A communication system includes a transmitter and remote receivers having each a set of receive elements. The transmitter includes a preprocessor and a set of transmit elements which radiate shaped beams including probing signals through a multipath communication channel. The preprocessor computes channel state information based on received responses to the probing signals, generate composited transfer functions based on the channel state information, generate the shaped beams based on the composited transfer functions, and process a plurality of input signals to be transmitted via the shaped beams to the remote receivers. The channel state information includes transfer functions, each characterizing at least one propagation path from one transmit element to one receive element. Each composited transfer function is a linear combination of the transfer functions. Each receive element is identified by a user element identification index in the transfer functions. Each remote receiver is identified by a user identification index.