An In-Depth Report on Millimeter Wave Technology in 5G Networks

This report provides a comprehensive overview of millimeter wave (mmWave) technology and its critical role in 5G networks. It begins by defining mmWave and its significance in achieving high data speeds and increased network capacity, essential for advancements like Ultra HD video streaming and IoT. The report explores the advantages of mmWave, such as increased bandwidth and the potential for smaller network components, as well as its limitations, including signal penetration challenges. It then discusses potential solutions, like the use of small base stations and integration with frequencies below 6 GHz. The report also delves into how mmWave is implemented in 5G NR, highlighting the use of massive MIMO antenna arrays and dual connectivity to overcome propagation and environmental challenges. Finally, the report concludes by emphasizing the transformative potential of 5G, driven by mmWave technology, and its impact on various aspects of modern society.

Task – 1
Part 1
The Received Signal Level (RSL) is defined by equation (1)
RSL=PT +GT +GR +GPR−LBR−LConn−LWG −FSL ----------------------------(1)
Where,
PT is transmitted power,
GT is transmitting antenna gain,
GR is receiving antenna gain,
GPR is aperture gain of passive repeater antenna,
LBR is branching loss,
LConn is connector loss,
LWG is wave guide loss,
And FSL is free space loss
FSL=92.44+ 20 log FGHz +20 log DKM
FSL=92.44+ 20 log FGHz +20 log DKM =133.267 dBm ----------------------(2)
Using equation (1) and (2)
RSL=PT +GT +GR +GPR−LBR−LConn−LWG −(133.267 dBm)
RSL=20 dBm+35 dBi+35 dBi+ 35 dBi−2 ( 2 dB ) −2 ( 1 dB ) −1 dB−(133.267 dBm)
RSL=−15.267 dBm (Answer)
Part 2
The main uses of passive repeaters are as under,
1. Passive antennas are used to overcome line-of-sight problem. That is, in case of obstruction like
buildings and mountains, passive repeaters are installed to ensure that the communication
happens.
2. It is also preferred over active repeaters because of low maintenance cost and because there is
no noise amplification in case of passive repeaters.
3. It provides aperture amplification and reduces the effect of losses in transmitting the signal.
Task – 2

Summary
The mmWave or millimeter wave is the other name of EHF (extremely high frequency) and is assigned
for radio frequencies which lie between 30 to 300 GHz (Giga Hertz). It is between Microwave (or super
high frequency band) and the infrared band. 5G as we know is one of the biggest thing which has
happened in telecommunication world so far. It can be at par with the invention of telephone. Like
telephone made the dream of people to communicate remotely, a reality; 5G will change the very
nature of society, from connected devices to innovations in industries to self-running cars, healthcare.
5G on its full potential will touch and change everything we can imagine. To enable this transformation,
we need a very powerful access technique. The one which can give 30 Gbps of data rate and 1000-fold
increase in existing network capacity. Millimeter wave or mmWave is the solution to this challenge.
Millimeter wave is still used for many civilian applications including for high speed indoor broadband.
The reason it could not so far be used for outdoor mobile network is because of its limitation to
overcome obstacles in its path and negative effect it has because of change in environmental conditions.
But with the invent of 5G NR we have a clear way to overcome these hurdles with the help of
technology which can simultaneously allow a device to be connected to both mmWave and sub 6 GHz
frequency to ensure seamless mobility and coverage along with excellent data speed. We will talk about
all of this and more in this report and see how millimeter wave will help driving 5G revolution.
Introduction
“The need for increasingly high data speed for mobile communication is driving latest innovations. The
requirement is coupled with new advancement in technology like Ultra HD (4K/8K) video streaming, and
IoT. Also, as the capability of mobile devices continue to get better and better with technological
improvements like higher resolution cameras, always connected cloud network and virtual reality
applications, so does the need to get better and faster mobile network. The ultimate solution to the
bandwidth requirement is fiber optics but problem here is, it is costly and not suited for mobile
communication. Millimeter wave technology is a potential answer to the problem: it gives bandwidth
comparable to the fiber optics with added advantage of cost and ease of deployment.
Wavelength in the range of millimeters are called millimeter waves or mmWave. In wireless
communication, the term generally corresponds to few bands of spectrum near 38, 60, 94 GHz, and in E-
band (between 70GHz and 90GHz).
Millimeter waves were discovered in 1890’s by J.C. Bose but it remained within the premises of
academic circles till 1960’s when its first use case happened in Radio Astronomy, followed by an
application in milatry space in 1970’s. The first consumer oriented application of millimeter wave
happened in 1990’s with advent of collision avoidance radar (operating at 77GHz frequency)
(Adhikari, 2019)
Role of mmWave in 5G
“There is a theory that mobile traffic will grow to 50 Billion GB per month by 2021. The requirement is
huge and many are looking at new 5G solution as final means which can enable technology to reach this

