Thinking across the generations

To understand future passive infrastructure requirements, it is of paramount importance to understand how networks are set to evolve. In this white paper, Ericsson explore how network architecture is set to change as the industry transitions towards 5G.

Until now, cellular network evolution has mainly been about moving from one generation of air interface to a new one that provides higher capacity and ever-increasing data rates. In essence, each mobile generation has been marked by technological advances in modulation schemes that improve efficiency to make optimal use of precious radio spectrum.

Networks of the future are going to be different.

Future mobile networks will not only need to continue to meet the increasing communication needs of the growing numbers of smartphone users. They will also provide a platform for a vast array of new applications – from massive Internet of Things (IoT) and rich enterprise collaboration services, through mass-market personalized video, to tactile, interactive virtual-reality gaming.

In this new environment, delivering a high-quality, valuable service will not just be about rolling out ever-increasing data rates for mobile broadband, although this will be important. There will be many use cases for which performance is measured in other dimensions: for some availability and responsiveness will be much more important than data throughput, while for others geographical reach, low device cost and low energy consumption will be vital.

The network will evolve to play very different roles for the wide variety of users and applications. It will support fast service innovation and delivery through the creation of logical network ‘slices’ on demand, under software control.

This new reality is reflected in the fact that 5G networks will not just offer access to new bandwidth in higher frequency bands. They will also incorporate evolved versions of today’s cellular technologies, particularly 4G LTE. They will be ‘modulation-agnostic’.

All this requires a new mindset when it comes to the role of current and future cellular networks, and how they will evolve to meet future needs across the generations.

Globally, the key drivers for expanding cellular network coverage and capacity are the exponential rise of smartphone adoption and mobile broadband usage, the growing numbers of new subscribers in developing markets and the introduction of cellular Internet of Things (IoT) services.

Operators need to meet these new demands, while also positioning themselves for innovation and differentiation – not just in smartphone-based mobile broadband services, but also in new growth areas, such as connecting things and the data associated with them in businesses, industrial sites and homes.

The drivers for traffic growth in mobile broadband networks can be summarised in two words: social and video. Data collected in 2015 shows that in every single minute of the day, nearly 140,000 hours of video were being watched on YouTube, 360 GB of data were being uploaded to Facebook, and more than 13 million WhatsApp messages were being sent. Clearly these sorts of statistics represent significant new demands on mobile networks. While a good social experience may only require 1–3 Mbps downlink speed, high-definition video requires 3–10 Mbps, and for professional users downlink speeds of at least 10 Mbps are needed for a good collaboration experience. Furthermore, users increasingly expect their mobile broadband experience to be snappy: they do not want to wait for a video to start playing or for a file to start downloading.

It’s worth remembering that for many people around the world, access to a mobile network is the first opportunity to connect to the internet. Low-cost devices and broad network coverage enable operators to offer services to these first-time users profitably. This demands low-CAPEX, low-OPEX and highly energy-efficient infrastructure.

With the rise of massive IoT and other use cases in a wide variety of applications, broad coverage, availability, battery life, responsiveness and low operational costs will all become just as important performance indicators as downlink speed.

This creates opportunities for mobile operators to differentiate and create targeted offerings aimed at different market segments, as well as to innovate and develop new business models in growth areas such as the Internet of Things (IoT) and interactive personalised video.

In preparing their networks for 5G, operators need to cater for continued subscriber growth, the shift to video and social media and the broad range of new applications for cellular data. This places new demands on the functionality of the network and calls for innovation in three key areas:

- Offering hardware, software and services that can deliver higher capacity and performance tailored to a wider range of needs

- Improving efficiency and cost through simplicity, flexibility and automation

- Creating optimised solutions for new growth areas such as IoT.

From now on, mobile networks will be ‘3xMulti’: multi-standard, multi-band and multi-layer.

Many operators already operate three technology standards in their networks: GSM, WCDMA and LTE.

As operators make plans for the addition of 5G over the coming years, Ericsson is placing a lot of emphasis on tight interworking between all standards in a multi-standard offering. With the addition of 5G it will be even more important to run the multi-standard networks in as optimised and automated a way as possible, to minimise operating costs and maximise performance.

The future is also about supporting multi-band operation as additional licensed and unlicensed frequency bands become available to enable the data rates, coverage and capacity needed to support the expanding role of cellular networks over the coming years. Adding support for additional spectrum at existing sites is often the most cost-efficient way to expand network capability. In LTE, it is already possible to use carrier aggregation across three or more bands.

Furthermore, to get the maximum performance out of each band, operators will need multi-layer deployments with a combination of macro and integrated small cells. This will enable them to successfully serve indoor areas, add outdoor small cell capacity, and deploy optimal baseband architecture to get the most out of their valuable spectrum.

This is why a key focus area for Ericsson is to maximise the coordination between standards, bands and layers, through features like carrier aggregation, multi-standard hardware, powerful baseband architectures and integrated small cells. To improve the performance and capacity of mobile networks we encourage a continuous process of macro layer improvement and densification complemented with the integration of small cells.

