TECHNOLOGY AND CAPABILITIES

To enable connectivity for a wide range of new applications and use cases, the capabilities of

5G wireless access must extend far beyond previous generations of mobile communication.

Examples of these capabilities include very high achievable data rates, very low latency,

ultra-high reliability, and the possibility to handle extreme device densities, and will be realized

by the continued development of LTE in combination with new radio-access technologies. Key

technology components include extension to higher frequency bands, advanced multi-antenna

transmission, lean design, user/control separation, flexible spectrum usage, complementary

device-to-device communication, and backhaul/access integration.

ericsson White paperUen 284 23-3204 Rev B | February 2015

5G radio access

5G RADIO ACCESS • WHAT IS 5G? 2

What is 5G?5G is the next step in the evolution of mobile communication. It will be a key component of the

Networked Society and will help realize the vision of essentially unlimited access to information

and sharing of data anywhere and anytime for anyone and anything. 5G will therefore not only

be about mobile connectivity for people. Rather, the aim of 5G is to provide ubiquitous connectivity

for any kind of device and any kind of application that may benefit from being connected.

Mobile broadband will continue to be important and will drive the need for higher system

capacity and higher data rates. But 5G will also provide wireless connectivity for a wide range

of new applications and use cases, including wearables, smart homes, traffic safety/control, and

critical infrastructure and industry applications, as well as for very-high-speed media delivery.

In contrast to earlier generations, 5G wireless access should not be seen as a specific radio-

access technology. Rather, it is an overall wireless-access solution addressing the demands and

requirements of mobile communication beyond 2020.

LTE will continue to develop in a backwards-compatible way and will be an important part of

the 5G wireless-access solution for frequency bands below 6GHz. Around 2020, there will be

massive deployments of LTE providing services to an enormous number of devices in these

bands. For operators with limited spectrum resources, the possibility to introduce 5G capabilities

in a backwards-compatible way, thereby allowing legacy devices to continue to be served on

the same carrier, is highly beneficial and, in some cases, even vital.

In parallel, new radio-access technology (RAT) without backwards-compatibility requirements

will emerge, at least initially targeting new spectrum for which backwards compatibility is not

relevant. In the longer-term perspective, the new non-backwards-compatible technology may

also migrate into existing spectrum.

Although the overall 5G wireless-access solution will consist of different components, including

the evolution of LTE as well as new technology, the different components should be highly

integrated with the possibility for tight interworking between them. This includes dual-connectivity

between LTE operating on lower frequencies and new technology on higher frequencies. It should

also include the possibility for user-plane aggregation, that is, joint delivery of data via both LTE

and a new RAT.

Figure 1: The overall 5G wireless-access solution consisting of LTE evolution and new technology.

3GHz1GHz 10GHz 30GHz 100GHz 3GHz1GHz 10GHz 30GHz 100GHz

Overall 5G solution

LTE evolution New technologyBackwards compatible

Existing spectrum

Below 6GHz Above 6GHzNew spectrum below 6GHz

New spectrumGradual migration

into existing spectrum

Interworking

In order to enable connectivity for a very wide range of applications with vastly different

characteristics and requirements, the capabilities of 5G wireless access must extend far beyond

those of previous generations of mobile communication.

MASSIVE SYSTEM CAPACITY

Traffic demands for mobile-communication systems are predicted to increase dramatically [1]

[2]. To support such traffic in an affordable way, 5G networks must be able to deliver data with

much lower cost per bit compared with the networks of today. Furthermore, in order to be able

to operate with the same or preferably even lower overall energy consumption compared with

today, 5G must enable radically lower energy consumption per delivered bit.

Another aspect of 5G system capacity is the capability to support a much larger number of

devices compared with today. The new use cases envisioned for 5G include, for example, the

deployment of billions of wirelessly connected sensors, actuators and similar devices. Each

device will typically be associated with very little traffic, implying that, even jointly, they will have

a limited impact on the overall traffic volume. However, the sheer number of devices to be

connected provides a challenge, for example, in terms of efficient signaling protocols.

VERY HIGH DATA RATES EVERYWHERE

Every generation of mobile communication has been associated with higher data rates compared

with the previous generation. In the past, much focus has been on the peak data rate that can

be supported by a wireless-access technology under ideal conditions. However, a much more

important capability is the data rate that can actually be provided under real-life conditions in

different scenarios.

> 5G should be able to provide data rates exceeding 10Gbps in specific scenarios such as

indoor and dense outdoor environments.

> Data rates of several 100Mbps should be generally achievable in urban and suburban

environments.

> Data rates of at least 10Mbps should be achievable essentially everywhere, including sparsely-

populated rural areas in both developed and developing countries.

