College of Computer Science and Engineering

Phase I Report on Integration of UMTS with WLAN at King Fahd International Airport (KFIA)

By

Adel Al-Shahrani (986074)

S.M.Rehman (230419)

Khalid Al- Otaibi (976452)

Taha Anwar (240262)

Submitted to

Dr.Marwan Abu-Amara CSE-550

CONTENTS

1. Introduction …………………………………………………… 3

2. Interworking Model and Requirements ………………………… 3

3GPP Scenarios …………………………………………… 3

Coupling Scenarios ……………………………………….. 5

3. Methodology Overview ……………………………………….. 8

Design Goals ………………………………………………….. 8

Assumptions …………………………………………………... 9

4. Simulation Model …………………………………………………… 12

5. Simulation Results ………………………………………………… 18

6. Conclusion …………………………………………………………. 22

7. Task Management …………………………………………………. 23

8. References …………………………………………………………. 24

1. Introduction The recent evolution and successful deployment of Wireless Local Area Networks (WLANs) worldwide has yield a demand to integrate them with third-generation (3G) mobile networks, such as GSM/GPRS, UMTS, cdma2000, etc. The key goal of this integration is to develop heterogeneous mobile data networks, capable to support ubiquitous data services with very high data rates in hotspots. The effort to develop such heterogeneous networks – also referred to as forth-generation (4G) mobile data networks – is linked with many technical challenges including seamless vertical handovers across WLAN and 3G radio technologies, security, common authentication, unified accounting & billing, WLAN sharing (by several 3G networks), consistent QoS and service provisioning, etc.

2. Interworking Model and Requirements We assumed a WLAN/3G interworking with each 3G public land mobile network (3G PLMN) based on UMTS technology and each WLAN is based on IEEE 802.11 technology. Through coupling, the main goal is to combine the wide area coverage of UMTS, with its associated

roaming and mobility properties and, on the other hand, to gain additional throughput and capacity by using WLAN in hotspots. 2.1. 3GPP Scenarios The following six scenarios defined by 3GPP are focused on the type and quality of the service offered to the user. Scenario 1 – Common billing and Customer care : This is the simplest form of integration, which provides only a common bill and customer care to the subscriber but otherwise features no real interworking between the WLAN and 3G PLMN. Scenario 2 – 3G-based Access Control and Charging : This scenario requires authentication, authorization and accounting (AAA) for 3G subscribers in a WLAN to be done by their 3G home PLMN. Scenario 3 – Access to 3G Packet Switched services: The goal of this scenario is to extent the access to 3G Packets Switched (PS) based services to subscribers in a WLAN environment. For example, if an operator maintains a Wireless Application Protocol (WAP) gateway for providing WAP and MMS services to his subscribers, under the interworking scenario 3, these WAP and MMS services should be accessible to subscribers also in a WLAN environment. Scenario 4 – Access to 3G Packet Switched-based services with service continuity: The goal of this scenario is to allow access to PS-based services as required in scenario 3 and in addition to maintain service continuity across the 3G and WLAN radio access technologies. For example, a user starting a WAP session from the 3G radio access technology should be able to continue this session after moving to a WLAN and vice versa. Scenario 5 – Access to 3G Packet Switched-based services with seamless service continuity: This scenario is one step further of scenario 4. Its goal is to provide seamless service continuity between the 3G and WLAN radio access technologies. That is, PS-based services should be utilized across the 3G and WLAN radio access technologies in a seamless manner, i.e. without the user noticing any significant differences. Scenario 6 – Access to 3G Circuit Switched-based services with seamless mobility: The goal of this scenario is to allow access to 3G circuit switched-based services (e.g. normal voice calls) from the WLAN system. Seamless mobility for these services should be provided. The following table summarizes the different interworking scenarios and indicates the operational capabilities of each one. Note that as we move from scenario 1 to scenario 6 the WLAN and 3G network become more tightly integrated and hence more and more demanding interworking requirements exist.

