The arrival of varied smartphones and devices has inevitably encouraged greater data consumption. Users are now more sophisticated and demand nothing less than best network performance. Smartphone generally accounts for higher ARPU and represents potential new revenue streams for enabling quad play services. Operators are aggressively addressing these challenges and improving the quality of their solution to retain existing customers and offering better service experience to build loyalty. WiFi adoption as data offloading is gaining momentum as it improves user experience while lowering the cost of service providers. Correctly implemented, it can ease up to 20% of traffic with substantial impact of freeing up the spectrum and load balancing. Offloading data to WiFi hotspots is economically attractive, because many carriers already operate a substantial number of hotspots. In this paper, we will examine how dynamic data offloading can be further optimized with 3GPP based Access Network Discovery Selection Function (ANDSF). ANDSF describes how the inter-system mobility between 3GPP systems and non-3GPP systems (ie: WLAN, WiMAX, CDMA) policies and priorities can control the conditions for which a device (UE) connects to which wireless network.

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APPLICATION NOTE

2. Abstract
The arrival of varied smartphones and devices has inevitably encouraged greater data consumption.
Users are now more sophisticated and demand nothing less than best network performance and
willing to switch providers at the slightest dissatisfaction. Smartphone generally accounts for higher
ARPU and represents potential new revenue streams for enabling quad play services. Operators are
aggressively addressing these challenges and improving the quality of their solution to retain existing
customers and offering better service experience to build loyalty.
WiFi adoption as data offloading is gaining momentum as it improves user experience while lowering
the cost of service providers. Correctly implemented, it can ease up to 20% of traffic with substantial
impact of freeing up the spectrum and load balancing. Offloading data to WiFi hotspots is
economically attractive, because many carriers already operate a substantial number of hotspots.
In this paper, we will examine how dynamic data offloading can be further optimized with 3GPP
based Access Network Discovery Selection Function (ANDSF). ANDSF describes how the
inter-system mobility between 3GPP systems and non-3GPP systems (ie: WLAN, WiMAX, CDMA)
policies and priorities can control the conditions for which a device (UE) connects to which wireless
network. Operators have the flexibility to manage context information in network discovery and
selection procedures in push and/or pull mechanism with a policy management and control
component as network-based and client-based solutions. The client-based implementation is
described with reference to applying real-time connection state and policy control. Policy
enforcement and policy management is mapped more accurately with an overall knowledge of the
network at any given point of time. By intelligently managing the distribution of network load,
congestion can be minimized.
APPLICATION NOTE
APPLICATION NOTE

3. Contents
Overview 01
Dynamic Data Offloading a Study Model 02
- WiFi or Femtocell
- Why Introduce Dynamic Data Offload (DDO)
- Data Offloading Tool
- WiFi Data Offloading
Access Network Discovery and Selection Function 07
- Where is the Intelligence in Dynamic Data Offloading
ANDSF Implementation 10
- Policy Control with ANDSF
Values of Dynamic Data Offloading Capability with ANDSF 12
- Prioritization of Access Based on Network Availability
- Time Based Policy Control
- Application Policy Control
- Power Management
- Traffic Routing
Conclusion 14
Offload Early, Connect Intelligently 15
References 16
APPLICATION NOTE

