.. SPDX-License-Identifier: CC-BY-4.0
-O-DU-L2 Architecture
+O-DU High Architecture
======================
-O-DU implements the functional blocks of L2 layer of a 5G NR protocol stacks.
-These layers primarily include NR MAC NR Scheduler and NR RLC layers.
+O-DU implements the functional blocks of L2 layer of a 5G NR protocol stack in SA(StandAlone) mode.
+These layers primarily include NR MAC, NR Scheduler and NR RLC layers.
O-DU modules are developed as shown in the below diagram.
-.. image:: ODUArch.jpg
- :width: 400
- :alt: ODU Arch diagram
+.. figure:: ODUArch.jpg
+ :width: 600
+ :alt: Figure 1 O-DU High Architecture Diagram
-O-DU Thread Architecture
---------------------------
+ Figure 1 - O-DU High Architecture Diagram
+
+O-DU High Thread Architecture
+-------------------------------
-As shown in Figure 1, there are multiple entities within O-DU. Modules sharing a
+As shown in Figure 1, there are multiple entities within O-DU High. Modules sharing a
given color belong to one thread. O-DU architecture can be defined at a thread
level as follows:
-- Thread 1: O-DU thread
+- Thread 1: O-DU thread
-- Thread 2: DU APP inclusive of Config Handler, DU Manager, UE Manager, EGTP Handler and ASN.1 Codecs
+- Thread 2: DU APP inclusive of Config Handler, DU Manager, UE Manager, EGTP Handler and ASN.1 Codecs
-- Thread 3: 5G NR RLC DL and MAC (inclusive of 5G NR SCH and Lower MAC)
+- Thread 3: 5G NR RLC DL and MAC (inclusive of 5G NR SCH and Lower MAC)
-- Thread 4: 5G NR RLC UL
+- Thread 4: 5G NR RLC UL
-- Thread 5: SCTP Handler
+- Thread 5: SCTP Handler
-- Thread 6: Lower MAC Handler
+- Thread 6: Lower MAC Handler
-O-DU Modules
+O-DU High Modules
--------------------------
DU APP
This module configures and manages all the operations of O-DU.
It interfaces with external entities as follows:
-- OAM: DU APP interacts with OAM on the O1 interface for configuration, alarms and performance management.
+- OAM: DU APP interacts with OAM on the O1 interface for configuration, alarms and performance management.
-- O-CU: DU APP interacts with O-CU for RAN functionalities over the F1 interface which is built on SCTP. Control messages are exchanged on the F1-C interface and data messages on the F1-U interface.
+- O-CU: DU APP interacts with O-CU for RAN functionalities over the F1 interface which is built on SCTP. Control messages are exchanged on the F1-C interface and data messages on the F1-U interface.
-- RIC: DU APP interacts with RIC on E2 interface over SCTP.
+- RIC: DU APP interacts with RIC on E2 interface over SCTP.
DU App submodules are as follows:
-- Config Handler manages the configurations received on O1 interfaces andstores them within DU APP context.
+- Config Handler manages the configurations received on O1 interfaces and stores them within DU APP context.
-- DU Manager handles all cell operations at the DU APP.
+- DU Manager handles all cell operations at the DU APP.
-- UE Manager handles UE contexts at the DU APP.
+- UE Manager handles UE contexts at the DU APP.
-- SCTP handler is responsible for establishing SCTP connections with O-CU, RIC.
+- SCTP handler is responsible for establishing SCTP connections with O-CU, RIC on the F1AP and E2AP interfaces
+ respectively.
-- EGTP handler is responsible for establishing EGTP connection with O-CU for data message exchange.
+- EGTP handler is responsible for establishing EGTP connection with O-CU for data message exchange on the F1-U
+ interface.
-- ASN.1 Codecs contain ASN.1 encode/decode functions which are used for System information, F1AP and E2AP messages.
+- ASN.1 Codecs contain ASN.1 encode/decode functions which are used for System information, F1AP and E2AP messages.
5G NR RLC
^^^^^^^^^^^^^^^^^^
on the various logical channels.
Functions of the 5G NR MAC module are as follows:
-- 5G NR MAC is responsible for multiplexing and de-multiplexing of the data on various logical channels.
+- 5G NR MAC is responsible for multiplexing and de-multiplexing of the data on various logical channels.
-- 5G NR SCH schedules resources on UL and DL for cell and UE based procedures.
