The method comprising a 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 N1 antenna elements along one axis with a regular spacing dx and N2 antenna elements along a perpendicular axis with a regular spacing dy, said users being characterized by angles (θ,φ) in a spherical coordinate system, where in order to achieve orthogonal multiple access the method comprises: selecting a grid spacing (Δu,Δv) in the (u, v) domain; discretizing the (u, v) domain; constructing a set of signals ST[k,l,f]; calculating time-domain excitations AT[n,m,t]for the antenna elements in the array given by coordinates (ndx,mdy) for generation of the downlink transmit signals; and obtaining the frequency contents SR[k,l,f] of the complex baseband signals received from the M users in the uplink.The system implements the method of the invention.