Tap Extraction for Dispersive Radio Channel Measurements Using the EM Algorithm

Digital Communications The over-all objective of this project is the modelling of an indoor radio channel through feature extraction from measurements including a small multi-antenna receiving terminal and several active base stations (cf. Section on Antennas and Propagation). More specifically, the aim has been to estimate a multi-tap representation of the measured radio channels in order to investigate, e.g. multi-channel diversity, delay-spread and channel variations. The project is carried out in cooperation with colleagues from the Antennas and Propagation Research Group. The tap extraction was based on the EM (Expectation Maximization) algorithm. The number of taps was determined in an iterative scheme in which one tap was added at a time. In this approach the trade-off between the wish for simplification (i.e. few taps) and data consistency (more taps) was a major concern. In the resulting representation the number of taps varies between 1 and 6. (Christoffer Rødbro, Søren Holdt Jensen, Wim Kotterman, Gert Frølund Pedersen)