This application discloses a communication
system and method, and a related device. The communication
system includes a CO device and a plurality of RRHs, where the plurality of RRHs constitute a
ring network by using optical fibers; the CO device is connected to the
ring network, and is configured to: modulate a
baseband signal to N first optical carriers that are generated by the CO device, to obtain N second optical carriers; and transmit the N second optical carriers to the
ring network by using a first
optical fiber. Any RRH of the plurality of RRHs is configured to: obtain a target optical carrier from received second optical carriers, convert the target optical carrier into an electrical
signal, and transmit the electrical
signal as a downlink signal. According to embodiments of this application, an all-
optical communication system is implemented by using a
layout of an optical component in an architecture and using an optical ring
network topology; and the communication system has a self-healing protection function.