Patent ID: 11936447
Assignee: NEC CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 13:
14. A non-transitory computer-readable recording medium recording storing a program causing a computer provided in an OAM (Orbital Angular Momentum) mode multiplexing transmission apparatus, which includes a UCA (Uniform Circular Array) antenna that includes N antenna elements (N is an integer of 2 or more) arranged in a ring shape at equal intervals and which is connected to a database that stores information about an ideal MIMO (Multiple Input and Multiple Output) channel matrix, which is calculated by using an array diameter of the UCA antenna, a number of antenna elements, an RF frequency, and a link distance as parameters, in a state in which transmission and reception UCA antennas face each other or which is connected to a calculation apparatus that calculates the information, to perform processing for:
regularly calculating correction values relating to signal phase rotation by using a MIMO channel matrix estimated with known signals embedded in received transmission frames and the ideal MIMO channel matrix;
correcting an antenna tilt and an individual difference in characteristics among RF circuits by using the correction values; and
regularly feeding back the correction values from a receiving end to a transmitting end.