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We study robust transceiver optimization in a downlink, multiuser, wireless system, where the transmitter and the receivers are equipped with antenna arrays. The robustness is defined with respect to imperfect knowledge of the channel at the transmitter. The errors in the channel state information are assumed to be bounded, and certain quality-of-service(More)
We consider the problem of sum rate maximization with joint resource allocation and interference mitigation by multiantenna processing in wireless networks. The denominators in the users' signal-to-interference-plus-noise expressions are assumed to be representable in the form of matrix-based, concave interference functions. It is shown that the problem of(More)
—The problem of transceiver optimization in multiuser multiple-input multiple-output downlink wireless systems is considered. The base station is assumed to possess only estimated, erroneous values of channel coefficients. The exact channels lie in uncertainty regions, specified by the Frobe-nius norms of the error matrices. An iterative optimization of the(More)
We consider a downlink wireless system with a multi-antenna base station (BS) and single-antenna users. The error in the channel knowledge at the BS is assumed to have Gaussian distribution. Power allocation strategies are designed in order to satisfy the users' quality-of-service targets with certain probabilities. Conservative solutions of the problems(More)
In EU FP7 project SAPHYRE, we study the nonorthogonal spectrum sharing scenario, in which multiple operators are allowed to utilize the same frequency band in the same location and time. A major impairment in such a scenario is the interference that the cochannel transmissions create. Assuming that the transmitters are equipped with multiple antennas, we(More)
This paper studies the convergence of a fixed point iteration algorithm for the problem of max-min signal-to-interference ratio (SIR) balancing. Differently from the existing work on the subject, the interference in the system is assumed to fall into the axiomatic framework of general interference functions. Monotonicity of the extremal SIR values during(More)
The knowledge of the channel at the transmit side of a communication system can be exploited by using precoding techniques, from which the overall transmission quality might benefit significantly. However, in practical wireless systems, the channel state information is prone to errors, which sometimes deteriorates the performance drastically. In this paper,(More)
Proportional fair resource allocation can be interpreted as a symmetric Nash bargaining game associated with a framework of axioms. However, the assumption of symmetry is not always appropriate, especially for users with different service and priority classes. Also, the axiom "scale transformation covariance" is quite restrictive in a wireless context. In(More)