摘要:
An optical transmitter for generating return-to-zero alternative-mark-inversion (RZ-AMI) optical signals and a method for generating the optical signals are provided. The optical transmitter includes a light source radiating at its output an intensity-modulated light beam based upon intensity of a first data, a precoder for precoding a second data having the information identical to the first data, and a Mach Zehnder modulator for phase-modulating the intensity-modulated light on basis of the precoded second data to generate a return-to-zero alternative-mark-inversion (RZ-AMI) optical signal.
摘要:
An optical transmitter for generating return-to-zero alternative-mark-inversion (RZ-AMI) optical signals and a method for generating the optical signals are provided. The optical transmitter includes a light source radiating at its output an intensity-modulated light beam based upon intensity of a first data, a precoder for precoding a second data having the information identical to the first data, and a Mach Zehnder modulator for phase-modulating the intensity-modulated light on basis of the precoded second data to generate a return-to-zero alternative-mark-inversion (RZ-AMI) optical signal.
摘要:
Disclosed is a data transmission method for an MBS in a broadband wireless access system. The method includes the steps of constructing a Wibro frame by adding an FEC zone to a downlink portion of the Wibro frame by a radio access station, the FEC zone containing an FEC packet for performing a packet-based FEC scheme; and transmitting data to a plurality of mobile stations by the radio access station, the Wibro frame constructing the data.
摘要:
An optical network for bi-directional wireless communication is disclosed. The optical network includes a remote antenna unit for converting a downlink optical signal into a downlink radio signal, transmitting the downlink radio signal wirelessly, and converting an uplink radio signal received wirelessly into an uplink optical signal. An optical line is used as a transmission medium of the downlink optical signal and the uplink optical signal. The optical network also includes a central base station including a circulator linked to the remote antenna unit through the optical line, so that the central base station outputs the downlink optical signal to the remote antenna unit through the circulator and detects the uplink optical signal inputted through the circulator.
摘要:
Disclosed is a data transmission method for an MBS in a broadband wireless access system. The method includes the steps of constructing a Wibro frame by adding an FEC zone to a downlink portion of the Wibro frame by a radio access station, the FEC zone containing an FEC packet for performing a packet-based FEC scheme; and transmitting data to a plurality of mobile stations by the radio access station, the Wibro frame constructing the data.
摘要:
Integrated wired and wireless wavelength division multiplexing passive optical network (WDM PON) apparatus using a light source mode-locked to fed incoherent light includes: a fed light generator for providing fed light for up/downstream signals via a broadband light source emitting an incoherent optical signal; a central office (CO) for receiving, mode-locking, and downstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting an upstream optical signal transmitted from a subscriber unit; and the subscriber unit for receiving, mode-locking, and upstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting a downstream optical signal transmitted from the CO, wherein a wired optical transmitter for transmitting a baseband wired signal and a wireless optical transmitter for transmitting a high frequency radio frequency (RF) signal are comprised for up/downstream optical transmission of the CO and the subscriber unit.
摘要:
A method for setting an output bit rate for video data transmission in a WiBro system in which an uplink state value for a predetermined unit time is calculated to determine an uplink network state of the predetermined unit time. An average of uplink state values for a predetermined number of unit times is calculated, and a video encoding bit rate is increased if the average of the uplink state values is larger than a predetermined first threshold. However, the video encoding bit rate is decreased if the average of the uplink state values is less than a predetermined second threshold.
摘要:
A method for setting an output bit rate for video data transmission in a WiBro system in which an uplink state value for a predetermined unit time is calculated to determine an uplink network state of the predetermined unit time. An average of uplink state values for a predetermined number of unit times is calculated, and a video encoding bit rate is increased if the average of the uplink state values is larger than a predetermined first threshold. However, the video encoding bit rate is decreased if the average of the uplink state values is less than a predetermined second threshold.
摘要:
Disclosed is a method for controlling bit rates in consideration of wireless channel environment by an apparatus that transmits and receives moving picture encoding data via a wireless network. The apparatus for transmitting/receiving data through a wireless communication network connected to the apparatus including a channel state analyzing unit for analyzing a wireless channel environment, an encoding controller for generating control information containing information about a quantization parameter, skip or non-skip of frames indication, frame type indication, and use or non-use of an Error Resilient Tool (ERT) indication, in consideration of an analyzation result received from the channel state analyzing unit, a moving picture encoding unit for encoding incoming moving picture data, based on the control information received from the encoding controller; and a data transmitting/receiving unit for transferring the encoded moving picture data through the wireless channel to an exterior.
摘要:
A thermoelectric refrigerator/warmer using no external power, and a refrigerating/warming method are disclosed. A natural energy such as the solar energy is utilized so as to make an external power needless. Thus a thermoelectric device is made to convert the natural energy into electric power based on the difference between the internal and external temperatures, and this electric energy is converted again into a thermal energy by means of a peltier device, thereby varying the internal temperature of the apparatus. An outer part 4 of a thermoelectric device 3 is attached on the side face of the refrigerator/warmer, and an inner part 5 of it is attached on a bottom plate 7 of the refrigerator/warmer. Thus a thermoelectromotive force is generated based on the temperature difference between outside and inside of the refrigerator/warmer. The voltage thus generated is supplied to a peltier device 6 to cool or heat the bottom plate 7. In this manner, the thermoelectric refrigerator/warmer can be operated even without using an external power.