+- 5G NR SCH schedules resources in UL and DL for cell and UE based procedures.
+ 5G NR SCH is completely encapsulated within the 5G NR MAC i.e., all interactions of the 5G NR SCH is via the 5G NR MAC.
+
+- Lower MAC interfaces between the MAC and the O-DU Low. It implements all the messages of FAPI
+ specification. It has a receiver thread to handle messages from L1.
-- Lower MAC interfaces between the MAC and the lower layers of the O-DU and implements all the messages of FAPI
- specification. It has a receiver thread to handle messages from L1.
O-DU Utility and Common Functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-These modules help in the working of O-DU and message exchanges between
-the O-DU modules.
+These modules contain platform specific files and support O-DU High functionality and message exchanges.
+
+
+O-DU-High Interfaces
+======================
+
+
+This section describes the other modules that O-DU High interfaces with, as shown in below diagram.
+
+.. figure:: O-DUHighInterfaces.jpg
+ :width: 600
+ :alt: O-DU High Interfaces
+
+ Figure 2 - O-DU High Interfaces
+
+
+As shown in Figure 2, O-DU High interfaces with the following modules:
+
+- O-CU: O-DU High communicates with O-CU on the F1AP interface. The control message exchanges are on F1-C while
+ data message exchanges are on F1-U interfaces. The below F1AP messages on F1-C are implemented, as per
+ 3GPP 38.473-f60 v15.3:
+
+ - Interface Management
+
+ - F1 Setup
+
+ - gNB-DU Configuration Update
+
+ - F1 Reset
+
+ - UE Context Management
+
+ - UE Context Setup
+
+ - RRC Message Transfer
+
+ - Initial UL RRC Message Transfer
+
+ - DL RRC Message Transfer
+
+ - UL RRC Message Transfer
+
+ - RRC Delivery Report
+
+- Near RT RIC: O-DU High communicates with Near RT RIC on the E2 interface. The below E2AP messages are
+ implemented, as per ORAN WG3.E2AP v01.00:
+
+ - Global Procedures
+
+ - E2 Setup
+
+ - Near RT RIC Functional Procedures
+
+ - RIC Subscription
+
+ - RIC Indication
+
+- O-DU Low: O-DU High communicates with O-DU Low on the FAPI interface. The below FAPI messages are supported,
+ as per FAPI interface files shared by Intel:
+
+ - P5 messages - PHY mode control interface
+
+ - PARAM.request/PARAM.response
+
+ - CONFIG.request/CONFIG.response
+
+ - START.request
+
+ - STOP.request
+
+ - STOP.indication
+
+ - P7 messages - Main data path interface
+
+ - DL_TTI.request
+
+ - UL_TTI.request
+
+ - SLOT.indication
+
+ - UL_DCI.request
+
+ - TX_Data.request
+
+ - RX_Data.indication
+
+ - CRC.indication
+
+ - UCI.indication
+
+ - RACH.indication
+
+- OAM: O-DU High communicates with OAM on the O1 interface.
+
+
+
+O-DU High functionality
+========================
+
+
+Cell Up and Broadcast Procedure
+--------------------------------
+
+This section describes the cell-up procedure within O-DU High.
+
+.. figure:: CellUpAndBroadcast.png
+ :width: 720
+ :alt: Cell Up and Broadcast Procedure
+
+ Figure 3 - O-DU High Cell Up and Broadcast Procedure
+
+
+As seen in the Figure 3,
+- The DU APP module of O-DU High sends F1 Setup Request to O-CU. This message contains a list of cells that the O-DU High has been configured with.
+
+- The O-CU responds with F1 Setup Response. This message contains a list of cells which must be activated.
+
+- The O-DU High scans the list of cells received and sends corresponding cell configurations to 5G NR MAC.
+
+- 5G NR MAC, in-turn configures the 5G NR SCH. It also configures the O-DU Low via the Lower MAC module.
+
+- On receiving the cell config response, DU APP sends a gNB DU Config Update towards the O-CU. The O-CU responds with
+ gNB DU Config Update ACK towards the O-DU High.
+
+- The DU APP now exchanges F1 Reset message with the O-CU to initialize the UE contexts.
+
+- DU APP sends Cell Start Req towards 5G NR MAC. This message is translated by the Lower MAC into the FAPI message START.request towards the O-DU
+ Low.
