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 1251 for “"transmit"”.
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Adaptive transmit beamforming for simultaneous transmit and receive
Simultaneous transmit and receive (STAR) is an important problem in the field of communications. Engineers have researched many different models and strategies that attempt to solve this problem. One such strategy is to place a transmit-side null at the receiver in order to decouple a system's …
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NOVEL PARALLEL TRANSMIT SYSTEMS FOR MRI APPLICATIONS
In this work a new RF transmitter design is presented for MRI parallel transmissionapplications. Benchtop measurements and imaging experiments were performed withdifferent prototypes to prove system’s performance and potential advantages versus asystem based on conventional MRI RF hardware. The …
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Transmit Diversity and its Application to Cooperative Networking
Wireless communications has been so far largely based on centralized control, which in effect has limited its deployment, coverage and application scenarios. The paradigm of peer-to-peer wireless communications is fundamentally to remove this bottleneck and to further expand wireless communications …
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Performance evaluation of communication systems with transmit diversity
Transmit diversity is a key technique to combat fading with multiple transmit antennae for next-generation wireless communication systems. Space-time block code (STBC) is a main component of this technique. This dissertation consists of four parts: the first three discuss performance evaluation of …
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Transmit antenna selection in fading wireless communication systems
… (MIMO) systems, we propose the use of the transmit antenna selection technique. In transmit antenna selection, the best performing antenna(s) is selected from all the available transmit antennas for transmission. Transmit antenna selection reduces the number of radio frequency chains, and …
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Transmit simulation and receive optimizations for 802.11b networks
… provides an implementation of a full simulated transmit chain from packet encoding through base band modulation for the 802.11b wireless networking standard. This forward transmit chain is coupled with a physical channel simulation that can introduce a number of different channel effects to …
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Spreading and power control for multiple antenna transmit diversity
This thesis proposes a new transmission scheme for multiple antenna transmission at the base station of a wireless cellular system. We develop our new scheme in a wideband CDMA framework using multiple phases of Gold codes for spreading on different antennas. We evaluate the performance of this …
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Slice-selective parallel transmit magnetic resonance imaging at 7T
… (pTx) technology, employing multiple transmit channels to dynamically control RF pulses, is a promising solution to overcome these limitations. While pTx has shown maturity in 3D neuroimaging with universal pulses, its application to 2D imaging suffers from optimisation complexities, …
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Transmit Precoder Design for Dual-Function Radar-Communication Systems
… modes use distinct baseband waveforms. A transmit precoder provides spatial multiplexing and power allocation among the radar and communication modes. Multiple optimization approaches for precoder design are developed based upon combinations of radar detection and communication receiver …
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Information theory of transmit diversity and space-time code design
… the achievable information rates for multiple transmit multiple receive antenna systems in fast fading channels. Then we consider non-ergodic channel, where we evaluate asymptotic expression for the outage probability and note its striking similarity with the error probability. After that, we …
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Self-Interference Cancellation for Simultaneous Transmit and Receive (STAR) Applications
Co-channel interference between transmit and receive antennas means that simultaneous transmission and reception (STAR) of signals on the same frequency is an engineering challenge when co-locating the transmit and receive channels. Due to advancements in Radio Frequency (RF) receiver and antenna …
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Optimization of transmit/receive array topology in 3D acoustic imaging
Acoustic imaging transmit and receive arrays pairs are simulated in the bistatic transmission case using Field II, an industry standard ultrasound toolbox. Analysis of imaging fundamentals, as well as simple transmit and receive array beam patterns reveals desirable beam pattern properties that can …
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Characterization of Uplink Transmit Power and Talk Time in WCDMA Networks
… it is important to know the operating uplink transmit power levels of a mobile phone in the WCDMA network. The work in this thesis makes two major contributions. First is the characterization of uplink transmit power in WCDMA networks based on current network data (collected in AT&T's WCDMA …
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Transmit Signal Design for MIMO Radar and Massive MIMO Channel Estimation
… control signal emissions from each antenna make transmit signal design increasingly important for radar and wireless communication systems. In the rst part of this work, we develop the framework for a MIMO radar transmit scheme which trades o waveform diversity for beampattern directivity. …
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Unitary Space-Time Transmit Diversity for Multiple Antenna Self-Interference Suppression
A common practice for government defense agencies and commercial aeronautical companies is to use dual antennas on test flight air vehicles in order to overcome occlusion issues during high-speed telemetric maneuvers. The dual antennas, though never being masked at the same time, unfortunately lead …
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Space -Time Transmit Precoding and Interference Suppression for a Wireless Downlink
… is interference suppression using space-time transmit filters for a multiuser system, assuming perfect channel feedback. The filter design is formulated as an optimization problem, and an iterative algorithm that converges to the global optimum is derived. Next, the effect of imperfections in …
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Parallel transmit pulse sequence design for ultra-high field (7T) MRI
… scanner has multiple independently-driven transmit channels, providing additional degrees of freedom for improved spatial and temporal control of the B+1 fields. This thesis aims to extend the methodology and applications of pTx for neuroimaging at 7 T, specifically on the first …
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Performance evaluation of transmit diversity techniques in the CDMA 2000 standard
… evaluates the performance of two forward-link transmit diversity techniques in the CDMA2000 standard: Space-Time Spreading (STS) and Phase-Sweep Transmit Diversity (PSTD). For each technique, the evaluation consists of conducting 9.6 kbps Markov calls in the field and measuring the mean …
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Multiphoton Parallel Transmit MRI for Flip Angle Mitigation Without SAR Concerns
… elements in a process known as parallel transmit (pTx). While these multiple high-power, high-frequency transmit channels can solve the flip angle inhomogeneity problem, they are expensive and complicate the management of electromagnetic power dissipation in the body, known as the …
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Computer controlled transmit receive system for an ultrasonic phased array transducer.
Thesis: M.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1976
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