Distributed digital reference clock

A method comprising:

• interfacing wireless spectrum for at least two wireless services at a master host unit between digital signals and N-bit words of digitized spectrum;
• generating a digital master reference clock signal at the master host unit;
• transporting the digitized spectrum as a multiplexed signal on a digital medium between the master host unit and a hybrid expansion unit;
• transporting the digital master reference clock on the digital medium between the master host unit and the hybrid expansion unit;
• converting wireless spectrum for the at least two wireless services between the N-bit words of digitized spectrum and a first set of bands of analog spectrum at the hybrid expansion unit;
• generating an analog reference clock signal based on the digital master reference clock signal received at the hybrid expansion unit;
• transporting the first set of bands of analog spectrum for the at least two wireless services on an analog medium between the hybrid expansion unit and at least one remote unit having an air interface for each of the at least two wireless services;
• transporting the analog reference clock signal on the analog medium between the hybrid expansion unit and the at least one remote unit;
• and
• communicating the wireless spectrum in analog format at the at least one remote unit.

A communication system, comprising:

• a plurality of base station units;
• a master host unit, the master host unit adapted configured to communicate digital signals with service provider interfaces the plurality of base station units;
• a hybrid expansion unit coupled to the master host unit by a communication link, the master host unit and the hybrid expansion unit adapted configured to communicate N-bit words of digitized digital spectrum over the communication link, the hybrid expansion unit further adapted configured to convert between the N-bit words of digitized digital spectrum and a first set of bands of analog spectrum,
• a remote antenna unit coupled to the hybrid expansion unit by an analog communication medium, the hybrid expansion unit and the remote antenna unit adapted configured to communicate the first set of bands of analog spectrum over the analog communication medium, the remote antenna unit further adapted configured to transmit and receive wireless signals over air interfaces;
• wherein the master host unit includes a master clock distribution unit, the master clock distribution unit adapted to generate a digital master reference clock signal, the master host unit further adapted configured to generate a digital master reference clock signal and communicate the digital master reference clock signal over the communication link;
• wherein the hybrid expansion unit is further adapted configured to receive the digital master reference clock signal from the master host unit over the communication link, the hybrid expansion unit further adapted configured to generate an analog reference clock signal based on the digital master reference clock signal, the hybrid expansion unit further adapted configured to send the analog reference clock signal across the analog communication medium;
• and
• wherein the remote antenna unit is further adapted configured to receive the analog reference clock signal across the analog communication medium.