André Pollok

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— 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)
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)
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)
This paper tackles the speech separation problem in a meeting room using a new acoustic beamforming method – adaptive blocking (AB) beamformer. The proposed method is an optimum beamforming with a structure similar to the generalized sidelobe canceller (GSC) structure, but simpler. Thus, it inherits the flexibility of GSC and functions well in dynamic(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)
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)
In this paper, we propose a novel algorithm for distributed and decentralized stochastic routing to optimize the convergence rate and the resilience of routing. More precisely, the novelty of our method is the provision of a stochastic routing technique which greatly improves the spectral gap of the routing matrix, as compared to existing methods. We define(More)
In a multi-speaker environment, voice activity classification (VAC) attempts to identify active speaker(s) at different recording periods. Using a beamformer-output-ratio (BOR) from a multi-beamforming system, an efficient solution for VAC is available by comparing the calculated BOR with pre-specified thresholds. Considering two speakers, this paper(More)