Engineering Commons^™

Spectrum Modeling Of Rf Amplifiers Based On Intercept Points With Measurement Improvements, Siyuan Yan

Dissertations and Theses

Orthogonal frequency-division multiplexing has been developed into a popular modulation scheme for wireless communication systems, used in applications such as LTE and 5G. In wireless communication system, spectrum regrowth caused by RF amplifiers will generate distortions to both passband in use and adjacent channels such that the transmission quality will be degraded. The study of this dissertation aims to predict the spectrum regrowth for OFDM based signals at the output of a RF amplifier due to the nonlinearity. Based on Taylor polynomial coefficients, a power spectrum expression for amplified OFDM signals in terms of intercept points up to nth-order is …

Power Efficiency Enhancement And Linearization Techniques For Power Amplifiers In Wireless Communications, Haider Al-Kanan

Dissertations and Theses

Wireless communication systems require Power Amplifiers (PAs) for signal transmissions. The trade-off between power efficiency and nonlinear distortion in PAs degrades the communication performance. Thus, power efficiency and nonlinearity are two main concerns of operating PAs in communication systems. Nonlinear behavioral models are typically used to quantify and mitigate the distortion effects of PAs on communication systems. This dissertation presents an estimation approach for modeling and linearizing the PA Amplitude-to-Amplitude (AM/AM) nonlinearity using the design specifications of PAs, such as gain, the third-order intercept point, and 1dB compression point. Furthermore, an enhanced approach for modeling solid-state power amplifiers is developed …

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 …

Nonlinear Analysis And Digital Pre-Distortion Of The Sc-Fdma Signals In Lte Uplink System, Changwen Zhu

Dissertations and Theses

Single-carrier frequency division multiple access (SC-FDMA) has become a popular alternative to orthogonal frequency division multiple access (OFDM) in multi-user communication on LTE uplink systems. This is primarily due to the low peak-to-average power ratio (PAPR) of SC-FDMA compared to that of OFDM. Long-term evolution (LTE) uses SC-FDMA on the uplink to exploit this PAPR advantage to reduce transmit power amplifier (PA) back-off in mobile user terminals. However, the latest generation of communication systems requires high power efficiency and a large quantity of capacity in transmitting mobile data, bringing out some other critical problems: 1) the nonlinearity of Radio Frequency …

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 …