Code rate, queueing behavior and the correlated erasure channel

This paper considers the relationship between code-rate selection and queueing performance for communication systems with time-varying parameters. While error-correcting codes offer protection against channel unreliability, there is a tradeoff between the enhanced protection of low-rate codes and the increased information transfer of high-rate codes. Hence, there exists a natural compromise between packet-level error protection and information rate. In the limiting regime where codewords are asymptotically long, this tradeoff is well-understood and characterized by the Shannon capacity. However, for delay-sensitive communication systems and finite code-lengths, a complete characterization of this tradeoff is still not fully developed. This paper offers a new perspective on the queueing performance of communication systems with finite block-lengths operating over correlated erasure channels. A rigorous framework that links code rate to overall system performance for random codes is presented. Guidelines for code rate selection in delay-sensitive systems are identified.