An adaptive bitload OFDM system for Low Voltage Power Line communication

Low Voltage Power line communication (LV-PLC) systems have the disadvantage of poor channel condition, since power lines are not designed for data transmission. Due to the complex and time variance characteristics in LV-PLC systems, people shall pay more attentions on the adaptive modulation technique in OFDM systems. In this paper, we built an OFDM system model with PLC channel model and noise environment. Then we adopted a bit-load algorithm to make the system adaptively modulate input signals according to sub-channel gains and signal noise ratio. The BER performances were compared with fixed-rate system. Simulation result shows that, when the BER requirement was set to 10
^-1
, the transmit power of adaptive system could be just about 12.5% of the fixed-rate one.