+
+- On receiving START.request, O-DU Low begins to send slot indications towards 5G NR MAC via the lower MAC.
+ The frequency of these slot indications is determined by the numerology(Mu) supported.
+ 5G NR MAC forwards these slot indications to the 5G NR SCH and DU APP modules.
+
+- When the first slot indication reaches the DU APP, cell is marked as up.
+
+- The 5G NR SCH, keeps tracking the SSB and SIB1 ocassions on receiving regular slot indications.
+ On detecting the relevant ocassion, 5G NR SCH schedules SSB/SIB1 and forwards the DL Scheduling Information to 5G NR MAC.
+
+- The 5G NR MAC mutiplexes the PDU and sends SSB/SIB1 packets towards the O-DU Low through the Lower MAC.
+
+
+
+UE Related Procedure
+-----------------------
+
+
+The O-DU High supports
+
+- All physical channels - PBCH, PRACH, PDCCH, PDSCH, PUSCH, PUCCH
+
+- All control logical channels - UL CCCH, DL CCCH, UL DCCH, DL DCCH
+
+- All control transport channels - BCH, UL-SCH, DL-SCH, RACH
+
+The above channels are used to achieve the below messages:
+
+- Cell broadcast of System Information which includes SSB and SIB1.
+
+- RACH Procedure
+
+ - RACH Indication
+
+ - Random Access Response
+
+ - RRC Setup Request
+
+ - RRC Setup
+
+- UE attach signalling flow
+
+ - RRC Setup Complete
+
+ - Registraton Request
+
+ - Security Mode Command
+
+ - Security Mode Complete
+
+ - Registraton Accept
+
+ - Registraton Complete
+
+ - Several NAS Message Exchanges
+
+ - RRC Reconfiguration
+
+ - RRC Reconfiguration Complete
+
+Figure 4 below depicts the above call flow, inclusive of all interfaces:
+
+.. figure:: UeAttach.png
+ :width: 800
+ :alt: O-DU High UE Attach Flow
+
+ Figure 4 - UE Attach Flow
+
+
+
+OSC Testcases Supported
+=========================
+
+The O-DU High partially supports below use-cases:
+
+- Traffic Steering
+
+- Health Check
| **Date** | **Ver.** | **Author** | **Comment** |
| | | | |
+--------------------+--------------------+--------------------+--------------------+
-| 2020-06-17 | 0.2.0 | Radisys | Bronze Release |
+| 2020-12-04 | 3.0.0 | Radisys | Cherry Release |
| | | | |
+--------------------+--------------------+--------------------+--------------------+
-| 2019-10-29 | 0.1.0 | Radisys | Amber Release |
+| 2020-06-17 | 2.0.0 | Radisys | Bronze Release |
+| | | | |
++--------------------+--------------------+--------------------+--------------------+
+| 2019-12-29 | 1.0.0 | Radisys | Amber Release |
| | | | |
+--------------------+--------------------+--------------------+--------------------+
Summary
-------
+Cherry
+^^^^^^^^
+This release contains the following:
+
+- Implementation of UE attach signalling procedure on single carrier.
+ All message exchanges within O-DU High are in line with WG8 AAD spec.
+
+- Enhancements to F1-C interface as required for UE attach procedure.
+
+- Enhancements to FAPI interface towards O-DU Low as required for UE attach procedure.
+
+- Support for all short PRACH formats.
+
+- Integration of FAPI P5 messages with Intel's O-DU Low in Timer mode.
+
+- Code support for alignment with latest FAPI interface files from Intel.
+
+- Implementation of O1 interface.
+
+- Partial implementation of Health Check use-case with get-Alarm list API.
+
+
Bronze
^^^^^^^^
This release contains the following:
- Partial implementation of RLC layer interfaces towards upper and lower layers
conforming to AAD spec.
