Proactive congestion control for fast switchover and optical path at mobile midhaul utilizing optimized parallel traffic prediction with multi-thread and multi-processing procedures

Abstract

According to the 3rd Generation Partnership Project, it is necessary to keep end-to-end latency to less than 5 ms in 5G mobile networks to achieve remote applications that replace on-site work and operations. The challenge here is that the bursty traffic (e.g., video) abruptly changes on a short timescale. Bursty traffic has an instantaneous high bitrate, which can exceed the link rate of the mobile midhaul (MMH) and thereby cause congestion, leading to an increase in latency. We propose a proactive congestion control method that performs parallel prediction of distributed unit (DU) traffic and fast switchover of the central unit (CU) and optical path in the MMH. Since the processing load of traffic analysis increases in accordance with the number of DUs, the CPU used for prediction becomes overloaded when many DUs are aggregated. This leads to concerns that the prediction cannot be completed in advance, that the timing of control is shifted, and that congestion occurs when switching is performed, thereby increasing the latency. The key idea of the proposed method is to optimize the number of CPU cores and threads for parallel prediction of the DU. To evaluate its feasibility and effectiveness, we experimentally optimized the number of CPU cores, thread allocations, and prediction periods and then estimated the maximum number of simultaneous predictions. The experimental results for a simple condition where video traffic and background traffic are mixed show that our prototype controller successfully achieved a latency at the MMH as low as 1 ms with appropriate congestion control. Our findings demonstrate the latency reduction effect of the proposed congestion control method for MMH in an aggregated DU configuration for applications with severe latency requirements such as remote control.