Author: Milan Milanović

Milan Milanović was Ookla's Technical Evangelist. Milan spent the last ten years in the tech industry, focusing on cellular technology.
Ookla Research™ Articles
| November 16, 2020

Rakuten is Leveraging O-RAN to Reimagine Mobile and it Could Change the Way We Use Our Phones Forever

Global Speeds

日本語

Japanese companies have often been at the forefront of applying innovative new technology to improve the everyday lives of their customers. For example, the world’s very first 1G phone service was pioneered and launched in Japan in 1979. So it’s no surprise that the most cutting-edge approach to mobile is already underway in Japan as Rakuten embraces the Open Radio Access Network (O-RAN) standard to build a cloud-native mobile network, Rakuten Mobile. This fully virtual mobile network allows Rakuten to reduce the costs associated with building and upgrading a network and also offers Rakuten Mobile’s customers a complete beginning-to-end user experience for their online activities.

Rakuten disrupts a well-established market

EN-Rakuten-Diagram

Prior to Rakuten Mobile’s entry, the Japanese mobile market was dominated by three major operators: NTT Docomo, au by KDDI and Softbank Mobile. All three have been in operation for over a decade and have deployed 5G throughout Japan.

NTT DoCoMo was spun off from Nippon Telegraph and Telephone (NTT) with 2G service in 1991. Over the next decade, the company transitioned to 3G. It currently offers LTE service on a combination of 700 MHz, 800 MHz, 1.5 GHz, 1.8 GHz, 2.1 GHz and 3.5 GHz bands. Recently the company has launched 5G service on 3.6GHz, 4.5GHz and mmWave.

KDDI was created in 2000 as a result of a merger of three companies: KDD, DDI and IDO. The company used CDMA technology for its 2G and 3G services, and currently offers LTE services using 700 MHz, 800 MHz, 1.4 GHz, 2.1 GHz and 3.5 GHz. Recently launched 5G service is rolled out on 3.8 GHz, 4.1 GHz and mmWave.

Softbank Mobile, the third major operator in Japan, entered the Japanese market in 2006 with the purchase of Vodafone Japan. Softbank Mobile’s LTE frequency bands span from 700 MHz to 3.5 GHz, and 5G is rolled out on 3.9 GHz and mmWave.

Rakuten is new to mobile, but this is only one part of a well-established business. Founded in 1997 as an e-commerce company with only six employees and one server, the company now has a global reach with a portfolio of over 70 companies and more than a billion membership and loyalty program customers worldwide. The enterprise now covers a wide variety of industries including banking, travel, online shopping, advertising, global messaging, video delivery, data analysis and now wireless, just to name a few.

What’s extremely interesting about Rakuten as a wireless operator is the company’s culture and decades of data-centric expertise in the cloud space. Offering end-to-end user experience and controlling the entire customers’ online journey certainly brings tremendous value to the company, but it also opens the idea of other tech giants like Amazon, Google and Apple entering the mobile telecom space. With the promise of running fully virtualized network functions, the costs associated with network rollouts and operational expenditure may be significantly reduced, and any new entrants to the telecom space may bring fresh perspectives on running and operating a mobile network.

Rakuten leverages the cloud to break the chains of infrastructure

Rakuten opted for a cloud-native mobile network approach using O-RAN instead of relying entirely on traditional network infrastructure equipment vendors for core and radio access technology. This means Rakuten is decoupling radio access from baseband processing and virtualizing a large amount of network functions. This approach relies on data centers and the cloud, which are Rakuten’s strengths.

In the traditional telco world, infrastructure vendors’ solutions typically provide an end-to-end vertical stack, which includes everything from radio access and baseband processing to the transport and core. This means that when operators lock into a contract with infrastructure giants like Huawei, Nokia and Ericsson, they are locked into a proprietary closed ecosystem of software and hardware.

Once hardware and software are disaggregated, operators will be free to deploy any software-defined functions offered by any company, small or large, following “white-box” O-RAN guidelines. This approach, called “virtualization,” can be run on any off-the-shelf computer server. Virtualization reduces the importance of traditional telco hardware, speeds up rollouts, drives innovation and significantly reduces the operator’s capital expenditures. Virtualization can quickly and easily disrupt the economics of traditional operators, paving the way for fresh opportunities both for new entrants and the industry as a whole. With O-RAN, operators can work with major infrastructure vendors like Nokia, NEC, Fujitsu, Cisco and Intel and smaller companies like Airspan and Altiostar to choose custom solutions.

This also means that multi-vendor interoperability and a multitude of innovations like virtualization and automation will largely depend on a vendor’s nimbleness in the research and development space.

The innovations behind O-RAN

O-RAN architecture is a concept designed to address the future needs of mobile network providers based on openness, interoperability and industry collaboration as a whole. Traditional network deployments rely on 3GPP-compliant hardware, typically designed by a single vendor providing a closed-box software and hardware solution as well as security aspects of the networks. On the other hand, the O-RAN Alliance and its members (which include leading telecom, cloud and chipset suppliers, as well as network operators) have been leading an effort to standardize virtual RAN functions and open interfaces to enable cloud-native deployments and multi-vendor interoperability.

O-RAN opens the door to new solutions

One of the goals of this initiative is to maximize the openness and use of common off-the-shelf hardware while minimizing the use of the proprietary telecom hardware. Creating a standardized multi-vendor virtual RAN environment allows third parties to access what used to be closed vendor RAN data and create a multitude of innovative services and applications.

O-RAN promises open interfaces that enable smaller vendors to introduce their products and services in ways that are tailored to suit operators’ unique needs. This should foster vendor diversity and infrastructure robustness while allowing the operators to minimize security risks by controlling all aspects of the network.

By using commercial off-the-shelf (COTS) hardware with virtualization software in the form of containers and virtual machines (VM), the Radio Access Network basically becomes the first app in the O-RAN app store.

Improving network security and agility

Another major aspect of O-RAN is the unparalleled view it provides into the security apparatus of the network, allowing the operator to have full end-to-end visibility and transparency into the entire stack — and to control the entire supply chain for each and every component. Furthermore, because of the software-based nature of O-RAN, the operator has the ability to add, inspect or replace network functions much faster than with traditional deployments which often require physical visits for upgrades. In this way O-RAN improves the efficacy and agility of the network.

This is potentially the first time in the history of the mobile industry where operators will be given the voice and the ability to custom-build networks. From an engineering perspective, moving hardware-based baseband to the virtual world is challenging, but also fun. With recent advancements in software-defined networks and virtualization, LTE and 5G networks have the potential to behave like Wi-Fi networks from installation through integration. The concept of a telecom app store will continue driving innovation, collaboration and industry support, while both private and government sectors will need to be engaged to drive this ongoing transformation in the industry.

Allowing applications to program the network

During the last decade, progress has been made on building applications that can run on top of the network. O-RAN promises to take this to the next level by allowing applications to actually program and run the network itself, which introduces the importance of artificial intelligence (AI). The use of AI to program a network could dramatically simplify the rollout and operation of 5G networks.

Leveraging automation, virtualization and artificial intelligence could also enable self-driving network operations and reduce operating expense. Future deployments could (ideally) depend on virtualized network elements and a standardized white-box approach, which would foster a multi-vendor, interoperable and autonomous RAN.

One of the main propositions of O-RAN architecture is to extend the software-defined network (SDN) concept of decoupling the control-plane (CP) from the user-plane (UP) into RAN, while bringing in embedded intelligence. Separating UP from CP allows for more scalability and cost-effectiveness on the UP. According to the O-RAN Alliance White Paper, this new architecture introduces a set of key interfaces between multiple decoupled RAN components. These include enhanced 3GPP interfaces (F1, W1, E1, X2, Xn) to enable multi-vendor interoperability. In addition to the proposed white-box hardware, many software components will be delivered on an open-source basis like the RAN intelligent controller, protocol stack, PHY layer processing and virtualization platform.

How Rakuten made the world’s first Open Radio Access Network

As a brand new entrant in the Japanese mobile space, Rakuten took its cloud-centric approach and virtualized everything from radio to the core with hundreds of virtual functions implemented. These functions are delivered from multiple computing centers leveraging COTS hardware.

Rakuten has also fostered innovation on the radio access side by having infrastructure giants like Nokia agree to open up the radio, which is typically a black box. This allows Rakuten to control all the hardware that goes into the network, the supply chain, the ecosystem as well as the security aspect of this platform. Rakuten prides itself in the “zero touch provisioning” which breaks free from traditional network rollouts, drastically speeds up the deployment process and requirements, and redefines the way telecom operators can architect, provision and deploy the network.

A company like Rakuten — with decades of experience running server-centric IP-based services — already has an advantage over traditional telcos because of the hundreds of edge data centers they operate. At this time, Rakuten has an infrastructure of nearly 300 edge data centers that can bring content geographically closer to the user and drastically reduce latency. The CP workloads are handled by central data servers, and the entire operation is managed by the horizontal cloud. Everything from radio access, transport and network functions are virtualized and orchestrated by the Rakuten Mobile operating system.
Mobile-Architecture_1120_en-1

The process of activating and provisioning a new site takes minutes, rather than hours or days, bringing significant savings in capital and operational expenditures. For the field technicians this means all they have to do is hang radio units, connect the fiber and power, and the new cell site will be up and running.

Rakuten began initial trials late last year. Using an app-based approach, they onboarded 5,000 customers to test and validate the world’s first end-to-end cloud-native architecture. The official April 2020 launch was on LTE only, and the initial network service area covers Tokyo, Nagoya City and Osaka City. Outside of the native coverage area, users will have the ability to roam on KDDI and Okinawa Cellular. Since the operator owns the end-to-end orchestration and automation of eNodeB as a virtual network function, and both hardware and software is 5G-ready from the get-go. This also means that new network feature rollouts and fixes are significantly easier than they are for a traditional telco. On September 30, Rakuten rolled out a commercial 5G network which will be the test of how easy this flexible software-based architecture makes rolling out core and network functions.

Rakuten Mobile is performing well so far

As revolutionary as Rakuten’s approach is, end users are more likely to care about performance than how the network is configured. We took a look at Rakuten’s performance over 4G LTE and 5G in Tokyo during Q2-Q3 2020. Data for 5G is limited to Q3 as Rakuten’s 5G is only newly commercially available.

Median Speeds for Rakuten Mobile in Tokyo
Speedtest Intelligence® | Q2-Q3 2020
Download (Mbps) Upload (Mbps)
Q2 LTE 38.05 18.28
Q3 LTE 31.68 19.51
Q3 5G 101.33 18.78

Rakuten delivered a median LTE download speed of 38.05 Mbps in Q2 2020. However, LTE download speed was 16.7% lower in Q3 2020. Upload speed over LTE increased slightly. Users with access to the 5G network layer that launched at the end of Q3 2020 experienced a median download speed of 101.33 Mbps, 166.3% faster than the median download speed over LTE in Q2 and 219.9% faster than median download speed over LTE in Q3. The median upload speed on 5G was slower than on LTE.

What operators can learn from the Rakuten model

The Rakuten model is a very early dive into the world of O-RAN architecture. It went from a proof-of-concept to a fully fledged commercial mobile network serving millions of customers in what felt like the blink of an eye. There are still many unknowns, in particular in terms of future scalability and security, but the operator seems to be very confident with its own Rakuten Mobile Platform (RMP). In fact, that same platform is being offered as a turn-key solution to existing mobile operators and new entrants.

This model promises a significant cost reduction in both capital and operating expense, including head count (due to the data-centric nature and the level of automation). This approach seems to pose a threat to the traditional telecom giants like Ericsson, Nokia and Huawei in terms of revenue. However, these companies’ willingness to open their radio components and allow customization for Rakuten’s specific needs implies that broader change is coming in the telecom world.
dish_spectrum_map_en-01

An operator that could benefit from the extension of this experiment is DISH, a recent entrant to the U.S. mobile market. Over the past few decades, DISH has acquired significant amounts of spectrum that spans from 600 MHz all the way up to the mmWave, including the potential acquisition of Sprint’s 800 MHz spectrum assets. Similar to Rakuten Mobile, DISH could potentially combine fallow spectrum and the promise of building and deploying a facilities-based O-RAN 5G network. Deploying a lean network could, at least in theory, enable a rapid deployment of DISH’s assets, which could create many new jobs while leveraging American companies that are eager to innovate and disrupt, such as Cisco, Altiostar, Mavenir, Qualcomm, Intel and Airspan (to name a few).

A recent announcement reveals VMWare as a strategic partner in providing a cloud-based abstraction layer, which is essentially a 5G operating system that will hold the silicon, software and cloud together, and will enable a hyper-scale of public cloud capacity where needed.

O-RAN would allow DISH and other mobile operators to expand beyond the constraints of vertical solutions provided by traditional telco vendors like Ericsson, Huawei and Nokia. The O-RAN concept would simplify and fully automate the network deployment using DISH’s greenfield environment. Nokia has been the most receptive to the O-RAN approach, agreeing to provide 5G core applications including subscriber management, device management and integration services (among others). DISH has recently signed a deal with Japanese giant Fujitsu, securing a large order of O-RAN-compliant radios while Altiostar and Mavenir will also be providing O-RAN software.

While all eyes will be immediately focused on Rakuten Mobile and its cloud-native O-RAN 5G network, operators and infrastructure vendors around the world are working together to improve the O-RAN concept. From a financial and operational standpoint, the O-RAN model makes a lot of sense, and a few operators are already looking into leveraging at least some tools from the O-RAN toolbox. India’s Reliance Jio has plans for a deployment similar to Rakuten’s, while U.S. telcos Verizon and AT&T are already making steps to allow for multi-vendor 5G interoperability in some markets. Recently, Telefónica Spain and STC in Saudi Arabia have shown interest in Rakuten’s mobile platform.

We are likely to see a lot more O-RAN announcements in the coming year, and we at Ookla will continue monitoring Rakuten’s network performance, so stay tuned.

