Impact of reconstruction error using canonical channel representation in direct-spread systems

To enable coherent detection and obtain a diversity gain in mobile communication systems, channel parameters like direction-of-arrival (DOA), delay and Doppler shift for each diversity branch must be estimated in the receiver. With canonical channel representation the channel is projected onto a fixed set of coordinates, resulting in a set of diversity branches with fixed parameters and reduced receiver complexity in dense multipath environments. The price to pay for this complexity reduction is an error introduced by the projection onto the canonical base. It is shown that the degradation in performance due to channel estimation, e.g., using pilot symbols, is dominating the error due to the canonical channel representation