Evaluation and Performance Analysis of Propagation Models for WiMAX

IRACST – International Journal of Computer Networks and Wireless Communications (IJCNWC), Vol. 1, No. 1, December 2011

Evaluation and Performance Analysis of Propagation Models for WiMAX

Md. Sipon Miah1, M Mahbubur Rahman2 ,Paresh Chandra Barman3,

Lecturer1, Professor2, Associate Professor3, Dept. of Information & Communication Engineering

Islamic University Kushtia-7003, Bangladesh

Bikash Chandra Singh4, Ashraful Islam5

Lecture3, MSc Student4, Dept. of Information & Communication Engineering

Islamic University Kushtia-7003, Bangladesh

Abstract—Worldwide Interoperability for Microwave Access (WiMAX) is the latest broadband wireless technology for terrestrial broadcast services in Metropolitan Area Networks (MANs). WiMAX has potential success in its line-of-sight (LOS) and non line-of-sight (NLOS) conditions which operating below 11 GHz frequency. Estimation of path loss is very important in initial deployment of wireless network and cell planning. Numerous path loss (PL) models (e.g. Okumura Model, Hata Model) are available to predict the propagation loss, but they are inclined to be limited to the lower frequency bands (up to 2 GHz. In this paper, we compare and analyze five path loss models (i.e. COST 231 Hata model, ECC-33 model, SUI model, Ericsson model and COST 231 Walfish-Ikegami model) in different receiver antenna heights in urban, suburban and rural environments in NLOS condition. We consider Bangladesh as three regions such: Urban, Suburban, flat area and use operating frequency 2.5 GHz. My observation shows that none of a single propagation model is well suited for all environments. SUI model showed the lowest prediction in urban environment. ECC-33 model showed the heights path loss and also showed huge fluctuations due to change of receiver antenna height. In suburban, SUI model predict the lowest path loss in this terrain with little bit flections at changes of receiver antenna heights. COST-Hata model showed the moderate result and ECC-33 model showed the same path loss as like as urban environment because of same parameters are used in the simulation. In flat or rural, COST 231 Hata model showed the lowest path loss.

Keywords-MANs, PL, SUI, NLOS, LOS

I. INTRODUCTION Now days people are enjoying wireless internet access for

telephony, radio and television services when they are in fixed, mobile or nomadic conditions. The rapid growth of wireless internet causes a demand for high-speed access to the World Wide Web. The IEEE 802.16 working group brought out a new broadband wireless access technology called “WiMAX” meaning Worldwide Interoperability for Microwave Access. It was introduced by the IEEE 802.16 working group to facilitate broadband services on areas where cable infrastructure is inadequate. It is easy to install and cheap. It provides triple play applications i.e. voice, data and video for fixed, mobile and nomadic applications. The key features of WiMAX including higher bandwidth, wider range

and area coverage, its robust flexibility on application and Quality of Services (QoS) attract the investors for the business scenarios. Broadband Wireless Access (BWA) systems have potential operation benefits in Line-of-sight (LOS) and Non-line-of-sight (NLOS) conditions, operating below 11 GHz frequency. During the initial phase of network planning, propagation models are extensively used for conducting feasibility studies. Propagation models are used for calculation of electromagnetic field strength for the purpose of wireless network planning during preliminary deployment. It describes the signal attenuation from transmitter to receiver antenna as a function of distance, carrier frequency, antenna heights and other significant parameters like terrain profile (e.g. urban, suburban and rural). Different models are used to calculate the path loss. There are numerous propagation models available to predict the path loss (e.g. Okumura Model, Hata Model), but they are inclined to be limited to the lower frequency bands (up to 2 GHz). In this thesis we compare and analyze five path loss models (e.g. COST 231 Hata model, ECC-33 model, SUI model, Ericsson model and COST 231 Walfish-Ikegami (W-I) model) which have been proposed for frequency at 2.5 GHz in urban and suburban and rural environments in different receiver antenna heights.

