PERFORMANCE AND HANDOFF EVALUATION OF HETEROGENEOUS WIRELESS

International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN

0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME

477

PERFORMANCE AND HANDOFF EVALUATION OF

HETEROGENEOUS WIRELESS NETWORKS (HWNS) USING OPNET

SIMULATOR

Dheyaa Jasim Kadhim

Electrical Engineering Department, University of Baghdad

Sanaa Shaker Abed

Electrical Engineering Department, University of Baghdad

ABSTRACT

The need for coupling Heterogeneous Wireless Networks (HWNs) such as WLAN,

WiMAX or UMTS, play a great role in developing towards fourth generation of wireless

networks. Hence, the algorithms for these networks must be developed especially handoff

algorithms to present a better performance in such heterogeneous networks. In this paper,

several projects have different types of networks were implemented and simulated in

different case studies offered by OPNET simulation to make Intra-technology handoff

(horizontal handoff) switching in each network and Inter-technology handoff (vertical

handoff) by interworking between two HWNs. OPNET simulation results show that the

superiors of WiMAX performance through this research on the WLAN and UMTS networks.

The performance of WiMAX throughput beats the other networks in much than 30%. Also,

the simulation results show the successful implementation and simulation of the deployment

of WLAN into WiMAX and UMTS network by using multiple network interfaces. In this

work, it found that it is very difficult to successfully complete the vertical handoff between

WLAN-WiMAX and WLAN-UMTS without carefully and accurately engineering the

WLAN network due to highlighting the fundamental different in HWNs.

General Terms: Wireless Networks, OPNET Simulator, Mobility Management and Handoff

Process.

Keywords: Heterogeneous Wireless Network (HWN), WLAN, WiMAX, UMTS, Handoff

Management and OPNET Simulation.

INTERNATIONAL JOURNAL OF ELECTRONICS AND

COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)

ISSN 0976 – 6464(Print)

ISSN 0976 – 6472(Online)

Volume 4, Issue 2, March – April, 2013, pp. 477-496 © IAEME: www.iaeme.com/ijecet.asp

Journal Impact Factor (2013): 5.8896 (Calculated by GISI) www.jifactor.com

IJECET

© I A E M E



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1. INTRODUCTION

Mobile users increased demand for access to mobile communication services is

accelerating the technological development towards the integration into the various modes of

wireless access communications with respect to coverage, QoS assurance, implementation,

operational costs supported features, etc. The integration should take into account the user

mobility from one access point to another. In wireless networks, mobility management

provide mobile users with continuously get the connection when they move among different

subnets based on their service needs. With this heterogeneity, users will be able to choose

radio access technology that offers higher quality, data speed and mobility which is best

suited to the required multimedia applications with the best performance and minimum cost.

It is necessary to ensure that the internet application efficient state is maintained while used

HWNs. This is one of motivation for conducting this work.

In this context, vertical handoff and interworking between heterogeneous wireless

access networks constitute important issues to the networking community. The mobile users

would like to seamlessly and dynamically roam among the different access networks to

maintain the most optimal network connectivity. In this case, choosing the correct time to

initiate a vertical handoff request and select the best network to connect becomes important.

Handoff management is one of the most important features of mobility management and the

Mobile user must be able to seamlessly handoff to the approximately best connection among

all available candidates based on some metrics that ensure no interruption will happen to any

ongoing connection. Hence, satisfying these requirements under the varied networks and

services refers to why handoff has gained importance and will probably continue to be a

major interest area of interest as newer technologies and services continue to proliferate the

wireless networking market [1][2]. Another work motivation behind the mobility and handoff

management is the need for a way to integrate and couple these heterogeneous networks,

such as coupling WLAN and any cellular networks.

