Fuente: Wipo "digitalization" A communication system includes master host unit, hybrid expansion unit, analog remote antenna unit, and digital remote antenna unit. Master host unit communicates analog signals with at least a first service provider interface using first bands of analog spectrum. Master host unit and hybrid expansion unit communicate first N-bit words of digitized spectrum over first digital link. Hybrid expansion unit converts between first N-bit words and second bands of analog spectrum. Hybrid expansion unit and analog remote antenna unit communicate second bands over analog medium. Analog remote antenna unit transmits and receives first plurality of wireless signals over air interfaces. Master host unit and digital remote antenna unit communicate second N-bit words of digitized spectrum over second digital link. Digital remote antenna unit converts between second N-bit words and third bands of analog spectrum. Digital remote antenna unit transmits and receives second wireless signals over air interfaces.