1.1 Drivers for 5G

Main drivers for the evolution of mobile networks in the past were mobile voice (2G/3G/Voice over Long Term Evolution [VoLTE]), messaging (Short Messaging Service [SMS], WhatsApp) and Internet access (Wideband Code Division Multiple Access [WCDMA], High Speed Packet Access [HSPA], Long Term Evolution [LTE]) whenever and wherever needed. Focus was on end consumers equipped with traditional handsets or smartphones.

Consumer demand continues to be insatiable with an ever growing appetite for the bandwidth that is needed for 4K and 8K video streaming, augmented reality (AR) and virtual reality (VR), among other use cases. On the same token, operators want the network to be “better, faster and cheaper” without compromising any of these three elements.

The biggest difference between 5G and previous “Gs” is the diversity of applications that 5G networks need to support. Objects ranging from cars and factory machines, appliances to watches and apparel, will learn to organize themselves to fulfill our needs by automatically adapting to our behavior, environment or business processes. New use cases will arise, many not yet conceived, creating novel business models. 5G connectivity will impact the following areas:

• Real world mobility. The way we travel and experience our environment;
• Virtual mobility. The way we can control remote environments;
• High performance infrastructure. The way the infrastructure supports us;
• 4th Industrial Revolution. The way we produce and provide goods.

We already have indicators about these long‐term trends and disruptions and they are not only driven by the Internet and the telecommunication industry but by a multitude of different industries. 5G will be the platform enabling growth in many of these industries; the IT, car, entertainment, agriculture, tourism and manufacturing industries. 5G will connect the factory of the future and help to create a fully automated and flexible production system. It will also be the enabler of a superefficient infrastructure that saves resources.

Smartphones are becoming more and more a commodity which means that consumers will differentiate themselves increasingly with new gadgets such as VR devices, connected cars and devices for connected health.

With the decline or at least flattened Average Revenue Per User/Average Revenue Per Device (ARPU/ARPD) in many markets worldwide (typical ARPU is around $30 per month, while ARPD is not more than $3 per month) the telecom industry is more and more considering new revenue streams besides traditional business models. This is where we see new business drivers and requirements, from vertical industries, the Internet of Things (IoT) and the digital society. In the past, the main driver for the mobile industry was connecting people, in the future it is about the “connected world” meaning connecting everyone and everything at any time. This will create new and additional revenue streams for Mobile Network Operators (MNOs). Connecting “things” like cars (e.g. 125 million vehicles to be connected by 2022), robots, meters, medical machines bring new challenges to the next generation of mobile networks. To name only a some of them:

• Ubiquitous, pervasively ultra‐fast connectivity;
• Resilient and secure networks;
• Massive radio resources and ultra‐dense networks; and
• Instantaneous connectivity.

Vertical industries and applications do have very diverse requirements with regards to throughput, latency, reliability, number of connections, security and revenue (see Figure 1.1).

This requires a highly flexible architecture of the new generation of mobile networks, on radio and core network side, as well as at the transport. Flexibility also includes a high degree of automation in deploying and maintaining networks, parts of a network or single resources (e.g. network slices). Flexible architecture is achieved by different means, from flexible frame structures and intelligent radio schedulers to edge computing, slicing, Software Defined Networking (SDN) and fully automated Orchestration capabilities. We will explain the most important technical solutions throughout this book in the chapters to follow (see also Section 1.6).

What are the concrete use cases that will drive the market? Nobody knows the answer today, but we can have a look at the industries that are forced into digital transformation by changes in their markets. There is an extensive list of possible use cases for various industry sectors where 5G may play a crucial role to interconnect people and things, to name only a few of them:

• Healthcare. Bioelectronic medicine, Personal health systems, telemedicine, connected ambulance including Augmented/Virtual Reality (AR/VR) applications.
• Manufacturing. Remote/motion control and monitoring of devices like robots, machine‐to‐machine communication, AR/VR in design (e.g. for designing machines, houses, etc.).
• Entertainment. Immersive experience, stadium experience, cooperative media production (e.g. production of songs, movies from various locations).
• Automotive. Platooning, infotainment, autonomous vehicles, high‐definition (HD) map updates, remote maintenance and SW updates.
• Energy. Grid control and monitoring, connecting windfarms, smart electric vehicle charging.
• Public transport. Infotainment, train/bus operations, platooning for buses.
• Agriculture. Connecting sensors and farming machines, drone control.
• Public Safety. Threat detection, facial recognition, drones.
• Fixed Wireless Access (FWA). Replacing fixed access technologies like fiber at the last mile by wireless access.
• Megacities. Applications around mission control for public safety, video surveillance, connected mobility across all means of transport including public parking and traffic steering, and environment/pollution monitoring.