Many researchers wrote on the scope of heterogeneous networks, seamless mobility

and vertical handoff some of them wrote on the role of it to improve the network performance

and others wrote on the field of optimizing its works. Mark Stemm in [3] has explored

methods which enable seamless mobility in wireless LAN networks with using 802.11

networks configured to work like a single umbrella network. Zahran [4][5] studied the

performance of vertical handoff using the integration of heterogeneous networks in 3G

cellular and wireless local area networks with MIP supported using loosely-coupled

architectures. The dissertation in [6] proposed virtual wireless services to evaluate the HWN;

the architecture of this solution based on client/server design. OPNET modular 14.5 was used

to build a test of HWN.

In this paper, three types of HWNs; WLAN, WiMAX and UMTS were implemented

and tested with different selected applications executed on the mobile node. So that three

different projects have different types of networks will implement and simulate using OPNET

14.5 modeler simulation. Then we will evaluate the performance of these heterogeneous

networks with many applications such as FTP, VoIP and video conference applications. The

work of this paper will discuss also the handoff implementation and evaluation for HWN in

addition to the integration, interworking and deployment in HWN between WLAN-WiMAX

and WLAN-UMTS. It is necessary to ensure that the internet application efficient state is

maintained while used HWNs. This is one of motivation for conducting this work.



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2. HANDOFF MANAGEMENT IN HWNS

General vision of 4G wireless networks are essentially the future of HWN. A HWN is

made up of multiple wireless access technologies. Each of these technologies has its own

characteristics with respect to coverage, QoS assurance, implementation, operational costs,

supported, features, etc. [7]. Presently, heterogeneous environments are expanding and

mobile devices often have built in support for multiple network interfaces. Seamless roaming

or mobility is crucial to ubiquitous computing and requires network management operations

to avoid service degradation. Both location management and handoff management constitute

mobility management. Location management involves two processes. The first process is

called location registration, or location update, in which the mobile terminal periodically

informs the network of its current location, which leads the network mobility and mobility

support procedures for wireless networks. Handoff management includes wireless terminal

handoff management considerations within one network called horizontal handoff and

handoff management across different wireless networks which could be based on different

wireless access technologies termed vertical handoff [8].

The handoff process is divided into three phases [9]: Network Discovery, Handoff

Decision and Handoff Implementation as shown in Figure 1. Periodically the system

monitors for a better network which the mobile terminal can be handed off. The handoff

considerations include several different criteria depending on the algorithms and the goals set

for handoff.

Figure 1: Handoff Phases

During the system discovery phase, the mobile terminal determines which networks

can be used. These networks may also advertise the supported data rates and Quality of

Service (QoS) parameters [10]. The handoff decision uses an algorithm that optimizes based

on a selected set of criteria to decide when to handoff. The decision is very crucial and

several different interesting solutions were proposed to address the problem [11]. In decision

phase, the mobile terminal determines whether the connections should continue using the

current network or be switched to another network. The decision may depend on various

parameters or metrics including the type of the application (e.g., conversational, streaming),

minimum bandwidth and delay required by the application, access cost, transmit power and

the user’s preferences. During the execution phase, the connections in the mobile terminal are

re-routed from the existing network to the new network in a seamless manner. This phase

also includes the authentication, authorization, and transfer of a user’s context information

[12]. Thus vertical handoffs are implemented across heterogeneous cells of access systems,

which are differ in several aspects such as bandwidth, data rate, frequency of operation, and

better QoS etc [13].

3. IMPLEMENTATION AND SIMULATION OF HWN

Three types of heterogeneous wireless technology WLAN, WiMAX and UMTS were

implemented and simulated with different selected applications executed on the mobile node

Heavy FTP, Heavy Video Conference and VoIP with PCM quality. The mobility used for this

project simulation speed is 10km/h with different location nodes at specified vector trajectory

Network

Discovery

Handoff

Decision Execution



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and simulation time was about 15 minutes. Selected performance of applications such as

VoIP, Video Conference and FTP and also the metrics such as average delay, throughput, and

received traffic were calculated and discussed.

