1. P00301-Assignment 4, 5G Report Page 1
P00301 Advanced Mobile Networks
Assignment 4:Research Report on 5G Technology
Student Name: Sivamoorthy Ranjan
Student Number: 14070800
Submission Date: 04/05/15
Word Count: 2178

2. P00301-Assignment 4, 5G Report Page 2
5G Technology
Introduction
5G technology is the next step in the development of mobile communications. Unlike previous
generations where the main motive of transition to the next generation was to provide higher data rate,
5G’s objectives are not only higher data rates but also to provide connectivity for a larger range of
devices including sensors, wearable devices or any other device that can use a data connection. This
proves to be a challenge as the devices vary in the requirement of quantity of data, data rate and
power utilization. Power utilization becomes critical in case of sensor nodes and as their power
resources are severely constrained.
One of the break-through developments in 5G would be the full realisation of internet of things.
Internet of things essentially means devices themselves being able to connect to internet and other
devices without human intervention. This can be made possible by enabling large number of
simultaneous connections to the network. The aim is to provide data connectivity anywhere, anytime
for anyone and anything [1]. It is considered as a single solution to the whole mobile communication
system. In order to achieve this objective, 5G envisions a new Radio Access Network (RAN) in
addition to the existing LTE-Advanced. 5G will not move entirely to a new radio access network, it
will still rely on LTE- advanced to provide mobile broadband as it is believed that LTE-Advanced can
be further developed to handle higher data rates. The new RAN will be embedded into the existing
system. This backward compatibility is essential for service provides. The transition to 5G is expected
to be gradual so supporting devices that uses older technologies is important for a service provider.
In this report we analyse the requirement of 5G technology and some of the existing technical
advancements developed in-order to achieve those requirements. In the later part we examine the legal
and social issues faced by a typical operator while deploying the 5G network. We assume that the
operator has acquired the technical requirements of 5G, such as new RAT additional to the LTE that
provides 1000 times the capacity of LTE and data rates in 10’s of GHz. The usage of the mmWave
(Millimetre wave) spectrum, achieving low overall latency, cost and energy requirements are
explained in the following sections. We then provide a summary highlighting the key points and
issues related to the 5G network implementation by a service provider.
5G Vision
Massive capacity improvement:
Since 5G supports a larger variety of devices like sensor nodes the number of connections that it has
to support increases tremendously and the amount of traffic to be handled is always on the rise. A
capacity improvement of at least 1000 times/square km more than the existing capacity provided by
4G is expected to be achieved. An estimate has indicated that the number of devices connected to the
internet would increase to 50bn in 2020 [2] and the mobile data rate is expected to increase to 24.3
Exabytes per month in 2019 [3], as shown in Figure 2.

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Figure 2: An estimated increase in data traffic and connected devices (from [2])
High data rate:
Every successive generation of mobile communication technology has come up with drastic
improvements in data rates than the previous generations. 5G aims to achieve this while supporting
wide variety of devices with varying requirements of data rate for each type of device. Although 5G
promises a peak data rate of greater than 50Gbps under ideal conditions, only a fraction of it would be
achieved in the real world [3] [4].
Figure 3: A comparison of data rates of 3G, 4G and 5G (from [2]).
While 4G provides a theoretical peak data rate of 1Gbps, 5G is expected to achieve a theoretical peak
data rate of 50Gbps and at least a practical rate of 1Gbps anywhere in the network as shown in Figure
3.
Lowlatency:
Latency is closely related to data rate. To achieve a high data rate, minimum latency should be
achieved. 4G had a minimum air latency of 5ms and 5G aims to reduce this to less than 1ms [4] [5].
There are several technical advances needed for this achievement, massive MIMO, network
densification and carrier aggregation are some these technologies. These technologies are explained in
the following sections.

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Figure 4: Latency comparison of 4G and 5G.
Lowdevice cost and energy consumption:
Since 5G connects devices such as sensors and actuators, it is essential to achieve low energy
consumption. Also new devices that support 5G services should be cost effective. There are several
methods to reduce energy consumption one important method is to reduce the signalling involved [5].
Support for machine type communication:
Certain devices employing 5G technology needs to communicate with other devices, these
communications are termed as machine type communication also termed as internet of things.
As explained earlier 5G uses both the enhanced LTE and the new RAT (Radio Access Technology)
and there is seamless integration between them. The new RAT would be utilizing the newly allocated
higher frequency spectrum, while the LTE sticking to its primary spectrum allocated earlier. When 5G
RAN network is well developed and familiarised, it is expected to be gradually inducted into the
primary spectrum.
Figure 5: 5G System Architecture
The 5G technology has LTE evolution in addition to the new RAN as shown in Figure 5. The new
RAN will achieve the capacity and data rate requirement envisioned by 5G. The support of LTE will