Table 1

2.2. Coupling Scenarios However, from an architectural point of view, these scenarios can be reduced to four levels of coupling. The first level is open coupling, presented in figure 1. In this case UMTS and WLAN make use of two separated access and transport networks and billing is common – although using different authentication mechanisms. The next level is the so-called loose coupling, shown in figure 2, which enables the use of common authentication mechanisms by providing a link between the authentication, authorization and accounting (AAA) server in the WLAN subsystem and the Home Location Register (HLR) in the UMTS subsystem, which are still kept separate. With tight coupling, the WLAN Access Point (AP) is connected like a Radio Network Controller (RNC) to the Serving GPRS Support Node (SGSN) in the Core Network (CN). This principle is shown in figure 3. An interworking Unit might be added. With tight coupling the handover between WLAN and cellular subsystems could be supported. Finally, with very tight coupling (figure 4) the WLAN access point is connected to the RNC.

Fig: 1: Open Coupling Model

Fig: 2: Loose Coupling Model

Fig: 3: Tight Coupling Model Fig: 4: Very Tight Coupling Model

Figure 5

When integrating WLAN and GPRS networks the question is if it is suitable to use a standard AAA server that works for both systems, or if separate servers should be used. An AAA server

for a GPRS network differs from a WLAN AAA. A combined server that is capable of handling different types of users would be a possible way of integration, so what is demanded of a shared AAA? • Authentication • Authorization • Accounting • IP address assignment and mobility management • Level of Service • Billing Hence the key element in the architecture is the 3G AAA Server, which is a new functional component incorporated in a 3G PLMN in order to support interworking with WLANs. The 3G AAA Server in the 3G home PLMN terminates all AAA signaling with the WLAN and interfaces with other 3G components, such as the Home Subscriber Server (HSS), the Home Location Register (HLR), the Charging Gateway/Charging Collection Function (CGw/CCF) and the Online Charging System (OCS). Both the HLR and the HSS are basically subscription databases, used by the 3G AAA Server for acquiring subscription information for particular WLAN MSs. 2.2.1 Open Vs Loose Architecture: Apart from the differences referred to in the figure 5, both Open and Loose Coupling models sharing same billing system. In this project, the billing system is under STC supervision. The main difference between these architectures is the authentication scheme, wherein the open coupling, every network has its own authentication system. However, in the case of loose coupling, AAA is the authentication scheme in both UMTS and WLAN. 3. Methodology Overview The simulation model is designed in OPNET™ Modeler 11.5. The simulation parameters were selected to accurately model an interworked WLAN-UMTS system supporting a “hot spot.” To compare the Loose and Open coupling, simulations were done in both architectures with the same simulation factors (number of nodes, traffic). 3.1 Design Goals The primary design goal for this project was to interwork WLAN with UMTS so that it can be utilized as an alternate radio access network for hotspots such as Airports. The remaining design goals were intended to focus the design in order to create an open simulation framework with the capabilities to study the issues and trades-offs for interworking WLAN with UMTS. Our project focuses on evaluating the performance of these integration schemes through open and loose coupling and selects the best of this for the next phase. 1. Focus the design on the 3GPP proposed Scenario 2 for supporting 3G authentication and access control. 2. Utilize IP cloud as the common service interface for applications in order to guarantee independence of applications from the underlying radio access network. 3. Minimize the number of changes to the existing UMTS protocols. 4. Minimize the number of changes to the existing WLAN protocols.

3.2. Assumptions: We have made the following assumptions to keep the simulation complexity manageable, while still meeting the research goals. This section describes assumptions made in modeling both the UMTS and WLAN data networks, as well as the interworking of these two technologies.

1) The number of users is 10 every network we simulated and collected statistics and mapped theoretically for 7000 users due to Opnet limitations.

2) The traffic generated is based on traffic distribution as follows:

Application Weight Traffic ( KByte/sec) FTP 20% 200 HTTP 40% 400 MM Streaming 40% 400

3) For Multimedia Streaming, custom authentication was simulated. 4) The authentication traffic packet is considered as 1 byte/second. 5) The authentication process has been simulated using custom application:

1. a. UMTS authentication was implemented using customer application and it has been simplified by eliminating SGSN contribution. Therefore, user equipment is communicating directly to HLR. UMTS authentication is shown in figure 6 using Authentication and Key Agreement (AKA).

2. b. WLAN is using user id & password authentication.

Figure 6: Normal AKA Procedure

The main system components of the UMTS packet domain architecture, (Figure 7) are modeled as the following OPNET™ nodes: the user equipment (UE), the Node-B, the Radio Network Controller (RNC) and the core network (CN).

