Holger Boche
ABSTRACT
In the investigation of equalizers and precoders for multiple-input multiple-output systems with intersymbol interference, completely new phenomena appear if the causality of theses filters is required. To investigate these phenomena, the inner-outer factorization is an important tool, both for theoretical investigations as well as a practical algorithm to calculate such filters. This paper investigates the properties of the inner-outer factorization operator for matrix valued transfer functions. It derives sufficient conditions on the transfer functions such that the inner and outer factors have the same system theoretical properties as the given transfer function, and such that this factorization operator is bounded. Acomparison to the spectral factorization mapping is provided and possible consequences for numerical algorithms are discussed.
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Index Terms
- MIMO - ISI channels: inner-outer factorization and applications to equalization
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