楽天がO-RANの活用でモバイルを一新、携帯電話の今後のありかたをまったく変える可能性を示す

日本の企業はこれまでに何度も、顧客の生活を豊かにする革新的な新技術導入の最前線にいました。たとえば、世界初の1Gの通話サービスは1979年に日本で初めて始まりました。そのため、楽天がOpen Radio Access Network（O-RAN）標準を採用し、クラウドネイティブなモバイルネットワークとして楽天モバイルを構築することで、携帯通信への最先端のアプローチがすでに日本で始まっていることも驚きではありません。楽天は、この完全に仮想的なモバイルネットワークにより、ネットワークの構築とアップグレードにかかるコストを削減し、さらに、楽天モバイルの顧客にオンラインでのアクティビティにおける一貫したユーザーエクスペリエンスを提供できるようになりました。

楽天が確立された市場を打破

JP-Rakuten-Diagram

楽天モバイルの参入以前、日本の携帯通信市場はNTT Docomo、au by KDDI、Softbankモバイルの3社の主要な事業者によって支配されていました。これら3社すべては10年以上運営されており、日本全国で5Gを展開しています。

NTT DoCoMoは日本電信電話（NTT）から派生し、1991年に2Gサービスを開始しました。その後10年間で、同社は3Gに移行しています。現在は、700MHz、800MHz、1.5GHz、1.8GHz、2.1GHz、3.5GHzのバンドでLTEサービスを提供しています。現在、同社は3.6GHz、4.5GHz、ミリ波で5Gサービスを開始しています。

KDDIは、KDD、DDI、IDOの3社が合併して2000年に設立されました。同社は2Gと3GサービスにCDMA技術を使用し、現在では700MHz、800MHz、1.4GHz、2.1GHz、3.5GHzを使用してLTEサービスを提供しています。最近開始された5Gサービスは、3.8GHz、4.1GHz、ミリ波で展開されています。

日本の3つめのキャリアであるSoftbankモバイルは、Vodafone Japanを買収して2006年に日本市場に参入しました。SoftbankモバイルのLTE周波数バンドは700MHzから3.5GHzで、5Gは3.9GHzとミリ波で展開されています。

楽天は携帯通信事業に初参入ですが、同事業は確立されたビジネスの一部となっています。1997年にわずか6名の従業員と1台のサーバーでEコマース企業として設立された同社は、現在では70社以上の企業のポートフォリオと、10億人以上の会員とポイントプログラムの顧客を世界中に抱え、グローバルに展開しています。同社は現在幅広い業界に展開しており、いくつか例を挙げると、銀行、旅行、オンラインショッピング、広告、グローバルメッセージ機能、動画配信、データ解析、そして携帯通信などです。

楽天が携帯通信事業者として非常に興味深い点は、同社の文化とクラウド事業における数十年分のデータ中心のノウハウです。エンドツーエンドのユーザーエクスペリエンスの提供と顧客のオンラインジャーニー全体の制御は、確かに多大な価値をもたらしていますが、同時に、Amazon、Google、Appleなどの情報技術系最大手企業が携帯通信事業に参入したことを連想させます。完全に仮想化されたネットワーク機能を実行するという約束のもと、ネットワークの展開と運用費用に関連するコストが大幅に削減され、新規通信事業者が増えることでモバイルネットワークの実行と運用に新しい展望をもたらすでしょう。

楽天はクラウドを活用してインフラストラクチャの鎖を解く

楽天は、核となる技術と無線アクセス技術について従来のネットワークインフラストラクチャの設備ベンダーに完全に依存するのではなく、O-RANを使用してクラウドネイティブなモバイルネットワークへのアプローチを採用しました。これは、楽天が無線アクセスをベースバンド処理から分離させ、多数のネットワーク機能を仮想化していることを意味します。このアプローチでは、楽天の強みであるデータセンターとクラウドを基盤としています。

従来の携帯通信業界では、インフラストラクチャベンダーのソリューションがエンドツーエンドの垂直スタックを提供することが一般的でした。これには、無線アクセスとベースバンド処理から、転送とコアに至るまでのすべてが含まれています。これは、事業者がHuawei、Nokia、Ericssonなどのインフラストラクチャの大手企業との契約に縛られると、ソフトウェアとハードウェアの私的に閉じられたエコシステムに閉じ込められることを意味します。

ハードウェアとソフトウェアが分離されると、事業者は大小あらゆる企業によって提供される、あらゆるソフトウェア定義機能を自由に展開できます。これは「ホワイトボックス化」されたO-RANのガイドラインに従っています。「仮想化」と呼ばれるこのアプローチは、あらゆる既成のコンピューターサーバー上で実行可能です。仮想化は従来の携帯通信ハードウェアの重要性を低減し、展開を高速化し、イノベーションを促進して事業者の資本支出を大幅に減らします。仮想化は従来の事業者の経済を一瞬で簡単に破壊させ得るため、新たな参入企業と業界全体の両方で新鮮な機会を創出しています。O-RANを使用することで、事業者は、Nokia、NEC、富士通、Cisco、Intelなどの大手インフラストラクチャベンダー、およびAirspanやAltiostarなどの小規模な企業と提携し、カスタムのソリューションを選択できます。

これは同時に、マルチベンダーの相互運用性と、仮想化や自動化などのイノベーションの数が、研究と開発分野におけるベンダーの俊敏性に大きく依存することも意味します。

O-RANの背景にあるイノベーション

O-RANアーキテクチャは、モバイルネットワークプロバイダーの将来のニーズに対応するために設計されたコンセプトで、オープン性、相互運用性、業界全体の協業性に基づいています。従来のネットワーク展開は3GPP準拠のハードウェアに依存しており、これは通常、クローズボックスのソフトウェアとハードウェアソリューション、およびネットワークのセキュリティ面を提供する単一のベンダーにより設計されています。一方で、O-RANアライアンスとそのメンバー（大手通信企業、クラウドおよびチップセットのサプライヤー、携帯通信事業者を含む）は、仮想RAN機能とオープンインフラストラクチャを標準化し、クラウドネイティブな展開とマルチベンダーの相互運用性を実現するための取り組みを進めています。

新たなソリューションへの扉を開くO-RAN

このイニシアチブの目標の1つに、私的な携帯通信ハードウェアの使用を最小限にしながら、オープン性と一般的な既成ハードウェアの使用を最大限にすることが挙げられます。標準化されたマルチベンダーの仮想RAN環境を作り上げることにより、サードパーティがかつてはクローズドだったベンダーのRANデータにアクセスし、多くの革新的なサービスとアプリケーションを作成できるようになります。

O-RANは、小規模なベンダーが、事業者固有のニーズに合うようにカスタマイズされた、自社の製品とサービスを導入できるようにするオープンなインターフェイスを確約します。これにより、事業者がネットワークのすべての側面を制御することでセキュリティのリスクを最小限に抑えながら、ベンダーの多様性を広げ、インフラストラクチャの堅牢性を強化することにつながります。

商用の既成（COTS）ハードウェアを、コンテナと仮想マシン（VM）の形で仮想化ソフトウェアとともに使用することで、基本的に無線アクセスネットワークがO-RANのアプリストア内の最初のアプリとなります。

ネットワークのセキュリティと俊敏性を向上

O-RANの他の大きな側面として、ネットワークのセキュリティ組織にもたらされる他にはない視点があります。これにより、事業者はスタック全体に完全なエンドツーエンドの視認性と透明性を手に入れることができます。そして、各コンポーネントすべてに対するサプライチェーン全体を管理できます。さらに、O-RANのソフトウェアベースの性質によって、アップグレードのために物理的に訪れる必要があった従来の展開よりもはるかに高速にネットワーク機能を追加、点検、交換することができます。このようにして、O-RANはネットワークの有効性と俊敏性を高めることができます。

事業者がカスタムに構築されたネットワークを表明し実行できるのは、携帯通信業界においてこれが初めてかもしれません。エンジニアリングの観点からは、ハードウェアベースのベースバンドを仮想世界に移行するのは困難ですが、同時に楽しさもあります。最近のソフトウェア定義ネットワークと仮想化の進歩により、LTEおよび5Gネットワークは、設置から統合までWi-Fiネットワークのように機能する可能性を秘めています。携帯通信アプリストアのコンセプトはこれからもイノベーション、コラボレーション、業界のサポートを推進しつづけます。一方で一般部門と政府部門の両方が業界におけるこの継続的な転換の促進に従事する必要があります。

アプリケーションによるネットワークのプログラミングを実現

ここ10年間で、ネットワークの上層で実行可能なアプリケーションの構築は進歩しています。O-RANは、アプリケーションが実際にネットワークそのものをプログラミングおよび実行できるようにすることで、これを次のレベルへと高めます。これは、人工知能（AI）の重要性につながります。ネットワークのプログラミングにAIを使用することで、5Gネットワークの展開と運用が劇的に簡素化できます。

自動化、仮想化、人工知能の活用により、自己駆動形のネットワーク運用が実現し、運用コストを削減できます。将来の展開は（理想的には）、仮想化ネットワーク要素と標準化されたホワイトボックスのアプローチに基づく可能性があり、これにより、マルチベンダー化、相互運用性、自律型RANが推進されます。

O-RANアーキテクチャの主な課題の1つに、埋め込みインテリジェンスをもたらしながら、同時に制御プレーン（CP）をユーザープレーン（UP）からRANに分離させるという、ソフトウェア定義ネットワーク（SDN）の概念を拡大することが挙げられます。UPをCPから分離させることにより、UPでのスケーラビリティとコスト効率性が高まります。O-RANアライアンスのホワイトペーパーによると、この新たなアーキテクチャによって、複数の分離されたRANコンポーネント間の一連の主なインターフェイスが導入されます。これには、マルチベンダーの相互運用性を実現するための3GPPインターフェイス（F1、W1、E1、X2、Xn）が含まれます。提唱されたホワイトボックスのハードウェアに加えて、多くのソフトウェアコンポーネントは、RANインテリジェントコントローラー、プロトコルスタック、PHYレイヤー処理、仮想化プラットフォームのように、オープンソースベースで提供されます。

楽天はいかにして世界初のオープン無線アクセスネットワークを作り上げたか

日本の携帯通信事業への新たな参入企業として、楽天はそのクラウド中心のアプローチを採用し、数百の仮想化機能を実装して無線からコアにいたるまでのすべてを仮想化しました。これらの機能は、COTSハードウェアを活用した複数のコンピューティングセンターから提供されます。

また楽天は、Nokiaのようなインフラストラクチャ大手企業の周波数を利用可能にすることについて合意を得ることで、無線アクセスにおける革新を促進しました。これは、通常はブラックボックスとなっています。これにより、楽天はネットワーク、サプライチェーン、エコシステム、そしてこのプラットフォームのセキュリティ面に使用されるすべてのハードウェアを制御できます。楽天は、従来のネットワーク展開から解放し、展開プロセスと要件を劇的に高速化させ、携帯通信事業者がネットワークを設計、プロビジョニング、展開する方法を再定義する「ゼロタッチプロビジョニング」に自信を持っています。

サーバー中心のIPベースのサービスを運用してきた数十年の経験を持つ楽天のような企業は、同社が運用する数百のエッジデータセンターにより、従来の携帯通信よりもすでに優位に立っています。現時点で、楽天は300か所近いエッジデータセンターのインフラストラクチャを有しており、地理的にユーザーに近い場所にコンテンツを配信することで、遅延を劇的に低減しています。CPのワークロードは中央データサーバーによって処理され、運用全体は水平的なクラウドによって管理されます。無線アクセス、転送、ネットワーク機能のすべては仮想化され、楽天モバイルのオペレーティングシステムによってオーケストレーションされます。
Mobile-Architecture_1120_jp

新たなサイトの有効化とプロビジョニングのプロセスは、数時間も数日もかかることなく、数分で完了し、資本コストおよび運用コストを大幅に削減できます。現場技術者にとってこれは、無線ユニットを吊るし、ケーブルと電源を接続するだけで、新たなセルサイトを稼動できることを意味します。

楽天は初期テストを昨年後半に開始しています。アプリベースのアプローチを使用することで、5,000人の顧客を招待して世界初のエンドツーエンドのクラウドネイティブなアーキテクチャをテストおよび検証しました。2020年4月に公式に運用開始したのはLTEのみで、当初のネットワークサービスでは東京、名古屋市、大阪市のエリアをカバーしています。ネイティブにカバーされているエリアの外では、ユーザーはKDDIおよび沖縄セルラーからローミングできます。事業者は、eNodeBのエンドツーエンドのオーケストレーションと自動化を仮想ネットワーク機能として所有しており、ハードウェアとソフトウェアの両方が最初から5Gに対応しています。これは、新たなネットワーク機能の展開と修正が従来の携帯通信よりも大幅に簡単であることも意味します。9月30日に、楽天は商用の5Gネットワークを展開しました。これは、この柔軟なソフトウェアベースのアーキテクチャによって、コアとネットワーク機能の展開がどれくらい簡単になるかのテストです。

楽天モバイルのパフォーマンスは順調

楽天のアプローチは革命的ですが、エンドユーザーはネットワーク構成の仕組みよりもパフォーマンスを気にします。2020年第2四半期から第3四半期の、東京における4G LTEと5Gの楽天のパフォーマンスを確認してみました。楽天の5Gは商用的に開始されたばかりのため、5Gのデータは第3四半期のみとなっています。

東京における楽天モバイルの中央速度
Speedtest Intelligence® | 2020年第2四半期から第3四半期
下り（Mbps） 上り（Mbps）
第2四半期LTE 38.05 18.28
第3四半期LTE 31.68 19.51
第3四半期5G 101.33 18.78

楽天は、2020年第2四半期のLTEの中央速度が下り38.05Mbpsでした。しかし、2020年第3四半期にはLTEの下り速度は16.7%落ちています。LTEでの上り速度はわずかに上昇しています。2020年第3四半期の終わりに開始された、5Gネットワークレイヤーにアクセスできるユーザーは、101.33Mbpsの下り中央速度で利用しています。これは、第2四半期のLTEでの下り中央速度よりも166.3%速く、さらに第3四半期の下り中央速度よりも219.9%速くなっています。5Gの上り中央速度はLTEよりも低速でした。

