Open RAN, Making the RAN flexible, smart and agile [ Telecom industry shift from OEM Centric to Operator Centric]

 


Telecom industry has evolve a lot in last 10 years . Open RAN is a shift from OEM centric telecom network to Operator Centric Telecom Network 

Monopoly of traditional telecom equipment’s like Nokia/ Ericsson / Samsung /ZTE / Huawei will not more exist [ Earlier who make telecom equipment also makes its software]

Open RAN offers verity of options and openness that nontraditional telecom equipment/software companies are taking interest and performing better than traditional OEMs.

We can identify that there are major 3 step evolution from traditional RAN to Open RAN when we talk about RAN evolution of 4G/5G specially. We can operate legacy technology 2g/3g with 4g/5g in open RAN concept .

Above image is almost self-explanatory with major changes, so if you see it multiple times you will have multiple smile on your face 

So Open RAN is a concept that says interfaces are nonproprietary, its open  [ Don’t confuse with O-RAN , O-RAN is an alliance and Open RAN is concept ]

O-RAN alliance work upon Open RAN concept and given above base architecture [ That can change further with evolution]

Basics of these evolutions are how hardware can be virtualized /softwarized and how basic building block communicate with each other without limitation of dependency of an telecom hardware/software  manufacturer 

As per my understanding Cloud -RAN was 1st step towrds out of box thinking and it was done in 2010 so after 10 years we are talking about Open RAN 

OPEN RAN – THE HOLISTIC PICTURE

OPEN RAN – Basic Building 



OPEN RAN TERMINOLOGY

Open RAN

Industry term for open radio access network architecture.This includes RAN with open interoperable interfaces, RAN virtualization, Big Data and AI-enabled RAN.

Open RAN is a cooperation between radio technologies, transport network,cloud data storage, network management and RIC control, time synchronization and security

O-RAN

Refers to the O-RAN Alliance, creates standards covering three different areas: RAN disaggregation, RAN automation and RAN virtualization. The O-RAN specifications complement the 3GPP specifications by defining interface profiles, additional new open interfaces and new nodes.

OpenRAN

Refers to initiatives driven by TIP’s OpenRAN Project Group.

vRAN

(‘v’ stands for virtual) denotes the development of 5G RAN as it becomes software-defined and programmable.Operators deploying Open RAN can choose between 3GPP-based vRAN or O-RAN architectures.

Cloud RAN

Is a virtualized RAN that is designed to be cloud native, built on a future-proof architecture and incorporating key elements such as microservices, CI/CD (continuous integration and deployment) and containerization.

MEC

Mobile Edge Computing, MEC, or Multi-Access Edge Computing, can provide execution resources (compute and storage) for applications with networking closer to the end users



O-DU

Open Distributed Unit (O-DU) is a commercial off-the-shelf (COTS) edge servers that can function as  baseband processing unit to handles high PHY layer, MAC and RLC layer with network function virtualization (NFV) or Containers. O-DU is best described here 

O-RAN Distributed Unit (O-DU) is the component responsible for all baseband processing, scheduling, radio link control (RLC), medium access control (MAC), and the upper part of the physical layer (PHY). The F1 is the northbound interface, and the O-RAN fronthaul is the southbound interface. The virtualization of this component is typical but requires some hardware assistance in the form of accelerators such as field-programmable gate arrays (FPGAs) or graphics processing units (GPUs)

https://www.techplayon.com/o-ran-distributed-unit-o-du-reference-architecture/

O-CU

O-RAN Central Unit: a logical node hosting RRC, SDAP and PDCP protocols

O-RAN Central Unit (O-CU) is the component of the RAN that is centralized and virtualized. It is responsible for the packet data convergence protocol (PDCP) layer of the protocol. Its northbound interface is the backhaul network to the core; its southbound interface is the F1 interface

O-CU-CP

O-RAN Central Unit – Control Plane: a logical node hosting the RRC and the control plane part of the PDCP protocol

O-CU-UP

O-RAN Central Unit – User Plane: a logical node hosting the user plane part of the PDCP protocol and the SDAP protocol

O-RU

O-RAN Radio Unit: a logical node hosting Low-PHY layer and RF processing based on a lower layer functional split. This is similar to 3GPP’s “TRP” or “RRH” but more specific in including the Low-PHY layer (FFT/iFFT, PRACH extraction).

O-RAN Radio Unit (O-RU) is the component responsible for the lower part of the PHY layer processing (for example, fast Fourier transform (FFT) / inverse fast Fourier transform (IFFT), beamforming), including the analog components of the radio transmitter and receiver. There is a remote possibility of virtualization of the O-RU; however, one working group in the O-RAN Alliance plans a “white box” radio implementation using off-the-shelf components. It enables anyone to construct a radio without proprietary components, which differs from virtualization

RIC

A RAN Intelligent Controller (RIC) is a software-defined component of the Open Radio Access Network (Open RAN) architecture that’s responsible for controlling and optimizing RAN functions. The RIC is a critical piece of the Open RAN disaggregation strategy, bringing multivendor interoperability, intelligence, agility, and programmability to radio access networks. The RIC enables the onboarding of third-party applications that automate and optimize RAN operations at scale while supporting innovative use cases that lower mobile operators’ total cost of ownership (TCO) and enhance customers’ quality of experience (QoE).

  • Non Real-Time RIC (RIC non-RT)[control functionality >1s]
  • Near Real-Time RIC (RIC near-RT) [[control functionality <1s]

RIC best described https://www.techplayon.com/5g-ric-ran-intelligent-controller/

RAN DISAGGREGATION – VARIOUS SPLIT OPTIONS

Open RAN Interfaces and transport

Orchestrator and RAN components – A1 interface.

RIC (RAN Intelligent Controller) and CU/DU – E2 Interface.

CU-CP (control plane) and CU-UP (user plane) – E1 Interface.

CU-DU – F1 interface.

DU-RU (radio unit) – Open FrontHaul.

Orchestrator and Cloud Platform (O-Cloud) – O2 Interface

FrontHaul

Fronthaul is defined as the fiber-based connection in RAN infrastructure between the Baseband Unit (BBU) and Remote Radio Head (RRH). Fronthaul originated with LTE networks when operators first moved their radios closer to the antennas. This new link was established to supplement to the backhaul connection between the BBU and central network core

MidHaul

The link between CU and DU is called the midhaul, midhaul characteristics will be similar to a 4G backhaul

BackHaul

Backhaul is a general term describing the transport infrastructure used to connect the radio access network (RAN) and the core of a mobile network. This vital link between cell tower location and provider hub is a central component of wireless/wired network infrastructure. 

The development of MIMO technology, RAN virtualization, and split architectural models have given rise to the fronthaul and midhaul, which augment the traditional backhaul definition. Combined backhaul, fronthaul, and midhaul architecture are also known as x-haul, with the backhaul component distinguished by its connecting link to the core.


Why Open RAN is so open


O-RAN CHALLENGES AND IMPACT ON TESTING[ Reality and Expectation]


Biggest Challange Below 

1. Interoperability of different OEM - 42%

2. Achieving  similar performance to single vendor networks - 20%

3.  Implementing virtualized/Cloud RAN - 14%

4. Achieving substantial cost saving - 15%

5. Harder to outsource networl maintenance -9%


 


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