WLAN Integration Proposal v2.1(1)

8/2/2019 WLAN Integration Proposal v2.1(1)

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KING FAHD UNIVERSITY OF PETROLUEMAND MINERALS

Computer Engineering Department

A Research Proposal on

Wireless Local Area Networks Integrationfor Mobile Network Operators

Proposed by:

Dr. Ashraf S. H. Mahmoud (Principle Investigator)

Dr. Marwan H. Abu-Amara (Co-Investigator)

Dr. Tarek Sheltami (Co-Investigator)

Computer Engineering Department

King Fahd University of Petroleum and Minerals

Dhahran 31261, Saudi Arabia

E-mail: {ashraf, marwan, tarek}@kfupm.edu.sa


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November 2004

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31261

{ashraf, marwan, tarek}@ccse.kfupm.edu.sa

2004

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Abstract

With the advent of wireless local area networks (WLAN), service providers of thirdgeneration (3G) wireless data networks can properly address traffic requirements in

hotspot locations. However, an important aspect to consider is the issue of integratingWLANs with 3G wireless data networks leading to hybrid mobile data networks. Suchhybrid networks allow subscribers to experience seamless and ubiquitous data servicesand very high data rates. In this project, we address the problem of the integration ofthese two classes of networks to offer such seamless connectivity. Specifically, wedescribe possible architectures and integration solutions relevant to existing and futureSaudi Telecom Company (STC) wireless networks. Moreover, we present a typicaldeployment scenario of a WLAN into an STC wireless network by specifying requirednetwork elements and providing the corresponding commercially available products.

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Table of Contents

KING FAHD UNIVERSITY OF PETROLUEM ANDMINERALS....................................................................................i

Computer Engineering Department...............................................i

Wireless Local Area Networks Integration for Mobile NetworkOperators.........................................................................................i

Abstract........................................................................................iii

Table of Contents.........................................................................iv

1 Background and Problem Statement...........................................5

2 Literature Survey.........................................................................7

3 Project Plan and Tasks..............................................................14

4 Summary of Deliverables..........................................................15

5 Project Management.................................................................15

6 Budget Requirements:...............................................................15

References...................................................................................17

Acronyms....................................................................................19

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1 Background and Problem Statement

The third generation (3G) wireless data networks are designed to offer both traditionalvoice communications and packet data services for multimedia applications with betterperformance and greater cost effectiveness. The Universal Mobile TelecommunicationsSystems (UMTS) is one of the standardized systems for 3G wireless data networks thatis considered by this project. A brief description of the UMTS-based networks is

provided in section 2.2.

Multimedia users are known to exhibit asymmetric bandwidth usage behavior, wherethe download bandwidth (i.e. from the network to the user) is usually two to threeorders of magnitude higher than the upload bandwidth (i.e. from the user to thenetwork). Furthermore, in a typical 3G wireless data network, there will remain some

geographical areas within the cell coverage where mobile stations require more usageof high-speed data services. Such geographical areas are referred to as hotspots.Temporary or permanent hotspot areas are created in heavily populated places such asairports, coffee shops, hotels, exhibitions, and convention centers. Microcell, picocell,and repeater solutions have been proposed, and the performance of such solutions has

been evaluated 6.26.26.2. However, such solutions are expensive, from cost perspectiveand/or installations perspective.

With the availability of WLANs, service providers of 3G wireless data networks canproperly address traffic requirements in hotspot locations with a less costly solution.The IEEE 802.11 defines the standard for WLANs. Based on the standard, the WLAN

operates in either ad-hoc mode or infrastructure mode. The infrastructure mode isrelevant to the integration with wireless networks. In infrastructure mode, an AccessPoint (AP) coordinates the transmission among nodes within its radio coverage area,called service set. A Mobile Node (MN) can only associate with one AP at a time. Allthe MNs associated with an AP communicate with each other either through the AP ordirectly coordinated by the AP. A number of APs can be interconnected through an IProuted network to form the WLAN IP network, as shown in Figure 1. An access router(AR) in the figure connects one or more APs to the network. The APs provide radiointerface to the WLAN network, and exchange IP packets with the access routers. TheMN is connected with a single AR at any given point in time, which is called theserving AR. The WLAN network is capable of routing IP packets to the serving ARwhile the MNs move through some form of mobile routing.