target. 5G is having many new things like type of waveform, access technology, and antenna type. But,
most importantly, it will need spectrum that can give required bandwidth which is where mmWave
comes into picture.
Millimeter waves lies between microwave and infrared waves and has required bandwidth to achieve
high data rate traffic. Even in present, mmWave is used of high speed indoor broadband setup which
can handle applications like ultra HD video streaming. Let us talk about advantages and limitations of
mmWave in detail in the context of 5G development.
(Tracy, 2019)
Advantages
“Wireless data speed can be increased either by increasing the spectrum utilization or by increasing the
bandwidth. Increasing the bandwidth is comparatively direct and simple solution for increasing the data
speed. It has been proved that increase in data rate is directly proportional to increase in frequency
bandwidth. Problem here is, all frequency bands below 5 GHz is extremely congested and therefore, it is
logical to look for new spectrum range, hence mmWave.
It is also a known understanding that the maximum bandwidth in wireless communication is about 5% of
the transmitting frequency. Now, if we compare the highest 4G frequency which is 2 GHz, the available
bandwidth is about 100 MHz, whereas in case of mmWave, the frequencies between 28 GHz and 60 GHz
is what is expected to be used in 5G and with that, we can see 10 to 20 times increase in spectral
bandwidth. This will enable enormous increase in data transmission rate.
(Alibaba Cloud Community, 2019)
“Effect of environmental conditions (dust, smoke, humidity, rain etc.) such as losses and attenuation on
mmWave is better when compared with Infrared and Optical frequency spectrum.
(Eng.tau.ac.il, 2019)
“High frequency spectrum also results in ability to reduce the size of the network component like
smaller antennas. Because of the extremely short wavelengths of mmWave, it is possible to have very
small antennas which can form highly focused signals with sufficient gain to overcome absorption losses.
The small wavelength also leads to feasible of having small antennas which can fit into mobile handsets
and which then can do dynamic beamforming.
(Tracy, 2019)
Limitations and possible solutions
Components needed for millimeter wave transmission are costly because of fact that mmWave will need
smaller component, there is a requirement to have greater accuracy and precision. But, the biggest
drawback of mmWave is its inability to penetrate obstacles such as buildings, bridges, trees etc. Even a
small leaf or a drop of rain can impact the signal strength. Possible solution to the problem is to adopt to
small base station method along with existing cell tower infrastructure. As explained above we will have

small antennas for mmWave and thus small base stations. We can say that most probably in future
there will not be large cell towers but many small base stations. This arrangement will also bring
coverage to the areas which were not covered by large base stations.
It is expected that ideal way to implement 5G by operators will be to use frequencies below 6 GHz in
open areas for greater coverage and use micro base stations coupled with mmWave technology indoors
for providing ultra-high data rate.
Millimeter wave and 5G NR
“As discussed already, with use of millimeter wave, it is feasible to have antennas with very small
dimensions. This feature of millimeter wave is applied in 5G NR; here NR stands for New Radio and is
developed by 3GPP for 5th generation mobile network. 5G NR uses massive MIMO antenna arrays to
make highly guided rays which can concentrate the transmitted RF signal for avoiding propagation and
path loss problems in mmWave. These high directional signal can also be reused in space. Various
millimeter wave simulations, channel measurements and field trials have revealed that it is possible to
increase channel capacity by capturing non line of sight signals and adding them with line of sight
signals. Therefore, it helps maintaining signal to a mobile device by using reflected signals even when
the mobile device moves completely out of sight to the transmitter. This arrangement is a reason we
think to expand role of millimeter wave in 5G network.
There is one more problem related to mmWave which 5G NR must handle. This is to deal with the
changing environment such as movement of body parts, moving traffic, which can change the channel
and impact its performance. For this, 5G NR millimeter wave system will use fast beam routing and
switching techniques to identify and switch quickly to the overriding beam path available within and
across access points. As millimeter wave will be used more for localized indoor and outdoor coverage
and frequencies below 6 GHz for general coverage, therefore 5G NR system will need to closely tied with
frequencies in 6 GHz bands to ensure perfect network coverage and user experience. This flexibility in
technology is achieved by having dual connectivity where multimode devices are at the same time
connected to sub 6 GHz bands for wide area coverage and millimeter wave bands for increased
bandwidth and capacity. Also in 5G NR mmWave coverage, mobile devices will concurrently connect to
sub 6 GHz (either 5G NR or 4G LTE technology) to allow fast system acquisition and deterrence to fading
and micro coverage holes. The central cell (most probably a sub 6 GHz or 4G LTE macro cell) ensures
coverage and does controlling of channel acquisition, paging and mobility, whereas a non-collocated
millimeter wave booster cell gives more of local high capacity services with flawless ability.
(Qualcomm.com, 2017)
Conclusion
We are the doorstep of 5G revolution which will impact everything around us, people, industries, and
society. Millimeter wave is coming out as the most important access technology it will use. In this report
we have tried explaining millimeter wave and how it is beneficial for 5G network. We also talked about

advantages and limitations of mmWave technology and possible ways to overcome those. Millimeter
wave is well poised to support 5G to reach its full potential and expectation.
References
Adhikari, P. (2019). Understanding Millimeter Wave Wireless Communication. [online] Loeacom.com.
Available at: http://www.loeacom.com/pdf%20files/L1104-WP_Understanding%20MMWCom.pdf
[Accessed 5 Oct. 2019].
Tracy, P. (2019). What is mmWave and how does it fit into 5G?. [online] RCR Wireless News. Available
at: https://www.rcrwireless.com/20160815/fundamentals/mmwave-5g-tag31-tag99 [Accessed 6
Oct. 2019].
Alibaba Cloud Community. (2019). Understanding How Millimeter Waves Power the 5G Network. [online]
Available at: https://www.alibabacloud.com/blog/understanding-how-millimeter-waves-power-the-
5g-network_593839 [Accessed 6 Oct. 2019].
Eng.tau.ac.il. (2019). [online] Available at: http://www.eng.tau.ac.il/~dbl/mmw.htm [Accessed 6 Oct. 2019].
Qualcomm.com. (2017). [online] Available at: https://www.qualcomm.com/media/documents/files/white-
paper-5g-nr-millimeter-wave-network-coverage-simulation.pdf [Accessed 6 Oct. 20