事業者が楽天モデルから学べること

楽天モデルでは、O-RANアーキテクチャの世界へかなり早い段階で踏み入りました。そこから概念実証が始まり、あっという間に数百万人のユーザーにサービスを提供する、完全に実用的な商用モバイルネットワークになりました。特に将来のスケーラビリティとセキュリティに関しては、まだ数多くの未知の部分があるものの、楽天は独自の楽天モバイルプラットフォーム（RMP）に非常に信頼を置いているように見えます。実際、この同じプラットフォームが既存の携帯通信事業者と新たな参入企業に対して、ターンキーソリューションとして提供されています。

このモデルでは、社員数を含む、資本コストと運用コストの両方の大幅な削減が確約されています（データ中心の性質と自動化のレベルによるものです）。このアプローチは、Ericsson、Nokia、Huaweiのような従来の携帯通信大手企業にとって、収益の観点からは脅威となる可能性を秘めているでしょう。ただし、これらの企業が無線コンポーネントを開放し、楽天固有のニーズに対するカスタマイズを快く許可したことは、携帯通信業界において大きな変化が訪れることを示唆しています。
dish_spectrum_map_jp-01

この試みが広がることでメリットを享受できる可能性のある事業者にDISHが挙げられます。同社は、米国の携帯通信市場に最近参入しました。過去数十年間で、DISHは600MHzからミリ波にいたるまでの十分な周波数を獲得しています。また、Sprintの800MHz周波数アセットも獲得予定です。楽天モバイルと同様に、DISHでは、使用されていない周波数と、施設ベースのO-RAN 5Gネットワークを構築および展開するという契約を組みわせることが検討されています。無駄のないネットワークの展開によって、少なくとも理論的には、DISHのアセットの迅速な展開が可能になります。これにより、Cisco、Altiostar、Mavenir、Qualcomm、Intel、Airspanなど（ごく一部の例ですが）の、革新と打破に意欲的な米国企業を活用しながら、多くの業務が新たに創出される可能性があります。

最近の発表では、VMwareが、シリコン、ソフトウェア、クラウドをまとめて有する本質的な5Gオペレーティングシステムであり、必要な場合にパブリッククラウドのキャパシティを拡大できるようにする、クラウドベースの抽象化レイヤーの提供における戦略的パートナーとなっています。

O-RANにより、DISHなどの携帯通信事業者が、Ericsson、Huawei、Nokiaなどの従来の携帯通信ベンダーにより提供されている垂直的なソリューションの制約を超えて拡張することができるようになります。O-RANの概念は、DISHの未開発環境を使用したネットワーク展開を簡素化し、完全に自動化するものになるでしょう。NokiaはO-RANアプローチを最も受け入れている企業であり、とりわけ登録者管理、デバイス管理、統合サービスなどの5Gコアアプリケーションの提供に合意しています。DISHは最近、O-RANに準拠した大量の無線を有している日本の大手企業である富士通との契約に署名しています。一方、AltiostarとMavenirもO-RANソフトウェアを提供予定です。

楽天モバイルとそのクラウドネイティブなO-RAN 5Gネットワークに多くの注目が集まる一方で、世界中の事業者とインフラストラクチャベンダーが協力してO-RANの概念を向上させています。経済的および運用的な観点からは、O-RANモデルは大変理にかなっており、小数の事業者はすでにO-RANツールボックスの少なくとも一部のツールを活用することを検討しています。インドのReliance Jioでは楽天に似た展開を計画しており、米国の携帯通信事業者であるVerizonとAT&Tではすでに一部の市場でマルチベンダーの5G相互運用性を許可するための手順を踏んでいます。最近では、サウジアラビアのTelefónica SpainおよびSTCが楽天のモバイルプラットフォームに興味を示しています。

来年にはさらに多くのO-RAN関連の発表があると思われます。Ooklaでは楽天のネットワークのパフォーマンスを引き続き注視していく予定です。

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Global Speeds

About the Author

Milan Milanović

Ookla Research™ Articles
| May 28, 2020

How T-Mobile’s Merger with Sprint is Changing the Game for 5G

Global Speeds

After almost two years and numerous legal battles, T-Mobile and Sprint are finally one. Equipped with a vast arsenal of spectrum assets, the new company aims to create an unparalleled 5G experience from urban areas to underserved rural communities across America. The biggest prize of this merger is 150 MHz of Sprint’s 2.5 GHz spectrum across top 100 markets. Combining Sprint and T-Mobile assets, T-Mobile now controls 319 MHz of sub-6GHz spectrum nationwide, and they have already started injecting some of this valuable capacity into the network and making it available to Americans.

The Philadelphia experiment

Because of the leasing and permitting work done in Philadelphia months ahead of the April 1, 2020 merger approval, T-Mobile was able to activate a number of 2.5 GHz (n41) sites on day one, followed by the official market launch on April 21. Massive MIMO radios were overlaid on T-Mobile’s existing cell sites, adding 60 MHz of spectrum in the 2.5 GHz band. Since Philadelphia wasn’t one of the nine markets where Sprint launched 5G, the fallow 2.5 GHz spectrum was readily available for use. T-Mobile had already covered Philadelphia with 5G in the 600 MHz band (n71), and the 2.5 GHz layer should provide a much-needed capacity boost. We can already see the increase in performance over the past four months.
t-mobile_5G_performance_philadelphia_0520-1

An analysis of all 5G tests taken on T-Mobile’s network in Philadelphia shows mean download speeds doubling during the month of April. A huge jump from 60.40 Mbps to 119.82 Mbps coincides with the rollout of 5G on the fresh mid-band spectrum. During the same month, we observed peak 5G download speeds exceeding 700 Mbps. Mean latency also fell from 30 ms to 21 ms over the period. Unlike the millimeter wave frequencies, which could offer greater speeds in a very small footprint, the 2.5 GHz band provides a good balance between coverage and capacity for mobile use.

T-Mobile’s layer cake in Manhattan

On May 5, T-Mobile launched its second mid-band 5G market in New York City. This launch marked the world’s first 5G network built on low, mid and high frequency bands. Paired with the multi-gigabit fiber backhaul, this 5G network is designed to deliver uncompromised performance. T-Mobile calls this the “Layer Cake 5G strategy.”
t-mobile_5G_performance_nyc_0520-1

Mean download speeds of T-Mobile’s 5G network in New York City increased from 79.18 Mbps in January 2020 to 98.96 Mbps in May (as seen through the 15th of the month). This represents a 25.0% jump across all three 5G layers. Mean upload speeds have also improved 11.0% during the same period.
t-mobile_5G_performance_NYC_Philadelphia_0520-1

Analyzing week-over-week performance, Speedtest Intelligence® offers unique insights on the upward-trending download speeds on T-Mobile’s 5G across these two markets. A combination of additional 600 MHz spectrum explained in our previous article and the new 2.5 GHz 5G layer were likely the main drivers behind this improved performance.

Field testing the layers of 5G

Users are typically not aware of the layers of technologies that they’re utilizing when they connect to a 5G network. To better understand the performance and capabilities of T-Mobile’s layer cake 5G network, I looked at the performance of each individual 5G layer separately. This process involved running over 300 tests on the ground in New York City between May 5 and 19 (while fully complying with the social distancing and health guidelines) and logging modem diagnostic messages. This allowed me to observe individual throughput contributions across three different 5G layers on two different devices, the Samsung Galaxy S20 Ultra 5G and the OnePlus 8 Pro. While both devices are powered by Qualcomm’s latest Snapdragon 865 5G Mobile Platform, only the Samsung Galaxy S20 Ultra 5G (and S20+ 5G) has the required mmWave hardware components to fully access the 5G spectrum layer cake. The open-market OnePlus 8 Pro could only access sub-6 GHz 5G.

According to T-Mobile’s published map of projected 2.5 GHz coverage, the newly launched mid-band 5G layer is mostly available in the eastern parts of Manhattan. That meant a quick ride to the areas east of Herald Square in Midtown as well as parts of East Village. Keep in mind that the walk tests were collected on a recently launched and lightly loaded mid-band 5G network. This report samples what this network is capable of and should not be considered predictive of future performance under normal use.

LAA boosts speeds

License Assisted Access (LAA) is LTE technology that leverages the unlicensed 5 GHz spectrum. While often overlooked, this technology has been deployed on T-Mobile sites in New York City since 2017, and adds ample downlink capacity (40-60MHz) using Ericsson’s micro Radio 2205, “assisted” by the anchor in the licensed LTE mid-band. This can significantly boost download speeds on capable devices, while at the same time offloading traffic from the licensed spectrum and improving the LTE experience for all users served by that cell.

In Manhattan, many low-build rooftop sites with Ericsson AIR 5121 mmWave radios originally received the LAA treatment and are excellent candidates to receive (or have already received) the 2.5 GHz 5G overlay. This means these NYC sites would gain 40-60 MHz of LAA downlink capacity in addition to the full three layer 5G deployed in the 600 MHz low-band, 2.5 GHz mid-band, the 28 GHz mmWave high-band spectrum and LTE. This would open up a variety of options in terms of network scheduling and capacity management.

What each NR layer contributes to download speeds

Based on personal field test data logged over the course of the last eight months, the observed peak download contribution of the NR physical layer (PHY) on Sprint’s (now decommissioned) 2.5 GHz 5G network using Nokia radio and 40 MHz bandwidth was 367 Mbps, achieved on Sprint’s 5G launch day in New York City, August 27, 2019.

T-Mobile’s new 2.5 GHz deployment — leveraging the same amount of spectrum, Ericsson AIR 6488 radio access, under similar network conditions — produced a peak downlink NR contribution in excess of 541 Mbps, an improvement in spectral efficiency of 47 percent. The downlink NR contribution measures the portion of the download speed arriving at the device only from the 5G layer, the remainder of the download speed comes from LTE.

Furthermore, on May 19, the NR bandwidth on some sites was increased from 40 MHz to 60 MHz, and I’ve since observed a peak NR downlink contribution approaching 900 Mbps. The increased bandwidth was observed on three locations in the East Village, while the majority of 2.5 GHz sites are still at 40 MHz. We should stress again that these peak 5G speeds are meant to show the full potential of this new network deployment and have been achieved in good outdoor signal conditions, on a lightly loaded 5G network.

When taking into account the 3:1 TDD frame configuration (75% downlink 25% uplink), the effective peak downlink spectral efficiency of the 2.5 GHz NR layer looks like this:
peak-spectral-efficiency_0520-2

Lower spectral efficiency on Sprint’s legacy network could be attributed to the lower distribution of 256 QAM and MIMO (Rank 3, 4). Granted, there could have been a potential performance penalty associated with an earlier software load on Nokia’s massive MIMO radios running in split-mode. These radios were logically partitioned for both n41 and LTE B41 concurrent operation, while pushing carrier aggregation across three LTE CCs and using 100-120MHz of spectrum in total. In contrast, T-Mobile’s existing deployment consists of Ericsson AIR 6488 radios delivering only n41, while LTE mid-band anchor bands are delivered from separate radios (B2, B66).

40 MHz of n41 delivered NR upload speeds of 33 Mbps on T-Mobile vs. 23 Mbps on Sprint, a 43.5% increase. Tests from May 19 using 60 MHz wide NR channel produced consistent speeds of 50 Mbps arriving from the NR layer.

peak-upload-contributions_0520-2

The benefits for both users and the operator are apparent as the aggregate (LTE B66 + NR n41) upload speeds achieved on capable user devices now well exceed 100 Mbps.

In addition to the new mid-band 5G (n41), T-Mobile’s low-band 5G (n71), which launched in early December, is providing the foundational layer for the future SA (Standalone) NR. The initial 5 MHz FDD deployment was, from my first-hand experience, capable of boosting the downlink performance at the capable user terminals with an additional 42 Mbps. As of the middle of March, that allocation was increased to 10 MHz, now delivering peak n71 speeds of roughly 100 Mbps. With wider NR channels comes an improved spectral efficiency.

Millimeter wave adds capacity

T-Mobile’s millimeter wave (mmWave) NR layer (n261) has been available in New York City since June 2019. Leveraging the existing macro grid, T-Mobile’s Manhattan mmWave overlay, in terms of cell site density, is one of the most impressive in the world. This layer leverages 100 MHz of spectrum (2×50 MHz) in the 28 GHz band (n261), adding peak n261 speeds of over 520 Mbps in addition to the LTE anchor bands. In comparison, T-Mobile’s mid-band 2.5 GHz NR layer is able to deliver similar capacity out of just 40 MHz of spectrum. This jump in spectral efficiency is attributed to the use of up to four data streams and 256 QAM modulation in the mid-band, something the current generation of mmWave chipsets can’t do.

During my testing, the Samsung Galaxy S20 Ultra 5G was able to switch between all three NR spectrum bands seamlessly and deliver consistent performance at hundreds of megabits per second. While 100 MHz of mmWave can deliver a speed boost of a few hundred megabits per second, the full potential of this spectrum can be unlocked by deploying much wider 400 MHz or 800 MHz blocks of mmWave spectrum, which can produce speeds of multiple gigabits per second, just on that layer alone. T-Mobile now controls 1,160 MHz of mmWave spectrum nationwide, including significant amounts of not-yet-deployed 24 GHz and 47 GHz licenses won in recent auctions.

Device limitations (and opportunities)

T-Mobile’s 5G network uses a mechanism called the EUTRA-NR Dual Connectivity (EN-DC) split bearer, which allows for combining of data traffic from LTE (master node) and 5G (secondary node) both on the downlink (sub-6 and mmWave) as well as on the uplink (sub-6). This improves user experience by enabling utilization of the maximum amount of data streams across two technologies supported by capable 5G devices. Both devices are capable of aggregating two mid-band LTE anchor bands (B2, B66) with sub-6 NR, but only the Samsung Galaxy S20 Ultra 5G has the ability to leverage up to four spatial streams on the two mid-band LTE bands and NR (n41) at the same time. The OnePlus 8 Pro supports EN-DC combinations with two streams per the mid-band LTE anchors paired with four streams on n41. This is likely related to the RF Front End design limitation on the OnePlus device.
field-test-t-mobile_5G_device_nyc_0520-1

In my field tests, both devices delivered excellent speeds, leveraging 40 MHz of 2.5 GHz 5G (n41) with two LTE mid-band component carriers (CC) on the downlink, while the OnePlus 8 Pro had an additional help coming from the LAA CCs. On the uplink, devices utilized dual connectivity combining one LTE CC with NR. The latency was also similar between devices, although I did observe latency as low as 7 ms.