Among the listed use cases motion control appears the most challenging and demanding one. Such a system is responsible for controlling, moving and rotating parts of machines in a well‐defined manner. Such a use case has very stringent requirements in terms of low latency, reliability, and determinism. Augmented Reality requires high data rates for transmitting (high‐definition) video streams from and to a device. Process automation is between the two, and focuses on monitoring and controlling chemical, biological or other processes in a plant, involving both a wide range of different sensors (e.g. for measuring temperatures, pressures, flows, etc.) and actuators (e.g. valves or heaters).

1.2 ITU‐R and IMT 2020 Vision

The International Telecommunication Union – Radio Sector (ITU‐R) manages the international radio‐frequency spectrum and satellite orbit resources. In September 2015 ITU‐R published its recommendation M.2083 [1] constituting a vision for the International Mobile Telecommunications (IMT) 2020 and beyond. In this document ITU‐R describes user and application trends, growth in traffic, technological trends and spectrum implications, and provides guidelines on the framework and the capabilities for IMT 2020. The following trends were identified, leading in a later phase to concrete requirements for the new 5G system defined by 3rd Generation Partnership Project (3GPP):

• Support for very low latency and high reliability communication;
• Support of high user density (in one area, one cell, etc.);
• Support of high accurate positioning methods;
• Support of the IoT;
• Support of high‐quality communication at high speeds; and
• Support of enhanced multimedia services and converged applications.

Regarding the growth of traffic rates, it was estimated (based on various available forecasts) that the global IMT traffic will grow in the range of 10–100 times from 2020 to 2030 with an increasing asymmetry between downlink (DL) and uplink (UL) data rates.

ITU‐R is not defining a new radio system itself but has listed some technology trends for both the radio and network side they deemed necessary to fulfill the new requirements and cope with new application trends and increased traffic rates. Technologies enhancing the radio interface capabilities mentioned in M.2083 are, e.g. new waveforms, modulation and coding techniques, as well as multiple access schemes. Spectrum efficiency enhancements and higher data rates can be achieved by techniques such as 3D‐beamforming, an active antenna system, and massive Multiple‐Input‐Multiple‐Output (mMIMO). Dual connectivity and dynamic Time Division Duplex (TDD) can enhance spectrum flexibility. On the network side features like SDN, Network Function Virtualization (NFV), Cloud Radio Access Network (C‐RAN) and Self‐Organizing Networks (SON) are mentioned.

One key item to allow for (much) higher data rates in future is the utilization of new spectrum, especially in higher frequency bands (above 6 GHz). ITU‐R Report M.2376 [2] provides information on the technical feasibility of IMT in the frequencies between 6 and 100 GHz. The report includes measurement data on propagation in this frequency range in several different environments. Both line‐of‐sight and non‐line‐of‐sight measurement results for stationary and mobile cases as well as outdoor‐to‐indoor results are included. Thus, ITU‐R Report M.2083 is highlighting the need for spectrum harmonization and contiguous and wider spectrum bandwidth (above 6 GHz).

ITU‐R is highlighting mainly three usage scenarios (rather use cases): enhanced mobile broadband (eMBB), ultra‐reliable and low latency communication (sometimes called critical‐machine type communication [cMTC]) and massive machine‐type communication (mMTC). These three usage scenarios are the fundamental basis of 5G system specification. Figure 1.2 gives an illustrative overview of the three usage scenarios and how they relate to each other.

When it comes to concrete capabilities for IMT 2020 and beyond, Report M.2083 lists the following eight key items:

• Peak data rate. Maximum achievable data rate under ideal conditions per user.
• User experienced data rate. Achievable data rate per user.
• Latency. The contribution by the radio network to the time from when the source sends a packet to when the destination receives it (in milliseconds [ms]).
• Mobility maximum speed at which a defined Quality of Service (QoS) and seamless transfer between radio nodes can be achieved (in km/h).
• Connection density. Total number of connected devices per unit area.
• Energy efficiency
• Spectrum efficiency. Average data throughput per unit of spectrum resource and per cell.
• Area traffic capacity. Total traffic throughput served per geographic area.

Enhanced user experience will be realized by increased peak and user data rate, spectrum efficiency, reduced latency and enhanced mobility support.

