AQM-based Buffer Delay Guarantee for Congestion Control in 5G Networks

In view of the stringent requirements for delay in 5G usage scenarios, the existing congestion control schemes based on terminal measurement and evaluation cannot meet the requirements due to their reactive nature and blindness to links. To this end, we propose a buffer state-driven rate control mechanism in 5G networks, namely active queue management (AQM) based buffer delay guarantee (AQM-BDG) to explicitly adjust the sending rate of the source. Specifically, the rate mismatch and buffer state in Radio Link Control (RLC) layer are comprehensively considered, which timely grasp the dynamics of the buffer to obtain the direction and urgency of rate adjustment. Then the incoming packets are marked proportionally as "increase" or "decrease" to adjust the sending rate. Meanwhile, the adjustment quantum is reallocated among the different Service Data Flows (SDFs) that are mapped to the same Data Radio Bearer (DRB), so that every SDF can obtain the throughput share according to the preset priority, no matter what rate it starts at. Experimental results demonstrate that AQM-BDG significantly outperforms classical congestion control schemes on network utility by achieving relatively high throughput while bounding queuing delay within the threshold.