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J. Maurer, J. Jaldén, D. Seethaler, G. Matz:
"Vector Perturbation Precoding Revisited";
Talk: Gastvortrag ETH Zürich, ETH Zürich (invited); 01-23-2009.

We consider the downlink of a multi-user system with multiple antennas at the base station. Vector perturbation (VP) precoding is a very promising variant of transmit-side channel inversion allowing for a low-complexity detection. Unfortunately, conventional VP is based on the following impractical and unrealistic assumptions: power normalization factor knowledge at the receivers, infinite dynamic range, and perfect channel state information.

In this work, we will first show that violation of any of the above idealizing assumptions results in an error floor. Motivated by these observations, we propose a novel scheme which we term transmit outage precoding (TOP). TOP uses a fixed power scaling and avoids transmitting when the available power is not sufficient to perform channel equalization at the transmit side, an event referred to as outage. We also show how to augment TOP to be able to deal with limited dynamic range at the receiving ends. A theoretical analysis of the diversity order and numerical results obtained by simulations illustrate the performance of our precoding scheme under a variety of CSI models.

We consider the downlink of a multi-user system with multiple antennas at the base station. Vector perturbation (VP) precoding is a very promising variant of transmit-side channel inversion allowing for a low-complexity detection. Unfortunately, conventional VP is based on the following impractical and unrealistic assumptions: power normalization factor knowledge at the receivers, infinite dynamic range, and perfect channel state information.

In this work, we will first show that violation of any of the above idealizing assumptions results in an error floor. Motivated by these observations, we propose a novel scheme which we term transmit outage precoding (TOP). TOP uses a fixed power scaling and avoids transmitting when the available power is not sufficient to perform channel equalization at the transmit side, an event referred to as outage. We also show how to augment TOP to be able to deal with limited dynamic range at the receiving ends. A theoretical analysis of the diversity order and numerical results obtained by simulations illustrate the performance of our precoding scheme under a variety of CSI models.

Multiuser MIMO systems, vector perturbation precoding, diversity order, dynamic range