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Figure 1: IEEE 802.11 WLAN.

An important aspect to consider when using WLANs to address traffic requirements inhotspot locations is the issue of integrating WLANs with 3G wireless data networksleading to hybrid mobile data networks allowing subscribers to experience seamless andubiquitous data services and very high data rates. The integration aspect of WLANswith 3G wireless data networks results in many technical challenges, includingseamless vertical handovers across WLAN and 3G radio technologies, security,common authentication, unified accounting and billing, WLAN sharing among several3G wireless data networks, and consistent Quality of Service (QoS) and service

provisioning 6.2.

The integration of WLANs and 3G wireless data networks leads to six possibleintegration scenarios ranging from the simplest form of integration, Common Billingand Customer Care, that provides only a common bill and customer care to thesubscriber but otherwise features no real interworking between the WLAN and the 3Gwireless data network, to the most complex form of integration,Access to 3G Circuit-Switched-Based Services with Seamless Mobility, that allows access to 3G circuit-switched services from the WLAN system, and seamless mobility to such services 6.2.

Note that there exist many solutions for generic scenarios. The purpose of this project isto examine these solutions in greater depth and attempt to provide a solution thatmatches the current network configuration for Saudi Telecom Company (STC). Thearrived at solution can be a novel one, a tailored solution, or a combination of existingones where the particulars of the local environment and network are reflected.Moreover, we present a typical deployment scenario of a WLAN into an STC wirelessnetwork by specifying required network elements and providing the correspondingcommercially available products. This work will help current operators launch new

services and facilitate network expansion.

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2 Literature Survey

2.1 Business Need

From a business point of view a 3G operator must ask the following question: Is

WLAN a competing technology to 3G technology or a complementing technology?Welling et. al. 6.2 showed that the economic profitability of WLAN as acomplementary, rather than a competing solution for 3G wireless data networkoperators, and that the combined infrastructure will provide the required seamlessmobile data services. Furthermore, analysts are predicting 20 million users of WLANsin Europe by 2006 with access to the network achieved by users being in hotspots 6.2.

2.2 Existing Architectures and Solutions

The Universal Mobile Telecommunications Systems (UMTS) is one of the standardizedsystems for 3G mobile systems. This solution is considered the natural evolution pathfor GSM/GPRS-based networks similar to the one currently employed to providemobile services by the STC. The basic architecture model of a UMTS-based network6.2 is depicted in Figure 2. The model consists of two basic components: The UMTScore network (UCN), and the UMTS terrestrial radio access network (UTRAN). TheUCN is the circuit-switched network responsible for providing voice and circuit-switched services, in addition to the packet-switched network responsible for providing

packet-based services. Functionally, the circuit switched domain consists of the mobileswitching centre (MSC) responsible for routing voice calls and the gateway MSC(GMSC) for interfacing with other public switched telephony or ISDN networks. Incontrast, the packet-switched domain is comprised of the serving GPRS support node

(SGSN), the gateway GPRS support node (GGSN), and other functional entitiesresponsible for routing, maintaining, and billing specifics of the data services such asDomain Name Servers (DNS) and Dynamic-Host Configuration Protocol (DHCP)servers and firewall platforms. The later functionalities are essential part of the 3Gnetwork to provide connectivity to the Internet and support packet-based data servicesover the wireless mobile network. Finally, the UTRAN component provides thewireless access to the services provided by the UMTS network and consists of acollection of radio network controllers (RNC), and base stations, referred to as Node B.

Node B is the network entity providing the immediate wireless access for mobilesubscribers, while the RNC assumes the management and control tasks within theUTRAN segment as well as the interface with the rest of the UMTS network.