VERY LOW LATENCY

Lower latency has been a key target for both 4G and the evolution of 3G, driven mainly by the

continuous quest for higher achievable data rates. Due to properties of the internet protocols,

lower latency over the wireless interface is critical to realize the higher data rates. 5G targets

even higher data rates, and this in itself will drive a need for even lower latency.

However, lower latency will also be driven by the support for new applications. Some of the

envisioned 5G applications, such as traffic safety and control of critical infrastructure and industry

processes, may require much lower latency compared with what is possible with the mobile-

communication systems of today. To support such latency-critical applications, 5G should allow

for an application end-to-end latency of 1ms or less.

ULTRA-HIGH RELIABILITY AND AVAILABILITY

In addition to very low latency, 5G should also enable connectivity with ultra-high reliability and

ultra-high availability. For critical services, such as control of critical infrastructure and traffic

safety, connectivity with certain characteristics, such as a specific maximum latency, should not

only be ‘typically available.’ Rather, connectivity with the required characteristics has to be always

available with essentially no deviation.

5G RADIO ACCESS • 5G – REQUIREMENTS AND CAPABILITIES 3

5G – requirements and capabilities

5G RADIO ACCESS • 5G – REQUIREMENTS AND CAPABILITIES 4

VERY LOW DEVICE COST AND ENERGY CONSUMPTION

The possibility for low cost and low energy consumption for mobile devices has been a key

requirement since the early days of mobile communication. However, in order to enable the vision

of billions of wirelessly connected sensors, actuators and similar devices, a further step has to

be taken in terms of device cost and energy consumption. It should be possible for such 5G

devices to be available at very low cost and with a battery life of several years without recharging.

HIGH NETWORK ENERGY PERFORMANCE

While device energy consumption has always been prioritized, high energy performance on the

network side has more recently emerged as a KPI.

> High network energy performance is an important component in reducing operational cost,

as well as a driver for better dimensioned nodes, leading to lower total cost of ownership.

> High network energy performance allows for off-grid network deployments relying on decently

sized solar panels as power supply, thereby enabling wireless connectivity to even the most

remote areas.

> High network energy performance is part of a general operator aim of providing wireless

access in a sustainable and more resource-efficient way.

The importance of these factors will increase further in the 5G era, and the possibility of very

high network energy performance will therefore be an important requirement in the design of 5G

wireless access.

5G RADIO ACCESS • MACHINE-TYPE COMMUNICATION 5

Machine-type communicationApplications such as mobile telephony, mobile broadband, and media delivery are, fundamentally,

about information for humans. In contrast, many of the new applications and use cases that

drive the requirements and capabilities of 5G are about end-to-end communication between

devices. In order to distinguish them from the more human-centric wireless-communication use

cases, these applications are often labeled machine-type communication (MTC).

Although spanning a wide range of different applications, MTC applications can be divided

into two main categories, massive MTC and critical MTC, depending on their characteristics and

requirements (see Figure 2).

Massive MTC corresponds to applications that typically span a very large number of devices,

such as different types of sensors, actuators, and similar devices. These typically have to be of

very low cost and have very low energy consumption, enabling very long battery life. At the same

time, the amount of data generated by each device is normally very small, and very low latency

is not a critical requirement.

Instead of providing direct mobile-network connectivity for all MTC devices, connectivity may

alternatively be provided by means of capillary networks. In a capillary network, local connectivity

is provided by means of some short-range RAT, for example Wi-Fi, Bluetooth [3] or

802.15.4/6LowPAN [4]. Wireless connectivity beyond the local area is then provided by the mobile

network via a gateway node.

Critical MTC corresponds to applications such as traffic safety/control, control of critical

infrastructure and wireless connectivity for industrial processes. Such applications require very

high reliability and availability of the wireless connectivity. Furthermore, they may often be

associated with requirements for very low latency. On the other hand, low device cost and energy

consumption is not as critical as for massive MTC applications.

There is a lot to gain from being able to provide as many different applications as possible,

including mobile broadband, media delivery and a wide range of different MTC applications by

means of the same basic wireless-access technology and within the same spectrum. This avoids

spectrum fragmentation and allows operators to offer support for new MTC services for which

the business potential is inherently uncertain without having to deploy a separate network and

reassign spectrum specifically for these applications.

Scalable and flexible access• Scalable and flexible bandwidths• Scalable and flexible signaling protocols• …

Capillary networks• Short-range radio + cellular

Very short transmission times

Contention-based access andfast channel assignments

Multi-level diversity

Device-to-devicecommunication...

Massive number of devicesLow device costLong battery lifeSmall data volumes

Massive MTC Critical MTCUltra-reliable

Very high availabilityVery low latency

Figure 2: Massive MTC and critical MTC.