The ‘3xMulti’ approach is instrumental in helping operators utilise their spectrum assets to the full, with a ‘one network’ approach built on the solid foundation of tight coordination before, during and after 5G deployment.

The drivers for multi-standard operations include are the continued introduction and expansion of mobile broadband, the need to manage the refarming of spectrum from older to newer standards, and the need to serve an ever greater and evolving device ecosystem. For operators, the key challenges are to ensure spectrum efficiency and minimise site impact and operational costs, while ensuring network simplicity and flexibility.

Ericsson has developed several key solutions to meet these challenges, including Thin Layer GSM, Zero Touch WCDMA, Ericsson Radio System and Ericsson Network Manager.

Thin Layer GSM is Ericsson’s strategy for GSM networks, focusing on five important aspects of efficiency, or ‘thinness’: spectrum, hardware, power consumption, competence and OPEX. Thin Layer GSM is designed to offer high levels of automation and synergies with other networks, while requiring no unique hardware.

With a ‘gold standard’ setting based on Ericsson recommendations, a ‘Zero Touch’ period is introduced in the WCDMA RAN software upgrade cycle. During this period, there is minimal need for an operator to configure or tune the network, except when dimensioning or expanding coverage. This radically reduces the management effort for a 3G installation, supports faster upgrades and can treble operational efficiency. It also maintains high-quality app coverage in both low- and high traffic-load conditions.

To enable mobile operators to address growth opportunities and transform their networks with 3xMulti architecture that can evolve to 5G, Ericsson has introduced he Ericsson Radio System - an innovative, modular system that delivers industry-leading performance, on the industry’s smallest site footprint with the lowest energy consumption. The system has been designed to accommodate the mobile data traffic increases expected over the coming years at the same – or lower – levels of energy consumption as today.

Ericsson Radio System features novel building practices, like one-bolt installation, which enable fast deployment, reduce time-to-revenue and minimise operating expenses. At the heart of the new system is Ericsson’s Many-Core baseband architecture, which supports massive multi-core processing with ten times the energy-efficiency of commercial, off-the-shelf processors. The Ericsson Radio System offers industry-leading performance, including the world’s first software-only baseband upgrade for TDD–FDD carrier aggregation.

Ericsson Network Manager offers harmonised operations, processes and efficiencies across all network technologies and domains (core, transport and access).

The key driver for multi-band operation is enabling sustained subscriber and traffic growth in mobile broadband. The primary challenges are spectrum availability, maintaining consistent user experience across different bands, implementing technologies to maximise spectrum efficiency, and ensuring cost-efficient expansion of mobile broadband at existing sites.

The spectrum challenge may be overcome in part by acquiring new radio spectrum and refarming existing bands, FDD/TDD convergence, and license-assisted access/unlicensed access. Operators are typically expected to have access to more than 100 MHz of bandwidth each across the spectral landscape in the coming years.

Multi-carrier and data acceleration also help ensure legacy WCDMA user experience is good across all bands. Data acceleration is a unique feature that Ericsson has developed with Qualcomm to deliver extra capacity in the uplink by compressing data in the handset and decompressing it in the Radio Network Controller (RNC).

Ericsson WCDMA Flow of Users enables operators to maintain optimal flow of smartphone users through their 3G networks. It uses a defined selection of software features and settings to automatically balance active user count and consumer experience. As a result, operators can maximise smartphone user experience, even during busy periods, while ensuring high-quality voice services.

Key radio solutions for multi-band operations include Antenna Integrated Radio (AIR) with four-way receive diversity and carrier aggregation/multi-carrier spectrally-agile solutions. 

We are likely to see multi-band deployments of LTE (with five or more bands) in the near future, and the technology continues to evolve both in terms of functionality and into new frequency bands. Operation at 3.5 GHz is already available, together with license-assisted access, carrier aggregation and LTE Unlicensed.

There will be a natural evolution to 5G, with current and future technologies (called NX) working together in  harmony. One example of this is in tight interworking between LTE on 2.6 GHz and NX on 15 GHz, for instance, which will deliver significant gains over and above a simple additive gain. Working together in this way, LTE and NX are able to provide at least 100 Mbps with 95 percent probability in a dense city deployment.

Multi-layer deployments, combining macro cells and integrated small cells, help meet the challenge of maintaining and improving cell edge and in-building coverage for excellent user experience. The greatest demand for high-speed mobile data services and app coverage is often from indoors (in office buildings, for example). A key solution in this area is the deployment of coordinated, cost-efficient small cells in traffic hotspots.

Small cells are needed in areas where immediate coverage is shielded or lacking (such as inside buildings) or where there is too much traffic for a macro cell to handle (such as localised in-building areas, street-level traffic hotspots and busy indoor areas like shopping malls, event venues, airports and train stations).

Often in dense urban or urban environments, physical changes on the macro network may not be able to solve the complex needs of adequate coverage for data and voice deep inside multistory buildings.

To meet the high requirements of private and enterprise users and to tackle the challenges of urbanising environments, we need to take a new approach to indoor network performance. Small cells alone improve the network performance in certain areas, but integrated small cells (macro and small cells combined) deliver even higher capacity and peak rates, with the potential to improve performance in the macro network by offloading traffic. 

