Abstract: 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.

Abstract: This application discloses an antenna apparatus, including an antenna array and an adjustable phase shifter. In each row of antenna elements in the antenna array, antenna elements on a same radio frequency RF channel are spaced by M antenna elements, where M is used to determine a quantity of beams in a first beam group and a quantity of beams in a second beam group, and M is an integer greater than 1. When the adjustable phase shifter is at a first angle, the first beam group is obtained; or when the adjustable phase shifter is at a second angle, the second beam group is obtained. This application discloses a beam adjustment method. In this application, a plurality of beams can be formed in a horizontal direction, and the beams are grouped by using an adjustable phase shifter, thereby effectively improving beam adjustment flexibility.

Abstract: This application discloses an antenna apparatus, including an antenna array and an adjustable phase shifter. In each row of antenna elements in the antenna array, antenna elements on a same radio frequency RF channel are spaced by M antenna elements, where M is used to determine a quantity of beams in a first beam group and a quantity of beams in a second beam group, and M is an integer greater than 1. When the adjustable phase shifter is at a first angle, the first beam group is obtained; or when the adjustable phase shifter is at a second angle, the second beam group is obtained. This application discloses a beam adjustment method. In this application, a plurality of beams can be formed in a horizontal direction, and the beams are grouped by using an adjustable phase shifter, thereby effectively improving beam adjustment flexibility.

Abstract: This application discloses a beam generation method and a base station. In some implementations, planar array antennas are stacked vertically, to form two half planes, and element weighting is independently performed on each half plane. A signal generated by using a baseband may be mapped to an upper-half planar antenna array of a planar array antenna, or mapped to a lower-half planar antenna array of a planar array antenna, or mapped to both an upper-half planar antenna array of a planar array antenna and a lower-half planar antenna array of the planar array antenna, to form a beam.