Transcript femtocell - 123SeminarsOnly.com

femtocell
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Femtocell Definition
• A small cellular base station, designed for use in residential or enterprise.
• Connects to the service provider’s network via broadband.
• Support 2 to 5 mobile.
• Allows service providers to extend service coverage indoors.
Femtocell Definition
• Confidential
• Incorporates the functionality of a typical base station but
• extends it to allow a simpler, self contained deployment.
• The concept is applicable to all wireless standards, including
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UMTS, GSM, CDMA-2000, TD-SCDMA and WiMAX
solutions.
Benefits for end-users
The main benefits for an end-user are the following:
• Excellent network coverage when there is no existing signal or poor coverage.
• Higher capacity, which is important if the end-user uses data services on his/her
mobile phone.
• Depending on the pricing policy of the MNO, special tariffs at home can be
applied for calls placed under femtocell coverage.
• For enterprise users, having femtos instead of DECT or Wi-Fi dual mode phones
enables them to have a single phone, so a single contact list etc.
Benefits for end-users
• Depending on the pricing policy of the MNO,
special tariffs at home can be applied for calls
placed under femtocell coverage.
• For enterprise users, having femtos instead of
DECT or Wi-Fi dual mode phones enables
them to have a single phone, so a single
contact list etc.
Architectures
Home Node B (HNB/HeNB):
• In 3GPP terms, LTE femto-cells are called Home Node B’s for HSPA and
Home eNode B’s for LTE. H(e)NBs are typically associated with
uncoordinated large scale deployments and therefore the connection to
the operators core network needs to be realized efficiently.
Architectures
Collapsed stack:
• The approach standardized by 3GPP in Release 8 is to collapse
network functionality into the femtocell, so it includes not just the
base station itself but also the controller that enables local radio
resource control. This connects back to the mobile operator core at
a higher point for central authentication and management. This
addresses the scalability concerns above, as the resource is located
locally.
Architectures
Historic approach/cellular base station:
• One approach for a femtocell is to use the traditional base station
architecture. In this case, the femtocell is a base station, connecting to the
core network using a standard interface;. The slight difference from a
typical base station deployment is that the backhaul would be carried over
broadband ("Iub over IP") which may have quality & security concerns. A
more significant drawback of this architecture is that standards-based
base station controllers are designed to support only a limited number of
high-capacity base stations, not large numbers of simple ones
Architectures
SIP or IMS:
• The final, and most sophisticated structure is to move to a full IP-based
architecture. In this case, even more functionality is included within the
femtocell, and the integration to the core is done using an IP-based
technology
Issues
Femtocells are a complicated technology and there have been a number of
issues and concerns which need to be addressed.
Interference
• The placement of a femtocell has a critical effect on the performance of
the wider network, and this is one of the key issues to be addressed for
successful deployment. Because femtocells can use the same frequency
bands as the conventional cellular network, there has been the worry that
rather than improving the situation they could potentially cause problems.
• As more analysis has been done, and more operators have deployed it is
clear that so long as femtocells incorporate appropriate interference
mitigation techniques (detecting macrocells, adjusting power and
scrambling codes accordingly) then this need not be a problem.
Issues
Equipment location
• There are issues in this regard for access point base stations sold to
consumers for home installation, for example. Further, a consumer
might try to carry their base station with them to a country where it
is not licensed.
• Other regulatory issues relate to the requirement in most countries
for the operator of a network to be able to show exactly where
each base-station is located, and for E911 requirements to provide
the registered location of the equipment to the emergency
services.
Issues
Quality of service
• In shared-bandwidth approaches, which are the majority of designs
currently being developed, the effect on Quality of Service may be an
issue.
Issues
Controversy on consumer proposition
• The impact of a femtocell is most often to improve cellular coverage,
without the cellular carrier needing to improve their infrastructure (cell
towers, etc.). This is net gain for the cellular carrier. However, the user
must provide and pay for an internet connection to route the femtocell
traffic, and then (usually) pay an additional one-off or monthly fee to the
cellular carrier. Some have objected to the idea that consumers are being
asked to pay to help relieve network shortcomings. On the other hand,
residential femtocells normally provide a 'personal cell' which provides
benefits only to the owner's family and friends.
Features of Femtocell
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Operates in the licensed spectrum
Uses fixed broadband connection for backhaul
It is managed by the NAP
The backhaul service provider may be different
from NAP/NSP
Principally intended for home and SOHO
Lower cost than PicoBS
Smaller coverage (low power) than PicoBS
Smaller number of subscriber (ten or less) than
PicoBS
Higher density
Deployment
• Irregular deployment will incur inevitable
interference
FAP System Specifications
Requirements
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A Femto Access point (FAP) is a low-power BS,
operating in licensed band, intended to:
Be end user installed without service provider manual
configuration (plug and play).
Provide service for a limited number of concurrent users
over small areas such as the home and SOHO
environment.
Use a shared broadband connection for backhaul that may
be operated by a different Service Provider.
Support limited user mobility (low speed, infrequent need
for handover).
FAP Value Proposition
Benefits to consumer
Benefits to operator
Fear :
Reduces cost(free calls)
Counters threat from VoIp
Improves coverage
Greed:
Simplicity: Single Device can be used by
multiple users
Increases both coverage and capacity
No need for new expensive device
Reduces churn
Increases 3G adoption
Works with all existing handsets
WiFi vs. FAP
WiFi vs. FAP
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Licensed vs. unlicensed spectrum
Operator need to use its 3G spectrum
Which will reduce the overall spectrum available
Tight frequency reuse planning
QoS better in licensed than unlicensed.
Convergence and vertical handover ☺
No SIP, IMS, MIH needed
Flat architecture
MAC Layer
WiFi MAC is simple
thus cheap, but not scalable
e.g. a single transmitting station takes up the entire bandwidth,
A lot of dead time between stations transmissions,
Femtocell rely on 3G standards.
WiFi lacks subscriber manageability (e.g. TPC, DFS): 3G
does have this.
Convergence and Interworking
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The combination of femtocells and wired IP
broadband ☺
Operators will re-use large scale elements of their
current core networks such as
billing, AAA, policy, and mobility services.
Security and mobility gateways are needed
To protect the integrity of operators’ core networks
from the public environment of the Internet,
To protect the integrity of users’ traffic, and to
support seamless transitions between the macro
and femtocell networks.
FemtoCell Open Areas and Challenges
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Radio and interference issues
Handover and mobility management
Synchronization and localization
QoS and Security issues
Conclusions
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Like FMC, Femtocells are on a road to
nowhere
Unsatisfactory coverage and the increasing
number of high-data-rate application are two
driving forces for femtocell development
Femtocells have the potential to provide highquality
network access to indoor users at low
cost
Improve coverage
Provide huge capacity gain