Configurable Low Delay Congestion Control Scheme for Cellular Networks

Loss-based TCP congestion control schemes suffer from high self-inflicted delay or low bandwidth utilization in cellular networks. To solve the problem, many delay-based algorithms are proposed to realize high throughput with the lowest possible delay. However, there is no need to achieve both two goals, as most delay-sensitive applications only need to maximize throughput while keeping the average delay below the predefined target delay to provide a high quality of experience (QoE). Thus, we propose CLDCC, a configurable low delay congestion control scheme. CLDCC estimates the RTT and RTT gradient in cellular networks as the congestion signals. Then it regulates congestion window size dynamically to keep its average delay below the target value. We test CLDCC in the trace-driven environment and compare it with many state-of-the-art schemes such as LEDBAT and BBR. The results show that CLDCC reduces 8.2% delay compared with LEDBAT, which is also designed for keeping average delay below the target value. And CLDCC can reduce 12.6 % delay with only 2.8 % throughput degradation in contrast with BBR.