II. RELATED WORKS Models such as the Harald.T. Friis free space model are

used to predict the signal power at the receiver end when transmitter and receiver have line-of-sight condition. The classical Okumura model is used in urban, suburban and rural areas for the frequency range 200 MHz to 1920 MHz for initial coverage deployment. A developed version of Okumura model is Hata-Okumura model known as Hata model which is also extensively used for the frequency range 150 MHz to 2000 MHz in a build up area.

Several performance evaluation and analysis have been presented in the literature. Comparison of path loss models for 3.5 GHz has been investigated by many researchers in many respects. In Cambridge, UK from September to December 2003 [1], the FWA network researchers investigated some empirical propagation models in different terrains as function of antenna height parameters. Another measurement was

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taken by considering LOS and NLOS conditions at Osijek in Croatia during spring 2007 [2]. Coverage and throughput prediction were considered to correspond to modulation techniques in Belgium [3]. September 1981, M. Hata, investigate some empirical formula for propagation loss in land mobile radio services in Sweden [4]. In [5], Path loss models have also been used and a comparison between these models and the collected data has been performed. In this paper, different receiver antennas have been used during the measurement campaign and the results have been compared. In [6], this paper describes various accurate path loss prediction methods used both in rural and urban environments. The Walfisch-Bertoni and Hata models, which are both used for UHF propagation in urban areas, were chosen for a detailed comparison. The comparison shows that the Walfisch-Bertoni model, which involves more parameters, agrees with the Hata model for the overall path loss. In Malaysia, May 2007, this paper deals with the performance of WiMAX networks in an Outdoor environment using the SUI channel models [7].

III. GENERAL ONCEPT OF WIMAX To take the edge off the dream to access broadband

internet “anywhere-anytime”, the IEEE formed a working group called IEEE 802.16 to make standards for wireless broadband in Metropolitan Area Network (MAN). The working group introduced a series of standards for fixed and mobile broadband internet access known by the name “WiMAX”. This name is given by the WiMAX Forum (an industry alliance responsible for certifying WiMAX products based on IEEE standards). In this chapter, we discussed on IEEE 802.16 family and some important features of WiMAX. WiMAX is the abbreviation of Worldwide Interoperability for Microwave Access and is based on Wireless Metropolitan Area Networking (WMAN). The WMAN standard has been developed by the IEEE 802.16 group which is also adopted by European Telecommunication Standard Institute (ETSI) in High Performance Radio Metropolitan Area Network, i.e., the HiperMAN group. The main purpose of WiMAX is to provide broadband facilities by using wireless communication. WiMAX is also known as “Last Mile” broadband wireless access technology.

In December 2001, the 802.16 standard was approved to use 10 GHz to 66 GHz for broadband wireless for point to multipoint transmission in LOS condition. It employs a single career physical (PHY) layer standard with burst Time Division Multiplexing (TDM) on Medium Access Control (MAC) layer [10]. In January 2003, another standard was introduced by the working group called, IEEE 802.16a, for NLOS condition by changing some previous amendments in the frequency range of 2 GHz to 11GHz. By replacing all previous versions, the working group introduced a new standard, IEEE 802.16-2004, which is also called as IEEE 802.16d or Fixed WiMAX. Another standard IEEE 802.16e-2005 approved and launched in December 2005, aims for supporting the mobility concept. This new version is derived after some modifications of previous standard. It introduced mobile WiMAX to provide the services of nomadic and mobile users. Nowadays, WiMAX is the solution of “last mile” wireless broadband. It

provided an enhanced set of features with flexibility in terms of potential services. Interoperable is the important objective of WiMAX. It consists of international, vendor-neutral standards that can ensure seamless connection for end-user to use their subscriber station and move at different locations. Interoperability can also save the initial investment of an operator from choice of equipments from different vendors. WiMAX gives significant bandwidth to the users. It has been using the channel bandwidth of 10 MHz and better modulation technique (64-QAM). It also provides better bandwidth than Universal Mobile Telecommunication System (UMTS) and Global System for Mobile communications (GSM). WiMAX systems are capable to serve larger geographic coverage areas, when equipments are operating with low-level modulation and high power amplifiers. It supports the different modulation technique constellations, such as BPSK, QPSK, 16-QAM and 64-QAM. The modern cellular systems, when WiMAX Subscribers Station (SS) is getting power, then it identifies itself and determines the link type associate with Base Station (BS) until the SS will register with the system database. WiMAX consist of OFDM technology which handles the NLOS environments. It provide higher encryption standard such as Triple- Data Encryption Algorithm (DES) and Advanced Encryption Standard (AES). It encrypts the link from the base station to subscriber station providing users confidentiality, integrity, and authenticity. WiMAX provides multiple architectures such as

