Multi-carrier spread spectrum power line communication system

Abstract

The invention provides a multi-carrier spread spectrum power line communication system. Communication equipment in the system comprises a signal transmission device and a signal receiving device; the communication equipment is characterized in that the signal transmission device comprises an encoder, a spread spectrum modulating unit and a carrier modulating unit, which are connected in sequence; the signal receiving device comprises a wavelet filter, a carrier frequency separator, a despreading unit, a data demodulator and a data decoder, which are connected in sequence; when in use, the spread spectrum modulating unit in the signal transmitting device carries out spread spectrum modulation on the data encoded by the encoder, and then the carrier modulating unit carries out multi-carrier modulation on the signal subjected to the spread spectrum in order to meet the orthogonality conditions, and transmits the signal subjected to the spread spectrum to the signal receiving device; the wavelet filter in the signal receiving module carries out wavelet filtering on a received signal, and then the carrier frequency separator carries out frequency separation on each filtered subcarrier, the despreading unit despreads, and the data demodulator demodulates the signal, sequentially, and finally the decoder decodes in order to gain the data.

Description

Technical field [0001] The present invention relates to the field of communication technology, in particular to a wired transmission system, in particular to a transmission system through a power distribution line. Background technique [0002] Power line communication technology is a communication method that uses power lines to transmit data and voice signals. This communication method effectively uses the existing distribution network as a transmission line without the need to lay additional cables, thereby greatly reducing line investment and reducing costs; at the same time, with the advancement of power line communication technology and the development of smart grids , The transmission rate of the power line network is getting higher and higher, the current rate can reach 200Mbps, which is not inferior to the optical cable and copper cable; not only that, the power line network also has the advantages of always online and wide coverage. Based on the above advantages, the m...

AI Technical Summary

Problems solved by technology

However, although the existing technical solutions of the multi-carrier spread spectrum power line communication system have high modulation efficiency and a satisfactory transmission rate, the structure of the OFDM receiver is complex, and the required protocol It is also complex, and the cost of construction is high. At the same time, because OFDM is implemented by fast Fourier transform, the frequency interval between subcarriers is fixed and reaches the minimum value. If there is any error in the carrier frequency, the carrier frequency will lose its correctness. It is extremely sensitive to strong noise interference, and its reliability and adaptability are not satisfactory in the power line transmission environment with large impulse noise interference.

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