation are presented. Relevant background …
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Power efficient designs for 5G wireless networks
… and we show that at the optimum, the end-to-end channel has only one non-zero tap. To extend the first work to high data-rate scenarios, we consider a second relaying-based network which consists of two OFDM-based transceivers and multiple FF relays. We propose two approaches to tackle a total …
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Algorithms and architectures for channel estimation in wireless CDMA communication systems
… access (CDMA) technology. The estimation of channel delays along with channel attenuation and phases of different users constitutes the first stage in the detection process at the receiving base station in a CDMA communication system. This stage, called channel parameter estimation, forms the …
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