Patent ID: 9276648
Filing Date: 2016-03-01
CPC Classification: H01Q,H04B,H04L

Claim Text:
1. A method for performing multiple access in wireless OFDM cellular systems considering both space and frequency domains, comprising at least one base station equipped with a large number of antennas according to a two-dimensional rectangular array and a number M of cell users, said rectangular array comprising N 1 antenna elements along one axis with a regular spacing d x and N 2 antenna elements along a perpendicular axis with a regular spacing d y , said cell users being characterized by spherical angles (θ,φ) in a spherical coordinate system, characterized in that in order to achieve orthogonal multiple access the method comprises using an orthogonal space-frequency processing unit for: selecting a grid spacing (Δu, Δv) in a (u, v) domain through the equations:  where λ denotes a wavelength of a system operating frequency, and the (u, v) domain is obtained from the following transformation of the spherical angles (θ,φ): discretizing the (u, v) domain according to the following expressions:  where a visible region of a grid corresponds to values enclosed within a unit circle according to the equation: constructing a set of signals S  where S calculating the time-domain excitations coefficients A  where N obtaining the frequency contents S