Patent ID: 11923905
Assignee: COMBA NETWORK SYSTEMS COMPANY LIMITED
Field: Telecommunications (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 14:
15. The signal transmission method according to claim 14, wherein: two adjacent ones of the digital-analog expansion units are cascaded by optical fibers through respective optical transceiver modules, and a first digital-analog expansion unit of the at least two digital-analog expansion units is connected to the source unit through an optical fiber; and
the signal transmission method further includes:
determining, by the digital-analog expansion unit according to whether features of multi-channel signals received by a current digital-analog expansion unit are the same, whether to digitally combine the received multi-channel signals;
if a signal feature of a first uplink digital radio frequency signal is the same as that of a second uplink digital radio frequency signal, digitally combining, by the digital-analog expansion unit, the first uplink digital radio frequency signal with the second uplink digital radio frequency signal to obtain a third uplink digital radio frequency signal of the current digital-analog expansion unit, converting the third uplink digital radio frequency signal to obtain an uplink optical signal of the current digital-analog expansion unit, and transmitting the uplink optical signal to an upper-stage digital-analog expansion unit or the source unit; wherein the first uplink digital radio frequency signal is obtained by processing the uplink optical signal of a lower-stage digital-analog expansion unit by the current digital-analog expansion unit; the second uplink digital radio frequency signal is obtained by performing analog-to-digital conversion and baseband processing on the uplink analog radio frequency signal of the remote cascade chain connected to the current digital-analog expansion unit by the current digital-analog expansion unit;
if the signal feature of the first uplink digital radio frequency signal is different from that of the second uplink digital radio frequency signal, converting, by the digital-analog expansion unit, the first uplink digital radio frequency signal and the second uplink digital radio frequency signal respectively to obtain corresponding uplink optical signals, and transmitting the uplink optical signals to the upper-stage digital-analog expansion unit or the source unit; and
framing, by the digital-analog expansion unit, a downlink digital radio frequency signal transmitted by the source unit, and transmitting the framed digital radio frequency signal transparently to a lower-stage digital-analog expansion unit through an optical fiber.