Receiver Design for General Nonorthogonal Unitary Space-time Constellations with Enhanced Channel Estimation ⋆

We propose a high-performance receiver for general nonorthogonal unitary space-time constellations (NOUSTC) in this paper. The received signals are transformed to derive new signals that bear channel state information (CSI). By using the output of the conventional noncoherent detector to transform the received signals in our scheme, we can obtain for each time block not only the past and the present CSIbearing signals as that in the previously proposed generalized quadratic receiver (GQR) using decisionfeedback method, but also the future ones, which can be all used to estimate the CSI, thus resulting in an enhanced channel estimation and ultimately a receiver for general NOUSTC with much better performance than the previously proposed GQR using decision-feedback method. Simulation results show the good performance of the proposed receiver.