1.3 NGMN (Next Generation Mobile Networks)

The Next Generation Mobile Networks (NGMN) Alliance is a mobile telecommunications association of mobile operators, vendors, manufacturers and research institutes. It was founded by major mobile operators in 2006 as an open forum to evaluate candidate technologies to develop a common view of solutions for the evolution of wireless networks. NGMN aims to establish clear functionality and performance targets as well as fundamental requirements for deployment scenarios and network operations. In February 2015 NGMN published a 5G White Paper [3] that contains requirements regarding user experience, system performance, device capabilities, new business models and network operation and deployment. The NGMN White Paper starts with a short introduction on use cases, new business models and value creation in the era of 5G, and is listing afterwards detailed requirements from operator perspective on user experience (data rates, latency, mobility), system performance (connection and traffic density, spectrum efficiency), devices (multi‐band support, power and signaling efficiency), enhanced services (location, security, reliability), new business models (connectivity provider, XaaS, network sharing) and network deployment (cost and energy efficiency). New business models, technology and architecture options as well as spectrum and Intellectual Property Rights (IPR) aspects are also considered in the paper.

NGMN is categorizing 5G use cases in several sub‐sets, e.g. broadband access in urban areas or indoor, 50+ Mbps anywhere, mobile broadband in vehicles, massive low‐cost/long‐range/low‐power machine type communication, ultra‐low latency and high reliability, broadcast like services.

For each of these use case categories NGMN has listed requirements for the user experience. User specific data rates of 1 Gbps are mentioned for special environments, and 10 millisecond latency in general while 1 millisecond must be achievable for selected use cases. Detailed requirements can be found in Table 1.1.

Regarding overall system performance requirements, use case specific requirements for connection and traffic density are provided (see Table 1.2). In general, it is assumed that 5G allows for several hundred thousand simultaneous active connections per square kilometer and data rates of several tens of Mbps for tens of thousands of users in hotspot areas. 1 Gbps shall be offered simultaneously to some tens of users in the same limited area. Spectral efficiency should be significantly better compared to 4G. 5G should allow higher data rates to be achieved in rural areas based on the current grid of macro sites (depending on the frequency bands used).

Some general statements are made regarding expected device capabilities such as multi‐band/multi‐mode support (e.g. simultaneous support of TDD and Frequency Division Duplex [FDD] operation), support of LTE and 5G radio technology and the high degree of programmability of the device. However, this does not lead to concrete requirements for the device for modem manufacturers, but can be seen as high‐level recommendations. More or the less the same applies for statements on subscriber security, privacy and network security, e.g. going beyond radio security to also consider end‐to‐end and higher‐layer security solutions. With respect to network reliability and availability 5G should enable 99.999% network availability, including robustness against climatic events and guaranteed services at low energy consumption for critical infrastructures and high reliability rates of 99.999% or higher, for ultra‐high reliability and ultra‐low latency use cases. By design the 5G system should also allow for cost and energy efficient deployments and for enhanced flexibility and scalability, e.g. through decoupling Core and Radio Access Network (RAN) network domains (access agnostic core).

1.4 5GPPP (5G Public‐Private Partnership)

The 5G Public‐Private Partnership (5GPPP) is one of or even the world's biggest 5G research program. It is a joint initiative between the European Commission (EC) and the European Information and Communication Technology (ICT) industry and aims to deliver 5G solutions, architectures, technologies and standards. 5GPPP was initiated by the EU Commission and industry manufacturers, telecommunications operators, service providers, small and medium enterprises (SME) and research institutes.

Within the 5GPPP, the 5G Infrastructure Association (5GIA) represents the private side and the European Commission, the public side.

5GPPP is working on the document “5GPPP use cases and performance evaluation,” with version 1 published in April 2016, version 2 is work in progress. This is a living document, i.e. it is constantly updated. The document provides an overview of use cases and models. It covers 5G scenarios, definitions of key performance indicators (KPIs) and models (e.g. of wireless channel, traffic or user's mobility), as well as corresponding assessment results. Developed use case families are mapped to corresponding business cases identified in vertical industries. Additionally, performance evaluation approaches are compared with the latest version of performance evaluation framework proposed in 3GPP.

5GPPP work is grouped round the three well‐known 5G services extreme mobile broadband (xMBB), ultra‐reliable machine‐type communication (uMTC), and massive machine‐type communication (mMTC).

