Power Allocation for HARQ-IR Systems Under QoS Constraints and Limited Feedback

This paper investigates power allocation for reliable downlink transmission in cellular networks subject to quality-of-service (QoS) constraints. The reliability of data transmissions is assured by hybrid automatic repeat request protocol with incremental redundancy (HARQ-IR). By developing and evaluating the effective throughput of the HARQ-IR protocol for the downlink transmission under buffer-limited QoS constraints, we propose a novel adaptive power allocation algorithm to efficiently exploit the available resources when only limited channel state information (CSI) is available. The proposed algorithm, based on monotonic optimisation, allows near-optimal performance to be achieved with reasonably low complexity.