What’s missing from the Galaxy S20 Ultra 5G — and what the OnePlus 8 Pro fully capitalizes on — is the ability to aggregate mid-band LTE with LAA and mid-band NR. As we’ve described, the existing Manhattan LAA cell sites in some areas conveniently located on every two to three city block corners are the obvious candidates for the 5G mid/high-band overlay, which is exactly what I observed on the streets of the East Village. The combination of 60 MHz of LAA, 30 MHz of mid-band LTE (B66+B2) and 60 MHz NR produced an outstanding user experience, delivering mean download speeds of 989 Mbps and mean upload speeds of 107 Mbps. During May 19 testing, I recorded peak speeds in excess of 1.2 Gbps with the NR contribution of 900 Mbps. This particular test utilized only a single LTE CC (B66), three LAA CCs and 60 MHz of NR.

field-test_Oneplus-8-pro-performance_0520-1

Considering that Samsung’s Galaxy S20 lineup uses state-of-the-art RF Front End components and is built to provide uncompromised user experience, we really hope to see LAA EN-DC support added via the future software updates for both sub-6 and mmWave, which would unlock the device’s full potential. The business case for operators is very appealing: the ability to free up the licensed LTE spectrum in densely populated areas while at the same time providing a significant boost in user experience, as shown in this report. It’s also worth noting that the branded Samsung Galaxy S20 lineup does support the use of higher order MIMO on both LTE mid-band and n41 concurrently, which could prove to be an advantage over the OnePlus device outside of the dense urban areas where LAA isn’t available.

How unique device features boost performance

While most smartphones today can’t aggregate multiple low-band component carriers across multiple low-band frequencies, T-Mobile’s branded devices powered by Qualcomm’s Snapdragon X55 5G Modem-RF System are capable of aggregating multiple low-band channels within the same frequency band (600 MHz). In other words, these smartphones (including the Samsung Galaxy S20 Ultra 5G, and the OnePlus 8 Pro) are able to leverage all of the deployed downlink 600 MHz capacity by way of EN-DC, which allows for concurrent use of LTE band 71 and n71, in addition to the use of mid-band LTE anchors (Band 2 and Band 66). These devices also support uplink carrier aggregation of the LTE anchor band and sub-6 NR.

Because the OnePlus 7T Pro 5G McLaren Edition was the first device to receive this feature, we analyzed its performance in the U.S. as a whole during the first four months of 2020. The software update on February 13 resulted in an improvement of over 30% in mean download speeds from those seen in January 2020. The concurrent use of multiple 600 MHz channels produced mean download speeds of 82.35 Mbps and a latency of 32 ms in April.
t-mobile_5G_performance_oneplus_0520

What the future holds

In markets like New York City, Sprint’s legacy 2.5 GHz LTE network (for the most part) operates on a 60 MHz contiguous chunk of spectrum (3CC LTE carrier aggregation) adjacent to T-Mobile’s 40 MHz (in some parts 60 MHz) NR. In addition to this 100 MHz contiguous spectrum block, Sprint uses a separate 20 MHz slice for its small cells applications, for a total of 80 MHz of deployed 2.5 GHz LTE capacity. Repurposing 20 MHz (or more) of LTE channels and widening the 2.5 GHz NR capacity could easily provide a quick incremental capacity gain for T-Mobile, as already seen on some sites in Manhattan.

Furthermore, the existing Nokia 64T64R massive MIMO radios used on Sprint’s sites still operate in split-mode (32T32R for LTE, 32T32R for NR), but the NR logical partition is not in use. These could have the NR portion of antenna elements remapped for 64T64R LTE which should, in theory, further enhance the LTE coverage through the use of beamforming and deliver an improved LTE sector capacity for users with legacy Sprint LTE B41 devices. When we consider that over 80% of Sprint’s postpaid subscribers own smartphones capable of accessing the T-Mobile network, and 10 million unique Sprint subscribers already utilize T-Mobile’s LTE network on a weekly basis, the accelerated refarm of the 2.5 GHz spectrum makes even more sense.

While T-Mobile could easily add LTE B41 capability to its n41 sites, most (if not all) T-Mobile branded devices aren’t currently capable of aggregating LTE B41 channels with all of T-Mobile’s existing LTE spectrum bands. Therefore, adding LTE B41 wouldn’t provide any immediate capacity gain to T-Mobile’s user base. To achieve that capacity gain, Class II Permissive Change would have to be filed with the FCC for the entire portfolio of T-Mobile’s branded devices and then T-Mobile would have to perform a large-scale software update push, which could be a massive undertaking, and frankly isn’t necessary.

As we described back in August integrating a portion of Sprint’s PCS spectrum onto T-Mobile’s network and widening the existing PCS channels to 15 or 20 MHz could further improve user experience and overall network efficiency for the combined network. This could be highly beneficial in markets with a high uptake of Sprint customers where Sprint’s PCS spectrum holdings sit adjacent to T-Mobile’s. Alternatively, PCS spectrum swap with other operators could produce similar results.

Top-Largest-Markets_TMobile-Sprint-03

Over the past few years, Sprint has done a lot of work to densify its network using small cells and distributed antenna systems (DAS). These nodes provide added coverage and capacity, but often operate on their own separate 2.5 GHz frequency block, different from the blocks used on Sprint’s macro sites. Repurposing Sprint’s network of small cells and outdoor DAS (oDAS) and retrofitting for T-Mobile’s LTE/NR at some point in the future could provide additional capacity in urban and suburban areas.

Standalone 5G should improve performance and coverage

Finally, the launch of the Standalone (SA) 5G slated for later this year will offer many core benefits, such as reduced latency, improved speeds and network slicing, to name a few. With the introduction of VoNR (Voice over NR), SA 5G should provide an improved 5G coverage, especially for customers in rural America, as the need for mid-band LTE anchors would be removed.

The existing portfolio of branded devices powered by the 2nd generation Qualcomm Snapdragon X55 5G Modem-RF System has the support for Standalone 5G, but will require a software update. Recent announcements of SA 5G lab and field testing using a commercial OnePlus 8 device indicate that T-Mobile is inching closer to commercializing this service. The upcoming 3rd generation Qualcomm Snapdragon X60 Modem-RF System will fully set the stage for standalone 5G deployments around the world by enabling mmWave-sub6 aggregation, as well as sub-6 carrier aggregation across FDD and TDD bands. This means that the upcoming portfolio of T-Mobile’s 5G devices will be able to combine n71 with n41, n261 with n41, and so on. The Dynamic Spectrum Sharing (DSS) feature, which enables coexistence of LTE and 5G in the same frequency channel at the same time, will likely find its purpose in T-Mobile’s toolbox by enabling the use of n2 and n66 frequency bands.

Two weeks of testing T-Mobile’s 5G in New York City delivered an impressive user experience, and it was just an early taste of a 5G layer cake that could continue to improve. Low-band 5G provides the foundational layer of the cake, the mid-band filling is already thickening and the mmWave at the moment is the cherry on top, with the potential to become a much bigger layer. We’re excited to see how other operators can learn from this approach and improve 5G performance across the globe.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Global Speeds

About the Author

Milan Milanović

Ookla Research™ Articles
| May 12, 2020

How U.S. Mobile Operators are Putting Fresh Spectrum to Use for the Masses

As U.S. consumers shifted their lifestyles and mobile usage in response to the coronavirus, U.S. mobile operators were working to ensure that mobile networks were ready for a potential spike in demand. They struck multiple temporary spectrum deals with various license holders of unused spectrum, including a variety of spectrum assets held by DISH. Today we’re examining how these temporary spectrum allocations have performed at providing incremental capacity gain across many markets and operators.

Verizon expands FDD LTE

On March 18, the Federal Communications Commission granted Verizon’s request for Special Temporary Authority (STA) to leverage licenses held by DISH’s designated entities, SNR Wireless and Northstar Wireless. These licenses enabled Verizon to add as much as 10 MHz of FDD LTE in some markets to boost user experience. With this added spectrum, Verizon was able to consistently deliver mean LTE download speeds of around 36 Mbps during the first four months of 2020. That performance represents a 10.7% increase in download speeds over the same period last year.
verizon_lte_performance_q1_2019_2020

AT&T leverages AWS

DISH also agreed to provide a portion of its unused Advanced Wireless Services (AWS) spectrum licenses to AT&T for 60 days, free of charge. Both Verizon and AT&T have already put some of this spectrum to use in a limited number of markets, on some (not all) cell sites.

Over the first four months of 2020, AT&T recorded a major performance boost, with mean LTE download speeds showing as much as a 32.6% year-over-year improvement.
att_lte_performance_q1_2019_2020

This significant improvement can be attributed to many factors:

  • In some markets, AT&T serves customers across as many as nine different spectrum bands, which provides ample capacity and flexibility.
  • Newer devices are able to leverage five-channel Carrier Aggregation, allowing users to complete download tasks and return resources back to the network much more quickly, resulting in a more efficient redistribution of resources across the network.
  • The FirstNet network integration required a technician’s visit to cell sites, which AT&T used to upgrade its existing radio access equipment while deploying more efficient LTE features like 4×4 MIMO and 256QAM, as well as NR capable radios in the cellular band (850 MHz).
  • AT&T also performed additional “under the hood” core network improvements.

T-Mobile doubles down on 600 MHz

T-Mobile has been the most active operator by far in reallocating spectrum to prepare for possible demand increases. First on Friday, March 13, DISH pushed out a press release late in the afternoon announcing that it allowed T-Mobile to use its 600 MHz spectrum licenses nationwide for 60 days as a relief during the pandemic. In a blog post the following day, T-Mobile confirmed the use of DISH’s spectrum, in addition to that of other 600 MHz spectrum holders, including: Bluewater, Channel 51, Comcast, Grain Management affiliate NewLevel LLC, LB Holdings and Omega Wireless LLC.

The FCC acted swiftly and approved the 60-day temporary spectrum access to T-Mobile on Sunday, March 15. Because T-Mobile already operates the 600 MHz network nationwide, and radio equipment made by Ericsson and Nokia already support both LTE and NR technologies, T-Mobile was able to deploy the incoming spectrum almost immediately by remotely reconfiguring the equipment. By the morning of March 17, T-Mobile’s LTE bandwidth quadrupled, in some cases jumping from 5 MHz to 20 MHz of total spectrum. On March 19, T-Mobile announced a successful deployment of the additional 600 MHz spectrum.

Likely a result of the quick activation of the additional DISH spectrum, T-Mobile’s mean download speed over LTE recorded a 10.5% improvement when comparing April 2020 with April 2019.
tmobile_lte_performance_q1_2019_2020

As operators continue to adapt their network strategies to changing consumer behavior, it will be interesting to watch how spectrum is allocated to accommodate increased demand. We will continue to follow mobile performance in the U.S. to see if mobile operators can capitalize on these gains once the 60-day window is up. If you’re interested in how networks have been performing in your region, learn more about Speedtest Intelligence™.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

About the Author

Milan Milanović

Ookla Research™ Articles
| March 30, 2020

Inside Japan’s Unique Approach to 5G

Network Evolution

日本語で読む

Japan has been a leader in mobile technology since its inception, and Japanese companies continue to occupy the cutting edge of mobile telephony. LTE networks in Japan have been able to deliver very competitive speeds in the densest urban areas, which speaks volumes about the cell density of the country’s networks. This article explores how Japanese mobile operators are applying this leading mindset to 5G.

How Japan utilizes spectrum

Japanese operators utilize a “layer cake” spectrum approach, which aggregates multiple frequency bands into data lanes that provide faster speeds. This approach utilizes low 700, 800 and 900 MHz bands, coupled with mid-band 1500 and 2100 MHz and topped off with the high-band 2500 MHz band. With this approach, users with modern devices are able to simultaneously access disparate spectrum bands, which enables better speeds and thus an improved user experience. Combined with Japan’s dense grid of existing cell sites, the spectrum layer cake should provide a good base for the overlay of sub-6 GHz spectrum that Japan has allocated for 5G services.

Timelines for launching 5G in Japan

For the past few years, Japan has been building toward the 2020 Summer Olympic Games in Tokyo as an opportunity to showcase their next-generation wireless technology. Japan began conducting 5G trials as early as 2017. In 2018, Japan’s Ministry of Internal Affairs (MIC) revised the spectrum allocation process to encourage new operators to enter the 5G market. Then in April 2019 the MIC approved 5G spectrum allocations to four applicants: KDDI (au), NTT DOCOMO, Rakuten Mobile and SoftBank.

KDDI, NTT DOCOMO and SoftBank launched 5G this month, with NTT DOCOMO and KDDI first to market on March 25. NTT DOCOMO’s initial 5G launch will leverage sub-6GHz spectrum assets, offering peak download speeds of up to 3.4 Gbps, and peak upload speeds of up to 182 Mbps. Later in June, the operator will start selling 5G devices capable of operating on the mmWave band and accessing 400 MHz of high-band spectrum. This will allow for peak download speeds of 4.1 Gbps and upload speeds of 480 Mbps. SoftBank will launch second on March 27. Rakuten plans to launch 5G by June 2020.

How Japanese operators will use spectrum for 5G

Japanese operators are deploying 5G networks in both FR1 (sub-6GHz) and FR2 (millimeter-wave) frequency bands. Each licensee has been awarded 400 MHz of FR2 spectrum and KDDI, NTT DOCOMO and SoftBank have been awarded 200 MHz of FR1 spectrum. The exception is Rakuten, which requested 100 MHz of FR1 spectrum.
Ookla_5G-Spectrum-Chart_Japan_0320_en

Early trials and infrastructure

KDDI (au) 5G trials started in 2017 with Ericsson, Nokia and Samsung. KDDI awarded all three vendors with 5G contracts. KDDI also inked a seven-year roaming deal with Rakuten, the newest entrant in the wireless space, to provide LTE coverage to Rakuten’s subscribers when they roam outside of their coverage area.

