Cross-Layer Design for Delay-Sensitive Packet Length Control Based on Fragmentation with Rate Adaptation in Wireless LANs

In this paper, we investigate how to determine the subframe length and data transfer rate for packet length control with rate adaptation in wireless LANs. Specifically, in order to reduce packet delay (i.e., to shorten the time of packet transmission), we propose a novel cross-layer design for packet length and rate control, which are jointly optimized among all layers. In our framework, a packet is divided into several subframes, and their sizes are adaptively changed. Unlike the conventional decision scheme, our criterion is calculated from both users' desired packet delay and channel state information (CSI). Moreover, we consider the combination between packet length control and rate adaptation. To demonstrate the effectiveness of our framework, we evaluate what in terms of fragmentation overheads and packet delay by computer simulation and numerical calculation. As a result, our method can reduce the overhead cost of packet fragmentation by 34.0% and 79.4% and reduce packet delay by 18.4% and 0.714% for bit error probabilities pb of 10-3 and 10-5, respectively.