Converse Bounds for Assorted Codes in the Finite Blocklength Regime
The authors study converse bounds for unequal error protection codebooks with k > 1 different classes of codewords. They dub these unequal error protection codes "Assorted codes". They extend a finite blocklength converse bound due to Polyanskiy-Poor-Verdu to apply to assorted codes and use this extension to obtain a refined asymptotic expansion for the performance of assorted codes over a discrete memoryless channel. Their main contribution is to demonstrate that there is indeed a loss in the rates of an assorted code compared to equivalent homogeneous (classical) codes.