4. Overview
Mobile networks are inherently constrained with the availability of spectrum and bandwidth to support the rapidly
growing demands of mobile data. In a recent report by Cisco¹, it is estimated that global mobile data traffic growth will
increase by a factor of 26 times between 2010 - 2015.
The way we interact with the internet is changing. The arrival of data-centric devices (eg: iPhone, Android , Blackberry),
lower subscription prices, easy access to applications is driving data consumption and content like never before. Even
with operators implementing transcoding methods to adapt smaller screen sizes, for pictures and videos , operators still
struggle to satisfy data demands, managing congestion and improving subscriber experience.
WiFi offload is an alternative method to ease the burden of bandwidth capacity. However, the methodology of offloading
can be made either tightly-coupled or loosely coupled to the core network. In the tightly-coupled method, the network
operator retains visibility and control over the traffic offload related to the location where traffic streams are offloaded or
bypassed over the network operator and relevant policies provisioned. Overall data offloading implementation can be
more secure and comprehensive by complementing i-WLAN framework with dynamic data offloading. Further
information to i-WLAN can be referenced in a previous whitepaper titled “Managing Data Offloading Securely over WLAN
access networks via I-WLAN”.
Within the loosely-coupled method, data offload is unmanaged. By forcing the user onto WiFi, the network operator has
no visibility on the user traffic and not subject to the operator’s policies. The user experience associated to the
accessibility of service for example to web browsing, online shopping, downloading music or streaming video will be at
risk of un-trusted network attacks such as disclosing or tampering of user details. Other issues pertinent, which may
involve some form of credit card purchase. Such transactions are not subject to operator controlled service rules – since
the user subscription relationship is decoupled from its control policy.
The applied access rules previously enforced within the walled-garden parameters will be “lost” once the IP traffic
bypasses the packet data network (PDN) en-route to the Internet directly. These IP traffic is identified and routed purely
on the IP address regardless of the policies enforced on the service application level.
01
¹ Source: The Cisco® Visual Networking Index (VNI) Global Mobile
Data Traffic Forecast Update 2011
APPLICATION NOTE

5. Dynamic Data Offloading a Study Model
Networks are generally not equally utilized at any given time. Take for example a 3G cell site in the central business district
of Kuala Lumpur during peak hours will have full utilization. The 3G cell supports up to 20 users at 14.4Mbps (assumes
average throughput of 512kbps/user). Due to congestion, the number of user doubles to 40, but the average throughput
per user is halved and continues to provide data services at sub-standard speeds with the risk of user dissatisfaction.
However, another operator operating an alternative access technology (be it WiFi or WiMAX) within the vicinity of
overlapping the 3G cell site is not fully loaded. Often, the internet bound traffic does not contribute to ARPU but occupy
the network capacity. How effectively can the 3G operator capitalize on the availability of bandwidth capacity of the
adjacent WiFi network to balance the network load efficiently and improve user experience?
WiFi or Femtocell
Given that spectrum is a premium limited resource, operators are turning to WiFi or femto-based offload to ease traffic
needs. The stark difference between WiFi and femtocells lie in the spectrum utilization. WiFi operates in unlicensed band
with a larger bandwidth capable of supporting data rates of 11Mbps up to 54Mbps (peak theoretical) and couples the
backhaul onto the fixed line, effectively freeing-up the 3G spectrum and improving capacity. Femtocells on the hand,
operates in licensed band wirelessly over the shared air interface of 3G network. Femtocells can improve indoor
coverage, but not increase capacity.
WiFi offload improves capacity at a fraction of the cost, since there is already WiFi infrastructure readily available.
Dynamic Data Offloading can be initiated with an intelligent connection client in the device (UE). The device (UE) is able
to determine the subscriber state early in the network and exchange information with the policy controller in real-time to
adjust network connection state.
02
APPLICATION NOTE

6. Why Introduce Dynamic Data Offload (DDO)
The periodic traffic surge is noticeable during peak hours. Instead of adding a second carrier on the 3G network or
adding new cell sites with impacts on radio planning and so forth, operators can take advantage of dynamic data offload
early to detect congestion and re-route the traffic to alternative WiFi access. The network selection and discovery
capability is heavily dependent on the intelligence behind connectivity. The main drivers for DDO is apparent in
- Improving over the air radio capacity
- Relieving transmission backhaul dependencies
- Delaying CAPEX investment for network upgrade
- Subscriber retention and improving user experience
- Creation of new revenue streams as a result of better analysis of usage behavior
- Separation of revenue generating traffic and low value bulk internet traffic
- Scalability of single connection client without cost impact to backend processes
Data Offloading Tool
Greenpacket’s Intouch Connection Management Platform (ICMP) is an easy to use, single-client connection
management solution that combines device (UE) and user management. The single-client software converge multiple
network access and executes data offloading transparently. Incorporating customizable features and capabilities, the
ICMP can intelligently detect the availability of access networks based on signal strength and user policies allowed for
accessing certain data services on a cellular network (such as 3G) and if there is less congested alternative network (such
as WiFi, WiMAX, EVDO) available in the same vicinity. ICMP switchers the user from 3G to WiFi without interruption to
connectivity by ensuring a seamless user experience. As a result of the in-built intelligence, the ICMP can determine the
best available networks for data offload within the pre-loaded local policy in the absence of network policy. The added
advantage of the make before break further enhances the seamless connection experience, without requiring a switch
of different connection profiles.
Figure 1: Intouch Connection Manager GUI.
03
APPLICATION NOTE

