Electronics and Telecommunications Research Institute

Minkyu Sung

Seung-Hyun Cho

Min Soo Kim

Joonyoung Kim

Hwan Seok Chung

Sang Rok Moon

Eon-Sang Kim

Won Kyoung Lee

Provided are an apparatus and method of generating a terahertz (THz) signal using a directly-modulated laser. An apparatus of generating a THz signal includes a first directly-modulated laser configured to output a local oscillator (LO) signal, a second directly-modulated laser configured to receive a baseband signal used as data and optically modulate the baseband signal, a band-pass filter configured to filter a spectral component of the baseband signal optically modulated and outputted through the second directly-modulated laser by using a specific frequency bandwidth, a coupler configured to couple the baseband signal filtered through the band-pass filter and the LO signal to each other, and a uni-travelling-carrier photodiode (UTC-PD) configured to generate a THz signal by beating the baseband signal and the LO signal coupled to each other.

Apparatus and method of generating terahertz signal using directly-modulated laser

Disclosed is a method and apparatus for phase error compensation having tolerance to a cyclic slip. The method includes determining first phase error candidates based on symbol phases of a first block of a received signal, determining an initial estimation error according to the first phase error candidates, determining second phase error candidates based on symbol phases of a second block of the received signal, determining a final estimation error according to the initial estimation error and the second phase error candidates, and compensating for a phase of the received signal according to the final estimation error.

Method and apparatus for phase error compensation having tolerance to cyclic slip

A transmission performance monitoring method for monitoring a transmission performance based on an analog optical link and an apparatus performing the method. The transmission performance monitoring method and apparatus centrally monitor an RF signal transmission performance in an analog optical link-based mobile haul or indoor distributed antenna system.

Transmission performance monitoring method for monitoring transmission performance based on analog optical link, and monitoring apparatus performing the method

An optical repeater performs an electrical-to-optical conversion based on a power level of an optical signal or an optical modulation index (OMI) required by a radio unit or a host unit connected to the optical repeater. Further, the optical repeater performs an optical-to-electrical conversion based on a power level of a radio frequency (RF) signal required by the radio unit or the host unit connected to the optical repeater.

Optical repeater adjusting power of output optical signal and output electrical signal and method performed by the optical repeater

A method and apparatus for adjusting a modulation index of an analog optical signal using an interference phenomenon of a coherent light, the method including dividing an analog optical signal for a first path and a second path, extracting an optical carrier from an analog optical signal divided for the first path, controlling an intensity and a phase of the optical carrier, and controlling a modulation index of the analog optical signal by combining an analog optical signal divided for the second path and the optical carrier of which the intensity and the phase are controlled.

Apparatus and method for adjusting modulation index of analog optical signal using interference phenomenon of coherent light

A host device uses an intermediate frequency determined based on frequencies of a second-order nonlinear intermodulation distortion component and a harmonic component which are generated in an analog optical link connected to the host device, for example, an analog optical link of a distributed antenna system (DAS), and precompensates for the second-order nonlinear intermodulation distortion component and the harmonic component generated in the analog optical link.

Host device preventing distortion of optical signal due to nonlinear noise, and distributed antenna system including the host device

Structures of a transmission apparatus and a reception apparatus using a mobile fronthaul that transmit and receive a frequency synchronization signal and a management control signal using at least one of in-band signaling and wavelength division multiplexing (WDM) in a single band or multiple bands of a mobile fronthaul using an intermediate frequency-over-fiber (IFoF) based analog transmission scheme.

Transmission apparatus and reception apparatus using mobile fronthaul

Provided is a frequency allocation method and a transmission apparatus for performing the method, the frequency allocation method may allocate a center frequency of a first intermediate frequency (IF) carrier of combined IF carriers at a position which is a predetermined interval apart based on direct current (DC) to avoid in view of a non-linear signal distortion component that is generated by an interaction between a chirp and a chromatic dispersion of a laser in a mobile fronthaul.

Frequency allocation method and transmission apparatus for performing the method

A host unit is provided between a remote radio head and a radio unit. The host unit performs a conversion between a digital optical signal used by the remote radio head and an analog optical signal used by the radio unit. A frequency of the analog optical signal converted by the host unit may be an intermediate frequency. The radio unit performs a conversion between an analog optical signal used by the host unit and an analog radio signal used by a user terminal. A frequency of the analog radio signal may be included in a millimeter wave band or radio frequency band.

Host unit and radio unit for distributed antenna system supporting large data traffic

A remote radio head disposed between a baseband unit and a host unit. The remote radio head may transmit and receive a digital optical signal to the baseband unit, transmit and receive an analog optical signal to the host unit, and convert the digital optical signal and the analog optical signal, a frequency of the analog optical signal transmitted and received by the remote radio head and the host unit may be an intermediate frequency of a baseband, the host unit may be disposed between the remote radio head and a radio unit, the host unit and the radio unit may transmit and receive the analog optical signal, and the frequency of the analog optical signal transmitted and received by the host unit and the radio unit may be the intermediate frequency with a baseband signal.

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Seoul, South Korea

Minkyu Sung