Adaptive Impulse Noise Suppression in OFDM Systems

摘要

Digital data transmitting, based on orthogonal carrier modulation is relatively old. Actually, it is a special case of parallel transmission realized by frequency division multiplex (FDM). In classical FDM, channel separation is based on non-overlapping frequency bands. Each subchannel is modulated with different carrier frequency. Resulting spectrum is superposition of subchannels spectrum that are non-overlapped. The main disadvantage of this scheme is in a poor spectrum efficiency. An improvement of the described FDM scheme can be achieved by choosing the orthogonal set of carriers. In that case, spectrum overlapping is permitted with the minimal interference between the adjacent channels, while the channel separation is maintained. Recently, an orthogonal frequency division multiplexing technologies (OFDM) is becoming very popular in wireless communication systems. Today it is implemented in DVB-T and WiMAX standards. Implementation is relatively simple by applying IDFT and DFT in transmitter and receiver respectively [1].