Cross-Layer CQI Feedback Window Adaptation for OFDMA Systems Under Feedback Budget Constraint

In this paper, the authors propose an adaptive feedback reduction scheme FWA (Feedback Window Adaptation) for OFDMA systems with limited feedback budget. The FWA algorithm adapts Channel Quality Indicator (CQI) feedback rate for each Mobile Station (MS) exploiting the signaling of MAC layer Automatic Repeat reQuest (ARQ) protocol and users application profile. The authors applied this FWA algorithm in two feedback mechanisms namely Prediction and Interval Based Feedback (PBF and IBF) schemes. They also developed a mathematical model to derive performance metric of both integrated schemes in terms of probability of adapting feedback window.