New results with blind time domain equalization for OFDM system
Résumé
The Multicarrier Equalization by Restoration of RedundancY (MERRY) algorithm has been shown to blindly and adaptively shorten a channel to the length of the guard interval in an OFDM system. Most published works on blind Time Domain Equalization (TEQ) convergence analysis are confined to Ts-spaced equalizers. The common belief is that analysis of fractionally-spaced TEQ (FSTEQ’s) is a straightforward extension with similar results. This belief is, in fact, untrue. In this study, we present a convergence analysis of MERRY fractionally-spaced TEQ’s that proves the important advantages provided by the FSTEQ structure. We show that the FSTEQ MERRY algorithm converges significantly faster than the non-fractional TEQ MERRY algorithm. The main reason is that a fractionally-spaced blind adaptive TEQ admits infinitely many realizations of perfect channel shortening for a specific delay whereas a non-fractionally-spaced TEQ admits only one realization. Computer simulation demonstrates the performance improvement provided by the blind adaptive fractionally-spaced TEQ using MERRY algorithm for OFDM system.