Figure 7

4. Simulation Model

Figure: 8 Simulation Model

As shown in figure 8, the simulation model consists of four main parts:

1. WLAN Network: a) Access Point (WLAN Router) b) AAA Server for authentication c) WLAN Workstation

2. UMTS Network a) Node B Access Point b) RNC c) SGSN d) GGSN e) HLR for authentication f) UMTS Workstation.

3. Internet Provider (in this project STC) consist of a) MMS (Multimedia Server) b) FTP Server c) HTTP Server d) Billing System e) Router

f) Switch 4. Simulation Parameter tools

a) Task Node to define custom applications i. WLAN authentication which is the different between loose

and open coupling where in loose coupling, WLAN authentication will communicate with HLR (five phase’s task). However in open coupling its is normal user ID and password between WLAN user and AAA (three phases task).

ii. UMTS authentication which occurs between UE and HLR and it consist of eleven phases.

iii. Multimedia task which communicate with MM server to get MM traffic.

b) Application Node to define exist applications i. HTTP ii. FTP iii. Multimedia (MM) iv. Billing application as DB traffic v. Custom Task 1: WLAN authentication. vi. Custom Task 2: UMTS authentication.

c) Profile Node to group the applications and assigned them to specific node or user

i. WLAN authentication. ii. UMTS authentication. iii. WLAN user applications iv. UMTS user applications v. Billing task.

The model entities have been configured accordingly to generated stated traffic. 4.1. Application Response Time FTP and Web application response times were chosen because they belong to two different UMTS QoS profiles. FTP download response time was defined as the time that elapses between a client sending a “get” request and receiving the entire file. It was measured from the time a client application sent a request to the server to the time it received the file. The FTP download response time included the time required to transmit the entire file—it was dependent on the file size. Web page response time was defined as the time required to retrieve an entire HTML page with all of its inline objects. Similar to the FTP response time, the web page response time was measured from the time a client browser application sent the request to the web server and ends when the client received the entire HTML page. 4.2. Simulation Parameters Values WLAN Data Rate 11 Mbps

4.3. Traffic Model The simulation model used the OPNET™ built-in application distribution models. The built-in OPNET™ application profiles were used to closely simulate traffic generated by a wireless data user. The application profiles used were the FTP, MM, and HTTP profiles. These profiles were combined and parameterized in order to define the Wireless Client application profile. In addition, since OPNET doesn’t support HLR, AAA and Billing system, the traffic for those components was generated via Task tools as described previously. The WLAN and UMTS profiles described a wireless data user’s activity over a period of time. The profile consisted of the standard network applications: FTP, MM, and HTTP. Also, authentication and billing profiles were generated to generate AAA, HLR and billing systems. Ten workstations has been created for every access point (WLAN and UMTS). So, there are total of 20 users in the whole network. 4.4. Network Design Analysis As discussed previously, the main difference between open and loose coupling is in the authentication where WLAN have to communication to HLR in loose coupling case. However, for open coupling the authentication is process in every network independently. Therefore, the expectation for is to have more traffic in loose coupling due to AAA-HLR communication during user authentication.

Fig 9: Open coupling authentication

Fig 10: loose coupling authentication (Additional traffic highlighted in yellow) As shown above, this traffic is affecting both WLAN and UMTS network.

5. Simulation Results: 1. WLAN Load:

Loose Coupling Open Coupling

As shown above, loose coupling has more load then open coupling. 2. WLAN Access Delay

Loose Coupling Open Coupling

As shown loose coupling has more access delay then open coupling due to authentication with HLR.

2. Throughput

Loose Coupling

Open Coupling

The throughput for loose coupling is higher then open coupling due to extra authentication traffic.

3. FTP Traffic

Loose Coupling Open Coupling

FTP traffic is very close between the loose and open coupling cases

4. HTTP Traffic

Loose Coupling

Open Coupling

5. UMTS downlink Traffic

Loose Coupling Open Coupling

Loose coupling has higher sent and receive traffic than open coupling which is due to authentication traffic from AAA. 4. UMTS uplink Traffic

Loose Coupling

Open Coupling

Also, the uplink traffic in loose coupling is higher then open coupling due to authentication traffic. 6. Conclusion: In fact, there is more traffic that needs to go between WLAN and UMTS for authentication purpose. However, loose coupling will strength the concept of integrating WLAN with UMTS by sharing authentication source. Implementing loose coupling will reduce the maintenance cost since STC will need to maintain the authentication in one entity instead of two with the cost of extra traffic. Therefore, there is a trade-off between integration advantage and extra network traffic.

