US 11,996,910 B2
Doppler codebook-based precoding and CSI reporting for wireless communications systems
Venkatesh Ramireddy, Erlangen (DE); Markus Landmann, Erlangen (DE); Marcus Groβmann, Erlangen (DE); and Sutharshun Varatharaajan, Erlangen (DE)
Assigned to Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Munich (DE)
Filed by Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Munich (DE)
Filed on Mar. 10, 2021, as Appl. No. 17/197,562.
Application 17/197,562 is a continuation of application No. PCT/EP2018/074444, filed on Sep. 11, 2018.
Prior Publication US 2021/0226674 A1, Jul. 22, 2021
Int. Cl. H04B 7/0417 (2017.01); H04B 7/01 (2006.01); H04B 7/0456 (2017.01); H04B 7/06 (2006.01)
CPC H04B 7/0417 (2013.01) [H04B 7/01 (2013.01); H04B 7/0486 (2013.01); H04B 7/0626 (2013.01); H04B 7/0632 (2013.01); H04B 7/0639 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A communication device for providing a Channel State Information (CSI) feedback in a wireless communication system, the communication device comprising:
a transceiver configured to receive, from a transmitter a radio signal via a time-variant, frequency-selective Multiple-input Multiple-output (MIMO) channel, the radio signal comprising downlink reference signals according to a reference signal configuration comprising a number of antenna ports, and downlink signals comprising the reference signal configuration; and a
processor configured to
estimate a CSI using measurements on the downlink reference signals on the radio channel, the downlink reference signals provided over a certain observation time,
select, based on a performance metric, a Doppler-delay-beam precoder matrix, W, for a composite Doppler-delay-beam three-stage precoder, the Doppler-delay-beam three-stage precoder being based on one or more codebooks, the one or more codebooks comprising
one or more transmit-side spatial beam components of the composite Doppler-delay-beam three-stage precoder,
one or more delay components of the composite Doppler-delay-beam three-stage precoder, and
one or more Doppler-frequency components of the composite Doppler-delay-beam three-stage precoder,
calculate either one or more of a Channel Quality Indicator (CQI), and/or a Precoder Matrix Indicator (PMI), and/or a Rank Indicator (RI), using the CSI and the composite Doppler-delay-beam three-stage precoder with the selected Doppler-delay-beam precoder matrix, W, and
report to the transmitter the CSI feedback comprising either one or more of the CQI, and/or the PMI and/or the RI, wherein the PMI and RI are used to indicate the Doppler-delay-beam three-stage composite precoder matrix for the configured antenna ports,
wherein the one or more delay components and/or the one or more Doppler-frequency components of the composite Doppler-delay-beam three-stage precoder are defined by one submatrix of a Discrete Fourier Transform (DFT) matrix or by a-one sub-matrix of an oversampled DFT matrix.