Andreas Kortke

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In this paper, we present the results of a measurement campaign regarding the 60 GHz in-vehicular wireless channel. The measurements have been performed inside an aircraft passenger cabin by the use of a modular setup covering a bandwidth of 1 GHz. We consider path loss aspects and investigate the time-dispersive nature of the channel. Additionally the(More)
Due to the extremely high user density in in-flight entertainment (IFE) systems, the required sum data rate is in the order of several Gbit/s, which can not be provided by existing standard wireless systems. To achieve such high data rates, the 60 GHz frequency band is very well suited due to its specific advantages. In this paper, a design concept for a(More)
In this paper we present a FPGA design of a digital predistorter (DP) for power amplifiers (PAs) regarding memory effects. As model description the baseband Volterra series are utilized. A reduction of Volterra coefficients can be achieved using their symmetry properties. An advantage of our DP approach is a direct offline model identification, without need(More)
In this paper we present a modular digital radio testbed, which has been developed to enable the implementation of novel wireless transmission concepts and signal processing algorithms. The highly flexible and reconfigurable hardware comprises a commercial FPGA platform, a self-developed converter board as well as various plug-on clock and RF modules. To(More)
Recently, much attention has been paid to frequency selective I/Q-imbalance, which can seriously limit the performance of broadband direct-conversion transceivers and degrade the baseband pre-linearization of the Power Amplifier in the transmitter. This paper addresses the issue of joint calibration of frequency selective I/Q-imbalance and modulator(More)
For communication systems with direct-conversion architecture, I/Q-imbalance can be a crucial performance limiting effect. Furthermore, as the datarates of the wireless communication systems increase, larger transmission bandwidths (BW) and high-order modulated waveforms are applied. As a result, the systems are sensitive to frequency dependent(More)
The performance of an Orthogonal Frequency-Division-Multiplexing (OFDM)-based 60-GHz system can be strongly degraded due to carrier frequency impairment and Phase Noise (PN). In this paper we present a practical approach to the design of a frequency synchronization and phase offset tracking scheme for a 60-GHz, Non-Line-of-Sight (NLOS) capable wireless(More)
Currently, a lot of research is being done to develop physical resource sharing mechanisms in wireless networks. These mechanisms are expected to enhance spectral efficiency, coverage, user satisfaction and operator revenue. In order to prove the feasibility of these mechanisms or to identify practical problems for mechanism optimization, a(More)
A method is presented to calculate discrete equivalent source current distribution functions from measured electric near field distribution functions. The calculated distribution functions possess a high spatial resolution of about a tenth of the radiated wavelength and therefore permit insight into the functional details of the investigated DUT antennas.(More)