They do this by enabling:

- Radio coordination, to deliver the highest performance  for the lowest TCO

- Reliable mobility across technologies, frequencies and locations for superior end user performance

- Management, for full visibility of network and user performance, everywhere.

Integrated small cells also make it possible to build indoor coverage without targeting dominant coverage of the indoor solution. By letting the macro coverage from outside handle part of the load in the building, the need for indoor equipment can be reduced dramatically compared with a dominant indoor coverage solution. This significantly reduces the cost to construct indoor systems.

Many operators around the world are already planning their 5G network rollouts, and Ericsson is involved in a number of 5G technology trials. We are likely to see commercial deployments of the technology by the end of the decade.

Unlike other generations of mobile cellular technology, 5G is designed from the start to incorporate evolved versions of current standards, most notably LTE. 5G is not just about a new Radio Access Technology (RAT); it is a combination of a new 5G RAT in new higher frequency spectrum, known as ‘NX’, together with evolved LTE, baseband, transmission, core networks and services. Tight interworking between evolved LTE and NX will be essential for good user experience.

This will enable operators to quickly introduce 5G in parts of their networks and rely on the evolved LTE functionality in the rest of their network to provide high-quality fallback for early users of the new technologies. Operators will need to be able to quickly and cost-effectively introduce a large number of new applications and services. Network virtualisation and abstraction capabilities such as Network Functions Virtualization (NFV), Software Defined Networking (SDN), Cloud RAN, including a virtualised RAN and new functional splits, along with efficient interworking with existing technologies will all have key roles to play.

5G technology will open up opportunities in applications that have not yet been possible to implement in current cellular networks – in critical control of remote devices, for example, where very short latency and extreme reliability will be vital. With the massive expansion of subscribers, devices and services enabled by 5G, a key target will be reduced energy consumption.

5G access networks are characterised by several key technology features.

One of its key features is flexibility. 5G radio access solutions need to be able to operate over a very wide spectrum range, from below 1 GHz well into the millimetre wave range. The details of the solution, for example in terms of waveforms and numerology, may vary between different bands but the ideal is to have a single unified framework.

The same is true for deployment. 5G wireless access must be able to operate across a wide range of deployments, from large macro deployments for wide-area coverage, to ultra-dense outdoor and indoor deployments.

Another key feature of 5G is ultra-lean design. Unlike current networks, which carry a lot of reference signals and broadcast system information, ultra-lean networks contain no ‘always-on’ reference signals and only a minimal amount of ‘always-broadcast’ system information. The basic principle is that resources are treated as un-defined, unless explicitly indicated otherwise; reference signal transmissions and measurements are scheduled.

As part of its industry-leading research and development for 5G, Ericsson has developed its ‘lean carrier’ approach which also has benefits in 4G LTE networks. Ericsson Lean Carrier delivers an up to 50 percent improvement in downlink throughput while reducing dropped connections by up to 20 percent.

Above all, 5G networks will be able to support a much wider range of use cases than previous mobile technology generations, with the ability to offer very low latency, extremely low device cost and low energy consumption, along with high capacity and high data rates.

The Internet of Things (IoT) is an enabler for a very wide variety of applications, each of which has different requirements that must be met to make them viable.

They can be split into two main classes: massive  Machine-Type Communication (MTC) and critical MTC. For massive MTC, it’s all about high volumes, quite possibly involving embedded devices with no access to on-grid power. For critical MTC, the focus is on safety, security, integrity and low latency, where trust in the system is essential – remote surgery or automated vehicle braking, for instance.

For the IoT to reach its full potential, current and 5G cellular technology must meet a variety of requirements for reliability, scale, low energy use and cost.

Cellular technology has some key properties that make it attractive for a wide range of IoT applications and business models. Cellular networks already have unmatched global coverage. The investment in many hundreds of nationwide networks has already been made, and the cellular device ecosystem is well established and developing continuously. Cellular also offers advanced functionality for quality of service and security.

3GPP standard technologies already have mechanisms to assign priority access to certain classes of device (such as smoke detectors) to ensure data gets through even in emergency situations when there may be network congestion. Security is an integral part of 3GPP cellular standards, and includes secure authentication and encryption of traffic. This gives service providers cost-effective and flexible ways to handle security and device management. And finally, cellular networks offer the highly automated connectivity management solutions that operators need for large-scale IoT deployments, and manage operational costs in areas like provisioning, monitoring and billing.

The implications for passive infrastructure

The 5G technology will change society and will be enabler for new ways of working, impacting many people, various industries such as transport and health sectors among others. But 5G will also impact passive infrastructure with rollout of huge number of 5G small cells, added new bands to already crowed sites, more advanced radios on the towers and higher requirements on data processing on the remote site, higher bandwidths in transport links, changes in power consumption, diversified need for reliability as critical MTC will impact backup requirements, etc.

This is a challenge where the telecom industry need to collaborate in thinking across generations to find attractive workable and competitive solutions to enable a successful 5G evolution