Power line carrier baseband signal modem based on COFDM (Coded Orthogonal Frequency Division Multiplexing)
A modem, power line carrier technology, applied in distribution line transmission system, multi-frequency code system, etc., can solve the problems of performance indicators such as communication system bit error rate deterioration, signal-to-noise ratio decline, sub-channel damage, etc.
Inactive Publication Date: 2011-01-19
SHENZHEN YESTUNED IND
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Problems solved by technology
[0008] Although OFDM has strong anti-interference ability, some sub-channels of OFDM signal may still be damaged due to fading, white noise, impulse noise, interference
The signal-to-noise ratio in these sub-channels suffering from fading or narrow-band interference drops significantly, making these sub-channels very unreliable, which seriously deteriorates performance indicators such as bit error rate of the entire communication system
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[0021] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0022] In the following description, the same drawing reference numerals are used for the same components even in different drawings, and matters such as detailed structures and components defined in the description are only for helping comprehensive understanding of the present invention. Therefore, it is apparent that the present invention can be carried out without those defined matters. Also, well-known functions and constructions will not be described in detail since they would obscure the invention in unnecessary detail.
[0023] figure 1 A short explanatory diagram of the COFDM baseband signal modem system is shown. The modulator 101 modulates the data into a preferred data format, and then uses the antenna to send the data to the demodulator 102, and the demodulator 102 also receives the data through the antenna and demodulates...
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The invention relates to a high-speed power line carrier communication modem, in particular to a method and a device for carrying out COFDM (Coded Orthogonal Frequency Division Multiplexing) modulation on a digital signal at a transmitting terminal and carrying out COFDM demodulation at a receiving terminal. The method comprises the following steps of: coding N digital signals obtained from an information source and converting the digital signals into digital baseband signals; mapping the digital baseband signals for improving information transmission rate thereof; converting signals obtained by carrying out Inverse Discrete Fourier Transform (IFFT) on the mapped data streams into analog signals through a digital to analog converter (DAC). The demodulation method is adverse to the modulation method, which comprises the steps of first carrying out OFDM demodulation in the COFDM process and then coding. The method can resist against the disturbances of the frequency selective fading, the multipath fading and like of a power line carrier channel, and can remarkably improve the transmission rate of the power line communication.
Description
【Technical field】 [0001] The present invention relates to a modem used in a power line carrier communication system, the modem performs coded orthogonal frequency division multiplexing (coded orthogonal frequency division multiplexing, COFDM) processing on a baseband signal, and is used in a power line network such as a distribution line network to communicate. 【Background technique】 [0002] Power Line Communication (PLC) is a communication method that utilizes an existing power line network as an information transmission medium. Because the power line network is widely distributed, using the power line as the communication medium does not require drilling holes in the room to rebuild the communication network, which has the advantages of low cost, convenient connection, and less interference from the outside world. In the field of traditional power system communication and emerging smart home network and broadband access, power line carrier communication has received more...
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Inventor 李智赵建华
Owner SHENZHEN YESTUNED IND