This dissertation presents a study of linearization techniques that have been applied to power amplifiers in the cellular communication industry. The objective of this work is to understand the limitations of power amplifiers, specifically the limitations introduced by the use of spectrally efficient modulation schemes. The digitization of communication systems has favored the use of new techniques and technologies capable of increasing the efficiency of costly power amplifiers. The work explores traditional and digital linearization systems; an algorithm based on the principles of natural recombination is proposed to directly address the limitations of previous embodiments. Previous techniques, although effective, have significant implementation costs that increase exponentially with the increasing signal bandwidths. The proposed software-hardware architecture significantly reduces implementation costs and the overall complexity of the design without sacrificing performance. To fulfill the requirements of this study, multiple systems are implemented through simulation and closed-loop hardware. Both simulation and hardware embodiments meet the expected performance metrics, providing validation of the proposed algorithm. The application of the algorithm to memory power amplifier linearization is a new approach to adaptive digital pre-distortion using narrowband feedback. The work will show performance improvements on an amplifier with memory effects suggesting that this technique can be employed as a lower-cost solution to meet requirements when compared to typical system implementations.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 189-194). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 189-194). Also available on the Internet.

M. Tech. Business Administration / Fixed-line operators in South Africa as well as globally have had a difficult battle, facing external pressures such as deregulation, a severe industry and economic downturn and declining prices. Capital Expenditure (CAPEX) is dropping as operators delay or cut back on spending. With the internet economy, digital media and other telecommunications activities still trying to establish, there is a need for modern and efficient infrastructure that is becoming more critical and therefore, collaboration in infrastructure sharing between organisations is becoming a growing subject of interest to the telecommunication industry, as it is seen as an opportunity to reduce the costs of deploying infrastructure and of gearing investment towards under-serviced areas. In this study, an effort is made to assess how collaboration in terms of a joint venture between Neotel, Vodacom and MTN can have an effect in terms of infrastructure sharing by establishing how the approach can reduce costs (infrastructure building and operating) in Neotel and to assess the risks associated with it.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.