Mobile data offloading

MOBILE DATA OFFLOADING:
FEMTOCELL VS. WIFI
ASTON PRIMERA PASTEUR HOTEL – BANDUNG, NOVEMBER 10-11, 2011
DR. IR. JOKO SURYANA
Laboratory of Radio Telecommunications and Microwave
Institut Teknologi Bandung

Outline
• MBB operator Problem
• Why do MBB operators need offloading ?
• What is Femtocell and Wifi offloading ?
• How do we implement ?
– Femtocell
– Wifi offloading
• Business Cases

Mobile Data Offloading: Femtocell vs. Wifi 2

Operator Options
Strategy to bridge the revenue gap :
1. Network sharing : all forms of operator
cooperation where sites or parts of the radio
access networks are shared.
2. Spectrum refarming : replace or mix radio access
technologies in specific frequency bands.
3. Offloading heavy data traffic : to local networks
or indoor systems.
4. Pricing strategies and service differentiation
5. New types of services and revenues : M2M, NFC


Operator Options :
Highlight on Offloading
Offloading heavy data traffic to local networks
• Instead of deploying a large number of outdoor base
stations for mobile broadband the heavy data traffic
can be offloaded to local networks or operators using
indoor systems or femtocell.
• In addition to the potential of substantially lowered
network costs a number of other motivations can be
identified:
– the data traffic is mostly (~90% ) generated indoors
– the users are stationary or nomadic
– the users are ”known” (at the office or at home)
– no need to deal with wall attenuation


FEMTOCELL-BASED OFFLOADING


Offloaded by Femtocell


Why is Femtocell Important?
• Femtocell is very important for the following reasons:
1. It can provide indoor coverage for places where macrocells
cannot
2. It can offload traffic from the macrocell layer and improve
macrocell capacity
3. Addition of a femtocell layer will significantly improve the
total network capacity by reusing radio spectrum indoors
4. There is a growing demand for higher and higher data rates
5. Femtocells can provide significant power saving to UEs
6. The use of femtocell is ‘greener’ than macrocells
7. Femtocell provides an ideal solution for FMC (Fixed Mobile
Convergence).
8. Femtocell plays an important role in mobile broadband and
ubiquitous communications.
9. Femtocell represents a major paradigm shift


FEMTOCELL CONCEPT


Evolution of Cellular Systems
2G
3G
4G

As throughput demand and usage
increases, cell size decreases

Current Traffic Future Traffic Trend
Macro Base Stations Trend
Outdoor
Home
Work

Femto Stations


Evolution of Cellular Systems: Cell Size
• Cell size decreases dramatically.

• Usage:
– Macrocell: Rural, highway.
– Microcell: Urban, street.
– Picocell: building, enterprise, station.
– Femtocell: indoor, very high-rate coverage


Cell Size v.s. Throughput and Usage
• As throughput demand and usage
increase, cell size decreases.


Traffic Trend (User Behavior)
• 29% of calls placed at home. [JD Power 2006]
• 57% of mobile usage at home or at work. [Northstream2007]
• 75% of 3G traffic to originate in-building by 2011. [VisionGain2006]
• In the future, more and more indoor mobile usage.


Shortcoming of Macrocell for Indoor Usage
• Macrocell cannot provide good signal strength for indoor
coverage. (Think about PHS.)


High-rate Indoor Coverage in Macrocell
• Small high-rate indoor coverage in macrocell.
• Poor coverage is major cause of churn. (Ex. 3G ⇔WiFior mobile ⇔fixed)
• People always want to use high-speed data–Femtocells can enable this.


Femtocell : Femtoforum
• Femtocells are low-power wireless access points that operate in licensed
spectrum to connect standard mobile devices to a mobile operator’s
network using residential DSLor cable broadband connections.
[Femtoforum]
• By 2011, 102 million users on 32 million access points worldwide. [ABI
Research]
• Femtocellbase station is also known as home base station, home access
point, or home NodeB.


Femtocell is Access Point
• Femtocell is a low-power domestic
access point
– Small-size cellular base stations (BSs)
for residential or small business
environments.
– Full-strength mobile technology but
simpler deployment.
– With full operator management.
– Improve indoor coverage and capacity.
– With internet-grade backhaul.
– At prices comparable with Wi-Fi access
points ($30~$200 for home usage).
– Typically support 2 to 6 concurrent
users.
– An alternative method to Fixed Mobile
Convergence (FMC).


