Rate Selection Algorithms for IR Hybrid ARQ

We obtain throughput expressions for an incremental redundancy (IR) hybrid ARQ (HARQ) system given delayed channel mutual information feedback using renewal process theory. We obtain the optimal rate selection algorithm for conditional throughput under a conditional outage constraint (due to finite horizon operation) in a single user scheduled per slot (non-adaptive) scenario. We compare performance with commonly employed other rate adaptation algorithms. We characterize the HARQ gain (and its components of time diversity and early termination) improving ε-outage capacity and study the impact of feedback and opportunistic scheduling at various mobile speeds.