wireless communication seminar by nisha menon

1. FEMTOCELLS : Past ,Present &
Future
Nisha Menon K
Mtech Communication Engg
25 October 2013
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2. Outline
Introduction
 Motivation
 Working of femtocell
 Femtocell requirements
 Features of femtocell
 Challenges
 Benefits of femtocell
 Conclusion
 Reference

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3. Introduction
The wireless capacity has doubled every 30 months
since 1957
– 25X improvement from wider spectrum
– 5X improvement by dividing the spectrum into smaller slices
– 5X improvement by designing better modulation schemes
• The
main problem of current cellular network
– The expensive deployment cost of network infrastructure
– Low signal strength received from an outdoor BS inside a
building
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4. Motivation
• Some
studies on wireless usage show
– More than 50% voice calls and more than 70% data traffic are
originated indoor
• Win-Win strategy
– Higher data rate and reliability for subscribers (User)
– Reduced amount of traffic on expensive macrocell network
(Operator)
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5. Macro
cells
Femto
cells
Cell
types
Micro
cells
Pico
cells
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6. Macro cell
Micro
cell
Pico cell
Femtocel
l
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7. What is Femtocell
• Femtocells are small mobile towers at home.
• Femtocells are used to provide licensed indoor
coverage.
• Femtocells combine the internet access
technologies like DSL and cable with mobile
technologies.
• It connects the operator via internet providing
excellent radio conditions.
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8. Working of femtocell
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9. How does femtocell work
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10. Femtocell Requirements
Femtocell itself
Internet router to enable the data to be passed to and from the
femtocell via the Internet
Internet link
Mobile telecommunications service provider
Core network gateway
The two key elements of the system are the femtocell which is
installed within the user premises and also the network
gateway that provides the link from the Internet into the
telecommunications network.
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11. Features of Femtocell
•
•
•
•
•
•
•
Operates in the licensed spectrum
Uses fixed broadband connection for
backhaul
Principally intended for home and
SOHO
Lower cost than PicoBS
Smaller coverage (low power) than
PicoBS
Self Organizing Network
Higher density
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12. Femtocell Access Control
Closed access
Open access
Hybrid access
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13. Femtocell Standardisation
In 3GPP terminology, a Home Node B (HNB)
is a 3G femtocell.
 Home eNode B (HeNB) is an LTE femtocell.

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14. Challenges
Challenges
Economic and
regulatory
issues
Technical
challenges
Cell
association
and biasing
Interference
Mobility and
soft handover
Health issue
Spectrum
issue
Regulatory
aspects
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15. Cell association and biasing

Irregular deployment will incur
inevitable interference
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16. Interference analysis
Random placements of FAPs.
 Cochannel spectrum sharing between
femtocells and macrocells
 Two types of interferences

• Cross layer interference
• Situations in which the aggressor (FAP) and
the victim (macro cell user) of interference
belong the different network layers
• Co layer interference
• Here the aggressor(FAP) and the
victim(neighbour femto cell user) belong to
same network layer
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17. Proposed methods to overcome
interference

Interference cancellation technique
◦ Disregarded due to errors in the cancellation
process

Use of sectoral antennas at FAP
◦ Reducing interference by decreasing the
number of interferers


Dynamic selection of predefined antenna
patterns
Interference avoidance (power and
subchannel management)
◦ Good alternative
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18. Handover

Handover in femtocells highly depends upon the access
mode being used. The number of handover is very
large in the case of open access, while are reduced in
closed and hybrid access modes

Soft handover is not supported by femtocells
Inbound: handover occurs from the macro-cell or
standard cellular network to the femtocell.
 Outbound: handover occurs from the femtocell to the
macro-cell or standard cellular network.
 Femtocell to femtocell: There will be situations where
handover will occur between one femtocell and another
close by. This will be commonplace in offices that may
have a number of femtocells to give continuous
coverage within a building.

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19. Femtocell spectrum issues
Radio spectrum is a particularly scarce
resource, especially when large amounts
of data are required. Planning the
available spectrum so that it can be used
with the possible huge numbers of
femtocells can require careful attention,
although in some instances single
channel operation with main base
stations may be required
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20. Femtocell regulatory issues:
Femtocells operate in licensed or
regulated spectrum. Unlike Wi-Fi which
operates in unlicensed spectrum,
femtocells need regulatory approval.
The spectrum and radio regulations vary
from one country to the next and therefore
regulations may need to be changed in
each country. International agreement
may also be required, because private
individuals may take femtocells from one
country to the next.
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21. Femtocells and health issues:
As a femtocell is a cellular base
station, there could be public concern
regarding the levels of RF radiation
received
The power levels emitted by femtocells
are small - no greater than most Wi-Fi
access points which are common in very
many homes. As a result it is not
believed by the industry in general that
there are any health issues that should
cause any concern.
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22. BENEFITS OF FEMTOCELLS
Technical Advantages





Low Cost
Low Power
Easy to Use
Compatibility & Interoperability
Deployment
Customer’s point of view




Increased Indoor Coverage
Load sharing
Better Voice Quality
Better Data/Multimedia Experience
Wireless Operator’s point of view



Lower CAPEX and OPEX
Increased network capacity
Newer Revenue Opportunities
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23. Today
Voice
coverage
Deep data
coverage
Capacity
Offloads
Tomorrow
Public access
Femtocells may begin to
proliferate in coffee shops
Corporate
malls and other hotspots
Begin to proliferate
corporate offices
ensuring employees
full access to high
Services
quality voice and fast
home
mobile data
automation
Integration
Sms alerts
A feature addition
to set top box or
integrated with a
dsl modem
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24. Conclusion

Unsatisfactory coverage and the increasing number of
application are two driving forces for femtocell
development

Femtocells have the potential to provide high-quality
network access to indoor users at low cost
– Improve coverage
– Provide huge capacity gain

Femtocells are considered to be the solution to meet the
future needs for high data rates and capacity in wireless
cellular networks.

The femtocells would also face tough competition from
the already established Wi-Fi technology and the
operators need to provide cheap services in order to
capture the future indoor wireless access market.
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25. Reference

Jeffrey G Andrews, Holger Claussen, Mischa Dohler, Sundeep
Rangan, Mark C Reed, “Femtocells: Past, Present and Future” IEEE
Communications Magazine, vol. 30,April 2012

V. Chandrasekhar, J. G. Andrews, and A. Gatherer, “Femtocell
networks:a survey,” IEEE Communications Magazine, vol. 46, no. 9,
pp.59–67, September 2008.

H. Claussen, L. T. W. Ho, and L. G. Samuel, “An overview of the
femtocell concept,” Bell Labs Technical Journal, vol. 13, no. 1, pp.
221–245, May 2008

P. Xia, V. Chandrasekhar, and J. G. Andrews, “Open vs. closed access
femtocells in the uplink,” IEEE Transactions on Wireless
Communications, vol. 9, no. 10, pp. 3798 – 3809, Dec. 2010

Informa Telecoms & Media, “Femtocell Market Status,” Femtoforum
whitepaper, 2011.
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26. Queries ???
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27. Thank you
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