Synchronization of frames in multiple streams in a wireless communications system (wcs)

A central unit device, comprising:

• a counter configured to place a frame counter number in a frame;
• a transmitter configured to send:
• a first frame with a first frame counter number to a first remote unit;
• and
• a second frame with the first frame counter number to a second remote unit;
• a receiver configured to receive:
• a third frame with the first frame counter number and a first timestamp from the first remote unit;
• and
• a fourth frame with the first frame counter number a second timestamp from the second remote unit;
• and
• a control circuit comprising a comparator;
• the control circuit configured to compare with the comparator the first and second timestamps in the third and fourth frames and calculate a delay for a stream of frames corresponding to the first frame.

A remote unit comprising:

• an input configured to receive a first frame in a first stream, the first frame having a first frame counter number;
• and
• a stamp and loopback circuit configured to:
• generate a timestamp on arrival of the first frame;
• insert the timestamp in a second frame;
• and
• cause the second frame to be sent back to an origin of the first frame.

A wireless communications system (WCS), comprising:

• a digital routing unit (DRU) coupled to a centralized services node via a baseband unit (BBU), the DRU comprising a frame counter;
• and
• a plurality of remote units each coupled to the DRU via a plurality of optical fiber-based communications media, respectively;
• wherein:
• the DRU is configured to:
• receive a downlink communications signal from the centralized services node;
• convert the downlink communications signal into a plurality of downlink communications signals;
• distribute the plurality of downlink communications signals to the plurality of remote units using frames having frame counter numbers from the frame counter;
• receive a plurality of uplink communications signals from the plurality of remote units, respectively;
• convert the plurality of uplink communications signals into an uplink communications signal;
• and
• provide the uplink communications signal to the centralized services node.