5GPPP defines the following KPI values for clustering the different use cases:

• Device density:
  1. ∘ High: ≥10 000 devices per km²
  2. ∘ Medium: 1000–10 000 devices per km²
  3. ∘ Low: <1000 devices per km²
• Mobility:
  1. ∘ No: static users
  2. ∘ Low: pedestrians (0–3 km h⁻¹)
  3. ∘ Medium: slow moving vehicles (3–50 km h⁻¹)
  4. ∘ High: fast moving vehicles, e.g. cars and trains (>50 km h⁻¹)
• Infrastructure:
  1. ∘ Limited: no infrastructure available or only macro cell coverage
  2. ∘ Medium density: Small number of small cells
  3. ∘ Highly available infrastructure: Large number of small cells available
• Traffic type:
  1. ∘ Continuous
  2. ∘ Bursty
  3. ∘ Event driven
  4. ∘ Periodic
  5. ∘ All types
• User data rate:
  1. ∘ Very high data rate: ≥1 Gbps
  2. ∘ High: 100 Mbps–1 Gbps
  3. ∘ Medium: 50–100 Mbps
  4. ∘ Low: <50 Mbps
• Latency:
  1. ∘ High: >50 milliseconds
  2. ∘ Medium: 10–50 milliseconds
  3. ∘ Low: 1–10 milliseconds
• Reliability:
  1. ∘ Low: <95%
  2. ∘ Medium: 95–99%
  3. ∘ High: >99%
• Availability (as related to coverage):
  1. ∘ Low: <95%
  2. ∘ Medium: 95–99%
  3. ∘ High: >99%
• 5G service type, comprising of:
  1. ∘ xMBB, where the mobile broadband is the key service requirement of the use case.
  2. ∘ uMTC, where the reliability is the key service requirement of the use case.
  3. ∘ mMTC, where the massive connectivity is the key service requirement of the use case.

In addition to these KPIs, localization and security requirements are important KPIs for vertical industries.

1.5 Requirements for Support of Known and New Services

5G use cases have been developed by a wide range of sources, including both the traditional telecommunications organizations such as Global System for Mobile Communications Association (GSMA), NGMN, and ITU, and the vertical industries such as automobile, gaming, and factory automation, that are considering how 5G can benefit them. In addition to the ITU‐R, NGMN and 5GPPP use cases already discussed in this chapter, several other standards and industry organizations have provided significant input to the 5G vision being developed in 3GPP. These include the China IMT 2020 Promotion Group, the German Electrical and Electronic Manufacturers Association, the METIS project, the ARIB 2020 and Beyond Ad Hoc Group. The 5G for Connected Industries and Automation (5G‐ACIA) and the 5G Automotive Association (5GAA) are focusing on 5G use cases and their requirements from the perspective of specific verticals. 5G‐ACIA serves as the central forum for addressing, discussing, and evaluating relevant technical, regulatory, and business aspects with respect to 5G for the industrial domain (see [4]). 5GAA on the other hand is considering requirements, architectures and solutions enabling 5G to become the ultimate platform for Cooperative Intelligent Transportation Systems (C‐ITS) and the provision of Vehicle‐to‐X (V2X) services. 5G will be able to better carry mission‐critical communications for safer driving and further support enhanced V2X communications and connected mobility solutions. Several white papers can be found at the 5GAA Internet page www.5gaa.org.

In general, 5G use cases can be grouped into five main categories (for details see [5]): massive IoT, time critical communication, eMBB, network operations, and enhanced V2X, as shown in Figure 1.3.

1.6 5G Use Cases

While we have already mentioned briefly some 5G use cases in Section 1.1 we will go into more detail in this chapter and explain use cases and the underlying business models (for more information see [8]). Different use cases require different technological solutions, e.g. enabling high throughput at high speeds, ultra‐low latency and extreme high reliability. Although some of the use cases can also be covered by LTE today, future use cases requiring extreme data throughput (e.g. 8K video) or low latency and high reliability (e.g. some industry applications and AR/VR applications) and a combination of these, can only be fulfilled by 5G. And 5G is promising to be the future‐proof technology for many or even all use cases we can think of today and the ones coming.

5G will most likely bring first benefits for MNOs and their customers in the following into three areas:

• 5G immersive and interactive experience. 5G will create life‐changing experiences for consumers in their homes and on public and private transportation systems.
• 5G live experience. 5G will provide new experiences for people attending large events and meet very high demand at traffic hot spots.
• 5G industry experience. 5G can become the communications standard of the fourth industrial revolution.

1.6.1 5G to the Home

Consumers living in households without fiber access can benefit from 5G bringing fiber‐like speeds to their houses, they can join the ultra‐broadband party including the world of Virtual and Augmented Reality.

