use volterra to achieve dispersion and nonlinear compensation of the fiber

I modified a 16QAM OFDM system， Through a period of fiber, I want to use volterra to achieve dispersion and nonlinear compensation of the fiber.
Just as it is written in the Liu L, Li L, Huang Y, et al. Intrachannel Nonlinearity Compensation by Inverse Volterra Series Transfer Function[J]. Journal of Lightwave Technology, 2012, 30(3):310-316.
Optical fiber compensation expression：A(ω,z)=H1(ω,z)A(ω)+∫∫∞−∞H3(ω1,ω2,ω−ω1+ω2,z)×A(ω1)A∗(ω2)A(ω−ω1+ω2)dω1dω2
H1(ω,z)=exp(−αz/2e−jω2β2z/2)
H3(ω1,ω2,ω−ω1+ω2,z)=−(jγ/4π^2)H1(ω,z)×(1−exp(−(α+jβ2(ω1−ω)(ω1−ω2))z)/(α+jβ2(ω1−ω)(ω1−ω2)))
But the result is wrong, I think my matlab file is not wrong, who can help me find where is wrong