O-RAN Fronthual CU/Sync/Mgmt 平面和协议栈
- O-RAN Fronthual CU/Sync/Mgmt 平面和协议栈
- O-RAN前端
- O-RAN 前传的协议栈
- O-RAN Fronthual C-U/Sync/Mgmt Planes and Protocol Stack
- O-RAN Fronthual
- O-RAN Fronthaul Planes
- C-Plane (Control Plane): Control plane messages define the scheduling, coordination required for data transfer, beam-forming etc.
- U-Plane (User Plane): User plane messages for efficient data transfer within the strict time limits of 5G numerologies.
- S-Plane (Synchronization Plane) : Synchronization plane is responsible for the timing and sync aspects between the O-DU and O-RU. In Cloud RAN deployments, a high accurate synchronization is required between O-DU and O-RUs to achieve controlled linking for inter-O-RU sync operation for TDD, Carrier Aggregation using multiple O-RUs, MIMO, and similar processes. Using S-Plane, O-RAN fronthaul specifications support protocols such as PTP and SyncE to achieve high-accuracy synchronization on the O-RU side by synchronizing with the clock high-performance available at O-DU side.
- M-plane (Management Plane) : Management plane messages are used to manage the radio unit. M-Plane provides a variety of O-RU management functions to set parameters on the O-RU side as required by the C/U-Plane and S-Plane , e.g. manage O-RU software, perform fault management, etc. O-RAN fronthaul specification for M-Plane provides various parameters as data models to FCAPS functions. This data models eliminates dependence on each O-RU vendorʼs implementation and makes a real multi-vendor Open RAN possible
- Protocol Stack for O-RAN Fronthaul
O-RAN Fronthual CU/Sync/Mgmt 平面和协议栈
O-RAN前端
DU 和 RU 之间的接口称为Fronthaul 。当此接口允许将任何供应商 DU 连接到任何供应商 RU 时，称为Open Fronthaul。为了实现这种多供应商DU和RU互连，需要一些信令格式和控制消息，这些由开放标准（即O-RAN 联盟）详细说明，作为 O-RAN前传规范的一部分。
这些规范预测了分布式单元 ( DU ) 和无线电单元 ( RU ) 交互的不同场景、底层5G的需求、两个端点之间的时间同步问题，并为服务提供商做好了部署准备。通过解决这些问题，O-RAN 标准确保了DU和RU供应商之间的互操作性。
O-RAN 前传平面
O-RAN Fronthaul定义了以下操作平面：
C-Plane（控制平面）：控制平面消息定义数据传输、波束形成等所需的调度、协调。
- 调度和波束形成命令
- DL 预编码配置
- 混合数学和 PRACH 处理
U-Plane（用户平面）：用于在 5G 数字严格的时间限制内实现高效数据传输的用户平面消息。
- 支持数据压缩
- I/Q数据传输
- DL 数据预编码
S-Plane（同步平面）
同步平面负责O-DU和 O-RU 之间的定时和同步方面。在Cloud RAN部署中， O-DU和 O-RU之间需要高精度同步，以实现TDD、使用多个O-RU 的载波聚合、MIMO和类似过程的O-RU 间同步操作的受控链接。使用S-Plane ，O-RAN 前传规范支持 PTP 和 SyncE 等协议，通过与O-DU端可用的高性能时钟同步，在 O-RU 端实现高精度同步。
- 同步类型
- 用于同步的 PTP 和 SyncE 配置文件
- 时间和频率同步指南
M-plane（管理平面）
管理平面消息用于管理无线电单元。M -Plane提供各种 O-RU 管理功能，以根据 C/U-Plane 和 S-Plane 的要求在 O-RU 侧设置参数，例如管理O-RU软件、执行故障管理等。M -Plane的 O-RAN 前传规范为FCAPS功能提供了各种参数作为数据模型。这些数据模型消除了对每个 O-RU 供应商实施的依赖，并使真正的多供应商 Open RAN 成为可能
- 支持分层/混合模型
- C/U 平面 IP 和延迟管理
- FCAPS 包括同步配置和状态
O-RAN 前传的协议栈
上述各平面的O-RAN前传规范协议栈如下图所示。
- C/U-Plane ，O-RAN 前传规范支持通过以太网直接传输eCPRI或以太网无线电(RoE) 所用数据的协议栈，以及通过 UDP/IP 传输信号的可选协议栈
- O-RAN 前传中的S-Plane支持通过以太网传输精确时间协议(PTP) 和SyncE 中使用的数据的协议栈
- M-Plane支持通过以太网传输NETCONF中使用的信号的协议栈 ，使用带有安全外壳(SSH) 的TCP传输 IP
O-RAN Fronthual C-U/Sync/Mgmt Planes and Protocol Stack
O-RAN Fronthual
The interface between DU and RU is known as Fronthaul. When this interface allows to connect any vendor DU to any vendor RU, know as Open Fronthaul. To enable this multi vendor DU and RU interconnection some signaling formats and control messaging is required are detailed by Open Standard i.e. O-RAN Alliance as part of O-RAN fronthaul specification.