NTT DOCOMO started early 5G trials using several infrastructure partners, including: Nokia and NEC Corp on 4.5 GHz spectrum band, Ericsson and Qualcomm on 4.5 GHz and the mmWave wave, and Huawei for mmWave. Fujitsu has proposed a software upgrade for existing LTE base stations which will enable 5G radio access. NEC Corp offered a small cells product supporting all three frequency bands (3.7 GHz, 4.5 GHz, 28 GHz) leveraging O-RAN (Open Radio Access Network Alliance), which aims to break the single-vendor-per-market lock and paves the way for a smooth transition to 5G software-defined networking and cloud services. NTT DOCOMO awarded NEC Corp, Fujitsu and Nokia with contracts, claiming the world’s first 4G/5G multi-vendor RAN (radio access network) interoperability.

SoftBank initially partnered with Chinese vendors Huawei and ZTE in 2017 to conduct mmWave trials in the 28 GHz frequency band. SoftBank awarded the contracts to Nokia and Ericsson.

A completely new approach from Rakuten, the “optimistic” entrant

Rakuten is a premier Japanese ecommerce company founded in 1997. Rakuten means “optimism” in Japanese, and now the company offers products and services across a multitude of industries, including: banking, mobile payment, mobile messaging (via the Viber app), travel and their own MVNO, to name a few. The company understands the importance of controlling the entire user experience for their customers — and the value of running their own facilities-based mobile network in addition to OTT (over-the-top) services.

Since Rakuten is deploying a mobile network from the ground up using greenfield licensed spectrum assets, the company has decided to do something that nobody has ever done before: disaggregating the hardware from the software and running a fully virtualized, cloud-native network. This LTE network has been fully operational with over 3,000 cell sites in three markets (Tokyo, Nagoya and Osaka) running limited trials since last year — and is expected to launch commercially on April 8. Because of its software-defined nature, the network can be upgraded to 5G, and the operator expects to have the upgrade pushed later this year.

Rakuten’s network architecture is unique, leveraging only antenna-integrated radios from traditional telecom vendors. Radios are fiber-fed via the fronthaul, and instead of processing at cell site cabinets, all the processing is happening remotely at centralized locations using off-the-shelf computer hardware running virtualized network functions. According to Rakuten CTO Tareq Amin, the process of activating a new cell site takes only eight and a half minutes instead of days. After Rakuten’s April launch, years worth of Rakuten’s research and development will be available to other operators globally via the Rakuten Mobile Platform (RMP), which could be very attractive to new entrants in the wireless space, such as DISH in the United States.

We will continue to monitor how these different 5G setups perform as 5G is rolled out in Japan and we look forward to providing future analysis on this topic.

日本国内における5Gへのユニークなアプローチ

日本は当初からモバイルテクノロジーのリーダーであり、日本企業は最先端のモバイルテレフォニーを占有し続けています。日本のLTEネットワークは、最も人口密度の高い都市地域でも非常に競争力のある速度を継続的に提供しています。これは、この国のネットワークの基地局密度の高さを物語っています。この記事では、日本の携帯電話事業者がこのような先進の考え方を5Gにどのように適用しているかを探ります。

日本のスペクトル活用法

日本の事業者は、複数の周波数帯域をデータレーンに集約して速度を高める「レイヤーケーキ」スペクトルアプローチを活用しています。このアプローチでは、700 MHz、800 MHz、900 MHzの低帯域と1500 MHz、2100 MHzの中帯域を組み合わせて、その上に2500 MHzの高帯域を乗せますこのアプローチにより、最新の電話機を所有するユーザーはさまざまなスペクトル帯域に同時にアクセスできます。これにより、高速化とそれに伴うユーザーエクスペリエンスの向上が実現します。このスペクトルレイヤーケーキと日本の既存の高密度基地局網との組み合わせは、日本が5Gサービスに割り当てた6 GHz以下のスペクトルのオーバーレイの良い基盤となります。

日本における5Gのローンチのタイムライン

日本は、2020年に東京で開催される夏季五輪を、次世代ワイヤレステクノロジーをアピールする機会ととらえ、ここ数年それに向けて準備を進めてきました。日本は、早くも2017年に5G実証実験を開始しました。2018年、日本の総務省は、新規事業者の5G市場への参入を促すため、スペクトル割り当て手続きを改訂しました。その後、2019年4月、MICは4つの申請企業への5Gスペクトル割り当てを承認しました。承認を受けたのは、KDDI（au）、NTTドコモ、楽天モバイル、ソフトバンクです。

KDDI、NTTドコモ、ソフトバンクは今月、5Gをローンチする予定です NTTドコモとKDDIが最初で、3月25日に発売された。NTTドコモの最初の5Gローンチでは、6GHz以下のスペクトルアセットを活用し、最大3.4 Gbpsのピークダウンロード速度と最大182 Mbpsのピークアップロード速度を提供します。7月後半、NTTドコモは、mmWave帯域で動作し、400 MHzの高帯域スペクトルにアクセスすることができる5Gデバイスの販売を開始する予定です。これにより、4.1 Gbpsのピークダウンロード速度と480 Mbpsのピークアップロード速度が可能になります。 ソフトバンクが2番目で、3月27日にローンチする予定です。楽天は2020年6月までに5Gを発売する予定です。

日本の事業者による5G用スペクトラムの使用方法

日本の事業者は、FR1（6GHz以下）とFR2（ミリメートル波）の両方の周波数帯域で5Gネットワークを展開しています。各ライセンシーは400 MHzのFR2スペクトルを割り当てられ、KDDI、NTTドコモ、ソフトバンクは200 MHzのFR1スペクトルを割り当てられました。例外は楽天です。楽天は100 MHzのFR1スペクトルを申請しました。
Ookla_5G-Spectrum-Chart_Japan_0320_jp

早期実証実験とインフラストラクチャ

KDDI（au）は、2017年にEricsson、Nokia、Samsungと共同で5G実証実験を開始しました。KDDIは、3つのベンダーすべてと5G契約を結びました。KDDIはまた、ワイヤレス市場の最も新しい参入企業である楽天と7年間のローミング契約を結び、楽天の加入者が楽天のサービス区域外でKDDIのLTEサービスを利用できるようにしました。

NTTドコモは、複数のインフラストラクチャパートナーと共同で早期5G実証実験を開始しました（4.5 GHzスペクトル帯域でNokiaとNEC、4.5 GHzとmmWave波でEricssonとQualcomm、mmWaveでHuawei）。富士通は、既存のLTE基地局を対象に、5G無線アクセスを可能にするソフトウェアアップグレードを実施することを提案しました。NECは、O-RAN（Open Radio Access Network Alliance）を活用して3つの周波数帯域（3.7 GHz、4.5 GHz、28 GHz）をすべてサポートする小型基地局製品を提案しました。このソリューションは、「市場ごとに1つのベンダー」体制を打破することを目的とし、5Gソフトウェアデファインドネットワーキングおよびクラウドサービスに円滑に移行するための道筋をつけるものです。NTTドコモは、NEC、富士通、Nokiaと契約を結び、世界初の4G/5GマルチベンダーRAN（無線アクセスネットワーク）相互運用をアピールしています。

ソフトバンクは当初、2017年に中国のベンダーであるHuaweiおよびZTEと提携し、28 GHz周波数帯域でmmWaveの実証実験を実施しました。ソフトバンクは、NokiaおよびEricssonと契約を結びました。

「楽観的」な新規参入企業である楽天のまったく新しいアプローチ

楽天は1997年に設立された日本の最大手eコマース企業です。楽天は日本語で「楽観主義」を意味しており、同社は現在、銀行、モバイル決済、モバイルメッセージング（Viberを使用）、旅行、楽天独自のMVNOなど、多数の業界に製品とサービスを提供しています。同社は、顧客のユーザーエクスペリエンス全体をコントロールすることの重要性と、OTT（オーバーザトップ）サービスに加えて独自の設備ベースのモバイルネットワークを稼働させることの価値を理解しています。

楽天は、認可を受けた未開発のスペクトルアセットを活用してモバイルネットワークをゼロから展開しているため、これまで誰もやったことがないことに取り組むことを決めました。それはハードウェアをソフトウェアから切り離し、完全に仮想化されたクラウドネイティブのネットワークを稼働させるというものです。このLTEネットワークは、3つの市場（東京、名古屋、大阪）で3,000以上の基地局によって完全に機能しており、昨年以降、限定的な実証実験が実施されています。商業ローンチは4月8日の予定です。このネットワークは、ソフトウェアデファインドの特性を持っているため、5Gにアップグレード可能で、楽天は今年の後半にアップグレードを行う予定です。

楽天のネットワークアーキテクチャは独特で、従来の電気通信ベンダーのアンテナ統合型無線のみを使用しています。無線は、フロントホールからファイバで送信され、基地局のキャビネットで処理される代わりに、リモートの集中拠点で仮想ネットワーク機能を実行する市販コンピューターハードウェアによってまとめて処理されます。楽天のCTOであるTareq Amin氏によると、新しい基地局は数日ではなくわずか8分半で稼働させることができます。楽天の4月のローンチ後、他の事業者は楽天モバイルプラットフォーム（RMP）を介して楽天の3年分の研究開発の成果を利用できるようになります。これはワイヤレス市場への新規参入を目指す企業（米国のDISHなど）にとって非常に魅力的でしょう。

私たちは、今後日本で5Gが展開されるにつれてこれらの異なる5Gセットアップがどのように機能するかを引き続きモニタリングしていきます。このトピックについての将来の分析を皆様にご提供できる機会を楽しみにしています。

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Network Evolution

About the Author

Milan Milanović

Ookla Research™ Articles
| August 14, 2019

Qualcomm’s Snapdragon X50 in the Wild: Analyzing 5G Mobile Performance in U.S. Cities

Devices

Most consumers are unaware how vital a modem is to a smartphone’s performance. From HD and 4K video streaming to augmented reality and cloud computing on-the-go — a fast modem makes all the difference in day-to-day user experience. Today we’re taking a closer look at the real-world performance of the Qualcomm Snapdragon X50 modem to find out how much faster 5G is than LTE, what 5G speeds look like in specific cities and where 5G upload speeds are outpacing expectations.

The Snapdragon X50 in the Samsung Galaxy S10 5G and LG V50 ThinQ 5G

Previously, we explored how the Snapdragon X24 integrated LTE modem helps the Samsung Galaxy S10 top the charts for speed. The Snapdragon X50 modem allows users to take advantage of the increased speed and bandwidth of 5G, adding support for up to 800 MHz of bandwidth (eight carriers) on the downlink and uplink in the FR2 and 100 MHz in the FR1 TDD (time division duplex). In the Galaxy S10 5G, the modem is paired with three QTM052 modules containing 5G NR transceivers, all of the RF front-end components and a phased antenna array supporting the millimeter wave (mmWave) frequency range. The LG V50 ThinQ device manages to pack a similar configuration into an even smaller footprint.

Designing mmWave handsets poses a significant technological challenge and, to the best of our knowledge, only the original equipment manufacturers (OEMs) leveraging Qualcomm’s complete modem-to-antenna solution have successfully been able to bring their designs to market.

How much faster is 5G than LTE?

We examined Speedtest IntelligenceTM data from July 2019 to understand the performance delta between when users have a 5G NR connection and when they can only connect to baseline LTE. To keep a level playing field in the analysis, we only looked at results from the Samsung Galaxy S10 5G and the LG V50 ThinQ 5G, which both use the Snapdragon X50. Because AT&T had not yet launched 5G for consumers in July 2019 and T-Mobile started offering 5G in late June, we’ve only included results from Sprint and Verizon in cities where they have 5G available.

Comparing 5G and LTE Download Speeds in the U.S.
Speedtest Data | July 2019

 
Operator 5G (Mbps) LTE (Mbps) % Difference in 5G vs. LTE Maximum on 5G (Mbps)
Sprint 236.09 79.25 197.9% 724.33
Verizon Wireless 870.34 102.23 751.4% 2353.44

Sprint, being the only U.S. operator offering 5G service in the sub-6 GHz (2.5 GHz TDD) frequency range, has the potential to deliver enhanced 5G coverage and capacity with the addition of 40-60 MHz of bandwidth. Speedtest Intelligence shows that tests initiated on Sprint’s 5G connection deliver a nearly 3X improvement in download speeds over its speeds on LTE. The network performance could improve even further with an increased utilization of higher-order MIMO (5G and LTE), a higher contribution of the LTE layer during EN-DC (dual connectivity) and an improved backhaul.

Verizon Wireless’s network currently relies on mmWave in the 28 GHz band. The limited propagation of this frequency band makes it suitable for dense urban deployments, and vast swaths of spectrum (400 MHz) deliver breathtaking speeds on mobile devices. On average, Verizon’s customers with 5G-capable devices were seeing more than 8X improvement in download speeds in 5G covered areas, and we’ve noted Speedtest results with peak speeds in excess of 2 Gbps on the Verizon Wireless network.

Measuring 5G with Speedtest

It’s important to note that Speedtest is uniquely positioned to measure 5G and other gigabit-and-beyond speeds. Speedtest uses a client and server testing engine capable of measuring high-speed connections (up to 10 Gbps) that dynamically scales the number of connections to the server in order to saturate and accurately measure the client-side connection. This allows us to measure the full extent of real-world performance and overcome the effects of network bottlenecks such as TCP slow start. In addition, Ookla has partnered with operators and device manufacturers all over the world to implement accurate in-app 5G detection — even as Android Pie, which powers the current generation of 5G devices, does not natively identify 5G connection types. Through this approach, we’re able to properly configure the parameters of a Speedtest and measure 5G tests.

Other tests, which instead only download a very small file from a CDN or server, are insufficient to properly understand how a connection might perform when downloading a video or updating a mobile game over a 5G connection.

5G vs. LTE in major U.S. cities

Looking at Speedtest results in several major cities where mobile operators have launched 5G, we found that the performance gap between 5G and LTE is even more striking at the city level.

