Nils Bornhorst

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—In this work, we consider optimal and suboptimal beamforming designs in a multi-operator two-way relaying network with a multiple-input-multiple-output (MIMO) amplify-and-forward (AF) relay. Such a network is interference limited and thus, an interference nulling strategy is reasonable. We first derive the necessary condition for interference nulling and(More)
We generalize the concept of multiuser peer-to-peer (MUP2P) relay networks to that of a multi-group multicasting (MGM) relay network where each source may broadcast its message to a group of multiple users. State-of-the-art beamforming methods, which have been proposed for MUP2P relay networks, are shown to be straightforwardly extendable to such MGM(More)
We consider the problem of transmit beamforming in multi-group multicasting systems with covariance-based channel state information (CSI) available at the transmitter where the total transmitted power is minimized subject to quality-of-service (QoS) constraints at the receivers. Previous approaches for this problem are based on semidefinite relaxation (SDR)(More)
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