A signal transmission method involving: receiving M·N digital transmit signal streams, each of which represents a transmit signal for a different corresponding antenna element of an M×N array of antenna elements; generating P digital transmit-beam signal streams from the M·N digital transmit signal streams, wherein each of the P digital transmit-beam signal streams is a corresponding linear combination of the M·N digital transmit signal streams; within an R×T Hybrid Massive MIMO system having R·T antenna elements, by applying appropriate phase shifts in an analog domain, causing the R×T Hybrid Massive MIMO system to simultaneously generate a set of P independent, differently directed transmit beams; and mapping each of the P digital transmit beam signal streams to a corresponding different one of the P independent, differently directed transmit beams, wherein M, N, P, R and T are integers, wherein R·TM·N, and wherein P