5G presents an opportunity for MNOs to offer massive broadband access to homes in areas where conventional fiber‐to‐the‐home is difficult or expensive to deploy (“5G for the last mile”). Avoiding the need for time‐consuming and high‐cost civil works to lay fiber, 5G delivers faster time to market and opens the home broadband market by enabling new entrants to compete against fixed line operator.

Analysis have shown that solutions using mmWave spectrum beyond 6 GHz (e.g. 28 GHz) allow each base station to serve tens of households. The 5G short‐range FWA is expected to sustain 1 Gbps per household in the downlink (DL). To achieve such a high speed and longer ranges for 5G fixed wireless service, for example beyond urban and more densely packed suburban markets as well as rural applications, cmWave and mmWave radio technology must support large bandwidths and Multiple Input Multiple Output (MIMO) antenna beam forming techniques (see Figure 1.4).

The business modeling is based on an addressable market of, e.g. 100 000 households with 6% served by fiber and a MNO market share of 35% with a 30% take rate for the service. The discounted cash flow (year on year) is yielded by the difference between the MNO costs (capital and operational expenses) and revenue (present value of the money) from connected households (domestic units, people who live together along with non‐relatives). With these assumptions in mind, the analysis shows that the MNO business case mostly depends on the number of households served per site, the site capital expenditure and the ARPU. Simulation results for period ranging from 2019 to 2028 show that the business case appears quite sensitive to ARPU, which needs to be kept above 40 Euros (premium) and number of households per site, which should be at least 30 for a positive business case, under the above assumptions. The price erosion is insignificant, hence the sooner the service is launched, the better it is for a successful business. It should be noted that this business case is also considered by some MSOs (i.e. cable operators) for two main reasons: One reason is to leverage 5G for the last mile where fiber is not deployed yet. Another reason is to position cable technology as a backhaul for 5G.

1.6.2 In‐Vehicle Infotainment

Public transport users with ultra‐broadband connectivity can make more of their time. Watching streamed high‐definition augmented reality or conducting business meetings via video calling, many passengers will welcome new experiences on the move enabled by 5G.

5G will enable MNOs to win revenue by delivering information and entertainment services to traveling subscribers, particularly in dense urban areas as depicted in Figure 1.5. Such services will include high‐quality video streaming, augmented and virtual reality applications, online gaming and video calling. The network must be able to deliver services consistently across the area and with superior performance simultaneously to many users on public transport, traveling at relatively high speed.

High performance services could also be provided for users of non‐5G devices by transmitting 5G to a vehicle and distributing bandwidth via Wi‐Fi, for example on a train or bus. This gives an MNO the chance to use early 5G deployments to win new revenue ahead of the widespread availability of 5G devices.

Analysis of a use case for infotainment services on public transport as part of a 5G deployment across a dense city center area using 3.5, 3.7, and 25 GHz bands have shown that meeting the predicted rise in mobile and video traffic demand, cell capacity needs to be increased from 1 Gbps in LTE to 10 Gbps downlink and 3 Gbps uplink peak, with more users being supported by each cell. In addition, 5G ultra‐low latency performance will be needed to support virtual reality, gaming and other delay‐sensitive applications.

The MNO could win revenue from high value passengers and from governments for supplying 5G bandwidth to public transport. Charging could be per trip for public transport, per time or per data volume.

Assuming that 5G ARPU increases in an analogous way as for LTE, the business analysis for the city center area shows that an MNO could achieve several hundred million Euros of additional Net Present Value (NPV) over 10 years.

1.6.4 Truck Platooning

In many countries, roads are clogged with traffic, creating jams that are a frustrating the drivers. Truck platooning in which several trucks travel in a tightly‐knit, automatically‐controlled convoy behind a lead human‐driven vehicle, promises not only to reduce congestion and lower fuel consumption, but also to cut transport costs for logistics companies.

While the concept of truck platoons as a means of cutting operating costs and reducing road congestion has been around for many years, the advent of 5G looks to be finally bringing the idea to reality. Safe platooning depends critically on 5G's ultra‐low latency and high reliability capabilities.

Small platoons are possible using LTE and Multi‐access Edge Computing (MEC), however longer platoons are more cost‐effective and require 5G (see Figure 1.6). Platooning will also become an integral part of the future of connected vehicles enabled by 5G, including infotainment, telematics and assisted driving. Ultimately, this will lead to autonomous driving.

Truck platooning should prove attractive to logistics companies by reducing their staff costs, fuel use and supporting more efficient use of the truck fleet. MNOs are also likely to partner with vehicle makers to provide an end‐to‐end solution.

