On error exponents for arbitrarily varying channels

The minimum probability of error achievable by random codes on the arbitrarily varying channel (AVC) is investigated. New exponential error bounds are found and applied to the AVC with and without input and state constraints. Also considered is a simple subclass of random codes, called randomly modulated codes, in which encoding and decoding operations are separate from code randomization. A universal coding theorem is proved which shows the existence of randomly modulated codes that achieve the same error bounds as "fully" random codes for all AVCs.