National Institute of Information and Communications Technology, Incorporated Administrative Agency

Yukiyoshi Kamio

Tetsuya Miyazaki

Satoshi Takahashi

Hiroshi Harada

Seiichi Sampei

Chang-Jun Ahn

An optical transmitter generates a transmission signal having a frame as a unit, the frame including a single optical pilot signal with a constant optical phase and a plurality of phase-modulated optical data signals, and outputs the transmission signal into a transmission line. In a receiver, a splitter splits the optical signal input from the transmission line. On a second arm of a Mach-Zehnder interferometer, an optical gate transmits the optical pilot signal and a duplicator duplicates the optical pilot signal output from the optical gate at predetermined time intervals. A balanced optical receiver converts the interfered optical signal output from the interferometer into an electrical signal. A gate and a discriminator extract the data from the electrical signal output from the receiver.

Method and apparatus for receiving data

An optical transmitter generates a transmission signal having a frame as a unit, the frame including a signal pilot signal with fixed amplitude and phase and two data bits to output the generated signal into a transmission line. In a receiver, a splitter splits the signal light from the transmission line. An optical delay delays the signal light for a 1-bit period. A first combiner combines the signal light from the transmission line and the output signal light from the optical delay. A photodetector converts the combined light into an electrical signal. A 3-bit optical delay, a second combiner, a BPF, and an oscillator generate a frame-timing signal. A gate separates a data from the output from the photodetector under the control of a gate control unit. A binary discriminator binary-discriminates the output signal from the gate.

Data transmission method and a system thereof

A communicating system is disclosed. The communicating system has a base station and a plurality of mobile stations that radio-communicate through an uplink channel and a downlink channel with frames each of which is composed of a plurality of time divided slots, each of the frames of the uplink channel and the downlink channel being transmitted in accordance with OFDM transmitting system. An OFDM sub carrier used in the OFDM transmitting system is divided in accordance with a predetermined diving method, each of the frames of the uplink channel or downlink channel being allocated to the divided portions of the OFDM sub carrier, a plurality of frames of the uplink channel or downlink channel being radio-communicated between one base station and a plurality of mobile stations.

Growing community of inventors

Tokyo, Japan

Yukiyoshi Kamio