Assuming average truck fuel consumption data and delivery distance statistics, considering fuel savings of 4% for a lead truck and 10% for following trucks a business case analysis has shown that an MNO could reach breakeven on its 5G investments in six years if it received a 12.5% share of the logistics company's cost savings.

It has been forecast that more than 7 million truck platooning systems could be shipped by 2025. With hundreds of private transportation companies running more than 100 trucks in their fleet, the overall revenue opportunity for an MNO could be immense.

1.6.6 Industry 4.0

As part of the so‐called fourth Industrial Revolution, smart (digital) factories (see Figure 1.7) will deploy greater automation, interconnecting all their areas and activities to vastly improve productivity, increase staff safety and become far more flexible to meet rapidly evolving market needs.

One of the most important enablers of the smart factory of the future will be vastly increased connectivity that will link machines, processes, robots and people to create more flexible and more dynamic production capabilities. About 90% of industrial connectivity today uses wired connections which provide the high performance and reliability needed for automation, but lack flexibility to be able to rapidly meet changing production demands.

5G is the first wireless technology with high throughput, low latency and extreme reliability that can replace wireline connectivity in the factory. Wireless connectivity allows additional machines to be connected by simply equipping them with wireless sensors and actuators and if required, scaling the network capacity to handle new traffic.

In factories 5G wireless connectivity has up to five times lower costs than wired connectivity. Wireless 5G connectivity can replace wired systems in an existing facility with a short payback period.

Functional safety is one of the most crucial aspects in the operation of industrial sites like factories (see also [4]). Accidents can harm people, machines and the environment. Safety measures must be applied to reduce risks to an acceptable level, particularly if the severity and likelihood of hazards are high. Like an industrial control system, the safety system also conveys specific information from and to the equipment under control. Thus, a 5G network used at industrial sites must be able to transport safety messages between entities in a fast, secure, and reliable manner. In addition, current industrial communication systems are often isolated from the Internet and not exposed to attacks from outside. This will change with wirelessly connected industry applications. Therefore, extreme high security measures must be applied to the used wireless technologies and the overall network architecture avoiding attacks from inside and outside.

1.7 Business Models

With the introduction of 5G the traditionalbusiness model with the MNO as a pure connectivity provider offering voice and short message services is outdated. In fact, one of the biggest changes for the telco industry coming with 5G is most probably the change from this simple business model to new business models where the mobile operator provides not only pure connectivity plus voice but also highly sophisticated services such as Infrastructure‐as‐a‐Service (IaaS). Network‐as‐a‐Service (NaaS), Platform‐as‐a‐Service (PaaS) to third parties, e.g. verticals, small/medium/large enterprises or tenants. These new models allow verticals to build their networks upon the mobile operator's infrastructure, optimized for their specific use cases. Consequently, many new players may be part of this game. In the past, it was mainly the MNO and the end consumer (individual people or enterprises). In future however, it is the MNO, various verticals, site (e.g. stadium or factory) owners, content owners, enterprises and their IT departments, authorities like public safety agencies, end consumers like “normal” smartphone users but also high‐end gamers. Partnerships need to be established on multiple levels ranging from sharing the infrastructure, to exposing specific network capabilities as an end to end service, and to integrating partner services into the 5G system.

The NGMN white paper [3] differentiates three roles of parties engaged in the 5G game.

1.8 Deployment Strategies

3GPP has defined different deployment options as to how 5G can be introduced into existing LTE networks (see [9]). We differentiate mainly between so‐called non‐standalone (NSA) and standalone (SA) deployment solutions. In the GSMA White Paper [10] these deployment options and their pros and cons are extensively discussed including support of voice via NSA and SA. For more information on this topic see also Chapter 4.

