QoS-aware cross-layer design in multirate wireless networks with ARQ feedback delay

To achieve higher throughput and guarantee Quality of Service (QoS), we analyze the queue model with adaptive modulation and coding (AMC) and truncated automatic repeat request (ARQ) protocol and develop a cross-layer scheme, where the feedback delay of ACK/NAK from receiver is considered. When the delay of ACK/NAK feedback is included in the queue model, some transmitted packets would be in the state of waiting for ACK/NAK feedback. We drop the packets in this state firstly to reduce the packet loss rate (PLR) and the queue delay. Moreover, we obtain the closed-form analytical expression of performance metrics such as throughput, average packet delay and PLR based on the stationary state probability of the queue state. The simulation is carried out to verify the validity of the proposed queue model and packet dropping policy.