3.1 WLAN Performance Evaluation

In this case study, the performance of WLAN network evaluation with using different

types of application. WLAN model based on IEEE802.11x standards is described in OPNET

modulator. This model includes various node models: wireless workstation, wireless server,

and wireless router or access point AP.

The objective of this case is to test the application performance and analyze the work

of Wi-Fi networks. Figure 2 displays the network topology of this case. In this case we used

three different applications; FTP, Video Conferencing and Voice over IP. We proposed that

a network model consists of one Access Point with six clients; each two clients have the same

application with the coverage of approximately 100 meters in a 1000 by 1000 meters of area.

IP cloud is used in this project, so the packets arriving on this cloud interface will be routed

to the output interface based on the destination IP address. The Routing Information Protocol

(RIP) or the Open Shortest Path First (OSPF) protocol may be used to automatically and

dynamically create the cloud's routing tables and select routes in an adaptive manner.

Figure 2: Wi-Fi Network Scheme Implementation

There are two versions of the wireless workstation node model, the simple and the

advanced models. The simple has only physical and multiple access control MAC layer but

the advanced model provides all the higher layers protocols.

The proposed model is measured for its performance by running data, voice and video traffic;

hence the average delay, throughput, load, and received traffic are the performance metrics

used in this work.

Table 1 displays the system parameters at the simulation setup used in the first case

study. A vector-based trajectory consists of a direction and a velocity that can be changed at

run time. We can specify that a site will use a vector-based trajectory by setting the site's

trajectory attribute to VECTOR. However, in OPNET Modeler the path of a site can change

during simulation if the bearing of the site is changed. In this case, the current

latitude/longitude coordinates of the site become the new origin and a new "great circle"

route is recomputed based on the new bearing and origin. The simulation time in all cases of

this project is taken to be 15 minutes.



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Table 1: WLAN Simulation Environment Parameters

System Parameters

Simulation time 15minutes

Data rate 54Mbps

Communication Range 100m

Physical characteristic Extended rate 802.11g

MAC Type 802.11 DCF

Transmit power (w) 0.005

Reception power threshold -95dBm

AP Bacon interval 0.02sec

Propagation model Free space

Trajectory Vector Based

3.2 WiMAX Performance Evaluation The WiMAX model suite includes a discrete event simulation model that let us

analyze a network performance in wireless metropolitan area networks. The WiMAX model

suite includes the features of the IEEE 802.16e standard with two types: simple and advance

node model. WiMAX-capable nodes are included in the WiMAX object palette which

includes routers, base stations, workstations, etc.

To understand the fundamental work and the performance analysis of WiMAX network

technology, we proposed a scheme of the network topology of this case study as shown in

Figure 3. WiMAX configuration and profile Configuration provide to define and attribute all

the applications that are used by the MN in this network case study. Three different

applications are used: FTP, Video Conferencing and Voice over IP. The proposed WiMAX

network model consists of seven Base Stations and seven cells; each cell has four mobile

nodes to serve all applications types. A vector-based trajectory is also used in this scenario.

The coverage of one cell is approximately 4km by 4km of area.

Figure 3: WiMAX Network Scheme Implementation

First we will use the same metrics used in the WLAN case study. Table 4.2 displays the

system parameters at the simulation setup in the second case study.



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Table 2: WiMAX Simulation Environment Parameters

System Parameters


Data rate 11Mbps

Basic rate 1Mbps

Antenna Gain 15 dBi

PHY profile Wireless OFDMA 20MHz

PHY profile type OFDM

Max. Transmit power (w) 0.5

Path loss Vehicular

BS MAC address Distance based

Trajectory Vector Based

3.3 UMTS Performance Evaluation

The objective of this scenario studies the performance of UMTS network using the

same set of application and the same performance metrics used in previous cases. Many node

models as part of the UMTS specialized model library are grouped in the UMTS and

UMTS_advanced object palettes in OPNET modulator such as routers, repeaters, stations,

RNC, etc,. In our simulation, the UMTS advanced node models were used.

