This paper discusses a possible program for improving the outer (converse) bounds on the finite-blocklength performance of multiple-access codes. The program is based on a certain conjecture involving Renyi entropy of a sum of two independent binary vectors. Some partial results towards showing the conjecture are presented. The problem of bounding the joint Renyi entropy in terms of the marginal entropies is addressed.
['Ganesh Ajjanagadde', 'Yury Polyanskiy']
Adder MAC and estimates for Rényi entropy