Study the Performance of WiMAX Network

in Three scenarios WiMAX Connection,

WLAN-WiMAX and Effect of Base

Frequency Anas Hashim, Safa Abdalla, Hajer Alnojomi, Hanim

Adel, Adel Gaafar

Department of Communication Engineering, Facultyof Engineering

Red Sea University, Sudan.E-mail: anashashim@hotmail.com

November 2014

Between work station and WLAN

router increases.

Third: Effect of base

frequency for the WiMAX

network, it found that the

lower base frequency (2.4GHz)

The higher performance of

WIMAX network.

1. Overview of WIMAX:

WIMAX is a

telecommunications technology

aimed at providing wireless

data over long distances in a

variety of ways, from point-

to-point links to full mobile

cellular type access. It is a

wireless digital

communications system that is

intended for wireless

"metropolitan area networks".

This technology can provide

broadband wireless access

(BWA) up to 30 miles (50 km)

for fixed stations, and 3 -

10 miles (5 - 15 km) for

mobile stations. WiMAX is a

standards-based technology

enabling the delivery of Last

mile wireless broadband

access as an

Abstract

WiMAX (Worldwide

Interoperability

for Microwave Access) is

broadband wireless

technology for providing

last mile solutions for

supporting higher bandwidth

and multiple service classes

with various quality of

service requirement. In this

paper we concentrated on the

applications of the WiMAX in

our daily life. The paper

constructed three scenarios

by using OPNET modeler 14.5.

First: WiMAX connection, to

examine its efficiency to

connection from base station

to the WiMAX work station,

it is found that the less

number of work stations and

the less distances gave a

better performance for

WiMAX.

Second: WLAN-WiMAX to test

the single FTP performance,

It is observed the FTP drop

dramatically when the

Distance

house and building, or

integrated in the personal

computer as memory card, or

built into a laptop as the

way Wi-Fi access does today.

Figure1: WiMAX 802.16

Network

1.2 The Protocol Layers of

WiMAX

802.16 standards defines

only the two lowest layers,

the Physical Layer and the

MAC Layer as show in figure2

Fig

ure 2: The Protocol Layers of

WiMAX

1.3MAC Layer:

The IEEE 802.16 MAC

(Medium Access Control) was

designed for point-to-

multipoint broadband

wireless access

applications. The primary

task of the WiMAX MAC layer

is to provide an interface

between the higher transport

layers and the physical

layer.The MAC

alternative to wiredbroadband like cable and

DSL. WiMAX provides fixed,nomadic, and portable or

mobile devices. WiMAXForum Certified systems

can be expected to delivercapacity of up to 40 Mbpsper channel, for fixed and

portable accessapplications. Many

companies are closelyexamining WiMAX for the

"last mile" connectivity

at high data rates.1.1 How WiMAX Works:

Basically, WiMAX system

mainly consists of two

parts, base station and

WiMAX receiver. Base station

is a tower which is similar

to the concept of cell-phone

tower that works together

with a set of indoor

electronics. A single WiMAX

tower can provide widely

coverage up to 30 miles

radius at maximum, depending

on the tower height, antenna

gain and transmission power.

Typically, the deployments

will use cells of radius

from 2 to 6 miles, so that

the wireless node could get

access within this range.

The center base station is

connected with a number of

subscriber’s station, which

is referred as Customer

premise equipment (CPE)

receiver.

The WiMAX communication

network utilizing base

station and CPE to build up

wireless communication

system are shown in figure1.

WiMAX receiver could be

either installed as a small

box out door of

OFDMA is the access method

that is based on the OFDM

modulation technique to

divide the carriers among the

users to form sub channels

each sub channel is allocated

a separate coding and

modulation parameters to

allow are adapted separately.

This technique optimizes the

use of spectrum resources and

enhances indoor coverage by

assigning a robust scheme.

2. Network Architecture

of 802.16

Figure 3: 802.16 architecture

ASN: access service network.

ASP: application service provider.

PF: policy function.

CSN: connectivity servicenetwork.

GW: gateway

HA: home agent.

NAP: network accessprovider.

NSP: network serviceprovider.

AAA: authentication,

authorization,

accounting

Layer takes packets fromthe upper layer, thesepackets are called MAC

service data units (MSDUs)and organize them into MAC

protocol data units(MPDUs) for transmission

over the air. For receivedtransmissions, the MAClayer does the reverse.

