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Full-Text Articles in Engineering

Power Spectrum Prediction Of Amplified Dual-Band Lte-Advanced Signals, Xianzhen Yang Mar 2018

Power Spectrum Prediction Of Amplified Dual-Band Lte-Advanced Signals, Xianzhen Yang

Dissertations and Theses

In wireless communication, the nonlinearity of a radio frequency (RF) power amplifier is an important issue for power amplifier designers. Since the nonlinearity is generated by the properties of physical components, it is hard to avoid it in producing power amplifiers. Power amplifier designers should know about the nonlinearity in order to compensate for it.

A two-tone test is a relatively widely used method to measure the nonlinearity of a power amplifier, which means the third order intercept point (IP3) can be measured from the two-tone test. Through the two-tone test, researchers have proposed some formulae to present what the ...


Nonlinearity Analysis And Predistortion Of 4g Wireless Communication Systems, Xiao Li May 2013

Nonlinearity Analysis And Predistortion Of 4g Wireless Communication Systems, Xiao Li

Dissertations and Theses

The nonlinearity of RF power amplifiers (PA) is one of critical concerns for RF designers because it causes spectral regrowth related to in-band and out-of-band spurious emissions control in communication standards. Traditionally, RF power amplifiers must be backed off considerably from the peak of their power level in order to prevent spectral regrowth. The digital predistortion (DPD) technique is being widely used for compensation of the nonlinearity of RF power amplifiers, as the high power efficiency becomes increasely important in wireless communication systems.

However, the latest generations of communication systems, such as Wi-Fi, WiMAX, and LTE, using wider bandwidth have ...


Spectrum Regrowth For Ofdm-Based Lte And Wimax Systems, Bosi Chen Jan 2013

Spectrum Regrowth For Ofdm-Based Lte And Wimax Systems, Bosi Chen

Dissertations and Theses

An abstract of the thesis of Bosi Chen for the Master of Science in Electrical and Computer Engineering presented Aug 1st, 2012. Title: Spectrum Regrowth for OFDM-based LTE and WiMAX Systems. In OFDM-based (Orthogonal Frequency Dimension Multiplexing) LTE (Long Term Evolution) and WiMAX (Worldwide Interoperability for Microwave Access) Systems, one of the critical components is the RF power amplifier. With current technologies, RF power amplifiers are not perfectly linear. The nonlinearity of an RF power amplifier is one of the main concerns in RF power amplifier design. The nonlinearity control is described by the out-of-band power emission levels, and the ...


Optimal Network Topologies And Resource Mappings For Heterogeneous Networks-On-Chip, Haera Chung Jan 2013

Optimal Network Topologies And Resource Mappings For Heterogeneous Networks-On-Chip, Haera Chung

Dissertations and Theses

Communication has become a bottleneck for modern microprocessors and multi-core chips because metal wires don't scale. The problem becomes worse as the number of components increases and chips become bigger. Traditional Systems-on-Chips (SoCs) interconnect architectures are based on shared-bus communication, which can carry only one communication transaction at a time. This limits the communication bandwidth and scalability. Networks-on-Chip (NoC) were proposed as a promising solution for designing large and complex SoCs. The NoC paradigm provides better scalability and reusability for future SoCs, however, long-distance multi-hop communication through traditional metal wires suffers from both high latency and power consumption. A ...


Logic Synthesis With High Testability For Cellular Arrays, Andisheh Sarabi Jan 1994

Logic Synthesis With High Testability For Cellular Arrays, Andisheh Sarabi

Dissertations and Theses

The new Field Programmable Gate Array (FPGA) technologies and their structures have opened up new approaches to logic design and synthesis. The main feature of an FPGA is an array of logic blocks surrounded by a programmable interconnection structure. Cellular FPGAs are a special class of FPGAs which are distinguished by their fine granularity and their emphasis on local cell interconnects. While these characteristics call for specialized synthesis tools, the availability of logic gates other than Boolean AND, OR and NOT in these architectures opens up new possibilities for synthesis. Among the possible realizations of Boolean functions, XOR logic is ...


Freeway Control Via Ramp Metering: Development Of A Basic Building Block For An On-Ramp, Discrete, Stochastic, Mesoscopic, Simulation Model Within A Contextual Systems Approach, Mohamed Yaser Alkadri Jan 1991

Freeway Control Via Ramp Metering: Development Of A Basic Building Block For An On-Ramp, Discrete, Stochastic, Mesoscopic, Simulation Model Within A Contextual Systems Approach, Mohamed Yaser Alkadri

Dissertations and Theses

One of the most effective measures of congestion control on freeways has been ramp metering, where vehicle entry to the freeway is regulated by traffic signals (meters). Meters are run with calibrated influx rates to prevent highway saturation. However, recent observations of some metering sites in San Diego, CA indicate that metering, during peak hour demand, is helping freeway flow while sometimes creating considerable traffic back-ups on local streets, transferring congestion problems from the freeway to intersections. Metering problems stem largely from the difficulty of designing an integrated, dynamic metering scheme that responds not only to changing freeway conditions but ...


Performance Theorems For The Resource Scheduling Functions Of A Multiprocessing System, George Arthur Nicol Jan 1979

Performance Theorems For The Resource Scheduling Functions Of A Multiprocessing System, George Arthur Nicol

Dissertations and Theses

In this dissertation, a multiprocess scheduling model is developed and a set of performance theorems is constructed for the set of scheduling functions associated with the model. Each theorem describes the conditions under which a scheduling function exhibits a particular type of performance.


Error Codes In Digital Data Communication Systems, Robert Hadley Cravens Jan 1977

Error Codes In Digital Data Communication Systems, Robert Hadley Cravens

Dissertations and Theses

Today’s digital communication systems perform data transfers at the rate of millions of bits per minute, with data errors in the order of l/6th error per day. This magnitude of errorless communication is now possible because of sophisticated error correcting codes. Many types of error codes are employed today in three distinct areas of digital data communication: human to computer; data source to computer; computer to computer; and intra-computer; we are concerned here with intra-computer communication.

This research is primarily a mathematical study of error codes in general to explore the possibilities of each major type for the ...