7. WiFi Data Offloading
The efficiency of offloading 3G cell to WiFi can be studied from the data rates, coverage radius and the density of
subscribers supported. The other considerations primarily will revolve around the transmission backhaul and
installation relevant in the CAPEX investment. Details of cost savings related to data offloading are not discussed here.
Reference to a previous whitepaper “Operators Can Save $14 million Yearly Through Data Offloading”, a TCO Study
describes it separately.
The efficiency of network planning directly impacts the performance and quality of the network. There is no defined
notion on the best network. Congestion is measured against how much data traffic deteriorates to affect user experience
that is expected of the service.
The support of voice service is 12bkps. Theoretically, in a given single 3G carrier at 5MHz channel bandwidth, S 111
configuration, it can support up to 1,000 voice subscribers. The number of subscribers supported per cell is dependent
on the radio planning parameters for a given speed and average throughput per cell. In case of a data service, the
minimum data speed is 256kbps to support VoIP.
For a given WiFi cell, the average cell throughput is 11Mbps (802.11a standard). It can go up to 54Mbps (802.11g
standard). The added advantage of WiFi is the greater channel bandwidth of 22MHz. Therefore, the achievable cell
throughput is higher by a factor of 4.
The study of WiFi channel deployment and 3G channel deployment can be looked at the capacity efficiency. Assuming
the comparison is made on average data speeds of 512kbps for both WiFi and 3G. A typical 3G carrier can deliver
average throughput per cell of 14.4Mbps. If under normal condition, the node B can support up to 28 subscribers at
the average 512kbps per user. Given that congestion occurs by 70% utilization, the number of active subscribers
supported per node B is approximately 20. (Active subscribers is defined as active concurrent users, excluding idle
and connected subscribers)
In WiFi (802.11 a), there are up to 3 non-overlapping channels. Therefore, the total throughput achievable is up to
33Mbps. At 70% utilization, the active subscribers supported per WiFi cell is approximately 45. The capacity supported
is 55% greater than a 3G node B.
Operator owned WiFi and Partner WiFi
Operators that have aggressively embraced a WiFi offloading strategy, such as PCCW and AT&T Mobility, estimate that
about 20 % of their overall data traffic is over WiFi networks.
In cases where operators do not operate WiFi networks but extends its coverage often partner a 3rd party WiFi provider.
Such wholesale method to support the additional traffic for a fixed cost is a feasible option with no direct impact to the
existing infrastructure and backhaul requirements.
With the acquisition of Wayport, AT&T expanded its WiFi network to offload traffic from its cellular network as a network
growth strategy. With coverage of 85%, it is an example of a successful WiFi offload strategy to ease the burden on its 3G
mobile broadband where the carrier has suffered as a result of iPhone driving data usage. Most* of AT&T's smartphones
now support auto-authentication at the carrier's AT&T-affiliated WiFi hotspots, which number more than 23,000-- WiFi
usage does not count against a subscriber's monthly smartphone data usage plan.
*source: Wi-Fi offload for mobile networks: 20% of traffic and counting
FierceBroadbandWireless http://www.fiercebroadbandwireless.com/special-reports/
04
wi-fi-offload-mobile-networks-20-traffic-and-counting#ixzz1MsZdbugd
APPLICATION NOTE

8. Site Count
40
35
30
25
20
15
10
5
0
3G WiFi
Supports up to 20 Supports up to 45
active users per site active users per site
Figure 2: WiFi and 3G Site Count Study for average user throughput of 512kbps.
In terms of the coverage, a 3G cell range is up to 5 times of a typical WiFi cell range. Within a dense urban morphology,
a 3G cell range can vary between 1-2km. (cell ranges are inter-dependent on radio planning parameters such as various
modulation schemes, terrain, density of subscribers, achievable speeds. This assumes the average vehicular speed of
30km/hour). On the contrary, WiFi cell range vary between 100-200m, equating to more WiFi APs per km2 coverage
radius. Despite WiFi cell range of 5 times less than a 3G node B (for every 1km, 5 WiFi APs are required), the trade-off of
cell capacity is far greater.
If for example the density per area is 1,000 users (assumes single device (UE), single user)per 1km2 radius with 70%
active users; the 700 active subscribers requires up to 35 3G cell sites to support. However, with WiFi the number of cell
sites is 55% less at 16. A typical WiFi AP cost is around USD100-200, while a 3G node B is USD30,000². For an
equivalent number of cell sites, the CAPEX savings are significant. Instead of deploying more node Bs, operators can
leverage on the WiFi network within the vicinity as means of extending its coverage and relieving heavy internet traffic
during or off peak hours.
² Average node B of S111 configuration in emerging markets.
05
APPLICATION NOTE