One of the specialized models used in OPNET simulation is the UMTS model based on the

3rd Generation Partnership Project (3GPP) specifications. The architecture of this model can

be found in simple and advance nodes. The MN model offers functionality related to terminal

equipment and mobile termination, responsible for terminating the radio link. The UTRAN

part consists of models for Node B and RNC.

During this case study, a simulation scenario was built and run in order to obtain the

desired results to achieve the objective. Figure 4 displays the network topology of this case;

the same sets of applications are used, so we used the same metrics used in the previous case

(throughput, delay, and traffic received). The proposed topology of UMTS network model

consists of Node_B, RNC, MN, and SGSN/GGSN nodes. The coverage of one cell is

approximately 5km by 5km of area.

Figure 4: UMTS Network Scheme Implementation

The following simulation parameters were used to obtain the results as shown in

Table 3. The path loss can be calculate by taking the difference between the transmitted

signal strength in the uplink direction at the mobile station and the received signal

strength at Node B.



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Table 3: UMTS Simulation Environment Parameters

System Parameters

Coverage area 5km *5km


UMTS MN cell state Cell_DCH

UMTS RLC process time 0.015

CPICH transmission Power 1W

Shadow fading Standard

deviation

10

Processing time 0.02sec

Path loss Outdoor to indoor and

pedestrian environment

UMTS GMM Timer 15/30/10

3.4 Performance Analysis of Different HWN Technologies Three types of heterogeneous wireless technology WLAN, WiMAX and UMTS were

implemented and tested with different selected applications executed on the mobile node

Heavy FTP, Heavy Video Conference and VoIP with PCM quality.

Table 4: The General Statistic Information of Video Conference. Traffic Sent

WiMAX Statistic Inf. kb/s Wi-Fi Statistic Inf. kb/s UMTS Statistic Inf. kb/s

horizontal, min : 0

max : 900

vertical, min : 0.0

max : 91,4

initial value : 0.0

final value : 91,3

expected value : 79,988

sample mean : 79,988

variance : 886,482

standard deviation : 29,77

horizontal, min : 0

max : 900

vertical, min : 0.0

max : 15,206

initial value : 0.0

final value : 15,2



variance :24,529


horizontal, min : 0

max : 900

vertical, min : 0.0

max : 15,262

initial value : 0.0

final value : 15,26



variance :


Figure 5: Video Conference Sent and Received Traffics



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The mobility used for this project simulation speed is 10km/h with different location

nodes at specified vector trajectory defined in chapter four and simulation time was about 15

minutes. Selected performance of applications such as VoIP, Video Conference and FTP and

also the metrics such as average delay, throughput, and received traffic were calculated and

discussed.

Figure 5 shows the video conference traffic sent and received for all HWN (Wi-Fi,

WiMAX and UMTS). Table 4 describes some of the general statistic information for this

performance. As a result, we can show WiMAX traffic sending was the best in about 60%,

but all were equal in response at received traffics.

On the other hand, Figure 6 and Table 5 show and describe the send traffics of VoIP

in this project; they show that the performance of WiMAX throughput beats the other

networks in sent and received traffics in about (30-100)%.

The response of the third application is FTP throughput as shown in Figure 7. Table 6

describes the statistic information for FTP traffic sent. We can conclude from them that the

superiors of WiMAX performance through this project are in the Wi-Fi and UMTS networks.

Figures (8-10) show the global delays and throughput in each network. The maximum delay

and minimum throughput are shown in UMTS network. On the other hand, the minimum

delay and the maximum throughput are shown in WiMAX networks.

