Fifth-generation (5G) cellular mobile networks are expected to support mission-critical low latency applications in addition to mobile broadband services, where fourth-generation (4G) cellular networks are unable to support Ultra-Reliable Low Latency Communication (URLLC). However, it might be interesting to understand which latency requirements can be met with both 4G and 5G networks. In this paper, we discuss (1) the components contributing to the latency of cellular networks and (2) evaluate control-plane and user-plane latencies for current-generation narrowband cellular networks and point out the potential improvements to reduce the latency of these networks, (3) present, implement and evaluate latency reduction techniques for latency-critical applications. The two elements we detected, namely the short transmission time interval and the semi-persistent scheduling are very promising as they allow to shorten the delay to processing received information both into the control and data planes. We then analyze the potential of latency reduction techniques for URLLC applications. To this end, we develop these techniques into the long term evolution (LTE) module of ns-3 simulator and then evaluate the performance of the proposed techniques into two different application fields: industrial automation and intelligent transportation systems. Our detailed evaluation results from simulations indicate that LTE can satisfy the low-latency requirements for a large choice of use cases in each field.

除移动宽带服务外，第五代（5G）蜂窝移动网络有望支持任务关键型低延迟应用程序，而第四代（4G）蜂窝网络无法支持超可靠的低延迟通信（URLLC）。但是，了解4G和5G网络都可以满足哪些延迟要求可能会很有趣。在本文中，我们讨论（1）导致蜂窝网络延迟的组件，以及（2）评估当前窄带蜂窝网络的控制平面和用户平面延迟，并指出减少这些延迟的潜在改进当前的网络（3）为延迟关键型应用程序实施和评估延迟降低技术。我们检测到两个要素，即短的传输时间间隔和半永久调度是非常有前途的，因为它们可以缩短将接收到的信息处理到控制平面和数据平面中的延迟。然后，我们分析了URLLC应用程序中减少延迟的技术的潜力。为此，我们将这些技术开发到ns-3仿真器的长期演进（LTE）模块中，然后将所提出的技术的性能评估到两个不同的应用领域：工业自动化和智能运输系统。我们通过仿真得出的详细评估结果表明，LTE可以满足每个领域中大量使用案例的低延迟要求。我们将这些技术开发到ns-3仿真器的长期演进（LTE）模块中，然后将所提出的技术的性能评估到两个不同的应用领域：工业自动化和智能运输系统。我们通过仿真得出的详细评估结果表明，LTE可以满足每个领域中大量使用案例的低延迟要求。我们将这些技术开发到ns-3仿真器的长期演进（LTE）模块中，然后将所提出的技术的性能评估到两个不同的应用领域：工业自动化和智能运输系统。我们通过仿真得出的详细评估结果表明，LTE可以满足每个领域中大量使用案例的低延迟要求。