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radio access network (GERAN). In the same manner, a third interface supportingWLANs can be defined. The Iu interface, currently being used between the 3G-SGSNand the RNC can be modified and standardized to provide the connectivity between theUMTS core network (3G SGSN) and the WLAN through its radio controller, theInterWorking Unit (IWU). This solution is referred to as the tightly coupling strategy

and is depicted in Figure 3. Tight coupling solution provides seamless handoffsbetween the two networks and allows the wireless LAN component to exploit all thepre-defined mobility, security and QoS functions defined at the UMTS core network.However, this requires the standardization of the new interface and the adaptation ofdata terminals (such as laptops and handheld devices) to use an embedded subscriberidentity module (SIM) card in a manner similar to existing mobile phones. This task hasalready been launched by the European Telecommunications Standards Institute (ETSI)in a project that will provide standardized integration for the HiperLAN2 network, aEuropean competing technology for the existing IEEE802.11-based WLANs.

An alternative solution to tight coupling is what is known as the loose coupling solution

which requires less standardization effort compared to the former solution. Accordingto this strategy the WLANs requires connectivity to the HLR entity in the UMTS corenetwork through its Authentication, Authorization and Accounting (AAA) entity. TheHLR stores the current subscribers locations and maintains the list of services allowedfor each of these subscribers. Figure 4 shows a simplified loose coupling scenario. Thecustomer care and billing services (CC&BS) with loose coupling, as it is with tightcoupling, is still centralized and transparent to WLANs mobiles. However, unlike tightcoupling, this alternative does not require specific network access equipment.

Finally, the last category of solutions is referred to as the open coupling alternativewhere no standardization is required and the linkage between the WLAN and the

UMTS network is performed only at the customer care and billing system. This solutionis depicted in Figure 5. In this solution, the AAA server sends information related to thesubscriber usage of the WLAN to the mobile network CC&BS. It is apparent that theWLAN in this situation is not employing the UMTS security or QoS mechanisms.However, this solution requires the least dedicated infrastructure and can utilizestandard commercial products. Therefore, in terms of deployment and network setup,this solution surpasses the other two strategies.

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subscribers without jeopardizing existing connections. As a third example, references6.2 6.2 propose two open coupling architectures capable of providing interworking

between 3G and WLANs. The first architecture enables 3G subscribers to roam into awireless LAN and still receive service, while the second one allows extends the firstmodel to allow 3G packet switched services for WLAN users. The later model will

allow 3G users to benefit from the high-speed service rates offered by WLANs instrategic hotspots (e.g. airports, hotels, etc.) and maintain access to the same packetswitched service supported by the mobile network.

2.3 Unsolved Issues

While generic solutions exist as has been demonstrated in the previous section, thesehowever provide only the general guideline for integration process. There remain anumber of unanswered questions and issues related to the integration process. Theseinclude the availability of bandwidth and the licensing public data network operation,the billing and accounting infrastructure, and the roaming functionality. In addition,

other issues like network security and management, and the availability and support ofapplications should be addressed before a full integration solution is specified. In thenext three subsections, the issues of radio frequency bandwidth, billing, and roam arehighlighted and example solutions are presented for these issues.

2.3.1 The availability of frequency bandwidth

Spread spectrum transmission technology is used by many wireless LANmanufacturers. The frequency at which signals are transmitted is called the Industrial,Scientific and Medical (ISM) band. This frequency band is reserved for ISM devices.The ISM band has three frequency ranges: 902-928, 2400-2483.5 and 5725-5850 MHz.

An exception to this is Motorola's ALTAIR which operates at 18 GHz. IEEE 802.11goperates on 2.4 GHz and IEEE 802.11i operates at both 2.4 GHz and 5 GHz. We willfocus on these two techniques in our study depending on the wireless frequencies used

by other applications.

2.3.2 Billing

UMTS is build is on top of the 3rd Generation Partnership Project(3GPP). Because of this fact, we will discuss 3GPP in this section. The3GPP-WLAN interworking system is aiming to provide chargeablepublic WLAN services for mobile operator subscribers. After

authentication and verification for network access, the WLAN accessnetwork grants the UE an access to an IP network. Each IP network isgiven a unique WLAN Access Point Name (W-APN), which is used by the UE toestablish the connection to the required destination network. The UE chooses theIP network with a W-APN. After receiving a request from a UE, thenetwork verifies and authenticates that the user right to use the W-PAN. Once the IP network is selected using the W-APN, tunnels are setup to route the user data to the chosen IP network. The tunnel will beterminated in the home network by Packet Data Gateway (PDG); thisis agreed upon in the 3GPP literature. The PDG works in a similar

fashion of the GGSN used in GPRS packets network and the referencepoint Wi in Figure 6 is analogues to the reference point Gi in GPRS.