9. Additional
Base Station
Increasing Cost
WiFi AP
55% greater
capacity
Increasing Capacity
Figure 3: Cost Comparison of WiFi AP and 3G Node B.
WiFi architecture exhibits significantly higher data rates than 3G and it could be easily modified to increase the number
of connection to open or partner WiFi network with the presence of a WiFi AP. 3G provides continuous connectivity
over further cell range, with lower data rates and relatively high cost while WiFi is intermittent with high bursts of data
(other consideration excluded in this study includes the impact of backhaul, leasing of transport network and
installation works).
With better control over data offload solutions, such as dynamic data offload via Access Network Discovery and
Selection Function (ANDSF), operators can understand the user state and commensurate network state contributing to
congestion. Most importantly, it detects the source of congestion trigger and resolves the issue early, before it affects the
service experience. The intelligent ANDSF enabled connection client can push connection status with granularity such
as location corresponding to cell ID or SSID to the Policy Charging and Rules Function³ (PCRF). The PCRF perform
real-time policy response network state at applications to identify the congestion point. Each service stream can be easily
identified by the IP address where it originates and the destination IP. By having a direct connection to PCRF, the policy
information is pulled by the ANDSF connection client to determine whether a handoff is necessary to maintain the
connection as applied in the examples above.
³ The PCRF server in this instance is 3GPP ANDSF standard compliant. ANDSF module can
06
exist independently or implemented within proprietary policy control and management server
that may comprise of several functional modules, depending on the network architecture.
APPLICATION NOTE

10. Access Network Discovery and Selection Function
Access Network Discovery and Selection Function (ANDSF) is a 3GPP standard defined in TS 22.278, TS23.402 and
TS24.312 specifications through which the operator can provide inter-system mobility policies and priorities to control
where and when, the conditions for which a device (UE) connects to which wireless network. It supports the
inter-working solution between 3GPP networks and non-3GPP access (ie: CDMA, WiMAX, WLAN) combining
network-based and client-based solutions for both trusted and un-trusted non-3GPP access networks.
For operators which have both WiFi and 3GPP infrastructures, it is possible to use ANDSF to implement dynamic data
offload. Dynamic data offload can complement WiFi data offloading in a structured method. Within ANDSF, the context
of offload can be made more accurately at the user level ie: bearer-aware and closely coupled to the policy management
and control component4 (eg: PCRF server). Instead of relying heavily on the policies enforced at the core network
(backend), actual decision making process can be made real-time as a result of direct relation to the user activity at the
device (UE).
The motivation for implementing ANDSF is largely driven by the need for better bandwidth utilization. Bandwidth
utilization is highly relevant to the control and optimization for mission critical applications like VoIP, P2P streaming and
video streaming.
In the following sections, we will discuss the impacts of applying intelligence in data offloading, where operators have the
flexibility to manage context information in network discovery and selection procedures in push and/or pull mechanism
with a policy management and control component. The study of ANDSF will be described from a client-based
implementation on the device (UE). Operators controlled and service-aware selection of wireless networks can bring
benefits to the operator looking to offload using WiFi. The ability to retain visibility of which IP traffic is routed over WLAN
(eg: best effort internet traffic like email, web browsing, which are non-revenue generating) and which IP traffic is
maintained on the 3G link (eg: VoIP that is quality sensitive). This may contribute to better understanding of the traffic
models relevant to minimizing congestion.
07
4 Policy management and control component is used interchangeably with
PCRF in this application note.
APPLICATION NOTE

