Fractionally spaced blind equalization: loss of channel disparity
Inbar Fijalkow, John R. Treichler, C.R. Johnson · 2002
Under certain conditions on the equalizer length and on the channel dynamics, temporal or spatial diversity allows one to achieve blind equalization perfectly by means of second-order statistics only. Loss of channel disparity causes perfect equalization to no longer be achievable. The achievable channel-equalizes combination then depends only on the part of the multichannel transfer function lacking disparity. We show that the fractionally spaced equalizer adapted by the constant modulus algorithm (FSE-CMA) still achieves "reasonable" equalization. Its performance equals that of the non-fractional CMA, with a slightly shorter baud-length equalizer than the FSE, applied to the part of the channel lacking disparity.