Patent ID: 11876589
Assignee: FRAUNHOFER GESELLSCHAFT ZUR FÖRDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 4:
5. The communication device of claim 1, wherein the channel tensor is a four-dimensional, 4D, channel tensor, or represented either by a 4D channel covariance tensor, a 4D beamformed-channel tensor, or a 4D beamformed channel covariance tensor, as indicated by the CSI-Ind indicator, and wherein
the plurality of dominant principal components of the compressed 4D channel tensor of dimension Nr×Nt×S×D comprise:
a first set of r1 basis vectors comprised by a matrix ŪR=[uR,1, . . . , uR,r1]∈Nr×r1;
a second set of r2 basis vectors comprised by a matrix ŪT=[uT,1, . . . , uT,r2]∈Nt×r2;
a third set of r3 basis vectors comprised by a matrix ŪS=[uS,1, . . . , uS,r3]∈S×r3;
a fourth set of r4 basis vectors comprised by a matrix ŪD=[uD,1, . . . ,uD,r4]∈D×r4; and
r1r2r3r4 associated high-order singular values sijkl, sorted such that Σj,k,l|si,j,k,l|2≥Σj,k,l|si+1,j,k,l|2, Σi,k,l|si,j,k,l|2≥Σi,k,l|si,j+1,k,l|2, Σi,j,l|si,j,k,l|2≥Σi,j,l|si,j,k+1,l|2, and Σi,j,k|si,j,k,l|2≥Σi,j,k|si,j,k,l+1|2 for all i, j, k, l.