Fronthaul
NTT DoCoMo achieves multi-vendor 4G/5G RAN using O-RAN specifications
NTT DoCoMo has announced that it has achieved multi-vendor interoperability across a variety of 4G and pre-standard 5G base station equipment from Fujitsu, NEC and Nokia. Equipment from those vendors supports the Open Radio Access Network (O-RAN) Alliance specifications, which are NOT standards as claimed in DoCoMo’s press release. This is believed to be the world’s first realization of this level of multi-vendor interoperability in 4G and 5G base station equipment conforming to O-RAN specifications.
Up until now, cellular telcos (cellcos) have been locked into single cellular base station vendor contracts when deploying their radio access networks (RANs). Despite ITU-R standardization and 3GPP specifications, operators have not been able to use one vendor’s baseband gear with another’s radio equipment. Working across different 4G and 5G vendor systems has been similarly problematic if not impossible. Critics say this interoperability dilemma has led to “vendor lock-in” and strengthened a small number of giant RAN vendors, namely Ericsson, Huawei and Nokia.
The Open Radio Access Network (O-RAN) Alliance wants to change that. It is an operator led industry group working to create more open and intelligent next generation radio access networks, including 5G networks. The O-RAN specifications include RAN fronthaul and X2 profiles. There are 21 network operator members shown on the O-RAN Alliance member list, which includes NTT DoCoMo, AT&T, Verizon, Deutsche Telekom, Orange, China Mobile, China Telecom and other tier 1 operators.
RAN fronthaul describes the connectivity between remote base stations and centralized cell units, enabling multiple remote units to be serviced by a single central baseband unit using open hardware specs. Ultimately, radio heads and baseband units may be mixed and matched to create a fully multi-vendor RAN.
The ability to deploy and interconnect base station equipment from different vendors will make it possible to select the equipment most suitable for deployment in any given environment, such as base stations offering broad coverage in rural areas or small base stations that can be deployed in urban areas where space is limited. This will in turn allow more rapid and flexible expansion of 5G coverage.
DoCoMo will deploy the equipment in the pre-commercial 5G service it plans to launch on September 20, 2019 in Japan. Concurrent with the pre-commercial launch of its 5G services, DoCoMo will expand 5G coverage by combining 5G networks with existing 4G networks using equipment from diverse vendors. The signal transmission specifications that will enable this follows lengthy discussions within the O-RAN Alliance, which DoCoMo is chairing.
4G and 5G multi-vendor interoperability:
O-RAN fronthaul interface specifications provide a foundation for interoperability between centralized units and remote units of 5G remote-installed base stations manufactured by diverse partners. With remote-installed base stations, centralization of the baseband processing will bring the following benefits:
- Improved communication quality through coordination of multiple remote units
- Pooling of resources through the aggregation of hardware
- Minimization of equipment footprint, leading to a reduction in space and costs.
In addition, through the provision of only radio processing, the remote unit can be further downsized, making it possible to install in a variety of locations that would previously have not been viable, such as small buildings or mountainous areas.
The O-RAN X2 profile specifications provide a foundation for interoperability between 4G base stations and 5G base stations manufactured by diverse partners in 5G non-standalone (5G NSA) networks by taking 3GPP X2 interface specifications and specifying details for their usage. 3GPP Release 15 based 5G NR-NSA networks connect devices using both 4G and 5G technologies. The connection of 4G and 5G base stations makes it possible to combine the high-speed, low-latency data communications delivered by 5G technology with the comprehensive coverage of 4G networks.
Going forward, DoCoMo will continue to refine and develop its cutting-edge base station communication technology, aiming to expand the provision of stable 5G coverage.
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Open Test and Integration Center (OTIC):
O-RAN has announced the Open Test and Integration Center (OTIC) – an initiative led by China Mobile and Reliance Jio along with participation from China Telecom, China Unicom, Intel, Radisys, Airspan, Baicells, CertusNet, Mavenir, Lenovo, Ruijie Network, Inspur, Samsung Electronics, Sylincom, WindRiver, ArrayComm, and Chengdu NTS.
The above named companies are collaborating on multi-vendor interoperability and validation activities for O-RAN compliant 5G access infrastructure. The initial focus is to ensure RAN components from multiple vendors support standard and open interfaces and can interoperate in accordance with O-RAN test specifications.