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PDG acts as a gateway to the chosen remote IP network, afterterminating the tunnel. One suggested solution is to collect charginginformation at the WLAN network and forward it to the 3GPP homeand/or visited networks 6.2. The home network of 3GPP AAA serverauthorizes each users access to the WLAN. 3GPP subscribers have

two ways of payment, prepaid and postpaid. For prepaid users, beforeauthoring an access to the WLAN, the 3GPP AAA server have to makea credit reservation from the user prepaid account in the OnlineCharging System (OCS) over Wo reference point 6.2. Accountinformation is gathered and forwarded by 3GPP AAA as WLAN accesscall detail records (WLAN CDRs) toward the Charging Gateway (CG)over Wf reference point. In the billing system, this information is usedto complete the charging process between the responsible devicesand create the bills for the postpaid users. For prepaid users, the3GPP AAA server monitors the received accounting information fromthe WLAN access network and returns any unused credit, if any, backto OCS. This is an example of one implementation, billing the WLAN isstill a hot topic for research. There are more than 12 internationalconferences addressing billing issues.

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Figure 6: 3GPP-WLAN interworking architecture.

2.3.3 Roaming

Roaming is one of the key factors when identifying the success of any wireless system.In the 3GPPWLAN interworking system should provide the ability for a 3GPPsubscriber to access the WLAN service while roaming between networks. There should

be a roaming agreement to identify the terms and conditions of the wireless serviceprovided to the subscribers 6.2. Roaming agreements are used where no company canoffer complete national and international coverage. Subscribers user equipment shall

be able to select visited network when accessing the WLAN service. Since 3GPP hasagreed to support visited network selection for WLAN interworking, so that users will

be able to select the visited PLMN (VPLMN) when several roaming routes areavailable via the W-APN, as mention above.

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3 Project Plan and Tasks

The three investigators will carry out the project cooperatively with the possible help ofa research assistant. The project progress and development is divided into four main

phases spanning the 18 months. The project phases are as follows:

3.1 Phase I (4 months) Literature Survey:

Performing a comprehensive and elaborate literature review: This step involvesthe gathering and reading of up to date literature and resources in the field. Theteam should focus on cutting-edge network technologies and up to dateliterature that is directly applicable to the problems of interest. Grouping andclassification of solutions found in the literature will aid in the analysis phase tofollow.

The team will also attempt to obtain literature in regard to evolution andexpansion plans of the Saudi Telecom Company (STC) that are available for

public, if possible, or that of a typical GSM-based operator.

3.2 Phase II (6 months) - Analysis and Evaluation:

Identification of most promising solutions using criteria that include but notlimited to: backward compatibility, smooth network evolution, most feasible interms of investment, greater return, etc.

Potential candidate architecture and network evolution paths shall be analyzedand evaluated in terms of their relevance to the current network infrastructureand the expected usage patterns.

Formulation of one of few winner solutions that may be based on existinggeneric solutions or be original and novel.

3.3 Phase III (4 months) Case Study:

Using the analysis and results obtained in phase II, the team will assume ahypothetical scenario where the mobile operator in Saudi Arabia (e.g. STC) is

planning to launch WLAN services in King Khalid Airport at Riyadh or anypotential candidate facility. The task is to provide a comprehensive plan forintroducing such service including all architectural changes and new networkentities needed. The team will also attempt to evaluate impact and ways tominimize this impact of this expansion on current mobile network.

3.4 Phase IV (4 months) Project Documentation:

This task involves providing a detailed document with the following majorsections: Comprehensive literature review of types of architectures found andtheir analysis, a list of potential solutions for GSM-based mobile networkoperators and a winner solution description and analysis for implementation atSTC. The report will include a case study analysis for a typical integrationscenario and the required infrastructure.

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4 Summary of Deliverables

1. Numerate architectures/solutions relevant to existing or future STC mobilenetwork infrastructure.

2. Propose UMTS compliant network infrastructure that is both backwardcompatible with existing infrastructure and incorporates WLANs data services.