Table 5: The General Statistic Information of VoIP. Traffic Sent


horizontal, min : 0

max : 900

vertical, min : 0.0

max : 31,564

initial value : 0.0

final value : 25,226



variance : 78,521


horizontal, min : 0

max : 900

vertical, min : 0.0

max :

initial value : 0.0




variance :


horizontal, min : 0

max : 900

vertical, min : 0.0

max : 11,57

initial value : 0.0

final value : 7,928


sample mean : 7,591

variance :


Figure 6: VoIP Sent and Received Traffics



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Figure 8: Throughput and Delay in WiMAX and Wi-Fi

Table 6: The General Statistic Information of FTP. Traffic Sent


horizontal, min : 0

max : 900

vertical, min : 0.0

max : 556,124

initial value : 0.0




variance : 21,939.000


horizontal, min : 0

max : 900

vertical, min : 0.0

max :

initial value : 0.0




variance :


horizontal, min : 0

max : 900

vertical, min : 0.0

max : 5,612

initial value : 0.0

final value :

expected value : 224.49 b/s

sample mean : 224.49 b/s

variance :


Figure 7: FTP Sent and Received Traffics



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Figure 9: Throughputs and Delays in UMTS Network

Figure 10: Overall Delay in the Three Networks

4. HANDOFF IMPLEMENTATION AND EVALUATION OF HWN

This section includes three different case studies to implement and evaluate Handoff

(HO) through WLAN, WiMAX and UMTS networks.

4.1 Handoff in WLAN

In this case study, we used three access point and forty-two Mobile Nodes (MNs)

with Wi-Fi connection were distributed over seven cells with the help of internet protocol.

The mobile nodes moves randomly by trajectory vector known previously between seven

wireless APs. These APs offer the service of WLAN_802.11g with data rate 54Mbps

including roaming features between these APs. The objective of this scenario is to provide

the performance of achieving HO during the moving of MN among cells when the speed of

MN is about 10km/h at simulation time is one hour.

The same set of metrics was used in this project too to set all nodes in the simulation. Figure

11 shows the details of the proposed HO_ WLAN topology.



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Figure 11: HO_WLAN Network Scheme Implementation

4.2 Handoff in WiMAX This case studied the performance evolution of WiMAX technology when MN moves

between BSs coverage area and HO occurred. The objective of this study is to explore how

the performance is affected during handoff occurrence with multiple BSs which support

WiMAX IEEE802.16e. So the same predefined set of metrics was used. The simulation time

in this case study is taken to be 15 minutes.

The Figure 12 shows the proposed WiMAX topology architecture. WiMAX setup included

seven BSs. The MN or MS moves in a selected trajectory so that it roams near the coverage

areas by these BSs alternately. The BSs were symmetrical and they were different only in

MAC address. The efficiency mode on WiMAX configuration attributed in mobility and

ranging ability, so MS was also set to support the WiMAX BSs services. IP cloud was used

in this case to support the mobility of MN among BSs. Figure 12 shows the proposed real

location applied in a selected region for BSs and for the MS trajectory moving around these

BSs.

Figure 12: HO_WiMAX Network Scheme Implementation



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4.3 Handoff in UMTS Figure 13 shows the UMTS platform setup which includes six BSs or node_B

connected directly to RNC node to be UTRAN based. Three MN A, B and C, A node

followed specified trajectoryto roam through the coverage areas by six BSs alternately. The

BSs were symmetrical and they were only different in MAC address. The MS also attributed

to support the UMTS BSs services. RNC conected directly to Corresponding node which

represented SGSN node. The conversation and interactive traffic class were attributed in all

mobile nodes. Ordinary to the achieved handoff in this case the UMTS UE cell (such as A

node) state must set in cell_DCH. Figure 13 shows the proposed real location applied in

selected region for BSs and the trajectory moving around these BSs. The simulation time in

this case was about 10minutes.

Figure 13: HO_UMTS Network Scheme Implementation

4.4 Performance analysis of Handoff Implementation in HWN The results and discussions included three cases studies: the evaluation of HO in

WLAN, HO in WiMAX and HO in UMTS.

