Cvx form for R=a(log2(1+b*c/a*d))?

in above equation “a” and “b” are variables.
i write this equation in cvx but could not run.
is this equation ok for above?

If you tried putting in some “random” numbers for the variables, you would see that is not equivalent to your original formula.

-rel_entr(a,a+b*c/d)/log(2) or -1/d*rel_entr(a*d,a*d+b*c)/log(2) will work.