Ramireddy, VenkateshVenkateshRamireddyLandmann, MarkusMarkusLandmannGroßmann, MarcusMarcusGroßmannRömer, FlorianFlorianRömer2022-03-082022-03-082019https://publica.fraunhofer.de/handle/publica/312482A communication device for providing an explicit channel state information, CSI, feedback in a wireless communication system includes a transceiver to receive, from a transmitter a radio signal via a radio time-variant frequency MIMO channel, the radio signal including downlink reference signals according to a reference signal configuration, and downlink signals comprising the reference signal configuration, and a processor. The processor estimates the CSI using measurements on the downlink reference signals of the radio channel according to the reference signal configuration over one or more time instants/slots, constructs a frequency-domain channel tensor using the CSI estimate, performs a higher-order principal component analysis, HO-PCA, on the channel tensor, identifies a plurality of dominant principal components of the channel tensor, thereby obtaining a compressed channel tensor, and reports to the transmitter the explicit CSI comprising the dominant principal components of the channel tensor.en621006patent3576361