On the delay performance of block codes for discrete memoryless channels with feedback

In this paper, a queueing model for discrete memoryless channels with block coding and feedback is developed. Blocks that cannot be decoded without error are retransmitted at once. Statistical delay bounds are derived using the framework of the statistical network calculus. The delay performance of block codes with more or less redundancy is investigated. Numerical results are shown for the BCH code family. It is found that coding rates in the wide range from 3/4 to 1/4 achieve comparably small delays. The model is extended to include soft combining. It is shown that soft combining can reduce delays significantly.