This report deals with the design of handover schemes for radio access networks (RAN) in 5G networks, using programmable data plane switches. In 5G networks, the NG-RAN architecture splits the Base Band Unit (BBU) into Central and Distributed Units (CU and DU). This structure has created a mid-haul Network, connecting CUs and DUs. The recent advancements in dataplane programmability can be used to enhance system performance. We show how P4 switches can be used to parse the packets between DU, CU, and Back Haul (Core Network) for potential system improvements. In particular, we consider the scenario of mobile handover. The proposed protocol is called SMARTHO, illustrating a smart handover. Programming Protocol-Independent Packet Processors (P4) is a programming language designed to support specification and programming the forwarding plane behavior of network switches/routers. In SMARTHO, we use P4 Switches to intervene in the handover process for fixed-path mobile users. A resource pre-allocation scheme that reserves resources before the UE reaches a future cell, is proposed. The solution is implemented using a P4-based switch introduced between the CU and the DU. The P4 switch is used to spoof the behavior of User Equipment (UE) and perform the resource allocation in advance. The proposed SMARTHO framework is implemented in the mininet emulation environment and in a reconfigurable hardware environment using NetFPGA-SUME boards. The emulation results show a handover response time improvement of 18% for a tandem of two HOs and 25% for a tandem of three HOs. For testbed implementation, we used NetFPGA-SUME boards as P4 switches. The handover time was measured to be approximately 50~milliseconds in the experiments conducted.

中文翻译：

---

SMARTHO 的设计与实现——NG-RAN 中的网络发起切换机制，基于 P4 的 Xilinx NetFPGA 交换机

本报告涉及使用可编程数据平面交换机设计 5G 网络中无线接入网络 (RAN) 的切换方案。在 5G 网络中，NG-RAN 架构将基带单元 (BBU) 拆分为中央单元和分布式单元（CU 和 DU）。这种结构创建了一个中程网络，连接 CU 和 DU。数据平面可编程性的最新进展可用于增强系统性能。我们展示了如何使用 P4 交换机来解析 DU、CU 和 Back Haul（核心网络）之间的数据包，以实现潜在的系统改进。我们特别考虑移动切换的场景。提议的协议称为 SMARTHO，用于说明智能切换。编程协议独立数据包处理器 (P4) 是一种编程语言，旨在支持规范和编程网络交换机/路由器的转发平面行为。在 SMARTHO 中，我们使用 P4 Switches 来干预固定路径移动用户的切换过程。提出了在UE到达未来小区之前预留资源的资源预分配方案。该解决方案是使用在 CU 和 DU 之间引入的基于 P4 的交换机来实现的。P4交换机用于欺骗用户设备（UE）的行为，提前进行资源分配。建议的 SMARTHO 框架在 mininet 仿真环境和使用 NetFPGA-SUME 板的可重新配置硬件环境中实现。仿真结果表明，两个 HO 串联的切换响应时间提高了 18%，三个 HO 串联的切换响应时间提高了 25%。对于测试台实现，我们使用 NetFPGA-SUME 板作为 P4 开关。在进行的实验中，切换时间被测量为大约50毫秒。