摘要:
A remote access unit (RAU) apparatus, coupled to a central station (CS) of an RoF network through at least one optical fiber, and which RAU apparatus includes at least one antenna, includes: first and second antenna ports coupled to the at least one antenna; first and second optical fiber ports coupled to the at least one optical fiber; a first coupler for decoupling a first downstream signal of a first duplexing method and a second downstream signal of a second duplexing method, which are input through the first optical fiber port; a circulator for outputting the first downstream signal input from the first coupler to the first antenna port and outputting a first upstream signal of the first duplexing method input from the first antenna port to the second optical fiber port; and a second coupler for outputting the second downstream signal input from the first coupler to the second antenna port and outputting a second upstream signal of the second duplexing method input from the second antenna port to the second optical fiber port.
摘要:
A radio over fiber (ROF) link apparatus capable of a stable TDD wireless service for a time division duplexing (TDD) baseband signal includes a central access platform (CAP) for receiving various kinds of data including the TDD baseband signal from upper layers, multiplexing the data, electro-optically converting the multiplexed data, and transmitting the converted data as downstream data through an optical fiber, and opto-electrically converting upstream data received through the optical fiber, demultiplexing the converted upstream data, and transmitting the demultiplexed upstream data to the respective upper layers, and a remote access unit (RAU) for receiving the downstream data through the optical fiber, opto-electrically converting the received downstream data to the multiplexed data, demultiplexing the multiplexed data, performing a wireless access process of the demultiplexed data, and transmitting the wireless access processed data to a wireless local area network (WLAN) service terminal through an antenna.
摘要:
Disclosed is a radio-over-fiber (ROF) system for supporting various services, the system comprising: a central access platform (CAP) for providing time division duplexing (TDD), frequency division duplexing (FDD), and broadcasting services, converting a TDD downward signal and FDD/broadcasting downward signals into optical signals, respectively, transmitting the converted optical signals to a remote access unit (RAU), converting a TDD upward signal and an FDD upward signal, which have been transmitted as optical signals from the RAU, into electric signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other; and the RAU for converting the TDD downward signal and FDD/broadcasting downward signals transmitted from the CAP into electric signals, respectively, converting the TDD upward signal and FDD upward signal to be transmitted to the CAP into optical signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other, wherein the RAU includes a plurality of signal filtering/separating/combining units, which wirelessly emit the TDD downward signal and FDD/broadcasting downward signals, having been converted into electric signals, through an antenna, and which separate wirelessly-received TDD upward signal and FDD upward signal from each other.
摘要:
Disclosed is a remote access unit for transmitting and receiving upstream and downstream data in which channels having different transmission scheme are multiplexed, and an optical network for bi-directional wireless communication using same. The remote access unit includes an antenna for receiving the downstream data and wirelessly transmitting same and for receiving the upstream data and providing same to the remote access unit, a switch for outputting downstream time division channels of the downstream data to the antenna and for receiving upstream time division channels of the upstream data from the antenna, and a controller for controlling the switch in order to prevent the upstream and downstream time division channels from overlapping.
摘要:
Disclosed is an ROF link apparatus for selecting an IF band in order to process various service signals through an MMF, which including transmitters for receiving the service signals, performing IF modulation for the service signals, and transferring the modulated IF signals, a first controller for scanning frequency characteristics of the MMF, searching for flat frequency bands, and transferring information regarding the flat frequency band, thereby controlling IF modulation to be performed, a link unit for combining the IF signals with output signals of the first controller, converting the combined signals into optical signals, transmitting the optical signals, converting the optical signals into electrical signals, and splitting the electrical signals, a second controller for receiving the output signals of the first controller, detecting information regarding the flat frequency band, and transferring the information to receivers, thereby controlling modulation to be performed, and the receivers for receiving the IF modulated signals, receiving the information from the second controller, and performing RF modulation.
摘要:
A remote access unit (RAU) apparatus, coupled to a central station (CS) of an RoF network through at least one optical fiber, and which RAU apparatus includes at least one antenna, includes: first and second antenna ports coupled to the at least one antenna; first and second optical fiber ports coupled to the at least one optical fiber; a first coupler for decoupling a first downstream signal of a first duplexing method and a second downstream signal of a second duplexing method, which are input through the first optical fiber port; a circulator for outputting the first downstream signal input from the first coupler to the first antenna port and outputting a first upstream signal of the first duplexing method input from the first antenna port to the second optical fiber port; and a second coupler for outputting the second downstream signal input from the first coupler to the second antenna port and outputting a second upstream signal of the second duplexing method input from the second antenna port to the second optical fiber port.
摘要:
Disclosed is a remote access unit for transmitting and receiving upstream and downstream data in which channels having different transmission scheme are multiplexed, and an optical network for bi-directional wireless communication using same. The remote access unit includes an antenna for receiving the downstream data and wirelessly transmitting same and for receiving the upstream data and providing same to the remote access unit, a switch for outputting downstream time division channels of the downstream data to the antenna and for receiving upstream time division channels of the upstream data from the antenna, and a controller for controlling the switch in order to prevent the upstream and downstream time division channels from overlapping.
摘要:
Disclosed is a radio-over-fiber (ROF) system for supporting various services, the system comprising: a central access platform (CAP) for providing time division duplexing (TDD), frequency division duplexing (FDD), and broadcasting services, converting a TDD downward signal and FDD/broadcasting downward signals into optical signals, respectively, transmitting the converted optical signals to a remote access unit (RAU), converting a TDD upward signal and an FDD upward signal, which have been transmitted as optical signals from the RAU, into electric signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other; and the RAU for converting the TDD downward signal and FDD/broadcasting downward signals transmitted from the CAP into electric signals, respectively, converting the TDD upward signal and FDD upward signal to be transmitted to the CAP into optical signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other, wherein the RAU includes a plurality of signal filtering/separating/combining units, which wirelessly emit the TDD downward signal and FDD/broadcasting downward signals, having been converted into electric signals, through an antenna, and which separate wirelessly-received TDD upward signal and FDD upward signal from each other.
摘要:
A radio over fiber (ROF) link apparatus capable of a stable TDD wireless service for a time division duplexing (TDD) baseband signal includes a central access platform (CAP) for receiving various kinds of data including the TDD baseband signal from upper layers, multiplexing the data, electro-optically converting the multiplexed data, and transmitting the converted data as downstream data through an optical fiber, and opto-electrically converting upstream data received through the optical fiber, demultiplexing the converted upstream data, and transmitting the demultiplexed upstream data to the respective upper layers, and a remote access unit (RAU) for receiving the downstream data through the optical fiber, opto-electrically converting the received downstream data to the multiplexed data, demultiplexing the multiplexed data, performing a wireless access process of the demultiplexed data, and transmitting the wireless access processed data to a wireless local area network (WLAN) service terminal through an antenna.
摘要:
A duobinary optical transmission device that uses a duobinary optical transmission technique is disclosed. The duobinary optical transmission device may use an X-cut Mach-Zehnder interferometer type modulator. The duobinary optical transmission device includes a light source that outputs a carrier wave. A duobinary encoder encodes an input non-return-to-zero (NRZ) electrical signal. A low pass filter (LPF) converts the encoded signal into a 3-level electrical signal. An optical intensity modulator modulates the phase and light intensity of the carrier wave according to the 3-level electrical signal and outputs a 2-level optical duobinary signal. The optical intensity modulator may be an X-cut optical intensity modulator including a substrate; an optical waveguide formed on the substrate, and an electrode for applying an electric field.