3. Provide a typical deployment scenario in support of required functionality byspecifying required network elements and possibly the correspondingcommercial available product.

5 Project Management

Phases

Investigators RA Time Schedule (Months) CumulativeMonths

AM MA TS RA 1 4 5 7 10 11 12 14 15 16 17 18 AM MA TS RA

Phase I X X X 2 2 2 0

Phase II X X X 8 8 8 0

Phase II X 8 8 8 4

Phase III X X X 12 12 12 4

Phase III X 12 12 12 7

Phase IV X 12 12 12 9

Phase IV X X X 14 14 14 9

Legend AM Dr.Ashraf S. H. MahmoudMA Dr. Marwan H. Abu AmaraTS Dr.Tarek Sheltami

RA Research Assistant

6 Budget Requirements:

6.1 Manpower:

1. Principle Investigator (PI): 1,200X 14 = 16,800 SR

2. Co-Investigators II (CO-I): 2 X 1,000 X 14 = 28,000 SR

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3. Research Assistant: 600 X 9 = 5,400 SR

Total Manpower: 50,200 SR

6.2 Equipment:

1. Two high end computer + printer: 18,500 SR

2. Miscellaneous and Stationery: 4,000 SR

3. Books and References: 2,500 SR

4. Publication: 4,400 SR

Total Equipment: 25,000 SR

Total budget for project: 75,200 SR

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References

[1] Ilari Welling, Jarmo Harno, Franois Loizillon, Kjell Stordahl, Dimitris Varoutas,Techno-Economic Evaluation of 3G & WLAN Business Case Feasibility Under

Varying Conditions, 10th International Conference on Telecommunications(ICT), 2003, Vol. 1, pp. 33-38.

[2] Embedded-Wi-Fi Market Undergoes shift,http://www.frontlinetoday.com/frontline/article/articleDetail.jsp?id=120364

[3] Wireless LAN Hardware Market Up 11% to $658M in 3Q03,http://www.80211bnews.com/publications/page207-654438.asp

[4] Sung-Eun Kim, and John A. Copeland, Interworking Between WLANs and 3GNetworks: TCP Challenges, IEEE Wireless Communications and Networking

Conference (WCNC), 2004, Vol. 2, pp. 1252-1257.

[5] J. Ala-Laurila, J. Mikkonen, J. Rinnemaa, Wireless LAN Access NetworkArchitecture for Mobile Operators, IEEE Communications Magazine, Vol. 39,

Nov. 2001, pp. 82-89.

[6] Apostolis K. Salkintzis, Interworking Techniques And Architectures ForWLAN/3G Integration Toward 4G Mobile Data Networks, IEEE WirelessCommunications, June 2004, pp. 50-61.

[7] Apostolis K. Salkintzis, WLAN/3G Interworking Architectures for Next

Generation Hybrid Data Networks, IEEE International Conference onCommunications, 2004, Vol. 7, pp. 3984-3988.

[8] Apostolis K. Salkintzis, The EAP-GPRS Protocol for Tight Integration ofWLANs and 3G Cellular Networks, IEEE 58th Vehicular TechnologyConference (VTC), Fall 2003, Vol. 3, pp. 1793-1797.

[9] Eero Wallenius, Timo Hmlinen, Timo Nihtil, Jyrki Joutsensalo, KariLuostarinen , 3G Interworking With WLAN QoS 802.11e, IEEE 58thVehicular Technology Conference (VTC), Fall 2003, Vol. 3,pp. 1803-1806.

[10] Hongbo Liu; H. Bhaskaran, D. Raychaudhuri, S. Verma, Capacity Analysis Of aCellular Data System With 3G/WLAN Interworking, IEEE 58th VehicularTechnology Conference (VTC), Fall 2003, Vol. 3, pp. 1817-1821.

[11] Wei Zhuang, Yung-Sze Gan, Kok-Jeng Loh, Kee-Chaing Chua, Policy-BasedQoS-Management Architecture in an Integrated UMTS and WLANEnvironment, IEEE Communications Magazine, Vol. 41, Nov. 2003, pp.118-125.

[12] G.M. Koien, T. Haslestad, Security Aspects of 3G-WLAN Interworking, IEEECommunications Magazine, Vol. 41, Nov. 2003, pp. 82-88.