Comparing 5G and LTE Download Speeds in Select U.S. Cities
Speedtest Data | July 2019

 
City Operator 5G (Mbps) LTE (Mbps) % Difference in 5G vs. LTE Maximum on 5G (Mbps)
Atlanta Sprint 246.30 81.45 202.4% 605.91
Chicago Sprint 256.79 64.37 298.9% 724.33
Chicago Verizon Wireless 873.20 128.71 578.4% 2034.76
Dallas Sprint 292.17 114.41 155.4% 633.60
Denver Verizon Wireless 988.37 107.41 820.2% 2018.62
Houston Sprint 296.64 91.78 223.2% 653.50
Minneapolis Verizon Wireless 931.98 91.59 917.5% 1935.10
Providence Verizon Wireless 1138.82 101.32 1024.0% 1835.80

Verizon Wireless showed faster 5G Speedtest results, on average, than Sprint in cities like Chicago, where both operators offer 5G. This is because Verizon Wireless utilizes larger swaths of mmWave spectrum. The downside is that mmWave does not propagate as far, so while Sprint’s sub-6 GHz 5G deployments are slower than Verizon’s, Sprint is able to cover a wider area by mostly overlaying the existing LTE macro sites.

The S10 5G and the V50 ThinQ, both powered by the Snapdragon X50 modem, recorded a 4X improvement on Sprint’s 5G network in Chicago. While in Providence, Verizon’s 5G network is 11X faster than its baseline LTE. It’s remarkable how devices that fit in the palm of your hand are now capable of delivering speeds that exceed most residential fiber deployments.

Where we see 5G being used for uploads

Knowing that non-standalone (NSA) 5G deployments use an LTE anchor for signaling information as well as the user plane (EN-DC), upload speeds over 5G typically vary only slightly from baseline LTE speeds. But in Providence (Verizon) and Chicago (Sprint) we saw a significant delta on the uplink between 5G upload speeds and those on LTE. Both Sprint and Verizon use Samsung infrastructure equipment in these two markets, which may indicate that Samsung’s existing software solution could be slightly ahead of the competition.

Comparing 5G and LTE Upload Speeds in Select U.S. Cities
Speedtest Data | July 2019

 
City Operator 5G (Mbps) LTE (Mbps) % Difference in 5G vs. LTE Maximum on 5G (Mbps)
Chicago Sprint 20.25 8.03 152.3% 40.96
Providence Verizon Wireless 50.55 28.28 78.8% 133.84

We can’t say what download/upload ratio Sprint uses to supplement LTE uploads, but we tested Verizon’s 5G network in Providence first-hand several weeks ago and have some theories. We saw that utility poles carry Samsung 5G-only radios forming a tight 5G cell grid. We did not notice very many LTE macro sites within that particular area of coverage. Peak upload speeds were around 130 Mbps, and we’ve verified that LTE UL-CA (carrier aggregation) isn’t being used, which indicates that Verizon either supplements the existing LTE uplink with mmWave — or, more likely, uses mmWave entirely for user plane traffic on the uplink. The signaling exchange messages from the S10 5G reveal that it supports 100 MHz-wide channels on the uplink in the mmWave spectrum, with two-layer MIMO and 64 QAM — and to our knowledge Verizon could be the first network in the world leveraging mmWave in the uplink:

supportedSubcarrierSpacingUL kHz120,
supportedBandwidthUL fr2 : mhz100,
mimo-CB-PUSCH
maxNumberMIMO-LayersCB-PUSCH twoLayers,
maxNumberSRS-ResourcePerSet 1,
supportedModulationOrderUL qam64

The highly complex modem-to-antenna architecture supporting mmWave on the downlink requires lots of advanced processing for features like beamtracking and beamforming. Other than Qualcomm, most chipset manufacturers are still working on delivering their first-generation product. Qualcomm’s ability to make a commercially available product that can deliver a stable uplink using mmWave in the field while utilizing 2×2 MIMO is impressive.

What we expect from the Snapdragon X55 5G modem

The recently announced Samsung Galaxy Note 10+ 5G T-Mobile and AT&T variants will feature the 2nd generation of the Qualcomm Snapdragon X55 5G modem. When this device hits the market sometime in Q4 2019, it will be the very first smartphone with support for 5G frequency division duplex (FDD) spectrum allocations. It will also unlock T-Mobile’s 600 MHz 5G network layer which aims to enhance its existing 5G coverage this year and bring broad nationwide 5G coverage next year.

The Samsung Galaxy Note 10+ 5G will also support the use of Dynamic Spectrum Sharing (DSS), expected to be ready and deployed on the infrastructure side sometime in the first half of 2020. This 5G feature will enable operators without fallow FDD spectrum assets, like AT&T and Verizon, to offer 5G coverage concurrently with LTE using existing LTE spectrum assets. By simultaneously running both technologies on the same spectrum allocation and dynamically switching on the subframe level, operators will potentially eliminate the immediate need for spectrum refarming.

There are also some unknowns with the Samsung Galaxy Note 10+ 5G. While Qualcomm’s Snapdragon X55 5G modem itself supports the concurrent use of FR1 (sub-6 GHz) and FR2 (mmWave) bands, the device design seeded to the U.S. market only seems to support FR1, which is used by T-Mobile and AT&T. Considering that the Snapdragon X55 is a multi-mode solution, we should expect integration of this modem into the next-generation system on a chip (SoC) from Qualcomm. Once coupled with QTM525 modules, this should further increase efficiencies. The FR2 Verizon variant will use the first-generation Snapdragon X50 modem. It will also be interesting to see if Samsung will implement a four-branch antenna design for low frequency bands on the FR1 Note variant (T-Mobile/AT&T), which would enable the use of carrier aggregation across two low-frequency bands or the use of four spatial streams on the 600 MHz and 700 MHz bands.

With the advent of 5G, chip manufacturers must tackle increasingly complex issues and OEMs must start using chips that are capable of meeting the demands of today’s consumers. According to our data, the Snapdragon X50 is already facilitating lightning-fast speeds in 5G-ready cities in the U.S. We’re excited to see the next generations of chips from Qualcomm and other manufacturers — as well as the wave of even faster speeds they make possible. For more detailed analyses of device capabilities and network performance, contact Ookla about enterprise solutions.

Editor’s Note: This article was updated on August 14, 2019 to correct the date of launch of T-Mobile’s 5G service.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Devices

About the Author

Milan Milanović

Ookla Research™ Articles
| August 6, 2019

T-Mobile’s Spectrum and Coverage in a Post-Sprint World

Spectrum

The U.S. Department of Justice (DOJ) officially cleared the merger between T-Mobile and Sprint, joining the FCC in support of the deal, and bringing the merger one step closer to closing. The DOJ’s settlement comes with stipulations, however, including divesting Sprint’s prepaid business and some spectrum holdings to DISH so that a viable fourth nationwide competitor can enter the market. Additionally, the settlement declares that both operators must deploy high-quality 5G networks for the benefit of American consumers. We’re taking a fresh look at what coverage and spectrum would look like in response to the DOJ’s proposed deal.

Capitalizing on spectrum synergies

According to the consent decree with the DOJ, T-Mobile will keep Sprint’s entire 2.5 GHz and PCS spectrum portfolio, which will be integrated when the deal is finalized. The new T-Mobile will build an LTE layer on a denser cell site grid using Sprint and T-Mobile PCS spectrum synergies in combination with T-Mobile’s 600 MHz, 700 MHz and AWS holdings. This will address the existing capacity demand and expedite the process of allocating most of the 2.5 GHz spectrum assets to 5G NR.

Ookla_Sprint-TMob_Spectrum_20190802

To boost capacity, 2.5 GHz 5G-capable radios will be overlaid on existing T-Mobile sites, and over time, the existing PCS radio equipment will be reconfigured to support additional PCS spectrum coming from Sprint. In many major markets, that spectrum is contiguous to existing T-Mobile assets and will allow for wider allocations and higher spectral efficiency.

Top-Largest-Markets_TMobile-Sprint-03

Looking closely at the PCS spectrum in top markets, the contiguity between Sprint and T-Mobile is staggering. In markets like Los Angeles, Chicago, Philadelphia, and Detroit, adding the Sprint G Block will allow the new T-Mobile to expand the existing PCS spectrum assets and deploy 20 MHz channels. In Miami and Atlanta, the contiguous PCS block is a whopping 30 MHz wide. In markets like Detroit and Dallas, T-Mobile will have two 20 MHz PCS channels. This will enable the new T-Mobile to offer significantly improved capacity while leveraging more spectrally efficient 20 MHz channels. All this additional capacity makes the PCS spectrum a strong candidate for the 5G network.

T-Mobile’s good-faith agreement with DISH will potentially allow T-Mobile to leverage additional unused 600 MHz spectrum licenses, and a similar reconfiguration could be applied to the existing 600 MHz radios — widening the existing 5 MHz and 10 MHz channels — should the leasing agreement with DISH come to fruition.

Ookla_TMob-Dish_600_Spectrum_20190731

Since DISH currently doesn’t have an existing network — and it will take them several years to build it — their 600 MHz spectrum licenses are sitting idle, and American consumers aren’t benefiting from that spectrum. T-Mobile and DISH have agreed to an arrangement through which T-Mobile will be able to lease that spectrum and put it to use on its network. The arrangement is mutually beneficial, providing DISH with a revenue stream that could help with their network buildout, and the new T-Mobile with additional spectrum to enhance and accelerate the network transition process.

Top-Largest-Markets_TMobile-Dish-01

In some of the top markets like New York City, Los Angeles, and Miami, DISH’s 600 MHz spectrum licenses are directly adjacent to T-Mobile’s licenses, creating larger, contiguous spectrum blocks and allowing for wider LTE or 5G channels. In markets like New York, T-Mobile currently runs LTE in the 600 MHz band using only a 5 MHz wide channel, while the other 5 MHz license is idle and likely to be used for 5G, once 5G-capable user devices in the 600 MHz band become commercially available. Adding DISH’s 20 MHz contiguous spectrum block will allow the new T-Mobile to leverage the widest defined LTE channels (20 MHz) and still have 10 MHz available for 5G deployment. This would offer the highest possible spectral efficiency on a frequency band with superior propagation characteristics to the mid- and high-band. In addition, new smartphone designs allowing four separate data streams on the low band have already hit the market, allowing carrier aggregation of two low-band frequencies, or 4×4 MIMO. But more on that later.

What the merger means for coverage

Ookla_Sprint-TMob_Coverage_20190731

An estimated 11,000 Sprint sites will be retained to improve capacity and/or coverage on the new network. These sites add additional capacity to metro areas and expand coverage to areas T-Mobile hasn’t previously served. The sites will receive support for T-Mobile’s frequency bands, which could include replacement of Sprint’s existing 2.5 GHz equipment. Because Sprint’s existing 2.5 GHz infrastructure has equipment from a variety of vendors, these may be replaced to ensure compatibility with T-Mobile’s single-vendor-per-market strategy.

Integrating tens of thousands of existing Sprint sites will also mean reducing the lengthy regulatory process and will be done on a market-to-market basis.

Merging the networks and migrating customers

The details of how T-Mobile and Sprint will merge their networks are much clearer now than when we last wrote about this potential merger. In order to expedite the migration of Sprint subscribers onto T-Mobile’s network, T-Mobile will bridge the two network cores together by routing the traffic to the T-Mobile anchor network. This will be accomplished through the use of Multi-Operator Core Network (MOCN).

T-Mobile used a similar approach several years ago when migrating MetroPCS CDMA subscribers to the T-Mobile network. The number of Sprint customers migrating to T-Mobile in major metropolitan areas like New York and Los Angeles would be very similar to the number of MetroPCS customers that migrated, according to T-Mobile.

Many customers will not require new devices. A large number of Sprint’s postpaid subscribers carry devices that support T-Mobile LTE frequency bands, including the common PCS band, and will only require an over-the-air software update to enable new features and services like Voice over LTE (VoLTE). This approach will offer immediate improvements in coverage and speed to Sprint subscribers, while freeing up Sprint’s PCS spectrum assets currently used for CDMA voice services.

What to expect from the new T-Mobile 5G network

5G is central to T-Mobile’s commitments to the FCC, including:

  • Covering 97% of the U.S. population with 5G in three years
  • Covering 99% of the U.S. population with 5G in six years
  • Offering in-home broadband nationwide, including in rural America

The spectrum portfolio and combined cell site grid will only improve the existing coverage and capacity, and the addition of Sprint’s 2.5 GHz and DISH’s 600 MHz spectrum assets will ease the transition of Sprint and DISH customers onto T-Mobile’s network. The new T-Mobile will hold around 160 MHz on average of 2.5 GHz mid-band spectrum in the top 100 markets, and potentially as much as 194 MHz. This will allow the new T-Mobile to deploy mobile 5G by layering low-band (600 MHz) and mid-band (2.5 GHz), which has the potential to provide the right balance of coverage and capacity. The excess capacity will be made available for in-home broadband, providing more options in underserved and rural areas. T-Mobile’s existing mmWave licenses will add additional capacity in dense urban areas.

To take advantage of the new T-Mobile’s spectrum and 5G network, smartphones must have the capability to aggregate both Sub-6 FDD and TDD (FR1) with mmWave (FR2), in addition to LTE. We expect to see 5G smartphones with chipsets capable of leveraging FDD low-band spectrum (FR1) become commercially available later this year, which will allow for 5G deployments in the 600 MHz band. This low frequency band can travel farther and penetrate through the walls better, which will allow T-Mobile to offer a nationwide 5G network. Existing 600 MHz LTE radios on T-Mobile’s cell sites are “5G Ready,” which means the network is only a software upgrade away from transmitting 5G throughout the existing 600 MHz footprint.

Also, the world’s first smartphone design supporting 4×4 MIMO and inter-band carrier aggregation on low bands has already entered the market, Sony Xperia 1 although the support for 600 MHz is lacking. We should expect similar designs supporting T-Mobile’s 600 MHz and 700 MHz bands in the future, which could potentially double user throughput, improving signal robustness and elevating the overall network efficiency and user experience.

Selecting Sprint “keep” sites

In conjunction with Speedtest IntelligenceTM data from Ookla®, T-Mobile developed an engineering model for forecasting both congestion and required capacity at the sector level. This model involves collecting KPIs within the radio network infrastructure and has been, according to T-Mobile, highly accurate.