These specifications anticipated different scenarios about Distributed Unit (DU) and Radio Unit (RU) interaction, what the underlying 5G will demand, time synchronization issues between two endpoints, and it make it deployment ready for Service Providers. By addressing these issues, the O-RAN standard is ensuring inter-op between DU and RU vendors.
O-RAN Fronthaul Planes
O-RAN Fronthaul defines following planes of operations:
C-Plane (Control Plane): Control plane messages define the scheduling, coordination required for data transfer, beam-forming etc.
- Scheduling and beam-forming commands
- DL precoding configuration
- Mixed numerology and PRACH handling
U-Plane (User Plane): User plane messages for efficient data transfer within the strict time limits of 5G numerologies.
- Support Data Compression
- I/Q data transfer
- DL data precoding
S-Plane (Synchronization Plane) : Synchronization plane is responsible for the timing and sync aspects between the O-DU and O-RU. In Cloud RAN deployments, a high accurate synchronization is required between O-DU and O-RUs to achieve controlled linking for inter-O-RU sync operation for TDD, Carrier Aggregation using multiple O-RUs, MIMO, and similar processes. Using S-Plane, O-RAN fronthaul specifications support protocols such as PTP and SyncE to achieve high-accuracy synchronization on the O-RU side by synchronizing with the clock high-performance available at O-DU side.
- Synchronization Typologies
- PTP and SyncE profiles for Synchronization
- Time and Frequency Sync guidelines
M-plane (Management Plane) : Management plane messages are used to manage the radio unit. M-Plane provides a variety of O-RU management functions to set parameters on the O-RU side as required by the C/U-Plane and S-Plane , e.g. manage O-RU software, perform fault management, etc. O-RAN fronthaul specification for M-Plane provides various parameters as data models to FCAPS functions. This data models eliminates dependence on each O-RU vendorʼs implementation and makes a real multi-vendor Open RAN possible
- Support Hierarchical/Hybrid Model
- C/U Plane IP and Delay management
- FCAPS including sync configuration and status
Protocol Stack for O-RAN Fronthaul
The O-RAN fronthaul specifications protocol stack of each above mentioned plane is shown in below picture.
- C/U-Plane, the O-RAN fronthaul specifications support a protocol stack that transmits data used by eCPRI or Radio over Ethernet (RoE) directly over Ethernet and an optional protocol stack that transmits the signals over UDP/IP
- S-Plane in O-RAN fronthaul support a protocol stack that transmits data used in Precision Time Protocol (PTP) and SyncE over Ethernet
- M-Plane support a protocol stack that transmits signals used in NETCONF over Ethernet with IP transported using TCP with Secure SHell (SSH)
https://www.techplayon.com/o-ran-fornthual-c-u-sync-mgmt-planes-and-protocols-stack/