National Yang Ming Chiao Tung University

Jiun-Yu Sung

Chien-Hung Yeh

Chi-Wai Chow

A visible light communication method. Firstly, a plurality of binary logic streams is sequentially received and a serial-to-parallel conversion is performed on them to obtain a plurality of binary signal sets corresponding to each binary logic stream. Then, all the binary signal sets are respectively mapped to obtain the first OFDM symbols in frequency domain. The first OFDM symbols are respectively transformed into the second OFDM symbols in time domain. Then, a parallel-to-serial conversion is performed on the second OFDM symbols. Adequate cyclic prefix is added in each of the second OFDM symbols. Next, the relative intensity of each of the second OFDM symbols is regulated, and then a digital-to-analog conversion is performed on the second OFDM symbols to obtain analog electrical signals. Finally, visible lights respectively corresponding to the analog electrical signals are generated.

Visible light communication method

An integrated passive optical network system is disclosed. The system comprises an optical distribution network (ODN), a time-division multiplexing (TDM)-optical line terminal (OLT), a wavelength-division multiplexing (WDM)-optical line terminal (OLT), a plurality of time-division multiplexing (TDM)-optical network units (ONUs), and at least one wavelength-division multiplexing (WDM)-optical network unit (ONU) comprising a first filter. The TDM-OLT and the WDM-OLT respectively transmit a first optical signal carrying a first downstream signal and a second optical signal carrying a second downstream signal to the ONUs through the ODN, and wavelengths of the second optical signal and the first optical signal are different. The TDM-ONUs respectively retrieve the first downstream signal. The WDM-ONU uses the first filter to retrieve the second downstream signal.

Integrated passive optical network (PON) system

A wavelength-division multiplexing (WDM) optical fiber network system is disclosed, which comprises a signal provider generating at least one set of wavelength signals of a plurality of different wavelengths and coupled to a plurality of modulation modules. The modulation modules respectively coupled to a user receiver. The modulation module comprises a control unit generating a random sequence and a control signal corresponding to the random sequence, and transmitting the control signal to a first modulation unit. The control unit is coupled to the signal provider to receive the wavelength signals and controls the first modulation to retrieve a wavelength signal according to the control signal. The control unit rapidly changes the control signal according to the random sequence whereby the first modulation unit rapidly retrieves the wavelength signals of different wavelengths and transmits them to the user receiver, so as to prevent a specific wavelength from attack.

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Taipei, Taiwan

Jiun-Yu Sung