This effort has led to 71% reduction in congestion, while traffic and customer growth have increased over the past several years. The model is also being used to analyze which T-Mobile and Sprint cell sites to keep to enhance the New T-Mobile cell site portfolio based on network coverage, traffic and spectrum available.

DISH, the new fourth competitor

Ookla_Dish_Spectrum_20190801

The DOJ’s response to the T-Mobile-Sprint merger also includes structural remedies to enable a viable fourth facilities-based nationwide operator, DISH, to enter the market. Over the past decade or so, DISH has acquired large amounts of mostly mid- and low-band spectrum that hasn’t been put to use. That includes the 600 MHz, 700 MHz, AWS and recently some millimeter Wave spectrum licenses.

The DOJ’s proposed structural remedies are meant to spur DISH to deploy unused spectrum assets, then enter the wireless business as a viable nationwide operator. Allowing DISH to acquire 800 MHz divested spectrum assets after three years — coupled with 20,000 (likely more) of Sprint’s redundant sites that already have the 800 MHz radio equipment and backhaul access available — should help DISH meet the agreed-upon buildout targets to have a facilities-based network by June 2023. Granted, these sites will stay running to support Sprint’s postpaid and divested prepaid legacy customers for at least three years, at which point DISH will have to make some investments for additional adjustments to the sites, such as gNodeB and radio equipment upgrades. After three years, if DISH elects not to purchase the divested 800 MHz nationwide spectrum licenses (penalties apply), T-Mobile will have the option to auction the 800 MHz spectrum at the same or higher cost, or keep it. In addition, DISH will be given access to several hundred retail locations the New T-Mobile plans to decommission.

Considering Sprint’s existing coverage, there is a high probability that these divested cell sites will be mainly concentrated in the metro areas. That said, DISH subscribers will be able to access the new T-Mobile’s nationwide network in areas not covered by DISH’s facilities-based network for a period of seven years, which should also provide plenty of time for DISH to expand its native network footprint.

Despite the upcoming legal challenges from 14 states, the consent decree from the DOJ is a key milestone in the potential merger between T-Mobile and Sprint. We’ll be watching its progress, using Mosaik research and solutions to monitor coverage and spectrum changes and Speedtest Intelligence to analyze performance.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Spectrum

About the Author

Milan Milanović

Ookla Research™ Articles
| April 29, 2019

Analyzing the Capabilities and Performance of the Samsung Galaxy S10 Series

Tech Insights

The recent launch of the Samsung Galaxy S10, Galaxy S10+ and Galaxy S10e marks the world’s first commercially available multi-gigabit LTE smartphone, with a theoretical max download speed of 2 Gbps. We took a look at how the phone performed during its first month on the market in the U.S. and the technology that makes multi-gigabit download speeds possible.

Performance comparison of Galaxy S10 models

It’s been three years since the very first Samsung 4Rx antenna design (Galaxy S7 Edge). This year’s Samsung Galaxy S10 series allows for up to 20 concurrent spatial streams depending on the spectrum availability and network deployments. This shines the light on Qualcomm’s Snapdragon X24 LTE modem and Qualcomm’s RF Front-End (RFFE). Together they enable the aggregation of up to five mid- and high-frequency bands, each leveraging up to four spatial streams, providing an end-to-end, modem-to-antenna solution. The Samsung Galaxy S10 series is the first Cat 20 commercially available smartphone to use this technology.

Ookla’s data science team took a closer look at U.S. performance across Samsung Galaxy S10 models during their first month on the market:

Speedtest® Results Among Galaxy S10 Models
United States | March 8-April 8, 2019
Model Mean Download (Mbps) Mean Upload (Mbps)
Samsung Galaxy S10+ 51.26 10.87
Samsung Galaxy S10 49.54 12.08
Samsung Galaxy S10e 49.18 12.61

In analyzing more than 606,000 Speedtest results performed on over 213,000 unique devices during March 8-April 8, 2019, we saw that the Galaxy S10+ mean download speed reached 51.26 Mbps. The Galaxy S10 and S10e closely followed with mean download speeds at just over 49 Mbps.

Comparing S10+ to other flagship phones

Numerous OEMs have shipped devices equipped with Category 16 and 18 LTE modems capable of up to 1 Gbps and 1.2 Gbps download speeds in recent years. These devices utilize a combination of three or four channel Carrier Aggregation, higher modulation and higher order MIMO to improve data rates. However, quite a few of these devices were limited to only eight concurrent spatial streams (Cat 15) by the carrier profile software load, which capped the full potential of the chipset and thereby the network.

Galaxy S10 Series vs. Other Flagship Phones
Speedtest® Results
United States | March 8-April 8, 2019
Model Mean Download (Mbps) Mean Upload (Mbps)
Samsung Galaxy S10+ 51.26 10.87
Samsung Galaxy S10 49.54 12.08
Samsung Galaxy S10e 49.18 12.61
Samsung Galaxy Note9 43.32 10.97
Apple iPhone Xs Max 43.04 11.23
Samsung Galaxy S9+ 42.25 10.95
Apple iPhone Xs 41.92 10.37
Google Pixel 3 XL 41.27 12.48
Apple iPhone Xr 33.17 10.78

As the table above shows, the Galaxy S10+ showed double-digit improvements over the mean download speeds of last year’s top flagship devices, beating the Note9 by 18.3% and the iPhone XS Max by 19.1% during the same period. The increase in speeds means that each S10+ data session completes significantly faster, making the wireless networks considerably more efficient.

Samsung was one of the first OEMs to overcome the challenges of implementing four spatially separated antennas into the handheld form factor in 2016. The company is further improving the isolation and reducing the antenna correlation necessary for high performing MIMO with each year’s design. The “plus” size of the S10+ seems to aid this process.

Upload speeds did not see the same improvement across Galaxy S10 models when compared to last year’s flagship phones. The Galaxy S10e did have the fastest upload speed among models included in this analysis with a 12.3% improvement over the iPhone XS Max and 14.9% over the Note9 during the same period. However, the Galaxy S10+ achieved slower upload speeds than either 2018 phone.

The technology behind the Samsung Galaxy S10’s multi-gigabit speeds

The Galaxy S10 is powered by Samsung’s own Exynos 9820 System on a Chip (SoC) in most of the world or Qualcomm’s Snapdragon 855 SoC in the U.S. and China. Both variants have an integrated LTE modem while the Qualcomm’s variant is capable of processing 20 concurrent spatial streams and reaching peak download speeds of 2 Gbps. This involves complex circuitry between the antennas and the RF transceiver responsible for transmitting and receiving the RF signals over the air.

Carrier Aggregation

The Galaxy S10 supports a whopping 7-channel Carrier Aggregation (CA). CA allows operators with multiple (disparate) frequency bands to offer faster download speeds to users by aggregating (bonding) multiple frequency bands into a faster “pipe.” As a result, subscribers complete data queries quicker, returning their devices to idle state which allows the operators to reuse the network resources.

256 QAM or higher order modulation

Another LTE-Advanced technology used by the Galaxy S10 is 256 QAM. 256 QAM allows for the transmission of more bits per symbol (8-bits) as opposed to 64 QAM (6-bits). This provides a spectral efficiency gain of 33%. However, devices need to report a relatively clean channel state or high Signal to Interference plus Noise Ratio (SINR), back to the network in order for 256 QAM payload to be scheduled. This means 256 QAM is typically limited to devices served at the very center of the cell.

4X4 MIMO

The Galaxy S10 also supports up to 5 channels running in a 4×4 MIMO configuration for a total of 20 spatial streams. 4×4 MIMO requires twice as many antennas as 2×2 MIMO at both the cell site and the user device. This increase in antennas allows for a potential doubling of the number of independent spatial streams (rank), which then can double the user’s data rates. To achieve a higher rank, the antennas at the cell site and the device need to be uncorrelated to provide independent paths for up to 4 data streams at the same time. Similarly to 256 QAM, this speed-boosting technique also depends on favorable signal conditions (high SINR).

One of the main benefits of 4×4 MIMO system is the antenna diversity gain which can provide signal robustness in areas of poor coverage. Because one or two data streams can be broadcast over four antennas, retransmissions are minimized and data rates improve. In order to achieve acceptable antenna de-correlation and isolation in a spatially constrained form-factor, the integration of 4 antennas into the smartphone design is limited to frequency bands above 1600MHz. Reaching the target throughput and spectral efficiency in a 4×4 network isn’t only a function of the radio access network optimization, but often times is limited by the user equipment modem-to-antenna performance.

4x4-mimo

The level of complexity that went into the Samsung Galaxy S10’s LTE design would have been unimaginable just a few years ago. This means that operators can provide even faster speeds to end users and deliver data more efficiently while leveraging existing spectrum assets.

Configuration of the Galaxy S10 in the U.S.

While 5G is only slowly trickling out to U.S. markets, the Galaxy S10 already supports virtually every imaginable Carrier Aggregation combination. This allows the S10 to take advantage of the specific configurations of all the top providers’ networks to provide faster speeds for consumers.

  • AT&T users benefit from the inclusion of Band 14, the FirstNet spectrum, when using the Galaxy S10. In addition, multiple mid- and high-band component carriers can leverage up to 4 data streams at the same time.
  • Sprint users can expect to see the aggregation of FDD and TDD spectrum. It’s worth noting that the Galaxy S10 can aggregate up to five TDD channels, all running in 4×4 MIMO mode, which allows for faster speeds and more efficient spectral utilization.
  • The Galaxy S10 can take advantage of T-Mobile’s new support for the aggregation of Band 71 (600MHz) with multiple mid-band component carriers in a 4×4 MIMO configuration. The company will also be able to take advantage of License Assisted Access (LAA) which is heavily deployed in dense urban markets like New York City to increase download speeds.
  • On Verizon, the Galaxy S10 enables the use of the recently opened up Citizens Broadband Radio Service (CBRS) spectrum on Band 48. This phone also enables Verizon to combine LAA Band 46 with licensed spectrum to offer even faster speeds.

Improved speeds using Wi-Fi 6

The Samsung Galaxy S10 is also the world’s first smartphone to support the Wi-Fi 6 (802.11ax) standard. This standard promises to deliver faster speeds, better user experience in crowded environments, better management of shared spectrum resources, and better use of Multi-User MIMO. Broadcom delivered the BCM4375 chip which takes care of the Wi-Fi and bluetooth connectivity.

Faster speeds to come with the Galaxy S10 5G

The Samsung Galaxy S10 5G promises to deliver the multi-gigabit experience of 5G out of the box when connected to a capable network. This device is powered by two different 5G discrete modems depending on the geographical region. For the global market Samsung is using its own Exynos 5100 5G modem, while the U.S. market is getting the Qualcomm Snapdragon X50. The Snapdragon modem supports TDD frequency bands, including the 2.5GHz and the millimeter Wave bands in the 28GHz and 39GHz range that are used in the United States.

We at Ookla are as excited as anyone to watch as 5G networks commercially launch. When they do, we’ll be watching Speedtest results to see how the Samsung Galaxy S10 5G performs in the wild.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Tech Insights

About the Author

Milan Milanović

Ookla Research™ Articles
| October 24, 2018

Everything You Need to Know about 5G

Tech Insights

What is 5G?

5G stands for “Fifth Generation” Wireless Technology and is the next evolution for mobile technology after 4G LTE. 5G will bring faster speeds and improved network capacity and efficiency. 5G enables operators to address exponential growth in mobile and internet of things (IoT) connections.

A brief history of cellular technologies

Every decade or so, a new generation of mobile technology brings ground-breaking performance improvements and introduces new applications and use cases. In the 1980s, 1G (analog cellular) enabled mobile phone calls. 2G in the 1990s brought digital voice and texting. In the 2000s, 3G brought the mobile internet, music streaming and picture messaging. And in 2010, 4G LTE delivered enough capacity for a true multimedia experience including streaming HD video.





Enter 5G and the future. Defined by the 3rd Generation Partnership Project (3GPP) standard body, 5G is listed as wireless standard “Release 15” and “Release 16.” 5G is also sometimes referred to as 5G NR, which stands for New Radio.

Why do we need 5G?

5G aims to deliver a significant technological leap from LTE, delivering an exponential increase in peak and average speeds and capacity. A significant increase in download and upload speeds could enhance many existing use cases including cloud-based storage, augmented reality and artificial intelligence.

5G will also enable cell sites to communicate with a greater number of devices. Reduced latency could enable edge computing, making possible remote graphic rendering for enhanced gaming. Primarily a mobile technology, 5G will also allow mobile operators to deliver “fiber-like” wireless broadband service, which also stands to increase speeds.

Is 5G really that much faster than 4G?

Yes. The initial wave of 5G smartphones expected in 2019 will be able to reach peak speeds of up to 5 Gbps. This is just the beginning. As networks and chipsets mature, peak speeds of tens (or even hundreds) of gigabits per second will theoretically be achievable and devices capable of 10-20 Gbps are expected in the next 5 years. In comparison, the fastest 4G LTE networks in the world are breaking the 1 Gbps mark and the latest 4G LTE devices are capable of reaching 1.4 Gbps.

T-Mobile and Ericsson have recently achieved over 12 Gbps on a 5G connection. The first global 5G end-to-end handset solution has recently been announced by Qualcomm, and will deliver mobile speeds of up to 5 Gbps to end users in 2019. Whether carriers choose to provide service at these speeds remains to be seen.

5G also introduces a host of new technologies that will make networks faster, more energy efficient, more responsive and more reliable including network slicing and beamforming and beamtracking.

Can Speedtest measure 5G?

Ookla, the company behind Speedtest, is ready for 5G. We’ve been optimizing the Speedtest app and preparing our infrastructure to accurately measure and display 5G-level speeds. In fact, we’re already seeing 5G tests as mobile operators use Speedtest to test their infrastructure.

When and where will 5G be available?

5G trials and pre-standard (5GTF) deployments are already underway. Both Verizon and AT&T offer fixed-wireless 5G in several major markets, including Sacramento, Houston, Indianapolis and Los Angeles. But the 5G NR (New Radio) networks based on 3GPP Release 15 standard are expected at the tail end of this year. AT&T promised to have the first mobile 5G “wireless hotspot” device shipping this year. And the first wave of 5G NR smartphones are expected during the first half of 2019.