5G RADIO ACCESS • SPECTRUM FOR 5G 6

Spectrum for 5GIn order to further extend traffic capacity and to enable the transmission bandwidths needed to

support very high data rates, 5G will extend the range of frequencies used for mobile

communication. This includes new spectrum below 6GHz, expected to be allocated for mobile

communication at the World Radio Conference (WRC) 2015, as well as spectrum in higher

frequency bands, expected to be on the agenda for WRC 2019.

It is still unclear what spectrum in higher frequency bands will be made available for mobile

communication, and the entire frequency range up to approximately 100GHz is considered at

this stage. The lower part of this frequency range, below 30GHz, is preferred from the point of

view of propagation properties. At the same time, very large amounts of spectrum and the

possibility of very wide transmission bandwidths, in the order of 1GHz or even more, will only

be available in frequency bands above 30GHz.

Thus, spectrum relevant for 5G wireless access ranges from below 1GHz up to in the order of

100GHz, as Figure 3 shows.

It is important to understand that high frequencies, especially those above 10GHz, can only

serve as a complement, providing additional system capacity and very wide transmission

bandwidths for extreme data rates in dense deployments. Lower frequencies will remain the

backbone for mobile-communication networks in the 5G era, providing ubiquitous wide-area

connectivity.

Spectrum range relevant for 5G wireless access

3GHz1GHz 10GHz 30GHz 100GHz

Figure 3: Spectrum relevant for 5G wireless access.

5G RADIO ACCESS • 5G TECHNOLOGY COMPONENTS 7

5G technology componentsBeyond extending operation to higher frequencies, there are several other key technology

components relevant for the evolution to 5G wireless access.

MULTI-ANTENNA TRANSMISSION

Multi-antenna transmission already plays an important role for current generations of mobile

communication and will play an even more important role in the 5G era. Especially for operation

at higher frequencies, the use of multiple antennas for beam-forming at the transmitter and/or

receiver site is a critical component to counter the worse propagation conditions at higher

frequencies. However, beam-forming will also be an important component for lower frequencies;

for example, to further extend coverage and to provide higher data rates in sparse deployments.

ULTRA-LEAN DESIGN

Ultra-lean radio-access design is important to achieve high efficiency in future wireless-access

networks. The basic principle of ultra-lean design can be expressed as: minimize any transmissions

not directly related to the delivery of user data.

Such transmissions include signals for synchronization, network acquisition and channel

estimation, as well as the broadcast of different types of system and control information.

Ultra-lean design is especially important for dense deployments with a large number of network

nodes and highly variable traffic conditions. However, lean transmission is beneficial for all kinds

of deployments, including macro deployments.

By enabling network nodes to rapidly enter low-energy states when there is no user-data

transmission, ultra-lean design is an important component for high network energy performance.

Ultra-lean design will also enable higher achievable data rates by reducing interference from

non-user-data-related transmissions.

USER/CONTROL SEPARATION

Another important design principle for future wireless access is to decouple user data and system

control functionality. The latter, for example, includes the provision of system information; that

is, the information as well as the procedures needed for a device to access the system.

Such a decoupling will allow separate scaling of user-plane capacity and basic system control

functionality. For example, user data may be delivered by a dense layer of access nodes, while

system information is only provided via an overlaid macro layer, a layer on which a device also

initially accesses the system.

The separation of user data delivery and system control functionality should be possible to

extend over multiple frequency bands and RATs. As an example, the system control functionality

for a dense layer based on new high-frequency radio access could be provided by means of an

overlaid LTE layer.

User/control separation is also an important component for future radio-access deployments

relying heavily on beam-forming for user data delivery. Combining ultra-lean design with a logical

separation of user-plane data delivery and basic system connectivity functionality will enable a

much higher degree of device-centric network optimization of the active radio links in the network.

Since only the ultra-lean signals related to the system control plane need to be static, it is possible

to design a system where almost everything can be dynamically optimized in real time.

An ultra-lean design combined with a system control plane logically separated from the user data

delivery function also provides higher flexibility in terms of evolution of the RAT as, with such separation,

the user plane can evolve while retaining the system control functionality.

FLEXIBLE SPECTRUM USAGE

Since its inception, mobile communication has relied on spectrum licensed on a per-operator

basis within a geographical area. This will remain the foundation for mobile communication in

85G RADIO ACCESS • 5G TECHNOLOGY COMPONENTS

the 5G era, allowing operators to provide high-quality connectivity in a controlled-interference

environment. However, per-operator licensing of spectrum will be complemented with the

possibility to operate under other spectrum regimes. This may include sharing of spectrum

between a limited set of operators, as well as operation in unlicensed spectrum.

Deviating from conventional per-operator spectrum licensing will mainly be relevant in frequency

bands above 10GHz.

In high-frequency bands, the focus will be on very wide transmission bandwidths. It may be

difficult to find sufficiently large spectrum blocks to allow for per-operator-dedicated spectrum

supporting such bandwidths for multiple operators.