According to the simulation and implementation in section 4.1, the throughput and

delay for case study one is shown in Figure 14 with specified vector trajectory and simulation

time 60 minutes. It is clear that the maximum value of throughput is about 30,484kb/s at

about 1800 second and the minimum value is 2.1kb/s at about 1950sec.

Figure 14: Throughput and Delay of Case Study 1-WLAN

Figure 15 illustrates the WLAN AP connectivity for several selected mobile nodes

during different locations and HO occurs in about one hour.



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Figure 15: AP Connectivity for Selected Nodes

Throughput and delay for all AP from one to seven are described in Figure 16. It can

be noted that max value is 20,647Kb/s and max mean value is 5,632Kb/s at AP1 because the

location of AP1 is in the center of coverage area. Also it can be noted that the max delay at

AP2 is about 4.12ms between 200-400 s; that occurs because the nodes mobility is out of the

AP2 coverage at these times as shown in Figure 17.

Figure 16: Access Points Throughput and Delay

Figure 17: Two Dimension Animation Viewer of WLAN Subnet



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According to the simulation and implementation of WiMAX in section 4.2, the

throughput, delay, HO delay, advertisement received and the mobility serving ID for this case

study are shown in Figure 18. The same selected vector trajectory in the previous case study

was used with a simulation time of about 15 minutes. From the Figure 18, we can note the

max throughput is 397p/s at about 520s and the min throughput is 35p/s at 490s due to MN

moving far of the coverage area of BS5 and BS6.

Figure 18: Throughputs, Delay, HO delay, Advertisement Received and Mobility

Serving ID

From Figure 19, we can see the throughput of all used BSs in the topology. The MN

was connected to BS0 at the start and moved through BSs, and then at the end of the

specified trajectory, it was back to BS0.

Figure 19: The BSs Throughput in WiMAX Subnet

In the third case study, UMTS HO implemented and simulated results can be shown

in Figure 20. Three active sets were used in simulation due to using three mobile nodes; the

statistic reports the number of the cells in the active set of the surrounding MN, which varies

during handoffs. Initially each MN is attached only to a single Node-B. Therefore, the

statistic starts with an initial value of 1. Then, throughout the simulation, whenever an



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addition or removal takes place to/from the Active Set, the new count of the cells after this

operation is recorded.

Figure 20: UMTS HO Results

The total traffic received throughput, end to end delay per QoS and the uplink

throughput of each BSs in UMTS subnet are shown in Figure 21. It can be noted that

throughput decreases after 355 second with max throughput value of 5.6Kb/s at BS0 due to

the MN stopping near the coverage area of BS5.

Figure 21: Throughput, End to End Delay and Uplink Throughput in BSs

5. INTEGRATION, INTERWORKING AND DEPLOYMENT IN HWN

The approach of this will consist from of two directions. The first direction includes

how to integration the Wi-Fi network into WiMAX network in order to work as a one

network. The second direction includes the interworking Wi-Fi network into UMTS network

to work as a one network.



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5.1 Integration of Wi-Fi / WiMAX Network The objective of this case study is to implement and evaluate the Wi-Fi/WiMAX

integration networks. This case study contains two different wireless service in coverage, bit

rate, operating frequency…etc.; hence, each network has to modify its protocols, interfaces

and services in order to support the interworking requirements [14][15]. To achieve this,

the BS of WiMAX and AP of Wi-Fi were enhanced and new interface were added in these

nodes. The application configuration, application profile and WiMAX configuration were

sets to support the one selected application HTTP as shown in Figure 22.