“China Mobile will initiate an OTIC in Beijing, China, which should provide the common platform for solutions to be operationally ready to enable end-to-end interoperability and deployment in scale; as well as to be hardened for reliability, performance, scalability, and security that operator networks require,” said Dr. Li Zhengmao, EVP of China Mobile.
“Jio is creating an OTIC to accelerate the telecom industry transformation by driving ready-for-commercialisation products and solutions,” said Mathew Oommen, President, Reliance Jio.
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Heavy Reading Comments:
“It is pretty significant for O-RAN because DoCoMo is a genuinely leading operator, a rainmaker in these things,” says Gabriel Brown, a principal analyst with Heavy Reading. “They have said this will conform with O-RAN specifications in what looks like the production 4G and 5G network.”
“One of the criticisms of the 5G RAN was about using the same 4G vendor, but the implication here is that you could do multivendor,” said Brown, pointing to NTT DoCoMo’s statements about the O-RAN Alliance’s X2 specifications. “What they don’t appear to be saying is that they have different baseband vendors for 4G and 5G, but they are saying they can do it. There is no question at all this is a big statement about O-RAN.”
NTT DoCoMo’s update is not a complete surprise, he says, because the operator had already been in trials with Fujitsu, NEC and Nokia. Today’s move aligns that model with the O-RAN specifications at an important moment. “Whatever they are doing has to be rock solid because the Rugby World Cup is coming in a couple of weeks,” says Brown. “That is a warm-up for the 2020 Olympics in terms of international attention on Japanese networks and all operators will be launching a limited 5G service.”
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Telco Testimonials and Deployment Plans for O-RAN:
“ The O-RAN Alliance was created to accelerate the delivery of products that support a common, open architecture and standardized interfaces that we, as operators, view as the foundation of our next-generation wireless infrastructure, while ensuring a broad community of suppliers driven by innovation and open market competition. ” — Alex Jinsung Choi, SVP Research and Technology Innovation, Deutsche Telekom “ Our industry is approaching an inflection point, where increasing infrastructure virtualization will combine with embedded intelligence to deliver more agile services and advanced capabilities to our customers. The O-RAN Alliance is at the forefront of defining the next generation RAN architecture for this transformation. ” — Andre Fuetsch, CTO and President AT&T Labs.
AT&T is a key proponent of O-RAN adoption. An AT&T employee, who presented on O-RAN at ONF Connect 2019, said the company is seriously evaluating adopting the Alliance’s specifications for 5G deployments sometime in 2020. AT&T has said that it foresees that it can bring the “whitebox” environment to the RAN by adopting open hardware specifications.
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References:
https://www.nttdocomo.co.jp/english/info/media_center/pr/2019/0918_00.html
https://www.o-ran.org/membership
https://www.o-ran.org/specifications
http://the-mobile-network.com/2019/03/taking-the-open-ran-commercial/
xRAN Forum approves Fronthaul Interface Specification for NexGen Open RAN architecture
Executive Summary:
On April 12th, the xRAN Forum (xRAN.org) announced the public availability of the xRAN Fronthaul Specification Version 1.0 – the first specification made publicly available from xRAN since its launch in October 2016. The specification was said to permit “a wide range of vendors to develop innovative, best-of-breed RRUs (remote radio unit) and BBUs (base band units) for a wide range of deployment scenarios, which can be easily integrated with virtualized infrastructure and management systems using standardized data models.”
Why is a new RAN architecture needed?
Current RAN architectures result in sub-optimal use of scarce spectrum and radio resources as well as make it hard for operators to program them quickly to meet emerging customer needs. Amid exploding demand for bandwidth and intense demands from new services, carriers need an alternative approach to address the escalating capital and operational costs of the existing design as well as make the network more agile to deploy new services.
Why It’s Important:
The new specification was said to “deliver on important operator member requirements.” It defines open interfaces between the remote radio unit/head (RRU/RRH), the baseband unit (BBU) and the operation and management (OAM) interface to simplify interoperability between suppliers. It’s significant because traditionally, the RRU and BBU had to come from the same vendor. By complying with this spec, different vendors (best of breed?) could provide each of those pieces of equipment. The desired outcome is for a wireless network operator to buy an RRU from one vendor and a BBU from another vendor such that they’ll work together via a common interface. Some say it’s going to bust up the old “cartel” of RRU/BBU suppliers.
