Reformulation of a non-convex constraint so that it become convex

I have an optimization problem as described below. My problem in the second constraint (y’*b>=1) which is a non-convex. My question is how to reformulate this constrain to become convex.

clc
a=randi(5,2,1);

cvx_begin

variable x(2,1) nonnegative    
y=exp(x);
c1=y(2)*a(2) + 1
maximize( log(y(1)*a(1)/c1) -  log(1+y(2)*a(2)/2)  )
subject to 
sum(x)  <=5
y'*b>=1

cvx_end

I have to agree with Mark here. Reforumulating nonconvex problems is simply outside of the scope of this forum. For one thing, it’s extremely unlikely that it’s even possible.