• What will be on 5G ?
• Ultra-Dense Network Architecture and Technologies for 5G
• Download speed at 5G over 4G and 3G for UDN
• Upload speed at 5G over 4G and 3G for UDN
• Why Ultra Dense Network at 5G
• Outlook towards 5G Ultra Dense Networks
• Applications of Ultra Dense Network
• Advantages of UDN
• Disadvantages of UDN
• Challenges of UDN
• Operator Challenges for Network Densification
• Scope of Researching in Future
• Interference Management & Mobility Concerns
To meet 1000× wireless traffic volume increment in the next
decade, the fifth generation (5G) cellular network
• The massive multiple-input multi-output (MIMO) technology
was proposed to improve the spectrum efficiency of 5G mobile
communication systems .
• The millimeter wave communications was presented to
extend the transmission bandwidth for 5G mobile
• The small cell concept has been appeared to raise the throughput
and save the energy consumption in cellular scenarios .
Ultra dense network (UDN) is a promising technique to meet the requirements
of explosive data traffic in 5G mobile communications. ... Software-defined
networking (SDN), network function virtualization, network slicing for
supporting heterogeneous UDNs.
Increasing the traffic density in areas like airports and large shopping malls
requires both outdoor and indoor deployment to provide seamless coverage
and capacity. Such an example requires indoor LTE small cells, unlicensed
LTE and WLAN/ 802.11n/ac solutions to complement outdoor macro and
8. What will be on 5G ?
The next generation of technology provides a greater amount of spectrum for
Smaller sizes of wireless cells.
More modulation schemes.
Letting greater numbers of wireless users share the spectrum.
5G technology offers at least one gigabit per second for connection speeds, shorter
delays than 4G technology, and millimeter wave (mmW) bands for supporting
applications requiring large capacity.
In July 2016, the FCC began creating rules for 5G technology, making the United
States the first country opening high-band spectrum for the technology
9. Ultra-Dense Network Architecture and Technologies for 5G
In recent years, with the growing popularity of smart device, our
daily life has come to revolve around with spectacularly
successful mobile Internet services, which lead to the explosion
of data traffic in mobile communication networks. The
requirement on communication networks has become a critical
issue. By 2020, the global mobile traffic volume will have about
1000 times growth compared to that of 2010. Recent research on
5G requirements indicates that the traffic density in crowded city
or hotspot area will reach 20~Tbps/Km2.
11. Download speed at 5G over 4G and 3G for UDN
The download speeds at up to 1000 times faster than 4G, potentially
Network Type Download Speeds
3G Network 384Kbps
4G Network 100Mbps
5G Network 1-10Gbps (theoretical)
13. Upload Speed at 5G over 4G and 3G for UDN
Network Type Milliseconds (ms)
3G Network 120ms (actual)
4G Network 45ms (actual)
5G Network 1ms (theoretical)
14. Why Ultra Dense Network at 5G
Cellular Network Cell Size Wave Base Station
3G Macro Cell 4-5 BS/km2
4G Micro Cell 8-10 BS/km2
5G Small Cell 40-50 BS/km2
15. Outlook towards 5G Ultra Dense Networks
LTE and LTE-A will enable ultra-dense network deployment with minimum
user cell edge data rates of 10-20 Mbps with monthly subscriber data of 20-50
GB data. In 2030 even higher data rates and data consumption is envisioned
and LTE will no longer suffice. It is clear that achieving the above
requirements in all cases is not practical. Sub-millisecond latency and extreme
data rates using new cmWave and mmWave spectrum calls for wide
distribution of the processing, close to the antennas and the end-user. All areas
of the networks will not use these extreme features. Further, the performance
difference between small cell and macro layer starts to increase and achieving
scalability at lowest possible network cost calls for a multi-layer approach.
Finally, with UDN levels expected in 5G, control and support functions for
better network optimization and automation will be needed
17. Applications of Ultra Dense Network
• Advanced radio access network architectures to
support heterogeneous ultra dense devices and users
• Coexistence of WiFi, Small Cells, HetNets and
LTE/LTE-A sharing unlicensed spectrum
• Self organizing and heterogeneous ultra dense small
• Advanced radio resource management for
heterogeneous ultra dense 5G networks
• Software-defined networking (SDN), network
function virtualization, network slicing for supporting
18. Applications of Ultra Dense Network
• Novel applications and service scenarios of ultra dense
5G networks in vehicular Internet, and IoT
• Energy harvesting, caching , and cognitive radio for
supporting heterogeneous UDNs
• Energy efficiency, spectral efficiency, and big data
techniques in heterogeneous ultra dense scenarios
• Novel multiple access techniques in heterogeneous
UDNs, such as SCMA, NOMA, PDMA, MUSA, etc.
• Supporting network applications, such as video
applications for heterogeneous ultra dense networks.
• Other topics in heterogeneous UDNs
19. Advantages of UDN
Higher data rate: Data rates of about 10 Gbps or higher can
be achieved. This provides better user experience as
download and upload speeds are higher.
Better coverage: Better coverage at cell end.
Smooth handoff: Due to involve UDN in 5G network
architecture handoff is smooth and hence it does not have
any effect on data transfer when mobile user changes cells.
Higher Capacity: Typically, 5G offers 100x traffic capacity
for using UDN.
Higher density: Typically, 5G offers 10x connection density
for using UDN.
Higher efficiency: Typically, 5G offers 3x spectrum
efficiency, 100x network efficiency for using UDN.
