A novel blind equalization structure for deep null communication channels

A new blind equalization structure that is well suited for communication channels whose zeros are close to the unit circle is proposed. Most blind equalizers which operate at the baud rate perform poorly for channels whose maximum phase zeros are close to the unit circle. This limitation is mainly due to the inability to model the inverse of such maximum phase zeros with a finite length filter. Our proposed structure adaptively models the inverse channel, completely, without the need to transmit a training sequence. Therefore Inter Symbol Interference (ISI) is removed even if the channel has deep spectral nulls. Another attractive feature of this structure is that it estimates the channel parameters directly, and as such may be used with “indirect” equalization techniques. Simulation studies are included to demonstrate the performance of the scheme