A cognitive link adaptation strategy with differentiated responses on Wi-Fi System-on-Chip

The dynamic change of wireless channel condition causes poor Wi-Fi quality of service. To cope with the channel variation of wireless communication, the essential strategy for the physical layer with multi-rate capability is the link adaptation. However, because definite guidelines for rate changes do not exist, most link adaptation algorithms can misleadingly increase transmission rates. Therefore, we propose a cognitive link adaptation scheme, sensing link adaptation urgency and responding with differentiated rate control such as the long-term rate adaptation with a short-term rate drop. To evaluate the proposed scheme, we implement the link adaptation scheme on Wi-Fi System-on-Chip, applying the optimal HW/SW partitioning technique to reduce the SW processing delay from heavy operating calculation for the algorithm. The experiment shows that the proposed algorithm increases the packet arrival rate in a real Wi-Fi environment by reducing transmission failure due to wrong rate changes.