An Isoperimetric Theorem for Sequences Generated by Feedback and Feedback-Codes for Unequal Error Protection

We derive an isoperimetric theorem for sequences generated by feedback and consider block codes for a binary broadcast channel with two receivers and noiseless feedback. By applying the isoperimetric theorem, we get an upper bound on the achievable rates for special cases of these codes with unequal error protection. We get a lower bound with a generalized Varshamov–Gilbert construction.