11. Where is the Intelligence in Dynamic Data Offloading
Today’s network is mixed with dual radio scenarios, such as WLAN and 3GPP based networks (ie: WiFi-3G). The two
access networks are not “aware” of each other. It lacks the intelligence to control the access network of the device (UE)
state in the other access network. Given that WLAN is not a “controlled” access network and works in unlicensed
spectrum the only network condition of radio quality and the performance through that WLAN is made available only to
the device (UE). Hence, the device (UE) is better positioned to decide the connectivity options. Most often, the network
selection is managed by a connection manager in the device (UE).
Connection Manager Policy Controller
Internet
Mobile Broadband Operator Core Network
(3G UMTS)
Each Network Policy includes:
• Access Technology Type (3G, WiFi) • Network Discovery List (3G, WiFi SSID)
• Access Network Priority • Policy Validity (8 hours)
• Location
Figure 4: Dynamic Data Offload with ANDSF.
08
APPLICATION NOTE

12. Default connection at RAN may not always be most optimal at a given point in time from core network connectivity, the
end-user, application or service perspective. However, intelligent connection managers allow it to search and prioritize
the best available connection based on pre-defined requirements such as signal strength and operator policies. In this
manner, intelligent resource management provides a cost-effective way to support the data traffic by optimizing network
radio resource, balancing the network load, reducing network congestion and delaying CAPEX for future upgrades.
ANDSF may provide a list of access networks available in the vicinity of the device (UE) for all the available access
technology types requested by the device (UE). Instead of unnecessary background scanning, the ANDSF connection
monitoring may be carried out to handover or perform cell selection/re-selection measurements in which the device (UE)
monitors the received signal strength indicator signal levels (RSSI) received from different base stations. This reduces the
battery drain on the device (UE) without continuously scanning in the background.
By selectively triggering the connection of device (UE) to a given threshold or the preferred available access network
types based on inter-system mobility policies, the network load can be balanced or spread out to the availability of
network radio resource at the point where congestion is likely to occur. Once the device (UE) receives the policy
relevant to location and validity of time interval, the ANDSF will apply the current conditions to match the policy.
Policies can be tailored for different access networks, regardless of devices (UE) to enable seamless connectivity
experience. In the longer term, effective access network monitoring can reduce the pressure of CAPEX upgrades to
sustain the increased capacity.
The added intelligence of ANDSF brings benefit to the negotiation of connection state by various operator policies
supported as
• Location-Aware Policy – cell ID or associated SSID is checked against the policy database for specific locations that
are preferred/relevant
• Access Network Discovery Policy – list of available access networks(RAT type) that are available within the vicinity and
facilitation of prioritized access network selection for network handover
• Time-based Policy – configuration of policy validity “time to live” interval to current location and profile
• Subscriber-based Policy – dynamic allocation of subscriber package and profile
09
WHITEPAPER NOTE
APPLICATION

13. ANDSF Implementation
Policy Control with ANDSF
Although operators are increasingly looking at using WiFi for offload in congested areas, it risks losing visibility over traffic
policies that were configured for the user once it routes through WiFi. What is lacking is a way for the network to
communicate to users (applications and/or websites they are using) a real-time or predicted measure of the network’s
congestion levels.
ANDSF keeps a direct relationship to the core network by providing dynamic provision of information to the device (UE)
for network discovery and selection procedures related to non-3GPP accesses; the ANDSF connection client can pull
and/or with a combination of pull-push may be supported with the policy charging and rules function (PCRF). ANDSF
complements both the PCRF and Deep Packet Inspection (DPI) module. By means of direct device (UE) communication
at applications level towards the PCRF, the ANDSF provides indication to the device (UE) on the selection of network by
reducing over the air processing required in the device (UE) to establish the wireless link.
Connection Policy Control
Manager Server Server
Application
Pull relevant
Server
connection policy,
cell-ID, time
Subscriber
Push policy decision database server
based on location, subscriber
entitlement, application type
ANDSF client in CM GGSN / PDSN Internet
3GPP Access
3G Network
WAG
Non-3GPP Access
Figure 5: ANDSF Architecture
10
APPLICATION NOTE

