  Fifth generation (5G) cellular standards are set to utilize millimeter wave
(mmWave) frequencies, which enable data speeds greater than 10 Gbps and
sub-centimeter localization accuracy. These capabilities rely on accurate
estimates of the channel parameters, which we define as the angle of arrival,
angle of departure, and path distance for each path between the transmitter and
receiver. Estimating the channel parameters in a computationally efficient
manner poses a challenge because it requires estimation of parameters from a
high-dimensional measurement -- particularly for multi-carrier systems since
each subcarrier must be estimated separately. Additionally, channel parameter
estimation must be able to handle hybrid beamforming, which uses a combination
of digital and analog beamforming to reduce the number of required analog to
digital converters. This paper introduces a channel parameter estimation
technique based on the multilinear singular value decomposition (MSVD), a
tensor analog of the singular value decomposition, for massive multiple input
multiple output (MIMO) multi-carrier systems with hybrid beamforming. The MSVD
tensor estimation approach provides a computationally efficient method and is
shown to closely match the Cramer-Rao bound (CRB) of parameter estimates
through simulations. Limitations of channel parameter estimation and
communication waveform effects are also studied.
