mobile data offloading

MOBILE DATA OFFLOADING:FEMTOCELL VS. WIFI

ASTON PRIMERA PASTEUR HOTEL – BANDUNG, NOVEMBER 10-11, 2011

DR. IR. JOKO SURYANALaboratory of Radio Telecommunications and MicrowaveInstitut Teknologi Bandung

• MBB operator Problem

• Why do MBB operators need offloading ?

• What is Femtocell and Wifi offloading ?

• How do we implement ?

– Femtocell

– Wifi offloading

• Business Cases

Outline

2Mobile Data Offloading: Femtocell vs. Wifi

Operator OptionsStrategy 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 networksor indoor systems.

4. Pricing strategies and service differentiation5. 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

cannot2. It can offload traffic from the macrocell layer and improve

macrocell capacity3. Addition of a femtocell layer will significantly improve the

total network capacity by reusing radio spectrum indoors4. There is a growing demand for higher and higher data rates5. Femtocells can provide significant power saving to UEs6. The use of femtocell is ‘greener’ than macrocells7. 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

Femto Stations

Macro Base Stations

2G3G

4G

As throughput demand and usage

increases, cell size decreases

Current Traffic Trend

Future Traffic Trend

Outdoor

Home

Work


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 usageincrease, 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 engineerintroduced a Home Base Station technology

• In 2007, vendors formed the Femto Forum topromote 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 theirfemtocell 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, DistribuedAntennas, 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 femtocellslimitscapacity.

– 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


Femto Characteristics• 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


Femto Characteristics• 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.


Key Attributes of Femtocells

• 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 femtocellnetwork 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 femtocellularnetwork.

• 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 viaappropriate 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


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