7. Task Management

Adel Al-Shahrani

( 986074)

1. Literature survey 2. Design of the model & simulations for loose coupling 3. Report Analyzing

S.M.Rehman

(230419) 1. Literature survey 2. Learning phase of UMTS Opnet models and Team management 3. Report Writing

Khalid Al- Otaibi ( 976452) 1. Literature survey 2. Simulating the design 3. Design of the model & simulations for open coupling

Taha Anwar (240262) 1. Literature survey 2. Simulating the design 3. Studying loose and open coupling scenario.

8. References

1) UMTS – OPNET Specialized Model Library www.opnet.com 2) Wireless Module Research in OPNET – OPNET and La Salle report. 3) UMTS and WLAN interoperability by Anja Louise Schmidt,

Technical University of Denmark Research Center COM, July 2004.

4) Capacity Analysis of a Cellular Data System with 3G/WLAN Interworking Hongbo Liu, Hamsini Bhaskaran and D. Raychaudhuri WINLAN, ECE Dept. Rutgers Univ. Piscataway, NJ, USA , and Shaily Verma, Thomson Multimedia Inc. Corporate Research 2 Independence Way, Princeton, NJ, USA .

5) Interworking Techniques and Architectures for WLAN/3G Integration Towards 4G Mobile Data Networks, Apostolis K. Salkintzis, Motorola.

6) A Network System Level Simulator for Investigating the Interworking of Wireless LAN and 3G Mobile Systems, Tracy L. Mann , Virginia Polytechnic Institute and State University

7) AAA And Network Security for Mobile Access Radius, Diameter, EAP, PKI and IP Mobility, Madjid Nakhjiri Motorola Labs, USA, and Mahsa Nakhjiri, Motorola Personal Devices, USA.

8) Aspects for the integration of ad-hoc and cellular networks, Gabriel Cristache, Klaus David, Matthias Hildebrand University of Kassel, Germany , and José Diaz, Rolf Sigle, Alcatel SEL AG, Research and Innovation, D-70499 Stuttgart, Germany.

9) Co-existence of Wireless LAN and Cellular, Henry Haverinen, Senior Specialist, Nokia Enterprise Solutions.

10) Simulation of General Packet Radio Service Network (GPRS), Ljiljana Trajković Communication Networks Laboratory, http://www.ensc.sfu.ca/research/cnl , School of Engineering Science, Simon Fraser University.

11) Simulation Of General Packet Radio Service Network by Ricky Pun Keung Ng, B.A.Sc. (Electrical Engineering), University of British Columbia, 1999.

12) Interworked WLAN_UMTS Contributed Model Usage Guide 13) Enhanced General Packet Radio Service OPNET Model, R. Narayanan, P. Chan, M.

Johansson, F. Zimmermann, and Lj. Trajković, School of Engineering Science, Simon Fraser University, Vancouver, BC, Canada.

14) Performance and Security of Streaming Data for Cellular Data Networks, University of Houston, Clear Lake.

15) Experimental Study of GPRS/WLAN Systems Integration, Information Networks, Linköping Institute of Technology by Joakim Nyström, Mikael Seppälä.

16) A Research Proposal on Wireless Local Area Networks Integration for Mobile Network Operators, Computer Engineering Department , King Fahd University Of Petroleum And Minerals, Saudi Arabia.

17) Investigation of WLAN-Cellular Integration Architecture for Cellular Operators and Deployment Issues at King Fahd International Airport , Senior Design Project, , Computer Engineering Department , King Fahd University Of Petroleum And Minerals, Saudi Arabia.

18) UMTS Authentication and Key Agreement - A comprehensive illustration of AKA procedures within the UMTS system, Information and Communication Technology, Jon Robert Dohmen ,Lars Sømo Olaussen,Grimstad - Norway, May 2001.