FTN method applied to OFDM for optical disc signal readout.

To increase the recording density of optical discs, analog recording techniques such as the use of orthogonal frequency division multiplexing (OFDM) method has been investigated. In OFDM method, the recording signal is separated into several sub frequency bands. So the readout channel becomes tolerant of the deterioration by disturbances such as defocus and disc skew in optical disc systems. Faster than Nyquist (FTN) signaling is known as the method to increase the transfer rate of OFDM channels in the area of telecommunication. In this paper, a possibility to achieve higher recording density of optical disc systems by applying the FTN is described. The readout signal of FTN-OFDM method was calculated using the optical disc readout and the signal processing models considering the crosstalk from adjacent tracks and FTN applied to a five-channel 64-QAM OFDM system. The calculation results show that the proposed system has a possibility of 1.5 times recording density of the conventional optical disc with a similar tolerance to disturbances. [ABSTRACT FROM AUTHOR]