Improved channel estimation algorithm based on virtual carriers of low-voltage power line OFDM system

The channel characteristics of low-voltage power line are analyzed and a channel estimation algorithm with increased pilot density is proposed, which replaces part of VCs(Virtual Carriers) by pilots and redistributes the pilots in the new OFDM(Orthogonal Frequency Division Multiplexing) with equal frequency interval among subcarriers to increase the channel estimation precision by reducing pilot frequency interval. The filters of OFDM system are enhanced by the linear combination of the window functions of raised-cosine and better-than-raised-cosine to avoid the increase of inter symbol interference due to the reduction of VCs. The low density parity check code is applied in system to obtain the better response characteristics of channel frequency. The simulative results show that the bit error rate and mean square error of channel estimation by the proposed algorithm are lower than those of conventional OFDM systems while the symbol transmission rate of system is not decreased.