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enable connectivity to the legacy devices, this backward compatibility is essential for the service
provider as the switch between the technologies is gradual and not sudden.
Some of 5G techniques
Using mmWave (millimetre wave) system
The mmWave bands are frequency spectrum available for spectrum greater than 6GHz, they provide
greater bandwidth and therefore are suitable for the higher data rate requirement of 5G. They provide
at least 10 times more bandwidth than the 4G bandwidths [4], as shown in figure 7. One of the
drawbacks is the higher pathloss and they are vulnerable to atmospheric conditions. For example
mmWaves are absorbed by rain and fog. As a result of this they can only be used for short distance
communication, the cell coverage area is reduced to few hundred metres. One of the advantages of
using mmWave is that highly directional beams can be formed using several antenna elements (since
the wave length is very short, the antenna size is small). These directional beams are used to
compensate for the high pathloss experienced by mmWaves [7] [8]. Achieving mobility in non-line of
sight regions is a challenge. Implementation of mmWaves has already been done in 60GHz
communication [9].
Multi RAN (Phantum Cells)
Multiple RAN’s operating at different frequency bands can be overlaid to a single user such that each
RAN can take over specific tasks [4]. For example a user overlaid with LTE- advanced RAN in the
licensed band and the new 5G RAN in the unlicensed band, can make use of LTE for signalling and
handover or VoLTE while the 5G RAN can be used for ultra-high speed data services. For acquiring
larger bandwidth carrier aggregation is used in which both the licensed and unlicensed frequencies are
combined to service a single user as shown in Figure 6.
Figure 6: Carrier aggregation in 5G.
Massive MIMO
In massive MIMO a base station employs large number of antennas (hundreds) which are in phase
with each other. With the use of higher frequency bands (mmWave spectrum, beyond 10GHz) the
electrical size of the antenna becomes small. These small size antennas can be co-located resulting in
a massive MIMO. The users who share a particular time-frequency signalling are serviced with
different set of antenna thus providing higher throughput and better SINR. We can form many beams

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which are very narrow and thus improve the overall throughput. One of the practical limitations of
massive MIMO is that base stations cannot accommodate large number (100’s) of antennas.
Advanced D2D communication
Devices that are at close proximity to each other must be able to communicate directly without
involving the cellular networks. This will cause a reduction in the overall latency and also offload data
traffic of the cellular network. The frequency bands in D2D communication can be reused among
multiple D2D communications if they are geographically separated enough.
Spectrum requirements
Figure 7: Millimetre Wave Spectrum
The data rate envisioned for 5G requires greater bandwidth which necessitates larger bandwidth
allocation for mobile communication. The Mobile World Congress 2015 is expected to allocate the
new spectrum above 6GHz [1] [5]. The microwave band (signals with wavelength of few centimeters
to 1 metre) which was considered as the suitable band for mobile communication has been completely
exhausted. There are no unused frequency bands available in this frequency range. This forces us to
go for higher frequency range in the mmWave band (30-300GHz). There are also several vacant
frequency bands in the 20-30GHz range as shown in Figure 7. One of the main disadvantages of
mmWave frequency band is that the propagation loss is too high. Since the pathloss is proportional to
f2
a slight increase in frequency results in large pathloss value. However a mechanism for reducing
this pathloss is discovered. The loss is reduced by maintaining a constant antenna aperture at the
transmitter and receiver. Several antennas add up the aperture eventually maintaining an optimum
level. This method has proven to improve the gain of the antenna proportional to f2
which is used to
compensate the high noise floor at this frequency range.
The other disadvantage is that these frequencies tend to exhibit low diffraction and get obstructed by
obstacles. Their penetration capacity is too low. This limits its usage to a small size cell providing
limited coverage. This is actually is what is needed by the 5G technology as it tries to improve the
data rate by network densification.
Technical issues
Assuming that the operator has acquired the necessary technical advancements needed for 5G services
we consider their practical implementation capability. One of the practical hurdles is the
implementation of massive MIMO which requires installation of hundreds of antennas in the base
station. Though the electrical size of the antenna is small, installing array of hundreds of antenna

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requires more space which the current base stations cannot accommodate. Also it is difficult to mount
such big antennas on the tower [10]. High wind speeds could easily damage the antenna.
Network densification is one of the aspects of 5G which requires large number of base station
installations. Massive MIMO technology at the base station makes large deployment difficult also the
operator has to undergo a number of legal procedures for acquiring the permission for installation. A
very large number of base stations will be required as the size of the coverage area is very small and
also the mmWave has very low penetration capability(low diffraction) therefore it would be required
to install in many places .
In device to device communication the operator might lose a considerable amount of revenue as the
communication is not controlled by the operator. A recent research [11] in this area shows how the
operator is able to control D2D communication.
Cost of the new RAT needs to be reasonable so that the operator can deploy on a large scale.
Deploying in the urban area alone could be a good strategy because the number of subscribers
wanting 5G services would be more in urban areas compare to suburban or rural areas.
Social Issues
5G technology would impact the people’s everyday life greatly. With the realisation of IoT and
support of sensor devices, 5G mobile communication would become an integral part of one’s life.
However, there is a long way to go for the full realisation of 5G vision. Existing mobile handsets
would not be able to support 5G services. People have to invest in devices that support 5G. The
mobile operators should make the 5G services affordable.
There are security and privacy issues that are to be addressed in the D2D communication. Huge
deployments of 5G base stations could cause obstruction to public transportation. Since their
operating frequency is higher new emission levels must be defined by concerned authorities, which
the operators would abide by.
Summary
We have discussed the various technological advancements needed for 5G services. Assuming the
operator has developed the new RAN for 5G services, we analysed the practical difficulties in real
deployments such as implementation of massive MIMO at the base station etc. The cost of the new
RAN would play a major role for the operator in deciding massive deployments. If the cost is high it
is best for the operator to wait until the cost of the technology is reduced because the change to 5G is
going to be gradual and there is a high risk of financial losses. The operator should only target the
urban population initially. The backward compatibility to 4G/3G/2G should be ensured at all times
and at all places. While providing the D2D communication, the operator should acquire the technical
know-how to charge the user while providing a reliable and secure communication.

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