New Business Opportunities
For wireless operators:
• Femtocell is expected to be a fixed-mobile substitution
(FMS) solution who can utilize it as a wireless DSL solution.
For wireline operators:
• Femtocell provides opportunity to enter the mobile virtual
network operator (MVNO)-based wireless markets


Femtocell Development
• In 2002, a group of Motorola engineer
introduced a Home Base Station technology
• In 2007, vendors formed the Femto Forum to
promote femtocell use
• In 2008, Sprint Nextel released home-based
2G femtocell built by Samsung Electronics that
works with any Sprint handset
• In 2009, Verizon and Vodafone rolled out their
femtocell network service with 3G standard


Existing Commercial Femtocell


Why Needs Femtocells? Data Coverage
• Problem:
– Mainly a issue for macrocellular
systems.
– Good voice coverage, but poor high
data rate coverage.
– Coverage degrades at high rates.
– Femtocells:Extend high-rate data
coverage.
– Mainly applies to: Cellular operators
with macrocell deployment.


Why Needs Femtocells? Basic Coverage
• Problem:
– RF coverage holes.
– Need to improve voice coverage.
• Femtocells:
– Provide basic service coverage.
– Home/Enterprise coverage.
– Mainly applies to : Operators for
suburban/rural coverage.


Why Needs Femtocells?
Capacity Enhancement
• Problem:
– Data loads exceeding capacity.
– Limited macro enhancement ability.
(Higher power may induce higher
interference.)
– Increase capacity economically by
offloading to femtocells.
• Femtocells:
– Provide localized capacity.
– Increase overall capacity.
– Mainly applies to:Highly saturated
operators.


Benefits of Femtocell Networks:
for Operators
• Low cost solution.
• Improve reliability.
• Increases both coverage and capacity.
• Reduce coverage holes and create new converged
services.
• Reduce macrocell backhaul capacity requirements.
• Reduces churn.
• Works with all existing handsets; no need for
expensive subsidizes on dual-mode (3G + WiFi).
• Increases 3G adoption.


Benefits of Femtocell Networks:
for Consumers
• Reduce cost. (Free calls at home!)
• No need for expensive new device.
• Superior indoor coverage and quality without
change in phones.
• Simplicity:
– One phone.
– One mode.
– One number.
– Location specific pricing.
• Seamless services across all environments.


Indoor Wireless Coverage: Femtocell
• Internet-grade service quality. (Wireline backhaul)
• Easy plug-and-play.
• Two typical operation modes of femtocells.
– Public (open)
– Private (closed)


Femto Usage Model
• Public (Open):
– No restrictions on subscriber to use the femtocell.
– All customers of a cellular service providers can access publicly
accessible Femto-AP.
– Hotspot type scenario: coffee shop or airport.
– The femtocell becomes another part of the public mobile network.
• Private (Closed):
– Only authorized users are allowed to connect to a privately accessible
Femto-AP.
– Access Control List.
– Non-authorised subscribers are denied access to the femto(redirected
back to the public macrocell network).
– Home or enterprise environments.


Competitors: UMA
• Universal Mobile Access (UMA), formerly
as Unlicensed Mobile Access
– Example: Cellular access outdoor + WLAN access
(VoIP) indoor.
– Requires a dual-mode mobile handset.
– Initial specifications were published in 2004.
– On the contrary, femtocell promises fixed mobile
convergence with existing handsets.


Comparisons of Femtocells, Distribued
Antennas, and Microcells
• These technologies enhances capacity and coverage by
shortening the communication distance.
• Comparisons from different perspectives.
– Capital expenditure (CAPEX).
– Operating expenditure (OPEX).
• Benefits and shortcomings.


Comparisons: Femtocells
• Consumers install mobile wireless
AP inside homes.
• Backhauls data through a
broadband gateway
(xDSL/cable/Ethernet/WiMAX)
over the Internet to the cellular
operator’s network.
• Capital expenditure
– Subsidized femtocell hardware.
• Operating expenditure
– Providing a scalable architecture to
transport data over IP.
– Upgrading femtocells to newer
standards.