20. Advantages of UDN
Operational Impact: An operator in a medium sized
country may have 8-10,000 base station sites, but as
the network becomes denser, the operator may have
more than 100,000 cells to manage in a complex
Minimized Cost and Higher Speeds: Small cells to
provide lower cost capacity and coverage at outdoor
hot spots. Small cells to offload the macro network
and provide low cost indoor capacity.
Indoor DAS solutions can be upgraded to LTE for
21. Disadvantages of UDN
• Need more skill: It requires skilled engineers to install
and maintain Ultra Dense network.
• Higher cost. UDN equipment’s are costly.
• Delay for security: It will take time for security and
privacy issues to be resolved fully in UDN.
• Higher loss: UDN will mainly use in 5G technology.
Coverage distance of up to 2 meters and 300 meters
can be achieved due to higher losses at high
frequencies. 5G mm wave suffers from many such
• Need upgraded cell phone: Updated Smartphones are
costly. If we want to use ultra dense network then we
have buy updated phone.
22. Challenges of UDN
The first challenge is the multi-hop relay optimization
in 5G ultra-dense cellular networks. In the distribution
network architecture, both the back-haul and front-
haul traffic must be relayed into the destination. The
selection of relaying small cell BS should be carefully
considered in 5G ultra-dense cellular networks. Hence,
the wireless multi-hop routing algorithm is a key
challenge for 5G ultra-dense cellular networks.
Although the small cell BS equipped with massive
MIMO antennas has enough antennas for
simultaneously transmitting backhaul traffic and front-
haul traffic, it is another important challenge how to
reasonably allocate massive antennas for backhaul and
23. Challenges of UDN
The second challenge is to figure out how to organize
adjacent small cells for co-operative transmission. For
example, how to dynamically group small cells for
seamlessly covering the high-speed mobile user track is an
open issue. The proportion between the computation power
and transmission power maybe reversed at wireless
transceivers adopting massive MIMO antenna and
millimeter wave communication technologies. In this case,
the computation power cannot be ignored for the BS energy
consumption. Considering the proportion change between
the computation power and the transmission power, the new
energy efficiency model need to be investigated for ultra
dense cellular networks with massive MIMO antenna and
millimeter wave communication technologies.
25. Challenges of UDN
Thirdly, as a perennial problem faced by every generation of
mobile communication system, interference is serious in
LTE since adjacent cells reuse the same frequency resource.
To cope with the interference between macro cells, some
static and semi static methods can be proposed as of now.
Static methods such as cell planning and partial frequency
reuse (PFR) use system configurations to avoid interference.
In semi-static methods, eNBs exchange information for
interference coordination via X2 interface with a period
ranging from 20ms to 200ms. For downlink, relative narrow
band transmit power (RNTP) is utilized to inform
neighboring eNBs of the bands with high power. For uplink,
overload indicator (OI) signals measured interference level
while high interference indicator (HII) reports the bands on
which high power uplink transmission may be scheduled.
26. Challenges of UDN
Fourthly, Mobility is another important issue which is
usually handled by handover in mobile
communication systems. Handover is not expected to
happen frequently as they were initially designed for
macro cells with large coverage in LTE. Thus a
complicated handover procedure with high signaling
overhead is adopted. Moreover, the hard handover
mechanism in LTE means connection to the source
cell is released before connecting to the destination
cell. This disruption in transmission may trigger the
congestion control process of transmission control
protocol (TCP), leading to violent fluctuation of data
27. Challenges of UDN
Lastly, energy consumption delivers a difficult challenge
when it comes to UDNs. Statistics show that mobile
communication industry produces 86 million tons of CO2
in 2007, accounting for 0.2% of global carbon footprint.
Even with an optimistic estimation, mobile
communication carbon emission is expected to triple by
2020. Since UDN means much more small cells, the
surge in energy consumption will be considerable if the
4G energy efficiency is not improved. High energy
consumption not only leads to environmental damage but
also puts pressure on the already huge bills of the
operators. Moreover with the advent of green energy,
green communication is becoming a hot research topic
and expectation for 5G to be more energy efficient than
previous technologies is becoming a significant drive.
28. Operator Challenges for Network Densification
Densifying the network aims principally to
keep customers happy by providing them
with better than expected services. Too many
users on the same cell will affect accessibility
and usability. Operators need to provide users
with optimum quality while keeping the Total
Cost of Ownership (TCO) to a minimum.
29. Scope of Researching in Future
From Mobile Companies side:
31. Scope of Researching in Future
From Countries Side:
The United States
Korea & China are being very active on national level.
32. Scope of Researching in Future
From Universities Side:
• Chalmers University of Technology, Sweden
• Chinese Academy of Information and Communications
Technology (CAICT), China
• King’s College, Great Britain
• Lund University, Sweden
• New York University, USA
• Royal Institute of Technology (KTH), Sweden
• Rutgers University, USA
• Stanford University, USA
• Swedish ICT/SICS, Sweden
• Technical University of Dresden, Germany
33. Interference Management & Mobility Concerns
• A densified network poses particular concerns for a mobile
operator. Today’s predominantly macro-based networks will
become small cell networks with a handful of macros.
Operators need a coherent long term strategy for deploying
small cells because if cells are not planned from the start,
interference levels can rise dramatically.
• As the population of cities continues to grow, the network
will evolve from hot spots, to hot zones, and finally to
densified networks. Operators will also need to re-evaluate
existing macro sites as in some cases they may no longer be
Even without a uniquely agreed quantitative
definition, UDN is expected to be an essential
element of 5G networks for various deployment
scenarios. In addition to implementation related
technologies, standards related designs are necessary
to realize its full potential. Comparing with the fast
development of mmWave or mMIMO technologies,
the progress of UDN specific work requires more
attention and effort.