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We study an analog of the well-known Gel'fand Pinsker Channel which uses quantum states for transmission of data. We consider the case where both the sender's inputs to the channel and the channel states are elements of a finite set (cq-channel with state information at the sender). While the receiver has no information about the channel states, we distinguish between two cases at the sender: he either...
We study the arbitrarily varying wiretap channel (AVWC) under average error criterion when external common randomness (CR) can be used between the legitimate parties. We consider three scenarios: In the first one the CR is known to the eavesdropper, in the second it is not known to her and in the third there is no CR available. For the second scenario, we prove a complete coding theorem. For the third...
We give an explicit example that answers the question whether the transmission of messages over arbitrarily varying quantum channels can benefit from distribution of randomness between the legitimate sender and receiver in the affirmative.
We prove coding theorems for two scenarios of cooperating encoders for the multiple access channel with two classical inputs and one quantum output. In the first scenario (ccq-MAC with common message), the two senders each have their private messages, but would also like to transmit common messages. In the second scenario (ccq-MAC with conferencing encoders), each sender has its own set of messages,...
This paper investigates a signal processing architecture for cognitive radio based on a sub-Nyquist sampling of the wideband signal. Then spectrum scanning is performed by applying an adaptive digital filter to scan the bands which might be used for cognitive radio. In particular, the paper studies detectors which are tailored for the applied signal processing scheme and which takes into account the...
In this work, we study the MIMO Gaussian bidirectional broadcast channel (BBC) with common message and characterize the capacity region. Moreover, we show that the transmit covariance matrix optimization problem has the same structure as the corresponding optimization problem of the BBC without common message which leads to the comfortable position to transfer results from one scenario to the other...
We consider the oversampled noise-shaping subband quantizer (ONSQ) with the quantization noise being modeled as white noise. The problem at hand is to design an optimal feedback filter. Optimal feedback filters with regard to the current standard model of the ONSQ inhabit several shortcomings: the stability of the feedback loop is not ensured and the noise is considered independent of both the input...
The concept of bidirectional relaying is a key technique to improve the performance in future wireless networks. It applies to three-node networks, where a relay node establishes a bidirectional communication between two other nodes using a decode-and-forward protocol. It divides the whole communication into two phases, namely the multiple access and bidirectional broadcast phase. Here, we concentrate...
We address the problem of a multi-user relay network, where multiple single-antenna node pairs want to exchange information by using a multiple antenna relay node. Due to the half-duplex constraint of the relay, the exchange of information takes place in two steps. In the first step, the nodes transmit their data to the relay, while in the second step, the relay is broadcasting the data by using linear...
This paper studies the properties of Nash equilibrium for noncooperative games in interference coupled wireless systems, where it serves as an incentive-compatible solution concept and an operating point. A broad class of noncooperative power control games played among the users of the wireless system is defined based on a general interference function framework, which models the interference coupling...
The concept of bidirectional relaying shows the potential to improve the performance in wireless networks such as sensor, ad-hoc, and even cellular systems. It applies to three-node networks, where a relay node establishes a bidirectional communication between two other nodes. In the first phase of a decode-and-forward protocol, the two nodes transmit their messages to a relay node, which decodes...
This paper investigates the possibility of having convex formulations of optimization problems for interference coupled wireless systems. An axiomatic framework for interference functions proposed by Yates in 1995 is used to model interference coupling in our paper. The paper shows, that under certain very natural assumptions -- the exponential mapping is the unique transformation (up to a constant),...
In this paper we analyze the convergence behavior of convolution-type system representations for the Paley-Wiener space PWπ1. We completely characterize all stable linear time-invariant (LTI) systems for which we have convergence in the distributional sense by giving a necessary and sufficient condition for convergence. Furthermore, we prove that there are stable LTI systems and signals in PWπ1 for...
The concept of bidirectional relaying is a key technique to improve the performance in wireless networks such as sensor, ad-hoc, and even cellular systems. It applies to three-node networks, where a relay node establishes a bidirectional communication between two other nodes using a decode-and-forward protocol. We assume that the communication is disturbed by unknown varying interference and analyze...
The paper characterizes the class of all concave resource allocation problems in interference coupled wireless systems. An axiomatic framework for interference functions proposed by Yates in 1995 is used to model interference coupling in our paper. The paper shows that there exists no transformation, which ensures concavity for all linear interference functions for all functions of SINR. The paper...
The paradigm shift from coordinated to uncoordinated wireless networks comes along with the need of new concepts for the frequency usage since interference will be an ubiquitous phenomenon. In this work, we analyze unknown varying interference in wireless networks with the help of the concept of arbitrarily varying channels. This concept shows that the unknown interference has a dramatic impact on...
One key feature to improve the performance of future wireless communication systems will be the use of relays. In this work, we consider the bidirectional relay channel, where a relay node establishes a bidirectional communication between two nodes, and study coding strategies for the case of unknown varying channels. In the first phase of a decode-and-forward protocol the two nodes transmit their...
The Toeplitz Corona Theorem characterizes the infimal ???? norm of a systems right inverses in terms of a Toeplitz operators smallest singular value. Recently, it has been shown that the finite section method can be used to approximate this infimal ???? norm. In this paper, we point out that these results can also be used to approximate the limit of the gamma iteration in discrete-time ???? full information...
In this work we study optimal coding strategies for bidirectional relaying under the condition of arbitrarily varying channels. We consider a three-node network where a relay node establishes a bidirectional communication between two nodes using a spectrally efficient decode-and-forward protocol. In the first phase the two nodes transmit their messages to the relay node, which decodes them. In the...
In interference coupled wireless systems, where it is not possible to "orthogonalize" all the users in the system, we characterize the impact of interference coupling on the convexity of certain utility functions and problems. We introduce a general class of competitive user utility functions and natural competitive user utility functions. We further introduce the signal-to-interference...
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