Comparisons: Femtocells
• Benefits:
– Lower cost, better coverage and
prolonged handset battery life
due to smaller cell.
– Capacity gain from higher SINR
and dedicated BS to home
subscribers.
– Reduced subscriber churn.
• Shortcomings:
– Interference from nearby
macrocellsand femtocellslimits
capacity.
– Increased strain on backhaul
from data traffic may affect
throughput.


Comparisons: Distributed Antennas
• Operator installed spatially
separated antenna elements
(AEs) connected to a macro BS
via a dedicated
fiber/microwave backhaul link.
• Capital expenditure
– AE and backhaul installation.
• Operating expenditure
– AE maintenance and backhaul
connection.


Comparisons: Distributed Antennas
• Benefits:
– Better coverage since user
communicate with nearby AE.
– Capacity gain by exploiting both
macro-and micro-diversity (using
multiple AEsper macrocelluser).
• Shortcomings:
– Does not solve the indoor coverage
problem.
– RF interference from nearby
AEsdiminishes capacity.
– Backhaul costs between BS and AEs.


Comparisons: Microcells
• Operatorinstalled microcell
towers.
• Improve signal in urban
coverage.
• Capital expenditure:
– Installing new cell towers.
• Operating expenditure:
– Electricity, site lease, and
backhaul.


Comparisons: Microcells
• Benefits:
– System capacity gain from
smaller cell size.
– Complete operator control.
• Shortcomings:
– Installation and maintenance
of cell towers is prohibitively
expensive.
– Does not completely solve
indoor coverage problem


Indoor Techniques Comparison


Femto Characteristics
• Physique
– Physically small for limited space in some
households/offices
– Silent in operation while generating low levels of heat
output
• RF Power
– Tx RF power is between 10-100mW (lower than 1W by
WiFi)
– 3G handset is able to transmit at lower power levels when
being close to the femtocell
• Coverage
– Dedicated 3G coverage within a household (10-200m)
– Designed for a capacity of 2 to 6 end-users


• Backhaul
– Utilize Internet Protocol (IP) with a flat BS architecture
– Link to operator networks via wired broadband
connections
• Interference
– Macrocells vs Femtocells
– Femtocells vs Femtocells
• Security
– Security risks due to broadband internet (open access)
– Network security is managed by the IPSec protocol


• Operation
– Compatible with existing 2G/3G handsets and devices
– Operates in licensed spectrum owned by operators
– Remote configuration and monitoring system similar to
that used by the macro networks
– Remote management to enable QoS at the edge of the
network
– Includes provision for a services environment on which
applications may be added
• Worldwide Standard Support
– Developed to support both 3GPP (UMTS) and 3GPP2
(CDMA)
– Also supports emerging technologies such as WiMAX and
LTE

Femto Challenge
• Low-cost Implementation
– Under $200 per FC unit (or subsidize by carriers)
– Integrate Femtocell-on-a-chip onto Cable/DSL Modems
• Network Architecture Harmonization
– Diversity in mobile core networks
(CDMA, UMTS, WiMAX, etc.)
– UMTS-centric: Leverages the mobile core for hand-off
functions
– SIP-based: More functions within FC plus IP integration
• Remote Device Management
– Update software/firmware, monitor
status/performance, and do diagnostic tests (All from a
console in the operator’s network)


Femto Challenge
• RF Interference
– FC can interfere both macro-cell networks and each other
– Auto-configuration functionalities with cognitive radio
techniques
• Quality of Services
– Shared IP access link (voice, data, video, P2P, etc.)
– Traffic prioritization is essential (ensures consumer
satisfaction)
• Time/Network Synchronization
– 3GPP specifies that BS Tx frequencies be closely
synchronized
– GPS timing reference in FC units
– Communication with overlaying macro-cell networks


Femto Challenge
• Provisioning
– Plug-n-play (i.e. seamless installation and activation)
– Strong control on the remote activation of FC (i.e. SIM)
• Consumer Concern
– Femtocells = Home Base Stations (i.e. health and safety
issues)
– Access control mechanisms for FC owners
– Security is always an issue for IP-based broadband
connections
• Marketing
– Technical alternatives such as UMA and WiFi
– Compelling value propositions aimed at appropriate
segments


Formal Femtocell Reference

Reference: FemtoForum.org


Key Attributes of Femtocells
• Mature mobile technology:
– Femtocells use fully standard wireless protocols over the
air to communicate with standard mobile
devices, including mobile phones and a wide range of
other mobile-enabled devices.
– Qualifying standard protocols include
GSM, UMTS, LTE, Mobile WiMAX, CDMA and other current
and future protocols standardised by 3GPP, 3GPP2 and the
IEEE.
– The use of such protocols allows femtocells to provide
services to more than 3 billion existing devices worldwide
and to provide services which users can access from
almost any location as part of a wide-area network.


