Patent ID: 11936429
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 4:
5. A wireless transmission method performed by a wireless transmission system including an accommodation station transmission unit and a base station transmission unit, the method comprising:
by the accommodation station transmission unit, modulating light to generate an optical signal based on an RF signal and outputting the generated optical signal;
by an optical demultiplexer included in the base station transmission unit, receiving the optical signal output by the accommodation station transmission unit from an input port, demultiplexing the received optical signal for a wavelength, and outputting the demultiplexed optical signal from, among a plurality of output ports assigned to a wavelength of the light, the output ports corresponding to the wavelength by each of a plurality of photoelectric converters included in the base station transmission unit being connected to each of the plurality of output ports of the optical demultiplexer, converting the optical signal output by the optical demultiplexer into an electrical signal to demodulate the RF signal and outputting the demodulated RF signal;
by a matrix operation unit included in the base station transmission unit including a plurality of first ports and a plurality of second ports, using each of the plurality of first ports as a reference port, performing, on a plurality of signals obtained by a plurality of reference ports, a BFN matrix operation of making a phase change that is different for a position of the reference port and the phase change that causes phases of signals output from the plurality of second ports to have a linear inclination, and by each of the plurality of first ports, receiving the RF signal output by the photoelectric converter connected to each of the plurality of first ports; and
by a plurality of transmission antennas included in the base station transmission unit, forming transmission beams in different directions for each wavelengths through emission of the RF signal, output from each of the second ports of the matrix operation unit, after the BFN matrix operation.