Khodaei and Faez's Technique Suffers with FOBP. It can be understood from the following discussion.
From Table 3 it can be observed that in both type 1 and type 2 of Khodaei and Faez's technique FOBP arises.
Techniques in [12,13] are extension of Khodaei and Faez's  technique, so they suffer with FOBP. Technique in  is extension of Wu and Tsai's  PVD technique.
Steganography techniques, those using the principles of LSB substitution and PVD, need to address three issues: (i) fall off boundary problem (FOBP), (ii) pixel difference histogram (PDH) analysis, and (iii) RS analysis.
 For the present purposes it is convenient to normalize all PSDs for unit signal power so that the FOBP is simply equal to the out-of-band power itself.
The FOBP is readily determined in closed form in terms of the [widely.sup.2] tabulated Si(x) function:
The frequency variable for FOBP has been defined by various authors as either the upper band edge frequency or the normalized doublesided bandwidth WT as previously illustrated in the PSD plots.
The resulting FOBP characteristic is similarly compressed in frequency, leading to FOBP2:
However, the expression for FOBP is somewhat more complicated than for the BPSK case.
All of these software packages will most likely suffice for the production of plots over the abscissa range shown previously in the FOBP plot.