Dear Sherif and Sharam,
As Martin mentioned above, there is no overlapping area because the sector assignment is done pixelwise, and one pixel can’t be assigned to two base stations at the same time. From your attached figure, it really looks like the coverage area of the two femtocells is overlapping (because the same colour is used to plot all femto coverage areas), but if you look at networkPathlossMap.maxSINR_assignment and plot it using the command imagesc(networkPathlossMap.maxSINR_assignment), then you will actually see the coverage area of each macro and femto base station and observe that there is no overlapping.
See the plot here CoverageAreas.jpg
Best regards,
Fjolla