The initial 5G NR deployments in late 2018 and early 2019 will be “non-standalone” (NSA). This timing means that operators will continue using their existing 4G LTE network core for voice, handoffs and signaling, and will bond the existing 4G signal with the 5G air interface using a technique called carrier aggregation for the time being. While the continued use of 4G LTE won’t achieve the true capability of 5G, it will ensure seamless transition to standalone (SA) 5G and allow operators to gracefully repurpose legacy spectrum over the next decade. Many operators continue heavily investing into LTE networks, expecting LTE to serve as the main workhorse coverage layer well into the 2020’s.

Can my phone get 5G?

Once a 5G network is deployed in your area, you will still need a capable smartphone to access it. The 5G-capable chipsets are currently being tested by smartphone manufacturers and network operators. The first commercial 5G smartphones are expected to be available in the first half of 2019. By that time all four operators are expected to launch mobile 5G networks in several markets throughout the U.S.

Network slicing helps 5G prioritize traffic

5G introduces a new technology called “network slicing”, which creates multiple logical partitions within resource allocations that are designed to address specific use cases ranging from mission-critical (e.g. self-driving cars) to IoT devices. This is preferable to the 4G scenario where all use cases have to share a single physical layer partition.

For example, IoT devices like smart meters and home appliances (which do not require fast speeds, low latency, or a high level of prioritization) talk to the network once a day or week. This means they can be supported with a small sliver of network resources. On the other hand, mobile operators can chose to prioritize the partition allocated for specific services like autonomous vehicles, remote surgery or remote manufacturing that require very low latency and high quality of service.

Best of all, the user experience on “best effort” consumer devices like smartphones and tables will not be affected on 5G because these special services will be delivered within their own relatively small slivers of spectrum. This type of resource management has never been possible before, and it leads to much improved spectral utilization and monetization of deployed resources.

How 5G uses spectrum

5G leans on a more optimized version of Orthogonal Frequency Division Multiplexing (OFDM)-based waveform, a modulation format used for popular wireless technologies like LTE and Wi-Fi.

For decades, operators have been investing billions of dollars to acquire 10 MHz, 15 MHz or 20 MHz slivers of spectrum to address exponential growth in capacity demand from subscribers. In order to deliver much faster speeds and massive network capacity, mobile operators in the United States are mainly investing in the millimeter Wave (mmWave) spectrum for 5G, specifically in the 28 GHz and 39 GHz band. The main attractiveness of this high-band spectrum is its immediate availability and quantity as the mmWave frequency range includes hundreds of megahertz of unused spectrum that’s available for immediate 5G deployment.

While the high band frequencies will offer very large amounts of bandwidth, the mmWave frequencies will be limited by their short range. They are also not well suited for deployments on large cell towers due to necessary quality measures. This short range will force operators to densify their networks using 5G small cells positioned much closer to users.

Advanced techniques for providing a quality signal on high-frequency bands

High-spectrum airwaves are finicky and bring challenges, including significantly reduced propagation characteristics, increased path loss and scattering. To tackle these issues, the use of advanced techniques like beamforming and beamtracking are absolutely mandatory.

Beamforming is the network signaling system implemented on network basestations that identifies the most efficient signal delivery to a user. Instead of flooding the area with a signal in all directions, beamforming focuses energy into a beam to minimize interference. Beamtracking, a technique implemented on mobile devices, helps with beam selection and signal retention. Beamforming and beamtracking require very powerful algorithms working together to focus the cleanest possible beam of electromagnetic energy to each user and reduce inter-site interference.

While we’re accustomed to seeing huge cell towers using giant antennas required for low and mid frequency bands, 5G mmWave will depend on dense small cell deployments. Instead of two or four antenna elements, each mmWave small cell will have hundreds required for beamforming and beamtracking to properly work. This is commonly referred to as massive MIMO (mMIMO). Massive MIMO in 5G will offer much better interference measurements and link adaptation via the improved channel state information (CSI) feedback mechanism. This will result in improved data rates and reduced retransmissions.

The upside is that the mmWave antennas are many times smaller than typical cell antennas and can be deployed on light posts, rooftops, city furniture and other areas typically found in inhabited environments. For this reason, cities will get mmWave 5G first as operators add capacity in high traffic areas.

5G at other frequencies

5G has also been proposed in the sub-6 GHz spectrum range. This frequency won’t offer as much capacity relative to mmWave, but it will deliver better coverage. Sub-6 GHz spectrum will also offer improved spectral efficiency by the way of Higher Order MIMO (4×4 MIMO) when paired with the mid-band spectrum (2.5 GHz, 3.5 GHz initially). In the U.S., Sprint has announced plans for 5G leveraging 2.5GHz spectrum.

T-Mobile’s sub-6GHz 5G deployments, expected in 2019, will include 600 MHz low-band. This should provide a strong coverage layer and serve as a foundation for future mid- and high- frequency band deployments, because the low-band frequency has better propagation characteristics than the mid- and high-band frequencies.

Outside the U.S. most operators are using 3.5 GHz for 5G.

What else can 5G do?

5G isn’t only about attaining the fastest speeds or ultra-low latency. 5G will enable the use of automation in a broad range of industries from autonomous manufacturing, autonomous vehicles, medicine, retail, education, to smart homes and smart cities. It will promote the use of low-cost sensors, which will talk to the network intermittently, use low amounts of data, and draw very little power. This will extend mobile device battery life from several hours to several years.

These sensors can be deployed anywhere, in autonomous vehicles for collision avoidance, autonomous drones providing temporary cell coverage in targeted areas, in the urban core (parking, traffic lights, bridge tolls, air quality, etc.) and in rural environments (help animals detect predators, alert farmers to changes in chemical composition of the soil, etc.).

That’s just the beginning. The endless potential of 5G has yet to be envisioned. Despite the benefits we already see in a hyper-connected society: the massive growth of IoT, faster speeds and lower latency, it’s likely that new services not possible with today’s technology will be developed, new use cases created, and our lives will never be the same.

From the technological standpoint, the 5G NR is designed to be future-proof and flexible enough to address known and unknown use cases as the way we use it evolves. The new air interface and 5G core network are also still being perfected, and over the next 2-5 years we are likely to see major technological leaps and major changes in how we interact with the internet. The next 10 years will be exciting!

If you’re implementing 5G on your network, Speedtest Intelligence can provide you insight into actual user experience.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Tech Insights

About the Author

Milan Milanović

Ookla Research™ Articles
| April 12, 2018

What Would a Merger Between Sprint and T-Mobile Mean for Customers?

Global Speeds

Editor’s note: Rumors of the merger of Sprint and T-Mobile were confirmed on April 29 through a video announcement featuring CEOs of both companies.

As was the case in October, rumors once again abound that a merger between Sprint and T-Mobile is coming. Though we cannot know if that is true, we are interested to explore what such a combination might mean for the online experiences of customers in the future.

Speeds

T-Mobile is the fastest of the big four carriers in the U.S. and Sprint is the slowest.

Existing Sprint customers would definitely benefit from T-Mobile’s recent infrastructure investments. Over the past six months, T-Mobile has been aggressively deploying LTE on their 600 MHz greenfield spectrum assets, which already cover more than 300,000 square miles, using 5G ready infrastructure equipment. These assets will be fully 5G operational once the vendors push over-the-air software upgrades, likely to happen sometime before the end of this year.

The 5 GHz License-Assisted Access (LAA) has already been deployed in a few urban areas, adding 60 MHz of downlink capacity to the existing network. This effectively provides up to 1 Gbps peak download speeds. T-Mobile spectrum assets also include 200 MHz of millimeter wave (mmWave) spectrum across 100 million people, which is readily available for 5G deployment mainly in urban areas where the network traffic is the highest. These mmWave spectrum assets alone could provide speeds of about 1 Gbps. The nature of the non-standalone (NSA) 5G, which we will be seeing next year, is to operate on top of the existing LTE network which significantly improves the overall user experience.

Perhaps the most interesting aspect of the merger, at least from the technological side, is the integration of Sprint’s 2.5 GHz 5G-ready spectrum into the existing T-Mobile core. This integration offers up to 100 MHz of greenfield 5G spectrum in addition to 60 MHz of already deployed LTE capacity. Unlike the 28 GHz and 39 GHz mmWave spectrum, 2.5 GHz is more suited for wider area coverage and will offer higher spectral efficiency by the way of Higher Order MIMO (4×4 MIMO) and Higher Order Modulation (256 QAM).

Some capacity-enabling technologies like Massive-MIMO and FD-MIMO (Full Dimension MIMO) are already being deployed by both operators, adding 32, 64, and even 128 antenna elements to the cell sites. This will not only support the upcoming 5G, but will have the immediate benefits in terms of speeds for users equipped with LTE terminals.

Mergers aren’t about taking the average of carriers’ speeds, though. They are about how networks improve when the assets of both companies are combined. In the case of a merger between Sprint and T-Mobile, spectrum holdings will play a huge role.

The difference spectrum makes

Spectrum is the range of radio frequencies used to transmit voice and data. Different carriers hold and operate on different parts of the spectrum. Sprint holds a massive 150 MHz of nationwide 2.5 GHz spectrum, which uniquely positions them to provide an outstanding consumer experience. To date, most of that spectrum has been underutilized due to lack of funding, changes in leadership and unorthodox deployment strategies. Only 20-60 MHz of Sprint’s 2.5 GHz spectrum has thus far been deployed for commercial use, with some additional spectrum used for wireless backhaul. Sprint also holds about 37 MHz of mid-band spectrum, which is then shared between the legacy 3G and LTE technologies, and about 12 MHz of low-band spectrum.

And while the high-band (2.5 GHz) spectrum is excellent for providing incremental capacity, due to its signal properties it can’t propagate very far or penetrate concrete structures very well. This is why Sprint subscribers often end up falling back to Sprint’s limited mid- or low-band LTE network layer, which can translate to slower speeds and increased load times. T-Mobile’s cell site density and excellent mid-band spectrum could come in very handy to radically improve Sprint customers’ experience in a post-merger world.

On the other hand, a tightly-spaced cellular grid is T-Mobile’s strong point. This grid is optimized for 70 MHz of T-Mobile’s mid-band spectrum and delivers wideband LTE experience using both the 2100 MHz Advanced Wireless Spectrum (AWS) and 1900 MHz Personal Communications Service (PCS) layers. Combining what’s already the fastest LTE network in the U.S. with the massive 2.5 GHz spectrum assets on a dense network grid could potentially deliver exceptional network performance. This is because fewer users are served by any individual cell which increases network resources, improving speeds and overall user experience.

Both Sprint and T-Mobile operate in the 1900 MHz PCS frequency band, and in many markets the carriers could combine the existing holdings into a wider contiguous spectrum allocation which will further improve user experience.

How spectrum integration might play out

The obvious benefits to the merger would be the synergies. Mostly network-driven, these would include decommissioning redundant Sprint macro sites and reducing the operating expenditure of the combined company. The remaining portion of Sprint’s cell sites would fortify the existing T-Mobile footprint, adding incremental network capacity. Timing is essential, though. Over the last six months, Sprint has commited to $6B in network investments and may have signed contracts with tower companies and backhaul suppliers. The execution of this investment is still in the early stage, but once it’s had an opportunity to ramp up some of the synergies will dissipate.

T-Mobile is well known for its network efficiencies. They run a lean LTE network with a strong focus on extracting the highest possible spectral efficiency out of the existing spectrum assets, and also spearhead efforts in commercializing the latest advanced LTE features.

T-Mobile’s previous experience with absorbing a CDMA operator (Metro PCS) could offer insight into how spectrum and resource sharing would be affected by a merger. In that case, T-Mobile successfully migrated the Metro PCS customer base onto its advanced network core in record time, repurposing the spectrum shortly after sunsetting the CDMA network. This type of approach offers additional cost efficiencies, as Sprint’s older CDMA infrastructure can be removed, and redundant cell sites decommissioned.

Another potentially positive outcome to a merger comes with the upcoming 5G standardization. T-Mobile could utilize Sprint’s rather limited low-band spectrum to provide a dedicated narrowband IoT channel.

Coverage

What about coverage? Maps of Speedtest results from the U.S. Market Report showed a larger footprint of results on T-Mobile.

The combined entity would potentially number over 130 million subscribers, which would be comparable in size to both Verizon and AT&T. Overlaying the Speedtest coverage maps, we see that although the strengths of both networks are in urban centers, there are some areas where we see Speedtest results on Sprint but not T-Mobile. This includes much of central West Virginia. Sprint also sees more tests in more rural parts of southwestern Oregon, southwestern Colorado (near Montrose), the Texas panhandle, eastern Nebraska, and much of Wisconsin.

T-Mobile shows results in the following areas where Sprint results are sparse: southwestern Montana, northern Nevada, southern Wyoming, northeastern Arizona, across North and South Dakota, northern Minnesota, throughout rural New Mexico and in the more suburban areas near the Alabama/Tennessee border.

Presumably, customers in areas that have only had access to one network would see the biggest benefit from a merger.

Good news or bad?

A combined Sprint and T-Mobile could make for one powerhouse of a carrier with the customer base and clout of Verizon and AT&T. Not only would Sprint’s 2.5 GHz spectrum portfolio be a major asset to the combined entity, a merger between the two would also expand their geographical footprint and improve the cell site density in many markets which will be the key for the upcoming high band 5G deployment.

That said, there are a lot of unknowns. These things take time and it could take years for consumers to benefit from the combined spectrum efficiencies. From an operational point of view, mergers of this size typically shed a lot of jobs. Reducing the number of major carriers in the U.S. from four to three will change the competitive landscape in a way that could increase prices. We also do not yet know how such a merger would impact speeds, but we’ll share data on that here when we do.

Editor’s note: An earlier version of this article appeared on this blog on September 27, 2017.

Ookla retains ownership of this article including all of the intellectual property rights, data, content graphs and analysis. This article may not be quoted, reproduced, distributed or published for any commercial purpose without prior consent. Members of the press and others using the findings in this article for non-commercial purposes are welcome to publicly share and link to report information with attribution to Ookla.

Global Speeds

About the Author

Milan Milanović