• Operating in licensed spectrum:
– By operating in licensed spectrum licensed to the service
provider, femtocells allow operators to provide assured
quality of service to customers over the air, free from
harmful interference but making efficient use of their
spectrum.
• Generating coverage and capacity:
– As well as improving coverage within the
home, femtocells also create extra network
capacity, serving a greater number of users with high data-
rate services.
– They differ in this from simple repeaters or ‘boosters’
which may only enhance the coverage.

• Using internet-grade backhaul:
– Femtocells backhaul their data over standard residential
broadband connections, including DSL and cable, using
standard internet protocols. This may be over a specific
internet service provider’s network, over the internet itself
or over a dedicated link.
• At competitive prices:
– The large volumes envisaged for femtocells will allow
substantial economies of scale, driving efficiencies in
manufacturing and distribution in a manner similar to the
consumer electronics industry and with pricing projected
to be comparable with access points for other wireless
technologies.


• Fully managed by licensed operators:
– Femtocells only operate within parameters set by the
licensed operator.
– While they have a high degree of intelligence to
automatically ensure that they operate at power
levels and frequencies which are unlikely to create
interference, the limits on these parameters are
always set by operators, not the end user.
– The operator is always able to create or deny service
to individual femtocells or users. This control is
maintained whether the femtocell itself is owned by
the operator or the end user.


FEMTOCELL DEPLOYMENT


Femtocell Configuration Scenarios

• Macrocells are operated by a mobile wireless operator, while femtocells are
privately owned and connected to a broadband service provider, such as an
Internet Service Provider (ISP).
• Thousands of femtocells may co-exist in a coverage area of a macrocell-based
cellular network.


Femtocell Network Configuration
• There are three possible types of femtocell
network configurations based on the
availability of a broadband connection
(e.g., ISP) and on the coverage of the
macrocellular network :
– Type A : a single stand-alone femtocell
– Type B : a network of stand-alone femtocells
– Type C : a femtocell network integrated with a
macrocellular infrastructure


Femtocell Network Configuration


Type A - a single stand-alone femtocell
• This could be the case of a remote area with :
– no macrocellular coverage
– a poor coverage area
• indoor
• macrocell edge
– when no other neighboring femtocells are
available.
• this type of a configuration extends the service
coverage into remote areas.


Type B - a network of stand-alone
femtocells
• In this scenario, multiple FAPs are situated within
an area in such a way that a radio signal from one
FAP overlaps with other FAPs’ signals.
– There is no macrocellular coverage
– Ethe coverage is poor.
• Femtocell-to-femtocell handovers are present
and need to be handled by the femtocellular
network.
• As the Type A configuration, the Type B
configuration is also able to extend the service
coverage into remote areas.


Type C - a femtocell network integrated
with a macrocellular infrastructure
• This scenario can be viewed as a two-tier
hierarchical network, where :
– the macrocells create the upper tier ; and
– the femtocells the lower tier
• Handover between macrocells and femtocells, as
well as handover between femtocells, are
common occurrence in this scenario.
• This configuration improves the indoor service
quality and reduces the traffic load of the
macrocells by diverting traffic to femtocells.