■ Point-to-Multipoint

■ Ubiquitous Coverage

■ Point-to-Point

WiMAX physical layer consist of OFDM that offer good resistance to multipath. It permits WiMAX to operate NLOS scheme. Nowadays OFDM is highly understood for mitigating multipath for broadband wireless. WiMAX has a capability of getting high peak data rate. WiMAX provides a lot of modulation and forward error correction (FEC) coding schemes adapting to channel conditions. WiMAX has enhanced reliability. It provided Automatic Repeat Requests (ARQ) at the link layer. ARQ-require the receiver to give acknowledge for each packet. WiMAX MAC layer has been designing to support multiple types of applications and users with multiple connections per terminal such as multimedia and voice services. The system provides constant, variable, real-time, and non-real-time traffic flow. WiMAX network architecture is based on all IP platforms. Every end-to-end services are given over the Internet Protocol (IP). The IP processing of WiMAX is easy to conversance with other networks and has the good feedback for application development is based on IP. Frequency band has a major consequence on the dimension and planning of the wireless network. We choose 2.5 GHz band in our studies because it is widely used band all over the world. Moreover, this band is licensed, so that interfere is under control and allows using higher transmission power. Furthermore, it supports the NLOS condition and better range and coverage than 2.5 GHz and 5.8 GHz.

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IV. BASIC PRINCIPLE OF PROPAGATION MODELS

A. Type of Propagation Models Propagation analysis is very important in evaluating the

signal characteristics. The site measurements are expensive and costly. Propagation models have been developed as low cost, convenient alternative and suitable way. In our thesis, we analyze five different models. We consider free space path loss model which is most commonly used idealistic model. We take it as our reference model; so that it can be realized how much path loss occurred by the others proposed models. Models for path loss can be categorized into three types

1. Empirical Models 2. Deterministic Models 3. Stochastic Models

B. Free Space Path Loss Model In telecommunication, free-space path loss (FSPL) is the

loss in signal strength of an electromagnetic wave that would result from a line-of-sight path through free space, with no obstacles nearby to cause reflection or diffraction. Free-space path loss is proportion to the square of the distance between the transmitter and receiver, and also proportional to the square of the frequency of the radio signal.

The equation for FSPL is

1

Where:

• is the signal wavelength (in metres),

• is the signal frequency (in hertz),

• is the distance from the transmitter (in

metres),

• is the speed of light in a vacuum, 2.99792458

× 108 metres per second.

This equation is only accurate in the far field; it does not hold close to the transmitter.If the separation d is continually decreased, eventually the received power appears greater than the transmitted power which is [obviously] impossible in reality, since free space is not an amplifier.

Free-space path loss in decibels

A convenient way to express FSPL is in terms of dB:

2

Where the units are as before.

For typical radio applications, it is common to find f measured in units of MHz and d in km, in which case the

equation becomes

3

For d in statute miles, the constant becomes 36.58.

C. Okumura Model The Okumura model is a well known classical empirical

model to measure the radio signal strength in build up areas. This model is perfect for using in the cities having dense and tall structure. Moreover, Okumura gives an illustration of correction factors for suburban and rural or open areas. By using Okumura model we can predict path loss in urban, suburban and rural area up to 3 GHz. Our field of studies is 2.5 GHz. We provided this model as a foundation of Hata-Okumura model.

