Recently, a closed-form approximated expression was proposed for the achievable
residual intersymbol interference (ISI) valid for the real valued and two independent
quadrature carrier case and for type of blind equalizers where the error that is fed
into the adaptive mechanism which updates the equalizer's taps can be expressed
as a polynomial function of order three of the equalized output. Thus the recently
proposed expression for the achievable residual ISI can not be applied for input
constellations such as the 32QAM or V29 case. In this chapter we propose for the
noiseless case, a new closed-form approximated expression for the residual ISI that
depends on the step-size parameter, equalizer's tap length, input signal statistics,
channel power and that is valid for the general case of input constellations. The
new closed-form approximated expression for the residual ISI is applicable for type
of blind equalizers where the error that is fed into the adaptive mechanism which
updates the equalizer's taps can be expressed as a polynomial function of order
three of the equalized output like in Godard's algorithm. Since the channel power
is measurable or can be calculated if the channel coecients are given, there is
no need anymore to carry out any simulation with various step-size parameters in
order to reach the required residual ISI.
Keywords: Blind deconvolution, intersymbol interference (ISI), convergence speed, perfect
equalization, polynomial function, convolutional noise power, residual ISI, step-
size parameter, equalizer's tap-length, channel power
