Abstract: The problem of Time Domain Equalization (TEQ) in multi-carrier system when channel spread time is longer than guard interval was analyzed, and the probability of heavy-fading in some sub-carriers in target channel after channel shortening was given. A new doubly Adaptive Allocation Multi-path Interference canceller (AL-MPIC) algorithm for multi-carrier system combating lower SNR frequency effect of heavy-fading sub-channels caused from channel shortening was proposed. The method combining the TEQ and adaptive allocation is not only able to suppress Cyclic Prefix Guard Interval (CP-GI) but also to improve system BER performance. The simulations of the algorithm under wireless channel condition using MONTE CARLO method were presented and show the effective improvement of the system performance.

Key words: communication, orthogonal frequency division multiplexing (OFDM), adaptive allocation (AL), multi-path interference canceller (MPIC), time domain equalization (TEQ), cyclic prefix guard interval (CP-GI)