No abstract

Direct-conversion architectures suffer from the mismatch between the In-phase (I) and the Quadrature-phase (Q) branches, commonly called I/Q imbalance. Even low I/Q imbalances imply poor performance of Orthogonal Frequency Division Multiplexing (OFDM) systems. In this paper, we propose a new algorithm that uses both training and data symbols in a decision-directed fashion to jointly estimate the channel and compensate for high receiver I/Q imbalance. Simulation results show that our method can compensate for high I/Q imbalance values and also estimate a frequency selective channel.

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In this paper, we propose a new channel equalization using frequency and/or time spreading for UWB multiband OFDM schemes. The proposed equalizer is optimal in the least square sense, and does not increase complexity compared to classical equalizers. The performance of this equalizer is studied for channel delay spread below the guard interval.