Median path loss model can be expressed as:

4

Where : Median path loss [dB]

: Free space path loss [dB] : Median attenuation relative to free space

[dB] : Base station antenna height gain factor

[dB] : Mobile station antenna height gain factor

[dB] : Gain due to the type of environment [dB]

And parameters : Frequency [MHz]

: Transmitter antenna height [m] : Receiver antenna height [m]

: Distance between transmitter and receiver antenna [km] Attenuation and gain terms are given in:

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http://en.wikipedia.org/wiki/Metres_per_second

http://en.wikipedia.org/wiki/Far_field

http://en.wikipedia.org/wiki/MegaHertz


5

D. Cost 231 Hata Model The Hata model is introduced as a mathematical

expression to mitigate the best fit of the graphical data provided by the classical Okumura model. Hata model is used for the frequency range of 150 MHz to 1500 MHz to predict the median path loss for the distance d from transmitter to receiver antenna up to 20 km, and transmitter antenna height is considered 30 m to 200 m and receiver antenna height is 1 m to 10 m. To predict the path loss in the frequency range 1500 MHz to 2000 MHz. COST 231 Hata model is initiated as an extension of Hata model. The basic path loss equation for this COST-231 Hata Model can be expressed as:

PL = 46.3 + 33.9 log10 (f) – 13.82 log10(hb) – ahm + (44.9 – 6.55 log10(hb)) log10 d + cm 6

where

d : Distance between transmitter and receiver antenna [km]

f : Frequency [MHz]

hb : Transmitter antenna height [m]

The parameter cm has different values for different environments like 0 dB for suburban and 3 dB for urban areas and the remaining parameter ahm is defined in urban areas as:

ahm = 3.20(log10 (11.75hr))2 – 4.79 for f > 400 MHz 7

The value for ahm in suburban and rural (flat) areas is given as:

ahm = (1.11log10 f – 0.7)hr – (1.5 log10 f – 0.8) 8

Where the is the receiver antenna height in meter.

E. Stanford University Interim Model IEEE 802.16 Broadband Wireless Access working group

proposed the standards for the frequency band below 11 GHz containing the channel model developed by Stanford University, namely the SUI models. This prediction model comes from the extension of Hata model with frequency larger than 1900 MHz. The correction parameters are allowed to extend this model up to 2.5 GHz band. The base station antenna height of SUI model can be used from 10 m to 80 m. Receiver antenna height is from 2 m to 10 m. The cell radius is from 0.1 km to 8 km. The basic path loss expression of The SUI model with correction factors is presented as:

9

For

Where the parameters are

: Distance between BS and receiving antenna [m]

: 100 [m]

: Wavelength [m]

: Correction for frequency above 2 GHz [MHz]

: Correction for receiving antenna height [m]

: Correction for shadowing [dB]

: Path loss exponent

The random variables are taken through a statistical procedure as the path loss exponent γ and the weak fading standard deviation s is defined. The log normally distributed factor s, for shadow fading because of trees and other clutter on a propagations path and its value is between 8.2 dB and 10.6 dB. The parameter A is defined as

10

And the path loss exponent γ is given by

+ 11

Where, the parameter hb is the base station antenna height in meters. This is between 10 m and 80 m. The constants a, b, and c depend upon the types of terrain, that are given in Table 3. The value of parameter γ = 2 for free space propagation in an urban area, 3 < γ < 5 for urban NLOS environment, and γ > 5 for indoor propagation.

The frequency correction factor and the correction for receiver antenna height for the model are expressed in

12

13

Where, f is the operating frequency in MHz, and hr is the receiver antenna height in meter. For the above correction factors this model is extensively used for the path loss prediction of all three types of terrain in rural, urban and suburban environments.

F. Hata- Okumura Extended Model The original Okumura model doesn’t provide any data

greater than 3 GHz. Based on prior knowledge of Okumura model; an extrapolated method is applied to predict the model

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for higher frequency greater than 3 GHz. The tentatively proposed propagation model of Hata-Okumura model with report is referred to as ECC-33 model. In this model path loss is given by

14

: Free space attenuation [dB]

: Basic median path loss [dB]

: Transmitter antenna height gain factor

: Receiver antenna height gain factor

These factors can be separately described and given by as

=92.4+20 15

=20.41+9.83log10 (d) + 20 log10 (f) + 9.56 [log10(f)]2

16

= 17

When dealing with gain for medium cities, the will be expressed in

= 18

For large city

= 19

Where

: Distance between transmitter and receiver

Antenna [km]

: Frequency [GHz]

: Transmitter antenna height [m]

: Receiver antenna height [m]

This model is the hierarchy of Okumura-Hata model.

