QCC: Driver-Queue Based Congestion Control for Data Uploading in Wireless Networks

Data uploading applications in wireless networks may suffer from the degrade of Quality of Experiences (QoEs), due to the untimely adjustment of congestion window (cwnd) in face of the rapid change of wireless channel. To mitigate this problem, we analyzed the relationship between the NIC driver queue length at the wireless sender and the end-to-end transmission performances, and found a strong correlation between them, since the bottleneck mostly occurs at the wireless link. Based on this observation, we designed QCC, a congestion control algorithm that adjusts cwnd according to the residual queue length after each round of NIC transmission. Since obtaining congestion information locally at the sender leads to a much shorter feedback path than waiting for the end-to-end ACK feedback, QCC can track the time-varying wireless links much faster and more accurately. In addition, QCC also presents adaptive slow start mechanism and MAC layer-assisted fast recovery mechanism, both of which make efficient use of residual queue length to further improve transmission performances. Experiment results on both real-world Wi-Fi and cellular networks reveal that QCC can achieve at least 2.36X lower delay than that of BBR while ensuring 98.5% throughput of BBR.