How can I transform this problem into a convex optimization problem?

Have you proven this is a convex optimization problem, following the standards of Why isn't CVX accepting my model? READ THIS FIRST! .

The low resolution image you posted doesn’t even make it clear to the reader what, if any, are the subtle distinctions between similar symbols. So we don’t even know what the optimization problem is. Presumably, you understand every nuance of the optimization problem definition - if not, you sure should before trying to implement it.