A new digital front end structure for cognitive PLC systems

Power line channel is hostile for communication. One concept we proposed for reliable communication in power line is to adjust the working band according to different channel conditions. In this paper, a new digital front end (DFE) structure, which combines equivalent complex baseband (ECB) structure and Nyquist windowing at both transmitter and receiver, is proposed to support this concept. By configuring parameters of ECB, it supports flexibly band selection. Besides, out-of-band interference is able to be attenuated to a large extent due to the cascaded low-pass filters in the ECB at receiver. Therefore, it is possible to apply much more simplified analogue front end. The Nyquist windowing at receiver makes side-lobe of narrowband disturbance fall down quickly and concentrates its energy on fewer subcarriers, which benefits the narrowband interference detection. Finally, system performance with the new DFE structure in the presence of in-band and out-of-band disturbance is simulated and compared with classic DFE and equivalent complex baseband (ECB)-based DFE.