O-RAN FAPI 5G TM Introduction

The ORAN FAPI 5G Translator Module (TM) is a standalone application that communicates with the ODU-High using the 5G FAPI protocol defined by the Small Cell Forum and communicates with the ODU Low using the Intel L2-L1 API using the Wireless Subsystem Interface Library (WLS) to handle the shared memory and buffer management required by the Interfaces. In addition the ORAN 5G FAPI TM requires the Data Plane Design Kit (DPDK) which is integrated with the WLS Library.

Table 1. Terminology

Term

Description

API

Application Platform Interface

BBU

Baseband Unit

CORESET

Control Resource Set

DOS

Denial of Service Attack

DPDK

Data Plane Design Kit

eNb

Enode B

EPC

Evolved Packet Core

EVM

Error Vector magnitude

FAPI

Functional Application Platform Interface

gNB

Next generation eNB or g Node B

IQ

In-phase and in-quadrature

ISA

Intel Software Architecture i.e. AVX2, AVX256, AVX512

MAC

Medium Access Control

MIB

Master Information Block

nFAPI

Network FAPI (Between VNF(L2/L3) and PNF(L1))

PDU

Protocol Data Unit

PHY

Physical Layer Processing

PMD

Poll Mode Driver

PNF

Physical Network Function

PSS

Primary Synchronization Signal

QPSK

Quadrature Phase Shift Keying

RAN

Radio Access Network

RE

Radio Equipment

REC

Radio Equipment Control

ROE

Radio Over Ethernet

RX or Rx

Receive

SCF

Small Cell Forum

SFN

System Frame Number ∈ {0,…,1023}

SIB

System Information Block

SSS

Secondary Synchronization Signal

TLV

Type Length Value

TX or Tx

Transmit

U-Plane

User Plane

URLLC

Ultra Reliable Low Latency Coding

VNF

Virtual Network Function

WLS

Wireless Subsystem Interface

WLS_DPDK

WLS that uses DPDK functions instead of accessing kernel functions

Reference Documents

Table 2. Reference Documents

Document

Document No./Location

1) FlexRAN 5G New Radio Reference
Solution L1-L2 API Specification
Rev 10.00 March 2021

CDI 603575 Intel Corp.

2) 5G FAPI:PHY API Specification,
Version 2.0.0, March 2020

222.10.02/ smallcellforum.org

Translator Module Top Level Design

The following diagram illustrates the different functions and components used by this module and how it interconnects to the L2 and L1 layers.

Figure 1. ORAN 5G FAPI Translator Module Top Level Architecture

Figure 1. ORAN 5G FAPI TM

Figure 1. ORAN 5G FAPI TM Top Level Diagram

The Translator Module consists of the following functions:

  • A 5G FAPI Parser facing the L2 interface.

  • An Inter API Mapper and Logic.

  • An Intel API Parser facing the L1 interface.

  • WLS dpdk based library supporting 2 instances.