The Receiver Design Of Narrow-Band Power Line Communication

With the advantages of wide distribution and in no need of the arrangement of wire, Narrow-Band Power Line Communication attracts lots of interests. The first generation of NB-PLC adopts the single-carrier technology and the modulation of PSK and FSK, while the transmission rate could not even reach10kbps. The second generation of NB-PLC uses the technology of OFDM and differential encoding to improve system performance. The standardization of the third generation has also started. In December.2011, ITU-T finished the physical layer communication protocol G.9955, in which OFDM is still in used, while differential encoding was abandoned. IEEE1901.2was proposed only a few days before this paper is finished. The data rate of the third generation has reached several hundred kbps.ITU-T G.9955is mainly discussed in this paper, where the receiving end is designed according to the procedure of transmitting end and characters of power line channel. In the receiving end, a module is needed to deal with the narrow-band interference and impulsive noise first, and the procedure of synchronization follows. The channel estimation and SNR estimation are also significant in the channel equalization, demodulation and decoding.This paper emphasizes the algorithms of interference cancellation, channel estimation and SNR estimation. In the module of interference cancellation, all the interferences are divided into two categories:narrow-band interference and impulsive noise, the interference cancellation algorithms are analyzed and assessed in detail. Due to the different fading in different sub-carriers, channel estimation and SNR estimation is none by every sub-carrier to improve the performance of demodulation and decoding. Since the serious interference of impulsive noise affects the system performance a lot, this paper proposed a modified concatenated encoder to improve the robust character of the system. According to G.9955, the channel coding includes the RS code and convolutional code, and the inner code (convolutional code) can correct some burst errors, and the outer code (RS code) is used to correct some random errors. The concatenated encoder in this paper is composed of shortened RS code, interleaver and convolutional code. The simulation results demonstrate that this scheme can improve this system’s ability of resisting the impulsive noise and decrease the BER (bit error rare) effectively.