Deployment : Greater Femtocell
• Not only for the home!
• Femtocell economies of scale deliver cost-effective deployments in offices
and in high-traffic or low coverage locations
• Femtos in the enterprise and metrozone
• Scope for cost-effective access to rural and developing markets via
appropriate backhaul solutions


Applications : Indoor Femto


Applications : Data Femto


Applications : Outdoor Femto


Femtocells Initially Target Residential
and Small Enterprise Hot Spots


Femtocells Evolving Towards Femto


WIFI-BASED OFFLOADING


Wifi-based Offloading Types
• We can divide the WiFi-based offloding into
three distinct offload categories based on
factors such as their specific network
consideration and customer profile:
– 1. Network bypass
– 2. Managed network bypass
– 3. Integrated data offload


Network Bypass
• Network bypass is the process of taking mobile
subscribers in Wi-Fi range and transparently moving
their data onto the Wi-Fi network – in the process
completely bypassing the core network for data access
(voice continues to be delivered via the core network).
• This can be achieved by putting a small application on
the subscriber’s device that detects when they are in a
Wi-Fi area and automatically moves all data access to
that network.
• It does not require that any additional network
equipment be installed.


Network Bypass


Network Bypass
• However it has two major drawbacks :
– First, the carrier loses visibility and control of their subscriber while
they are in the Wi-Fi area. This will prevent the carrier from billing for
usage (if they have a metered service like in some countries) or
providing any other features that they generally provide to their
customers on their 3G networks.
– Second, since there is no connectivity between the core network and
the device, the carrier is unable to deliver any 3G content leading to
potential loss of revenue.
• In spite of these drawbacks, some carriers have opted to deploy
such a solution as an immediate work around to their network
overload problem – especially since they are reasonably easy to
deploy.
• But that is just a stop gap and in the longer term they will have to
enhance their solution to move to one of the next two offerings.


Managed Network Bypass
• The next levels of carriers are those that are uncomfortable with this level
of desegregation of the two networks and the resulting loss of subscriber
control.
• That could be for multiple reasons.
– Some carriers provide metered network access which requires subscriber
control.
– Others deliver services, like parental control/filtering, that they are not able to
provide in a completely desegregated network.
– Others insist on secure access for their subscribers when they are accessing
internet services via Wi-Fi.
– And finally others simply want to be aware of subscribers browsing habits for
targeted marketing or security reasons.
• This solution can be delivered without having to fully integrate the two
networks. However, while this solution does allow the carrier to ‘manage’
their subscribers, it still prevents them from delivering any carrier
subscribed content is in the Wi-Fi zone (a rather irritating user experience
for some!).
• Nevertheless, it does solve the issue of data overload and may work well
for some carriers that do not have any significant walled garden content to
deliver.

Managed Network Bypass


Integrated Data Offload
• The final set of carriers insist on full integration of their
core and Wi-Fi networks to provide a completely seamless
experience to their subscribers when they move between
the two networks.
• They want to not only manage the customer but also want
to be able to deliver all carrier subscribed content to the
subscriber while they are in the Wi-Fi network.
• These carriers tend to have a significant amount of content
available to them via their 3G network (e.g. IP. TV. etc.).
• This is only possible when a ‘bridge’ is established between
the two networks through which data flow can be
established between the two networks.


Integrated Data Offload


Wifi Offload based on 3GPP I-WLAN
• Mobile operator and WISP communities has been to devise
improvements that would deliver a more ubiquitous; more
automated; more secure; and ultimately more utilized mobile Wi-Fi
offload experience.
– SIM Authentication – where the subscriber credentials contained on
the SIM/USIM card can be used to authenticate capable Cellular
devices on the Wi-Fi network.
– Mobile Network Interworking – specification of hardware and
software elements required for these newly defined authentication
methods to interact with the mobile network.
– The components specified by the 3GPP included :
• A WLAN Access Gateway (WAG) to handle the policy enforcement
• Accounting functions and additional Packet data gateway (PDG) functionality
to handle session management, IPsec tunnel termination routing and charging
events in the interaction between the connected device with the core packet
services of the operator.
• These specifications have been defined under a 3GPP architecture known as I-
WLAN


Wifi Offload based on 3GPP I-WLAN


Commercial Worldwide Wi-Fi


Public Wi-Fi Usage


US Offload Scenarios


WiFi Offloading Cost Reductions

• The cost savings associated with offload are significant according
to exclusive data provided by Chetan Sharma Consulting.
• Operators deploying a WiFi offload strategy can expect savings in
the range of 20 to 25 per cent per annum.
• In the US market, operators will save between $30 and $40 billion
per annum by 2013 through an offload strategy alone.

THANK YOU


Mobile data offloading

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