Preconditioned iterative inter-carrier interference cancellation for OFDM reception in rapidly varying channels

Abstract

The attractiveness of OFDM decreases with the rising of inter-carrier interference in quickly time-varying channels. Classical OFDM low-complex detection is impaired and more elaborated techniques are required to mitigate the need for full matrix equalization. We present here a fresh approach to this subject, introducing novel fast-converging iterative techniques based on preconditioning. Moreover, we interpret windowing under a new perspective in association with the Basis Expansion Modeling of the time-varying channel. We discuss the complexity of the proposed methods, showing that they are still linear to the OFDM block size. We conclude by illustrating their competitive performance by means of numerical simulations.

Low-complexity minimum-SER channel equalization for OFDM underwater acoustic communications

“…The frequency offset is very harmful since it gives rise to ICI, which significantly deteriorates the system performance. To mitigate the ICI, many ICI countermeasures have been proposed for OFDM UWA communications [3,4]. Compared with the others, frequency-domain equalization attracts much more attention for its simplicity and effectiveness [5].…”

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

“…These parametric estimation schemes always need a large number of pilots and become infeasible with larger delay spread and higher Doppler. Some iterative detection schemes were then emerged to utilize tentative decision partially instead of training symbols or pilots [8]. Although these schemes can alleviate the lack of frequency efficiency to some extent, they still have high complexity under high-speed situation owing to more iterations needed for accurate estimation.…”

Regularization property of linear interference cancellation detectors

“…For example, N in mobile WIMAX (IEEE 802.16Wireless MAN standard) [7] can reach up to 2048,and therefore to implement the decorrelator or the LMMSE detector, an inversion of a 2048-by-2048 system's crosscorrelation matrix is needed which imposes real challenges for its practical implementation. To overcome this problem, linear interference cancellation (IC) structures such as the linear successive interference cancellation (LSIC) and the linear parallel interference cancellation (LPIC) detectors, are introduced to approximate the decorrelator/LMMSE detector but with much less computational complexity O(N 2 ) [8][9][10]. An important phenomenon that was noticed in the literature of linear IC detectors is their semi-convergence behavior, i.e., the best Bit Error Rate (BER) is obtained prior to convergence.…”