Method, communication device and communication system for mimo communication

A communication device for MIMO communication, comprising:

• a transmitting module, transmitting data;
• a receiving module, receiving data;
• and
• a processor, coupled to the transmitting module and the receiving module, and configured at least for:
• obtaining antenna information and channel information;
• determining eigenvalues of an intermediate matrix according to the antenna information and the channel information, wherein the intermediate matrix is related to an L-term approximated matrix for Neumann series expansion of a matrix inversion, the matrix inversion is an inverse of a K×K matrix, L is a positive integer, and K is a positive integer according to the antenna information;
• determining coefficients of the L-term approximated matrix from the eigenvalues of the intermediate matrix by calculating a coefficient approximation, wherein the coefficient approximation is mathematically expressed as
• [
• 1
• 1
• -
• φ
• 1
• 1
• 1
• -
• φ
• 2
• M
• 1
• 1
• -
• φ
• K
• ]
• ≈
• [
• 1
• φ
• 1
• Λ
• φ
• 1
• L
• -
• 1
• 1
• φ
• 2
• Λ
• φ
• 2
• L
• -
• 1
• M
• M
• M
• M
• 1
• φ
• K
• Λ
• φ
• K
• L
• -
• 1
• ]
• 
• [
• α
• 0
• α
• 1
• M
• α
• L
• -
• 1
• ]
• ,
• ϕ1˜ϕK are the eigenvalues of the intermediate matrix, and α1˜αK are the coefficients of the L-term approximated matrix;
• determining the matrix inversion according to the L-term approximated matrix with the determined coefficients of the L-term approximated matrix;
• and
• applying the matrix inversion for precoding transmit data or equalization on received data.

A communication system for MIMO communication, comprising:

• K first communication devices, each of the communication devices comprising single antenna, and K being a positive integer;
• a second communication device, comprising N antennas, wherein N is a positive integer, and the second communication device is configured at least for:
• obtaining antenna information and channel information;
• determining eigenvalues of an intermediate matrix according to the antenna information and the channel information, wherein the intermediate matrix is related to an L-term approximated matrix for Neumann series expansion of a matrix inversion, the matrix inversion is an inverse of a K×K matrix, L is a positive integer, and K is determined according to the antenna information;
• determining coefficients of the L-term approximated matrix from the eigenvalues of the intermediate matrix by calculating a coefficient approximation, wherein the coefficient approximation is mathematically expressed as
• [
• 1
• 1
• -
• φ
• 1
• 1
• 1
• -
• φ
• 2
• M
• 1
• 1
• -
• φ
• K
• ]
• ≈
• [
• 1
• φ
• 1
• Λ
• φ
• 1
• L
• -
• 1
• 1
• φ
• 2
• Λ
• φ
• 2
• L
• -
• 1
• M
• M
• M
• M
• 1
• φ
• K
• Λ
• φ
• K
• L
• -
• 1
• ]
• 
• [
• α
• 0
• α
• 1
• M
• α
• L
• -
• 1
• ]
• ,
• ϕ1˜ϕK are the eigenvalues of the intermediate matrix, and α1˜αK are the coefficients of the L-term approximated matrix;
• determining the matrix inversion according to the L-term approximated matrix with the determined coefficients of the L-term approximated matrix;
• and
• applying the matrix inversion for precoding transmit data or equalization on received data.