InFRA: In-frame rate adaptation in fast fading channel environments

In wireless networks, frame retransmission is used to increase reliability with the use of additional wireless resources. Recently, various approaches have been proposed to reduce the overhead for retransmission. However, they still suffer from performance degradation due to unpredictable wireless channel variation during a frame transmission in fast-fading environments. In this paper, we propose an in-frame rate adaptation (InFRA) scheme as a solution for mitigating the retransmission overhead. In InFRA, a receiver estimates the channel SNR of incoming symbols and feeds it back to the sender. According to the feedback information, the sender adaptively changes its symbol transmission rate during a frame transmission. In this way, InFRA significantly increases the reliability of frame transmission even when the channel state changes within a frame transmission. To evaluate the effectiveness of InFRA, we mathematically analyze its performance and compare it with the existing schemes. Finally, our simulation results show that InFRA achieves significant throughput improvements over the other competitive schemes in fast fading channel environments.