Low-Complexity Equalisation Methods for OFDM Systems in Doubly Selective Channels

Comparative Analysis of Various Inter-Carrier Interference Cancellation Methods

“…The proposed scheme performs similarly but complexity has reduced by 43% for the given value of Q. Zero-forcing serial banded equalizer gives the worst performance and the conventional 1-tap equalizer shows a comparatively better performance than the former one where at an SNR of 20 dB, conventional equalizer has a BER of approximately and the serial and block MMSE (both banded) give approximately similar performance at around with serial MMSE performing better. One-Tap Equalizer (OTE), MMSE equalizer (SIREQ) based on signal to interference ratio (SIR) [21] and computation of inverse of the equalization matrix in a recursive fashion have been used in another technique named as Improved SIREQ (ISREQ) [22]. The SER of SIREQ and OTE + ISIREQ at a tap length of 15 is the same.…”

Multiple Doppler shifts compensation and ICI elimination by beamforming in high-mobility OFDM systems

“…In order to mitigate the Doppler effect emerged in highmobility OFDM systems, some works resort to perform equalization directly on the time-variant channel matrix and try to reduce the computational complexity of the equalizer. Since the most power of ICI cames from neighboring subcarriers, block diagonal structure of channel matrix is considered in [3]- [4] to partially suppress interferences. These methods neglect off-diagonal elements, whose inversion demands less computational complexity but fails to capture the effect of ICI sufficiently for larger Doppler.…”