Data transmission method, radio frequency unit, baseband unit, and communication system
This application provides a data transmission method, a radio frequency unit, a baseband unit, and a communication system. The baseband unit includes: a multi-wavelength integrated light source, configured to generate a first optical carrier and a second optical carrier that have different wavelengths; a first modulator, configured to modulate downlink data sent to the first radio frequency unit to the first optical carrier, to obtain a first downlink optical signal; a second modulator, configured to modulate downlink data sent to the second radio frequency unit to the second optical carrier, to obtain a second downlink optical signal; and a multiplexer/demultiplexer, configured to multiplex the first downlink optical signal and the second downlink optical signal into a downlink combined optical signal and send the downlink combined optical signal.
1 . A radio frequency unit, comprising an input/output interface, a power splitter and a modulator, wherein
the input/output interface is configured to receive an optical carrier modulated with downlink data from a baseband unit;
the power splitter is configured to split the optical carrier into a first part of the optical carrier to a photoelectric detector for downlink data reception and a second part of the optical carrier to the modulator for uplink data modulation;
the modulator is configured to modulate uplink data sent to the baseband unit to the second part of the optical carrier, to obtain an uplink optical signal; and
the input/output interface is further configured to send the uplink optical signal to the baseband unit.
2 . The radio frequency unit of claim 1 , wherein
the optical carrier and the uplink optical signal are transmitted in a same optical fiber; or
the optical carrier and the uplink optical signal are transmitted in two different optical fibers.
3 . The radio frequency unit of claim 1 , wherein the modulator is configured to amplify the second part of the optical carrier and erase the downlink data in the second part of the optical signal before modulating the uplink data.
4 . A system comprising a baseband unit and a plurality of radio frequency units, wherein
the baseband unit comprises a multi-wavelength integrated light source configured to generate a plurality of optical carriers for the plurality of radio frequency units, a first optical carrier of the plurality of optical carriers being modulated with downlink data from the baseband unit;
a first radio frequency unit of the plurality of the plurality of radio frequency units is configured to receive the first optical carrier of the plurality of optical carriers, and send a first uplink optical signal to the baseband unit, wherein the first radio frequency unit comprises:
a power splitter, configured to split the first optical carrier into a first part of the first optical carrier to a photoelectric detector for downlink data reception and a second part of the first optical carrier to a modulator for uplink data modulation;
the modulator, configured to modulate uplink data of the first radio frequency unit to the second part of the first optical carrier to obtain the first uplink optical signal.
5 . The system of claim 4 , wherein the multi-wavelength integrated light source is configured to generate at least two optical carriers for each of the plurality of optical carriers, the at least two optical carriers including an optical carrier for downlink data modulation and an optical carrier for uplink data modulation.
6 . The system of claim 5 , wherein the baseband unit comprises;
a multiplexer/demultiplexer, configured to multiplex optical signals over the plurality of optical carriers to obtain a combined optical signal, the optical signals including a first part of optical signals modulated with downlink data and a second part of optical signals without downlink data modulated; and
an optical circulator, configured to receive a combined uplink optical signal from a same fiber of that for transmitting the combined downlink optical signal.
7 . The system of claim 4 , wherein the modulator is configured to amplify the second part of the first optical carrier and erase the downlink data in the second part of the first carrier before modulating the uplink data.