Femto Network

Dr. Monir HossenECE, KUET

Department of Electronics and Communication Engineering, KUET

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What is Femto Cell? Why Femto Cell? History of Femto Cell Working of Femto Cell Femto Cell Basic Concept Features of Femto Cells Advantages of Femto Cell Femto Cell Interference Scenarios Handover Scenarios

Agendas of This Lecture

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What is Femto Cell? (1/2) A small cellular base station in residential or small

business environments It connects to the service provider’s network via

broadband (such as DSL or cable) Typically it supports 2 to 5 mobile phones in a residential

setting It allows service providers to extend service coverage

inside of your home - especially where access would otherwise be limited or unavailable - without the need for expensive cellular towers

It also decreases backhaul costs since it routes your mobile phone traffic through the IP network    

It is sometimes referred to as a “home base station”, “access point base station”, “3G access point”, “small cellular base station” and “personal 2G-3G base station”

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What is Femto Cell? (2/2)

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Why Femto Cell?

• Technical motivations Reduced separation distance between transmitter

and receiver Interference is isolated by building structure Limited number of users

• Business motivations Half of voice calls and a majority of data traffic

originate indoor Operators expand network capacity and

coverage without much investments on infrastructure.

Subscribers get better radio service at low price

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History of Femto Cell

The first interest in Femto cells were started around 2002 when a group of Engineers at Motorola were investigating possible new applications and methodologies that could be used with mobile communications.

In 2004, the idea was beginning to gain some momentum and a variety of companies were looking into the idea.

The Femto Forum was set up in July 2007. Its aim was to promote the wide-scale adoption of Femto cells.

The Femto Forum also played a coordinating role in ensuring that the standards were agreed and released as fast as possible.

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Working of Femto Cell

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Femto Cell Basic Concept

Macro Cell

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Features of Femto Cells Operates in the licensed spectrum Uses fixed broadband connection for backhaul It is managed by the Network Access Point (NAP) The backhaul service provider may be different

from NAP/NSP (network service provider) 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

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Users Benefits - Reduced “in home” call charges

- Improved indoor coverage (Base station in your bedroom)

- Continued use of current handset

- Reduced battery drain

- Reduced call drops

- Fast/Higher performance 3G services

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Operators’ Benefits Improves coverage Reduces backhaul traffic Provides capacity enhancements Easy radio coverage for rural areas Where there is ADSL you can have mobility Stimulates 3G usage Addresses the fixed mobile convergence market

with a highly attractive and efficient solution Reduces installation cost of new macro cell

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Advantages of Femto Cell (1/2) 1. Low Device Cost: => Efficient, low-cost power amplifiers, highly sensitive

receivers, flexible channel bandwidth, reliable RF filters, low cost and low power implementation, etc.

2. System Interference Management: => Minimize interference to macro (and vice versa),

minimize interference to adjacent Femtos, coping with unplanned rollouts, coverage estimation, interference cancellation, etc.

3. Femto Cell Capacity Maximization:=> Link and access management (handover, admission

control, resource management, load balancing and flow control), dynamic bandwidth allocation and sharing, etc.

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Advantages of Femto Cell (2/2)

4. Backhaul Issues:

=> Wired or wireless backhaul, reducing signalling load, QoS provisioning and traffic periodization, joint access and backhaul design, etc.

5. Viable System Architecture:

=> Control & data planes, access control, authentication, local breakout, efficient forwarding, seamless mobility, etc.

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Femto Cell Interference Scenarios (1/2)

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Femto Cell Interference Scenarios (2/2)

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Irregular deployment will incur inevitable interference

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Solutions to Interference Problem

Adaptive pilot power control

Dynamic Femto cell receiver gain management

Mobile phone uplink power overlaying/ Covering

Extended Femto cell receiver dynamic range

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Handover Scenarios

There are 3 main scenarios for Femto cell handover: Inbound (from the Macro cell to the

Femto cell) Outbound (from the Femto cell to

the Macro cell) From one Femto cell to another

Femto cell

Thanks for Your Kind Attention

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