The xRAN Fronthaul spec was said to address several key operator-defined requirements, including:
• BBU – RU interoperability based on well specified control, user and management plane interfaces.
• Efficient bandwidth scaling as a function of user throughput and spatial layers to address
increasing bandwidth needs and Massive MIMO deployments.
• Support for LTE, NR, associated features, 2T – 8T RU products and Massive MIMO beamforming
antenna systems.
• Advanced receivers and co-ordination functions.
• Ethernet based transport layer solutions.
• Extensible data models for management functions to simplify integration.
The xRAN Forum Front Haul Working Group is chaired by Verizon. A spokeswoman for Verizon, told Lightreading in an email that the xRAN spec defines an “open Internet-based standard on which future RAN products will be built,” while ORAN is an effort to “ensure various proprietary CPRI-based systems can understand one another’s languages and operations.”
Note: CPRI (Common Public Radio Interface) defines the interface between Radio Equipment Controllers (REC) and Radio Equipment (RE) such that multiple vendors can provide different parts of a base station.
Selected Quotes:
“Our vision to develop, standardize and promote an open alternative to the traditionally closed, hardwarebased RAN architecture is becoming a reality,” said Dr. Sachin Katti, Professor at Stanford University and Director of the xRAN Forum. “Our operator members have been very focused and clear on requirements and our ecosystem of contributing members have risen to the challenge. The Fonthaul Specification is the first of several open interface specifications we expect to be released in 2018.”
“The release of the xRAN Fronthaul Specification is a groundbreaking advancement toward enabling an open RAN architecture to support next-generation products and services,” said Bill Stone, Vice President, Network Technology Development and Planning at Verizon. “xRAN compliant radios coupled with virtualized basebands provide much needed flexibility to support rapid development and deployment of RAN products. By adopting xRAN specifications, we will be able to speed innovation, increase collaboration, and be more agile to a quickly evolving market.”
“We are pleased to have worked with xRAN members in reaching the key milestone of delivering the first open xRAN fronthaul specification,” said Dr. Hiroshi Nakamura, EVP and CTO of NTT DOCOMO. “We believe that the completion and publication of this specification will contribute in further advancing the RAN and in expanding the ecosystem in the 5G era. DOCOMO will keep contributing to this activity with the experience we had in realizing multi-vendor interoperable RAN with our partners using common interfaces for our LTE network.”
“The xRAN Fronthaul Specification is a foundational component in the xRAN architectural vision and vital to accelerating the worldwide deployment of next-generation RAN infrastructure network operators demand,” said Alex Jinsung Choi, SVP Research & Technology Innovation, Deutsche Telekom. “Going forward, by connecting these specification activities to the broad architectural scope in ORAN, we can ensure the implementations across a wider community of suppliers to promote both innovation and open market competition.”
“xRAN’s release of this jointly-developed open specification creates the first wave of a positive sea change for our industry, transforming the way next-generation RAN infrastructure will be built, managed and optimized,” said Andre Fuetsch, CTO and President AT&T Labs. “Equipment that supports open specifications from xRAN (and ORAN in the future), combined with increasing RAN virtualization and data-driven intelligence, will allow carriers to reduce complexity, innovate more quickly and significantly reduce deployment and operational costs.”
The specification is designed to allow for a range of vendors to develop best-of-breed RRUs and BBUs for various deployment scenarios. (Pixabay)
About xRAN Forum:
The xRAN Forum was formed to develop, standardize and promote an open alternative to the traditionally closed, hardware-based RAN architecture. xRAN fundamentally advances RAN architecture in three areas – decouples the RAN control plane from the user plane, builds a modular eNB software stack that operates on common-off-the-shelf (COTS) hardware and publishes open north- and south-bound interfaces to the industry.
xRAN Forum operator members include: AT&T, Verizon and Deutsche Telekom, KDDI, NTT DoCoMo, SK Telecom and Telstra. The vendor and academic community is also represented in the xRAN Forum by AltioStar, Amdocs, Aricent, ASOCS, Blue Danube, Ciena, Cisco, CommScope, Fujitsu, Intel, Mavenir, NEC, Netsia, Nokia, Radisys, Samsung, Stanford University, Texas Instruments and University of Sydney.
References:
http://www.xran.org/resources/