With an NSA solution one radio technology (5G or LTE) is “anchored” at the other one (LTE or 5G) by using a dual‐connectivity mechanism. Only the master base station, the anchor point, maintains a signaling connection to the core network (either S1‐C to Evolved Packet Core (EPC) or N2 to 5GC). The signaling connection state in the device, Radio Resource Control (RRC) state, is based on the RRC state of the master base station. In addition to the master, data can be received and transmitted from/to the device or the core network via the secondary (or slave) base station. The secondary base station can also decide to establish a signaling connection to the device, which is used to send reconfiguration messages and measurement reports. There is always a signaling connection between master and secondary node enabling the master to manage data radio bearers at the secondary base station. In a standalone deployment option, the 5G or enhanced LTE base station is directly connected to the 5G Core and maintains a signaling connection with the mobile device and the 5G Core. The NSA options 3, 4, and 7, as well as standalone options 2 and 5 with the 5G base station respectively the enhanced LTE base station directly connected to the new 5G Core are shown in Figure 1.8. Note that options 3, 4, and 7 have different flavors, depending on whether there exists a user plane path between LTE and 5G base station, respectively between secondary base station and core network. We focus on options 3X and 7X as these provide several benefits compared to other flavors of options 3 and 7 (e.g. less signaling between radio and core in case of mobility events). In NSA option 4 and its flavor 4a master and secondary roles are exchanged compared to options 3 and 7, i.e. 5G base station is now the master and LTE base station serves as secondary. Therefore, option 4 works well only if 5G radio can provide sufficient coverage to maintain a connection to the devices. In option 4, there is a user plane path between the two base stations, while in option 4a user plane path is directly between core network and each base station. Introducing NSA or SA deployment options with a new 5G Core requires interworking between existing EPC and new 5GC. Native interworking between 5G and legacy technologies such as 2G and 3G is not foreseen.

The solid lines indicate data paths (user plane) between two nodes while dotted lines indicate signaling connections (control plane).

Obviously, introducing 5G with NSA option 3X based on the existing LTE/EPC network deployment is the fastest and easiest way to provide 5G services such as low latency data connections and high user throughput to the end consumer. Option 3X requires only minor changes to the existing EPC (e.g. in Mobility Management Entity [MME] and HSS), it allows aggregation data rates on LTE and 5G and can leverage features like VoLTE already implemented in LTE. LTE provides wide area coverage, while 5G can boost the throughput in certain (limited) areas. In addition, 3GPP has accelerated option 3X, thus option 3X standard was completed several months earlier than option 2 and implementations can also start earlier. Option 3X requires an upgrade on the LTE base station to act as master for 5G, but this is mainly a SW upgrade at the sites where 5G is introduced, e.g. first in hot spot and urban areas where more capacity per user and cell is needed. However, it is not required that 5G and LTE base stations are deployed at the same site.

Most operators worldwide have decided to start their 5G deployment with one of the NSA option 3 versions and potentially evolve later to NSA option 7 (i.e. evolve EPC to 5GC and upgrade LTE to connect to 5GC and EPC in parallel) and/or to standalone option 2. NSA option 3 with EPC, NSA option 7 and standalone option 2 with 5GC are expected to co‐exist for some time, together with the existing legacy LTE/EPC network (and potentially 2G/3G General Packet Radio System [GPRS] networks). In the long term, it is expected that operators migrate toward one of the options 2, 4, 5, 7 with 5G Core, so that they can smoothly shut down the EPC.

With standalone option 2 and other options with 5G Core, the operator can offer new 5G end‐to‐end services such as Network Slicing, Edge Computing, Ultra Reliable and Low Latency Communication (URLLC) services, lower latency without use of LTE, lower setup times and there is no need for LTE network upgrades. Also, operators can leverage cloud native enablers for improving availability and reliability of their Network Functions. One issue with options 2 and 4 is limited coverage of early deployments especially in high bands. This could lead to frequent handover events between 5G and LTE or requires use of a 5G coverage layer in low bands (e.g. below 1 GHz). Only few operators will start with standalone option 2 from the very beginning due to bigger investment costs.

1.9 3GPP Role and Timelines

In the context of 5G, the most important Standards Developing Organization (SDO), which is creating the 5G standards for the radio and system architecture, is the 3rd Generation Partnership Project 3GPP. 3GPP is a joint international standardization initiative between North American (Alliance for Telecommunications Industry Solutions [ATIS]), European (European Telecommunications Standards Institute [ETSI]) and Asian organizations (Telecommunications Standards Development Society India [TSDSI] in India, Association of Radio Industries and Businesses [ARIB] and Telecommunication Technology Committee [TTC] in Japan, Telecommunications Technology Association [TTA] in Korea and China Communication Standards Association [CCSA] in China) that was originally established in December 1998. The participating organizations are also called organizational partners. The scope of 3GPP was to specify a new worldwide mobile radio system. Global System for Mobile Communications (GSM) was a European initiative, while Code Division Multiple Access (CDMA) was initiated in North America, and these are not compatible with each other. The new system would be based on the evolved GSM techniques GPRS/Enhanced Data Rates for Global System for Mobile communications Evolution (EDGE). This activity has led to the standardization of the third generation (3G) Universal Mobile Telecommunications System (UMTS), which consists of WCDMA as radio technology and a core network supporting both circuit‐based voice calls and packet‐based data services. UMTS was meant as a universal standard that allows subscribers to use their UMTS capable mobile phones and subscriptions worldwide through roaming agreements between mobile operators. UMTS is a considerable success story.