Furthermore, high-frequency bands will typically be used for very dense deployments for which

one can expect much more dynamic traffic variations. Statically dividing the spectrum between

different operators may, in such situations, not necessarily lead to the most efficient spectrum

usage. Rather, making it possible for operators to jointly access at least part of the spectrum in

a dynamic way could, potentially, lead to more efficient overall spectrum utilization.

FLEXIBLE DUPLEX

FDD has been the dominating duplex arrangement since the beginning of the mobile

communication era.

For lower frequency bands, FDD will remain the main duplex scheme in the 5G era. However,

for higher frequency bands, especially above 10GHz, targeting very dense deployments, TDD

will play a more important role.

In very dense deployments with low-power nodes, the TDD-specific interference scenarios

(direct base-station-to-base-station and device-to-device interference) will be more similar

to the ‘normal’ base-station-to-device and device-to-base-station interference that also

occurs for FDD.

Furthermore, for the dynamic traffic variations expected in very dense deployments, the ability

to dynamically assign transmission resources (time slots) to different transmission directions

may allow more efficient utilization of the available spectrum.

Therefore, to reach its full potential, 5G should allow for very flexible and dynamic assignment

of the TDD transmission resources. This is in contrast to current TDD-based mobile technologies,

including TD-LTE, for which there are restrictions on the downlink/uplink configurations, and for

which there typically exist assumptions about the same configuration for neighbor cells and also

between neighbor operators.

DIRECT DEVICE-TO-DEVICE COMMUNICATION

The possibility for limited direct device-to-device (D2D) communication has recently been

introduced as an extension to the LTE specifications.

In the 5G era, support for D2D as part of the overall wireless-access solution should be considered

from the start. This includes peer-to-peer user-data communication directly between devices but

also, for example, the use of mobile devices as relays to extend network coverage.

D2D communication in the context of 5G should be an integral part of the overall wireless-access

solution rather than a stand-alone solution. The possibility for direct D2D communication should

extend the capabilities and enhance the overall efficiency of the wireless-access network. Furthermore,

in order to avoid uncontrolled interference to other links, direct D2D communication should be under

network control. This is especially important for the case of D2D communication in licensed spectrum.

ACCESS/BACKHAUL INTEGRATION

Wireless technology is already frequently used as part of the backhaul solution. Such wireless-backhaul

solutions then typically operate under line-of-sight conditions using proprietary radio technology in

higher frequency bands, including the millimeter wave (mmW) band.

In the future, the access (base-station-to-device) link will also extend to higher frequencies.

Furthermore, to support dense low-power deployments, wireless backhaul will have to extend to

cover non-line-of-sight conditions, similar to access links.

In the 5G era, the wireless-access link and wireless backhaul should therefore not be seen as two

separate entities with separate technical solutions. Rather, backhaul and access should be seen as

an integrated wireless-access solution able to use the same basic technology and operate using a

common spectrum pool. This will lead to more efficient overall spectrum utilization as well as reduced

operation and management effort.

5G RADIO ACCESS • CONCLUSION 9

Conclusion5G is the next step in the evolution of mobile communication and will be a key component of

the Networked Society. To enable connectivity for a wide range of applications and use cases,

the capabilities of 5G wireless access must extend far beyond those of previous generations.

These capabilities include very high achievable data rates, very low latency and ultra-high

reliability. Furthermore, 5G wireless access needs to support a massive increase in traffic in an

affordable and sustainable way, implying a need for a dramatic reduction in the cost and energy

consumption per delivered bit.

5G wireless access will be realized by the evolution of LTE for existing spectrum in combination

with new RAT primarily targeting new spectrum. Key technology components of 5G wireless

access include extension to higher frequency bands, advanced multi-antenna transmission, lean

design, user/control separation, flexible spectrum usage, device-to-device communication, and

backhaul/access integration.

5G RADIO ACCESS • REFERENCES & GLOSSARY 10

References[1] 4G Americas, October 2014, 4G Americas’ Recommendations on 5G Requirements and Solutions, available at:

http://www.4gamericas.org/files/2714/1471/2645/4G_Americas_Recommendations_on_5G_Requirements_and_

Solutions_10_14_2014-FINALx.pdf

[2] Ericsson, November 2014, Ericsson Mobility Report, available at:

http://www.ericsson.com/res/docs/2014/ericsson-mobility-report-november-2014.pdf

[3] Bluetooth Special Interest Group, accessed January 2014, available at:

http://bluetooth.org

[4] IETF, accessed January 2014, IPv6 over Low power WPAN (6lowpan), available at:

http://datatracker.ietf.org/wg/6lowpan

GLOSSARYD2D device-to-device

mmW millimeter wave

MTC machine-type communication

RAT radio-access technology

WRC World Radio Conference

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