Synchronization for Multi-User Communications Waveforms Generated Using Filter Bank Trees: A Promising Alternative to OFDM

Recent contributions to an IEEE 802.22 meeting in January 2006 by France Telecom and North American Philips propose filtering to improve on OFDM. The proposals use designs of M-band synthesis and analysis filter bank pairs for OFDM-like multiuser communications systems to improve on the properties of OFDM systems by using the naturally superior characteristics of filtering of filter banks. A number of papers are also discussed on designs of M-band filter banks aimed at improving the filtering properties of OFDM communication systems. Synchronization for these M-band filter banks has not been discussed in the literature so far, and is likely to raise problems not foreseen for such filter banks if the designs do not use linear-phase filters. Reasons are discussed for the choice of linear-phase filters in filter bank tree designs. In particular the high sensitivities in the design of a synchronization scheme make non-linear phase filters an undesirable design choice. It is proposed that filter bank tree designs using linear phase filters be studied as an alternative to the filtering used in OFDM systems, and to provide a potentially superior design choice to the M-band designs