But 3GPP did not stop work after UMTS; in the years that followed enhancements of UMTS like High Speed Packet Access [HSPA/HSPA+], new services like Multicast/Broadcast delivery, Location services and the Internet Protocol Multimedia Subsystem (IMS) were introduced. As a next step, LTE with a new Orthogonal Frequency‐Division Multiplexing (OFDM) based radio technology and an All‐IP core network architecture was developed to simplify the overall network architecture leading to increased operational efficiency and to cope with the rising demands on data throughput caused by new smartphone and tablet generations. The latest step in this evolution story is the development of the 5th Generation (5G) system comprising of a new radio and new core network that can fulfill the requirements on higher bandwidth and reliability, lower latency, increased operational efficiency and much higher network densification. 5G allows a wide variety of new use cases in the industrial (“digitization of industries or Industry 4.0”), enterprise and consumer market to be addressed.

3GPP is organized in different working groups (see Figure 1.9) that are responsible for various parts of the 3GPP system. The RAN groups define the radio parts of the GERAN/UMTS/LTE/5G system, the physical layer and radio protocols. The System Architecture (SA) and Core/Terminal (CT) groups specify all parts of the overall system (e.g. architecture, security, charging) and all other protocols (between the mobile device and network, within the network and between networks).

3GPP follows a phased approach; working output is delivered as a set of Technical Specifications (TS) in so‐called System Releases. Technical Specifications contain normative requirements that must be implemented by chipset, device and network equipment vendors. Interim results of ongoing work in 3GPP are usually captured in non‐normative Technical Reports (TR). Test specifications are also created by 3GPP (mainly test cases for UE to network communication). It must be noted that 3GPP defines only functions and protocols, how these functions are implemented in concrete network nodes or whether some functions are implemented in the same node is up to the network vendor. One basic design principle in 3GPP's standardization process is backward compatibility of new features with existing ones. This ensures that new features can be introduced in one network without the need to upgrade all inter‐connected networks or all other nodes within this network at the same time. Also, it ensures that the upgraded network can provide services to legacy devices that are not upgraded yet.

Table 1.9 provides a brief overview of the official release dates and milestones of the 3GPP releases up to Release 16.

Figure 1.10 illustrates the given 5G timeline in 3GPP for completing the different 5G options. Options 3 and 2 are first to be specified by 3GPP, followed by options 4 and 7 completion in a late drop beginning of 2019. Option 5 (LTE base station connected to 5G Core) is completed by Q3 2018. Abstract Syntax Notation No. 1 (ASN.1) freeze follows usually three months after specifying the architecture and interfaces.

For more information on the history and structure of 3GPP, visit the official 3GPP site at http://www.3gpp.org/about‐3gpp/about‐3gpp.

References

All 3GPP specifications can be found under http://www.3gpp.org/ftp/Specs/latest. The acronym “TS” stands for Technical Specification, “TR” for Technical Report.

1. 1 ITU‐R M.2083‐0: “IMT Vision – Framework and overall objectives of the future development of IMT for 2020 and beyond” (see https://www.itu.int/rec/R‐REC‐M.2083‐0‐201509‐I/en), 2015.
2. 2 ITU‐R M.2376‐0: “Technical feasibility of IMT in bands above 6 GHz” (see https://www.itu.int/pub/R‐REP‐M.2376), 2015.
3. 3 NGMN Alliance: “5G White Paper” (see https://www.ngmn.org), 2015.
4. 4 5GACIA: “5G for Connected Industries and Automation White Paper” (see https://www.5g‐acia.org), 2018.
5. 5 3GPP TR 22.891: “Feasibility Study on New Services and Markets Technology Enablers”, 2016.
6. 6 3GPP TR 22.261: “Service requirements for the 5G system”, 2018.
7. 7 3GPP TR 22.186: “Enhancement of 3GPP support for V2X scenarios”, 2017.
8. 8 Nokia White Paper: “Translating 5G use cases into viable business cases” (see https://networks.nokia.com/innovation/5g‐use‐cases/home), 2017.
9. 9 3GPP TR 23.799: “Study on Architecture for Next Generation System”, 2016.
10. 10 GSMA White Paper: “Road to 5G: Introduction and Migration, April 2018” (see https://www.gsma.com/futurenetworks/5g/road‐to‐5g‐introduction‐and‐migration‐whitepaper), 2018.