The IEEE 802.16-2004 andIEEE 802.16e-2005 MAC

design includes aconvergence sub layer that

can interface with avariety of higher-layer

protocols, such as ATM TDMVoice, Ethernet, IP, and

any unknown future

protocol.1.3 Physical layer:

The WiMAX physical layer

(PHY) is designed to work

with different

specifications for licensed

and unlicensed frequency

bands. For example, one is

based on a single carrier

(SC) to support line of

sight with high data rates ,

others use orthogonal

frequency division

multiplexing (OFDM), and

OFDMA to support both line

of sight (LOS) and none line

of sight (NLOS) .

1.5 OFDM /OFDMA:

OFDM is an efficient

modulation scheme used for

transmitting large amount of

data over radio waves. OFDM

is a multi carrier

transmission method that is

based on dividing the

frequency of a carrier into

orthogonal frequency sub

carriers each carrying

different stream of data and

is can be modulated and

coded separately.

attributes included in theWiMAX configuration

Figure 4: WiMAX connection

model.

For the first model, we

build only 4 work stations

around a WiMAX base station.

For the second model, we

build 12 work stations

randomly spread in the area.

For the third model, we set

17 work stations around a

base station but more

concentrate to the work

station as show in figure 5.

Figure 5: Three differenttopologies of WiMAXconnection model.

By comparing the

connection result of those

models, we could analysis the

connection efficiency of a

WiMAX base station.

3. Simulation of WiMAX:

OPNET modeler 14.5 is

used to simulate the WiMAX

network, where we concern on

some performance metric as

follow: Mean Opinion Score

(MOS), Packet end to end

delay, Throughput, load,

delay, Path loss and Signal

to noise ratio (SNR).

3.1 WiMAX Connection

model:

The basic WiMAX

connection

model we built is show in

figure. In this scenario,

the models we used are list

below:

WiMAX config.

WiMAX base station.

4 WiMAX workstations.

The global configuration

object is used to configure

parameters such as service

classes and PHY profiles. In

the WiMAX configuration

object, the contention

parameters, efficiency mode

and MAC service class

Definitions are chosen. The

fixed WiMAX base station

node model with router

functionality, this node has

Ethernet interfaces and

WiMAX interfaces. For the 4

WiMAX SS (Subscriber

Station) workstations, stand

for the mobile subscribe

station node model with

workstation functionality.

On base station node models

and the subscriber station

node models, all of the

parameters needed to specify

to match the

3.3 Effect of Base

Frequency model:

One of the feature of

WiMAX devises is the wide

range of base frequency from

2 to 66 GHz, on both licensed

and free licensed spectrum

In this project the effect of

base frequency on the WiMAX

network performance will be

studied .we concern on three

famous frequency (2.4,3.5 &

5.8GHz) which most of the

WiMAX devises work on them.

We will study network of 12

WiMAX workstation connect and

call each other by one WiMAX

base station during 300

second.

Figure 7 is

simple design of the

studied WiMAX network

contains flowing nodes

Base station.

12Workstation.

WiMAX configuration

Applications node.

Profiles node.

Figure 7: Network

form.

The following table will

resumes the network setting

for all nodes:

3.2 WLAN-WiMAX network model:

Figure 6 shows the model

we build

to test the FTP performance,

the node we

used is list below:

Application config.

Profile config.

WiMAX config.

WiMAX base station.

Application server.

WiMAX WLAN router.

4 WiMAX work stations.

Profile Configuration is

used to choose the

applications using form

correspond to different

scenarios. The WiMAX

configuration defines the

contention parameters,

efficiency mode and MAC

service class Definitions.

The WiMAX base station

performs the same work as

last graph, and application

server which is the mobile

subscriber station node

model offers the

functionally server. The new

icon appears in the

following picture is the

mobile subscriber station

node mobile can route the

signal transferred from the

WiMAX base station

functionally to the 4

wireless work stations.

Figure 6: WLAN-WiMAX Network

mode

Connection Efficiency =

Admitted connections / Total

connections

Model 1: 16/18 = 88.9%

Model 2: 40/58 = 76.9%

Model 3: 58/72 = 80.56%

By comparing the result,

we found that the connection

performance is best for the

least work-station topology.

And the model with more (17

work stations) concentrate in

to the base station is even

having a better performance

than the model (14 work

stations) has a less work

stations.

4.2 WLAN-WiMAX Network model

Throughput between Base Station

and WLAN-WiMAX router

The result we compare for

this model is the throughput

between Base Station and

WLAN-WiMAX router

Figure 8: Throughput between

Base Station and

WLAN-WiMAX router.

