Abstract: A communications system includes a plurality of transmitting units that each generate a pilot signal modulated using quantum level overlay modulation to apply at least one orthogonal function to the pilot signal and transmit the modulated pilot signal from the transmitting unit over a pilot channel. A base station unit including a MIMO receiver for receiving the pilot signals over the pilot channels from the plurality of transmitting units, demodulating the modulated pilot signals using the quantum level overlay modulation to remove the at least one orthogonal function from the pilot signals and outputting the demodulated pilot signal. The at least one orthogonal function applied to the pilot signals are orthogonal to each other and substantially reduces pilot channel contamination between the pilot channels.