Figure 22: Implementation of Wi-Fi/WiMax Integration

5.2 Integration WLAN into UMTS Network The purpose of this case study is to implement, simulate and test a network system

environment to allow investigators to study and verify the trade-offs for interworking the

infrastructure-based wireless LAN (WLAN) technologies into cellular systems, specifically

UMTS. In this case study, we focused on the interworking of WLAN to provide data

services; therefore, the circuit switched domain was not required. The tight coupling

approach was used in this case. Hence, The WLAN-UMTS system was tightly coupled at the

RNC using the WLAN technology as an alternate radio access technology for “hot spots”.

This case was achieved in a simulation containing the Enhanced WLAN Access Point

(termed WLAN_UMTS_AP), the Enhanced User Equipment (termed UW_1), and Enhanced

the Core Node (SGSN/GGSN). The enhanced node models in [16] was used and

implemented and then evaluated in our proposed system.

The application traffic models used in this case generating traffic based on standard

applications such as HTTP and E-mail applications with a simulation time of 15minutes.

Figure 23 shows the proposed WLAN_UMTS interworking topology implementation in

OPNET simulator.



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Figure 23: Implementation of WLAN/UMTS Integration

The GMM protocol must be implemented in this case. The GMM protocol, which

logically operates between the MN and the SGSN, provides the authentication and the basic

signaling mechanisms for controlling mobility management into the UMTS domain[17]. The

authentication center (AuC) and visitor location register (VLR) operations were impeded

SGSN/GGSN enhanced node.

5.3 Performance Analysis of the Integrated Networks Two case studies are evaluated in this section. The first section includes results and

discussion of WiFi/WiMAX integrated networks and the second section includes the results

and discussion of interworking WiFi network into UMTS network.

Figure 24 illustrates the throughput and delay in WLAN/WiMAX deployment for a

simulation time of 24 minutes. The max value is 1.75Mb/s at 17minutes and the min value is

about 106.6Mb/s at 3minutes. We can note that the delay in WiMAX network is10 times

greater than the delay in Wi-Fi. This figure represented the trade-offs for interworking of the

infrastructure-based Wireless LAN (WLAN) technologies into WiMAX technology.

Figure 24: WiMAX/WiFi Throughput and Delay

It can be shown in Figure 25, the HTTP traffic received and sent throughput, according to the

static information concluded, the maximum and minimum values of throughput are (15.6,

4.8)Kb/s at (9, 21) minutes respectively.



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Figure 25: The HTTP Traffic Received and Sent Throughput

It is clearly shown that the BSS0 and BSS1 was equal load. The load mean value according to

the static information is about 630b/s due to the same numbers and the same types of MN as

shown in Figure 26.

Figure 26: WLAN Network Load

In the second part of case study two analyses, Figure 27 illustrates the delay and throughput

of WLAN, it can be note that the max value of throughput is 12801b/s and the max delay

value is at 65ms.

Figure 27: WLAN Delay and Throughput

Figure 28 represents the response of the selected applications HTTP and E-mail over

the integration between the two networks. It can be shown the HTTP traffic sent and received

throughput is 10 times greater than the E-mail application due to servings.



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Figure 28: HTTP and Email Application

Figure 29 shows the UMTS GMM delay in several cases. It is very clear that the

delay in WLAN is less than that in UMTS.

Figure 29: UMTS GMM Delay

6. CONCLUSIONS

In this study, we present a performance analysis of various types of wireless networks

with many applications and many types of handoff using OPNET simulator. The OPNET

simulation results show that the superiors of WiMAX performance compared with WLAN

and UMTS, WiMAX ranked first in maximum throughput followed by WLAN, but in

minimum delay WLAN ranked the first and then followed by WiMAX. Also, the simulation

results show the successful implementation and simulation of the deployment of WLAN into

WiMAX and UMTS network by using multiple network interfaces. It found that it is very

difficult to successfully complete the vertical handoff between WLAN-WiMAX and WLAN-

UMTS without carefully and accurately engineering the WLAN network due to highlighting

the fundamental different in HWNs.

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Documents

PERFORMANCE AND HANDOFF EVALUATION OF HETEROGENEOUS WIRELESS