The throughput between the

WiMAX Base Station and a

WLAN-WiMAX router is nearly

the same. Therefore the

information lost is very low

in WiMAX signal transmitted

send by WiMAX Base Station.

Table 1: Network Setting

Base station and work stationsetting

Parameter Basestation

Workstation

Antennagain dB

15 dB 1 dB-Transmitted power

38 w 0.5 w

PHYprofile

WirelessOFDMA 20

MHz

Wireless OFDMA20 MHz

PHYprofiletype

OFDMA OFDMA

WiMAX ConfigurationWiMAX Attribute

Efficienc Physical

y mode layerenable

Frameduration

5 msec

Symbolduration

102 msec

Numberof

subcarrier

2048

Duplexingtechnique

TDD

Basefrequency

2.4.3.5.5.8GHz

Channelbandwidth

10 MHz

The scenario is repeated

with change the distance

from 1 to 54 km with each

base frequency.

4. Result and Discussion 4.1 WiMAX Connection:

For this model, we

simulate a connection

report to reveal the

connection efficiency of

the WiMAX

Table 2: Result of WiMAX

connection model

No ofSS

No ofadmitted

connections

No ofrejected

connections

4 16 212 40 1217 58 14

4.3 Effect of Base

Frequency:

OPNET modeler can give us

the result as graphs, this

graphs form a relation

between the studied metric

and simulation times or other

effected factor like number

of users. Also these results

can be converted to excel

data sheet to deal with them.

The simulation duration is

300 second and the scenario

is repeated with change the

distance from 1 to 54 km with

each base frequency.

Mean Opinion Score (MOS):

From figure 11 we show

the mean opinion score with

all used base frequency and

no big different among them,

as we only test 12

workstation so the effect not

appears clearly.

Figure 11: Mean Opinion

Score (MOS).

The throughput between

the WiMAX Base Station and a

WLAN-WiMAX router is nearly

the same. Therefore the

information lost is very low

in WiMAX signal transmitted

send by WiMAX Base Station.

Load and delay between two

work stations

The next figures show a load

and delay between two work

stations with different

distance between stations

and router

Figure 9: load between two

work stations

Fig

ure 10: Delay between two

work stations

The FTP performance

drop dramatically when

distance between work and

WLAN routers increases.

But the WiMAX file

transfer performance in

this area is nearly

perfect. Therefore in this

model the limitation of

this network is the WLAN

transfer performance Path loss:

Figure 14 Show how the

path loss will influence by

the Distance between the base

station and the work

stations, where it from 1km

to 54 km with base frequency

2.4, 3.5and 5.8 GHz and

channel Bandwidth 10 MHz

Figure 14: path loss

Signal to Noise Ratio (SNR):

Figure 15 Show how the

SNR (signal to noise ratio)

will influenced by the

distance between the base

station and the work

stations, where it changes

from 1km to 54 km with base

frequency 2.4, 3.5and 5.8 GHz

and channel bandwidth 10

MHz .

Fig

ure 15: Signal to Noise Ratio

We can explain these

results as follow:

Packet End to End Delay:Figure 12 show that

packet end to end delay goes

up as the distance increases

between workstations and

base station, also it is

noticed that packet end to

end delay increases sharply

with high base frequency to

unacceptable value, but with

lower frequency increases

slowly.

Fi

gure 12: Packet End to End

Delay

Throughput:

Figure 13 show that the

throughput go down with the

distance increasing between

work stations and base

station with each base

frequency because the

attenuation that happened to

signals , but what we notice

that the lower base

frequency 2.4 GHz has the

maximum throughput at any

distance.

Fig

ure 13: Throughput

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07458, 2007.

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"Fundamentals of WiMAX

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2007.

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When the base frequency

decrease from 5.8 to 2.4 GHz

the signal is more able to

diffract and penetrate

through the obstacle and

that will explains the high

SNR and low Path Loss for

lower frequency.

Conclusions

There are two factors

affect to the connection

efficiency :

- The numbers of the

work stations, the

less number of work

stations gave a

better performance.

- The distances of each

work station between

base stations,

the less distances

gave a better

performance.

By improvement the

overall performance of

the network, it could

use a WiMAX work

station instead the

WLAN router with WLAN

work stations.

The lower base frequency

(2.4GHz) is the higher

performance of WIMAX

network.