André Pollok

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In this paper, we examine turbo synchronization in the presence of carrier frequency uncertainties and phase offsets for the DVB–RCS standard. As turbo synchronization can only achieve high estimation accuracy if the initial parameter offset is sufficiently small, we employ a coarse synchronization unit for pre-compensation. Especially for frequency offset(More)
The 60 GHz band is an attractive candidate for wireless indoor communications as it offers a large amount of license free spectrum. Non-rich scattering situations, which commonly arise at 60 GHz due to the particular propagation conditions, result in relatively high spatial correlation. Spatial multiplexing, a widely considered concept for multiple-input(More)
OFDM is well suited to indoor wireless communication systems that suffer from multipath delay spread. However very high rate systems may impose severe computational demands in both the modem and codec. This paper considers analog filter requirements and the effects of timing drift in Gbit Wireless LAN systems using OFDM. Due to the high data rates we assume(More)
When realizing carrier frequency offset estimation at low signal-to-noise ratios, a typical feed-forward synchronization unit solely relies on known pilot symbols. The importance of the position of these pilot symbols within the burst has been elaborated on in the literature. In this paper, we discuss the importance of the pilot symbol constellation for(More)
We consider least squares estimators of carrier phase and amplitude from a noisy communications signal. We focus on signaling constellations that have symbols evenly distributed on the complex unit circle, i.e., M-ary phase shift keying. We show, under reasonably mild conditions on the distribution of the noise, that the least squares estimator of carrier(More)
Timely and reliable delivery of critical information is vital for military applications and disaster relief applications. Such applications rely on communications networks, which in practice operate via unreliable links. Improving the packet delivery ratio while reducing the end-to-end delay is a major challenge for stochastic routing in networks with(More)
We consider least squares estimators of carrier phase and amplitude from a noisy communications signal that contains both pilot signals, known to the receiver, and data signals, unknown to the receiver. We focus on signaling constellations that have symbols evenly distributed on the complex unit circle, i.e., M-ary phase shift keying. We show, under(More)
In a conversation between multiple speakers, each person participates in the speech at different times. Therefore the active speakers in each speech segment are unknown. However, identifying the voice activity (VA) of the speakers of interest is required for adaptive beamforming techniques such as minimum variance distortionless response beamforming and the(More)