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http://www.frontlinetoday.com/frontline/article/articleDetail.jsp?id=120364http://www.80211bnews.com/publications/page207-654438.asphttp://www.frontlinetoday.com/frontline/article/articleDetail.jsp?id=120364http://www.80211bnews.com/publications/page207-654438.asp


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[13] Muhammad Jaseemuddin, An Architecture for Integrating UMTS and 802.11WLAN Networks, Proceedings of the Eighth IEEE International Symposium onComputers and Communication (ISCC03), Vol. 2, pp. 716-723.

[14] M. Buddhikot, G. Chandranmenon, S. Han, Y.W. Lee, S. Miller, L. Salgarelli,

Integration of 802.11 and third-generation wireless data networks, INFOCOM2003. . IEEE Twenty-Second Annual Joint Conference of the IEEE Computerand Communications Societies, Vol. 1, pp. 503-512.

[15] S. A. Ghorashi, L. Wang, F. Said, A. H. Aghvami, Non-Real Time PacketTransmission For A Microcell (Hotspot) Embedded In CDMA MacrocellSystems, IEEE International Conference on Communications, 2003. ICC '03,Vol. 2 , pp. 997-1001

[16] H. Andersson, R. S. Karlsson, P. Larsson, P. Wikstrm Improving SystemPerformance in a WCDMA FDD Network using Indoor Pico Base Stations,,

IEEE 56th Vehicular Technology Conference (VTC), Fall 2002, Vol. 1, pp. 467-471.

[17] M. Rahman, P. Ernstrm, Repeaters for Hotspot Capacity in DS-CDMANetworks, IEEE Transactions on Vehicular Technology, Vol. 53, No. 3, May2004, pp. 626-633.

[18] m-Travel.com, 20 Million European Wireless LAN Users by 2006,http://www.m-travel.com/111.29.shtml , 24/06/03

[19] Vijay K. Garg, Oliver T.W. Yu, Integrated QoS Support in 3G UMTS

Networks, IEEE Wireless Communications, Sept 2000, pp. 1187-1192.[20] Kalle Ahmavaara, Henry Haverinen, and Roman Pichna, Interworking

Architecture Between 3GPP and WLAN Systems,, IEEE CommunicationMagazine, pp. 74-81, November 2003.

[21] Geir M. Kien and Thomas Haslestad, Security Aspects of 3G-WLANInterworking, IEEE Communication Magazine, pp. 82-88, November 2003

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Acronyms3G 3rd Generation

3G-SGSN 3rd Generation - Serving GPRS Support Node

3G-GGSN 3rd Generation - Gateway GPRS Support Node

3GPP 3rd Generation Partnership Project

AAA Authentication, Authorization and Accounting

AP Access Point

AR Access Router

AUC Authentication Center

CC&BS Customer Care and Billing Services

CG Charging Gateway

DHCP Dynamic-Host Configuration Protocol

DNS Domain Name Server

EDGE Enhanced Data Rates for GSM Evolution

EIR Equipment Identification Register

ETSI European Telecommunications Standards Institute

GERAN GSM/EDGE Radio Access Network GGSN Gateway GPRS Support Node

GMSC Gateway MSC

GPRS General Packet Radio Service

GSM Global System for Mobile Communications

HLR Home Location Register

IEEE Institute of Electrical and Electronic Engineers

IOTA Integration of Two Access TechnologiesISM Industrial, Scientific and Medical

IWU InterWorking Unit

MN Mobile Node

MSC Mobile Switching Center

OCS Online Charging System

PDG Packet Data Gateway

PLMN Public Land Mobile Network

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QoS Quality of Service

RNC Radio Network Controller

SGSN Serving GPRS Support Node

SIM Subscriber Identification ModuleSS7 Signaling System 7

STC Saudi Telecommunications Company

UCN UMTS Core Network

UE User Equipment

UMTS Universal Mobile Telecommunications System

UTRAN UMTS Terrestrial Radio Access Network

VLR Visitor Location Register VPLMN Visited PLMN

W-APN WLAN Access Point Name

WLAN Wireless Local Area Network

Documents

WLAN Integration Proposal v2.1(1)