14. Detecting users, locations, applications or device (UE) type is crucial in determining the conditions for triggering offload,
and under what circumstances. Increasingly, applications and devices (UE) are becoming more aware of their context –
what network they are connected to, what is the state of performance of the network and so forth for a given time and
location.
The ANDSF connection client pull subscriber state information (location based cell ID, preconfigured policies and time
configurable connection policy), from the PCRF. The ANDSF connection client will check the existing policy. If the policy
is alive, it applies the current policy. Otherwise, the ANDSF connection client will request for a new policy. Similarly, the
business rule engine in the PCRF pushes dynamic and subscriber specific policy decisions by checking the subscriber
specific data (eg: subscriber package, access entitlement/restriction) accordingly.
Based on this information, PCRF dynamically modifies the connection policy rule depending on the type of policy control
required, acting as a policy management point. The policy decisions are delimited by validity of the location, time of day
and discovery information. The ANDSF connection client is an intelligent module that learns of subscriber state and
network state parameters over time to detect the corresponding bearer (WiFi, 3G, WiMAX) to the suitability of context
(service, device type) connection. These parameters ensure that the operator retains visibility of which IP traffic are
critical and retained on the 3G or WiFi connection.
Through connection shifts based on context information and by combining knowledge about real-time network levels,
applications and devices (past data usage history), gives greater control on offload strategy rather than a single isolated
measurement of the radio conditions. By re-prioritizing subscribers on a congested cell site or offload all mobile data
traffic or laptop to WiFi, during peak congestion periods, specific times of day, days, weeks or combination of them,
operators can have the flexibility of controlling bandwidth, QoS availability and application-specific service corresponding
to service level agreements.
11
APPLICATION NOTE

15. Values of Dynamic Data Offloading Capability with ANDSF
Prioritization of Access Based on Network Availability
During network selection process, the ANDSF can provide a list of access networks available in the vicinity of the device
(UE). The configurable network access discovery is facilitated by the ANDSF connection client that interacts with the
PCRF at the application level communication. Dynamic discovery information of location by ANDSF connection client is
communicated to the device (UE) in a pull mechanism.
The PCRF provides information and policies on the neighboring cells to determine when to offload traffic or triggered due
to congestion. By means of prioritization of congested networks, the PCRF pushes decisions to the device (UE) via the
ANDSF connection client to manage congestion at per subscriber level or per cell level connection. In data offloading,
the intelligent policy control information exchange with ANDSF complements the offload decisions based on the
availability of WiFi networks in range or otherwise.
Time Based Policy Control
The device (UE) initiated connection switching is a carried out by ANDSF connection client. The ANDSF connection client
downloads the user policy relevant to location, connection policy and configurable “time to live” policy - matching it
locally to the pre-provisioned operator policy. If the connection policy is alive, it applies the current policy. In case of the
near expiry or already expired, the ANDSF connection client will request for new policy from the PCRF.
Upon receiving the newly generated connection policy from PCRF, the ANDSF connection client replaces the existing
policy with the new policy and the re-prioritized access network list comes into effect until expiry (ie: if switched from
3G to WiFi, the ANDSF connection client shall not connect to 3G network until expiry of policy or change of location).
In case of failure to update policy, the ANDSF connection client can apply the localized rule manager within according
to priority, best performance or most economic policy (eg: ANDSF connection client’s connection policy is configured
to WiFi by default).
12
APPLICATION NOTE

