Information rates for a discrete-time Gaussian channel with intersymbol interference and stationary inputs

Bounds are presented on Zi,i,d,-the achievable information rate for a discrete Gaussian channel with intersymbol interference (IS11 present and i.i.d. channel input symbols governed by an arbitrary predetermined distribution p , (x ) . Upper bounds on I , the achievable information rate with the symbol independence demand relaxed, are given as well. The bounds are formulated in terms of the average mutual information of a memoryless Gaussian channel with scaled i.i.d. input symbols governed by the same symbol distribution p , ( x ) where the scaling value is interpreted a s a n enhancement (upper bounds) o r degradation (lower bounds) factor. The bounds apply for channel symbols with a n arbitrary symbol distribution p,(x), discrete as well us continuous, and thus facilitate bounding the capacity of the IS1 (dispersive) Gaussian channel under a variety of constraints imposed on the identically distributed channel