+
Amber
^^^^^
This release contains the following:
Release Data
------------
+Cherry
+^^^^^^
++--------------------------------------+--------------------------------------+
+| **Project** | ODUHIGH |
+| | |
++--------------------------------------+--------------------------------------+
+| **Repo/commit-ID** | o-du/l2/ |
+| | 27d8d877e837c2879a452538cdbe81afe48be|
+| | d62 |
+| | |
++--------------------------------------+--------------------------------------+
+| **Release designation** | Cherry Release |
+| | |
++--------------------------------------+--------------------------------------+
+| **Release date** | 2020-12-04 |
+| | |
++--------------------------------------+--------------------------------------+
+| **Purpose of the delivery** | Cherry Release |
+| | |
++--------------------------------------+--------------------------------------+
+
Bronze
^^^^^^
+--------------------------------------+--------------------------------------+
| **Release designation** | Amber Release |
| | |
+--------------------------------------+--------------------------------------+
-| **Release date** | 2019-10-29 |
+| **Release date** | 2019-12-29 |
| | |
+--------------------------------------+--------------------------------------+
| **Purpose of the delivery** | Amber Release |
Feature Additions
-^^^^^^^^^^^^^^^^^
+------------------
**JIRA BACK-LOG:**
-+---------------------------------------------+--------------------------------------+
-| **JIRA REFERENCE** | **SLOGAN** |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-1 | F1-C enhancement |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-5 | F1-U implementation |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-11 | E2 implementation |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-9 | Cell broadcast procedure |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-10 | UE attach procedure till msg-4 |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-8 | FAPI interface implementation |
-| | |
-+---------------------------------------------+--------------------------------------+
-| https://jira.o-ran-sc.org/browse/ODUHIGH-27 | RLC layer interface enhancements |
-| | |
-+---------------------------------------------+--------------------------------------+
+Cherry
+^^^^^^^
+
++-----------------------------------------------+-----------------------------------------------+
+| **JIRA REFERENCE** | **SLOGAN** |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-10 | UE attach procedure with basic scheduling |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-188 | Support for all short PRACH formats |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-191 | Explore O1 interface |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-189 | Integration with O-DU Low |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-214 | get-AlarmList implementation on O1 interface |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-196 | CM Support on O1 interface |
+| | |
++-----------------------------------------------+-----------------------------------------------+
+
+Previous Releases
+^^^^^^^^^^^^^^^^^^
+
+
++---------------------------------------------+-------------------------------------------------+
+| **JIRA REFERENCE** | **SLOGAN** |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-1 | F1-C enhancement |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-5 | F1-U implementation |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-11 | E2 implementation |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-9 | Cell broadcast procedure |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-10 | UE attach procedure till msg-4 |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-8 | FAPI interface implementation |
+| | |
++---------------------------------------------+-------------------------------------------------+
+| https://jira.o-ran-sc.org/browse/ODUHIGH-27 | RLC layer interface enhancements |
+| | |
++---------------------------------------------+-------------------------------------------------+
Bug Corrections
-^^^^^^^^^^^^^^^
+----------------
**JIRA TICKETS:**
Deliverables
-^^^^^^^^^^^^
+-------------
Software Deliverables
-+++++++++++++++++++++
+^^^^^^^^^^^^^^^^^^^^^^
-This release contains O-DU code, along with test code as part of CU stub, RIC stub and phy stub.
+This release contains O-DU High code, along with test code in the form of CU stub, RIC stub and phy stub.
Instructions to build and execute ODU, CU and RIC stub binaries are also present.
All of the above can be found in the o-du/l2 repo.
Documentation Deliverables
-++++++++++++++++++++++++++
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
This release contains
single HARQ transmission
-- Support for single UE.
+ single UE.
+
+- This release implements a basic scheduler with fixed scheduling for single UE.
- Cell broadcast is for SSB and SIB1 only.
-- This release implements a basic scheduler with fixed scheduling.
+- FAPI files not in-line with SCF FAPI 1.0.5.
+ O-DU High currently compatible with FAPI files provided by Intel.
+
+- Implementation of F1 reset is limited to intializing UE contexts.
- E2 interface is limited to Traffic Steering Usecase.
- On the F1-U interface, UE, RB and tunnel configurations are static.
-- System runs on preconfigured values due to absence of O1 interface.
+- System runs on preconfigured values due to absence of CM support on O1 interface.
- O-DU High has not been integrated with O-DU Low and O-CU.
-- FAPI files not in-line with SCF FAPI 222.10.01.
- O-DU High currently compatibale with FAPI files provided by Intel.
-
Known Issues
-^^^^^^^^^^^^
+^^^^^^^^^^^^^
None
**JIRA TICKETS:**
Workarounds
^^^^^^^^^^^
-NA
+O-DU High uses FAPI interface files provided by Intel and therefore, not completely in-line with SCF FAPI 1.0.5.
Code Review / o-du / l2.git / commitdiff