16. Application Policy Control5
The PCRF supports time based metering and subscriber based policy for fair usage control. Take for example a capped
postpaid fair usage plan. Operators usually enforce an average bandwidth threshold policy with flexibility of some burst
access. Through the adaptive policy control approach of the PCRF, the operator has continuous access to real-time
information about the subscriber’s behavior, collected throughout the session.
If high level of traffic is continuously sustained over the aggregate total usage volume (daily/weekly/monthly) and the
subscriber policy is breached, it may trigger the PCRF to generate a new policy decision based on subscriber specific
data such as data plan/package, access entitlement and usage pattern. Similarly, the ANDSF connection client (at the
per cell-level connection or per subscriber level) interacts with the PCRF data offload module by pushing the available
SSID list within the vicinity to the PCRF access to network bandwidth resources accordingly. As a result, the selective
data-offload is invoked with a re-ordered SSID list. The service level is downgraded to the next service tier to protect the
network against abuse until the congestion subsides. Alternatively, the PCRF can also trigger alert notice to upgrade to
the next service tier subject to charge difference, depending on the implementation configured.
This approach enables the operator to distinguish between temporary, unexpected increases in subscriber traffic and
network abuse. The mechanisms which context awareness from the perspective of PCRF can facilitate policy
enforcement through the device (UE) include configuring WiFi on/off directive and forcing offload through the ANDSF
connection client.
Power Management
The network discovery and selection has been an issue from a device (UE) perspective, because of battery consumption
and turning on and off two radios simultaneously. With real-time network congestion state information from ANDSF
server, the ANDSF connection client may employ the policy to avoid unnecessary background scan by the device (UE)
to prolong battery life. Different access networks have different effects on the speed and connection establishment time
that affects the intensity of battery consumption. The access network selection process can be made more efficient with
the ANDSF ordered access network list.
Traffic Routing
Operators routing traffic directly to the Internet as a result of offloading, loose the visibility of control over the subscriber
policies. With a managed data offload approach, operators can have visibility of IP traffic which is routed over WLAN (eg:
best effort internet traffic) and which IP traffic is maintained on the 3G link (eg: VoIP). The combination of PCRF, DPI and
ANDSF to conduct granular data offload, ensures traffic routing across the network allocated to particular services can
be optimized for specific bearer types. By having the visibility of IP traffic, operator can analyze user behavior related to
the bulk of IP traffic generated. The added intelligence can be applied in user segmentation and creation of new service
streams to segregate high ARPU potentials, moderate users and low bandwidth users.
5 Application policy control is part of the ANDSF standard. The deployment is proprietary,
depending on the implementation of the ANDSF server and network architecture.
13
Greenpacket ANDSF client is currently testing the functional attribute with select vendors.
(vendor names are withheld due to non disclosure agreement in effect)
APPLICATION NOTE

17. Conclusion
Wi-Fi is suited for data offload as echoed in AT&T and PCCW’s business model. Today millions of subscribers are
already using WiFi as their primary source for data/internet access whether as part of their subscription plan or a free
service. As observed, WiFi has played a role in relieving congestion, but at the same time generating more usage.
The implementation of Dynamic Data Offloading via ANDSF can further enhance the both the 3G and WiFi experience.
Dynamic data offloading is necessary to minimize congestion. The earlier a congestion trigger is controlled and managed
the operator can continue to improve the distribution of network resources from the perspective of spectrum planning.
Since networks do not behave identically nor follow the same traffic model, data offloading exercise can facilitate
balancing the load whenever congestion occurs. Policy enforcement and policy management is mapped more
accurately with an overall knowledge of the network at any given point of time, rather than a silo representation at the
aggregation point at the backend. More and more operators are embracing data offloading as means to satisfy the
bandwidth requirements. With dynamic data offloading methodology, the operators can capitalize on extending its
network, while maintaining a balanced network investment.
14
APPLICATION NOTE

18. Offload Early, Connect Intelligently
Greenpacket welcomes you to embark on dynamic data offloading today with ANDSF for optimizing your network
operations. At Greenpacket, we understand the demands placed on Operators like you. Our solutions are designed to give
you the flexibility to constantly deliver cutting-edge offerings without exhausting your capital and operating expenditures.
With Greenpacket, limitless freedom begins now!
Free Consultation
If you would like a free consultation on how you can apply data offloading with ANDSF, feel free to contact us at
marketing.gp@greenpacket.com. Kindly quote the reference code, SAP0611 when you contact us.
15
APPLICATION NOTE

19. References
1. The Cisco® Visual Networking Index (VNI) Global Mobile Data Traffic Forecast Update 2011.
2. The Role of Adaptive Policy Control and Smart Caps in Managing Mobile Data Growth.
3. 3GPP TS 23.402 V8.0
3. Bearer-aware policy management and charging, Disruptive Analysis, Dean Bubley.
16
APPLICATION NOTE

20. About Green Packet
Greenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board
of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,
Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in
readiness for new markets.
We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications
Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric
multimedia communications services regardless of the nature and availability of backbone infrastructures.
At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade
solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new
demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless
freedom in wireless communications and continuously commit to meeting the needs of our customers with leading
edge solutions.
With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in
4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is
further enhanced by our strategic alliances with leading industry players.
Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX
players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider
in APAC catering to both 4G and 3G networks.
For more information, visit: www.greenpacket.com.
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