We consider the downlink scenario of multiuser multiple-input-single-output (MU-MISO) communication systems with constant envelope (CE) signals emitted from each antenna. This results in energy efficient power amplifiers (PAs). We propose a holistic CE precoding scheme based on the symbol-wise minimum squared error (SMSE) criterion. Additionally, we analyze the distortions introduced by low-res...

Predistortion (PD) lineariser for microwave power amplifiers (PAs) is an important topic of research. With larger and larger bandwidth as it appears today in modern WiMax standards as well as in multichannel base stations for 3GPP standards, the relatively simple nonlinear effect of a PA becomes a complex memory-including function, severely distorting the output signal. In this contribution, tw...

Coherent beam combining enables power scaling beyond the limits of single amplifiers. Therefore, improving the performance and simplicity of coherent combination techniques is of great interest for many high power applications. Here, we show all-fiber coherent beam combining of two ytterbium doped amplifiers with and without a dedicated phase actuator and a total output power up to 25 W. Instea...

Radio frequency fingerprint (RFF) identification distinguishes wireless transmitters by exploiting their hardware imperfection that is inherent in typical radio (RF) front ends. This can reduce the risks for identities of legitimate devices being copied, or forged, which also occur conventional software-based systems. paper analyzes feasibility device unique non-linear memory effect transmitter...

Since the xDSL specifications impose stringent linearity requirements to ensure the integrity of the data transferred, current line drivers use linear amplifiers. The downside of these solutions is their power consumption, as the xDSL modulation has a high peak to average ratio, forcing the amplifier to operate in its least efficient region. An alternative is the use of switching amplifiers, wh...

Power-amplifier efficiency is a significant issue for the overall efficiency of most wireless system. Therefore, currently there are different kind of Switched mode power amplifiers are developed which are showing very high efficiency also at higher frequencies but all of these amplifiers are subjected to drive with the constant envelope signals. Whereas, for the increasing demand of high data ...

This story has been happening as the demand for high-speed data increases and battery capacity has not matched advances with communications technology. It’s not the battery at fault but the technology needed to power the amplifier on the phone. For years, normal DC-DC converters managed the battery power flowing in the phone to different chips. This included the power amplifier (PA) for driving...

High efficiency and linearity are indispensable requirements of power amplifiers. Unfortunately they are difficult to obtain simultaneously, since high efficiency PAs are nonlinear and linear PAs may have low efficiency. In order to satisfy the efficiency and linearity requirements, designers preferred to prioritize the efficiency of PAs in the design process and to later recover the linearity ...