G. Cost 231Walfish-Lkegami Model This model is a combination of J. Walfish and F. Ikegami

model. This model is most suitable for flat suburban and urban areas that have uniform building height. The equation of the proposed model is expressed in:

For LOS condition

20

And for NLOS condition

21

For urban and suburban

If Lrst + Lmsd >0

Where

= Free space loss

= Roof top to street diffraction

= Multi-screen diffraction loss

Free space loss

= 22

Roof top to street diffraction

23

Where

24

Note that

The multi-screen diffraction loss is

25

Where

26

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27

28

29

for suburban of medium size cities with moderate tree density fot metropolitan / urban.

where

: Distance between transmitter and receiver antenna [m]

: Frequency [GHz]

: Building to building distance [m]

: Street width [m]

: Street orientation angel w.r.t. direct radio path [degree]

In our simulation we use the following data, i.e. building to building distance 50 m, street width 25 m, street orientation angel 30 degree in urban area and 40 degree in suburban area and average building height 15 m, base station height 30 m.

H. Ericsson Model To predict the path loss, the network planning engineers

are used software provided by Ericsson Company is called Ericsson model. This model also stands on the modified Okumura-Hata model to allow room for changing in parameters according to the propagation environment. Path loss according to this model is given by

30

Where is defined by

31

And parameters

: Frequency [MHz]

: Transmission antenna height [m]

: Receiver antenna height [m]

V. SIMULARTION ENVIRNMENT & MODELS

A. Simulation Environment For analyzing the performance of propagation models for

WiMAX, I have used MATLAB software package. MATLAB is a software package for high-performance numerical computation and visualization. It provides an interactive environment with hundred of built-in function for technical computation, graphics and animation. Best of all, it also provides easy extensibility with its own high-programming language. The name MATLAB stands for MATrix LABoratory.

B. Simulation Design For evaluating and analyzing the performance of WiMAX

propagation models I have used MATLAB simulation. A typical simulation model is shown in fig (4.1).

Figure 1. Simulation process flow chart for three different environments.

In this model I have used three different environments (Urban, Suburban and Flat) with different parameter.

C. Simulation Parametras The following Table 4.2 presents the parameters we applied in our simulation.

Parameters Values

Transmitter antenna height 40 m in urban and 30 m in suburban and

START

Input Parameter

Choose Environment

Output Path loss

END

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20 m in rural area

Receiver antenna height 3 m, 6 m and 10 m

Operating frequency 2.5 GHz

Distance between Tx-Rx 5 km

Building to building distance

50 m

Average building height 15 m

Street width 25 m

Street orientation angle 300 in urban and 400

in suburban Correction for shadowing 8.2 dB in suburban and

rural and 10.6 dB in urban area

Table 4.1: Simulation parameters

VI. PERFORMANCE ANALYSIS AND DISCUSSION

A. Analysis of Simulation Results in Urban Area In our calculation, we set 3 different antenna heights (i.e. 3

m, 6 m and 10 m) for receiver, distance varies from 250 m to 5 km and transmitter antenna height is 40 m. The numerical results for different models in urban area for different receiver antenna heights are shown in the Figure 2, 3 and 4.

Figure 2. Path loss in urban environment at 3 m receiver antenna height.



The accumulated results for urban environment are shown in figure 5. Note that SUI model showed the lowest prediction (128 dB to 121 dB) in urban environment. It also showed the lowest fluctuations compare to other models when we changed the receiver antenna heights. In that case, the ECC-33 model showed the heights path loss (156 dB) and also showed huge fluctuations due to change of receiver antenna height. In this model, path loss is decreased when increased the receiver antenna height. Increase the receiver antenna heights will provide the more probability to find the better quality signal from the transmitter. ECC-33 model showed the biggest path loss at 10 m receiver antenna height.

Urban

156 154138 126

149

109

154 150136 124

147

109

150 147 135121

142109

0

50

100

150

200

Distance at 2.5 km

Path

loss

dB

Rx height 3m 156 154 138 126 149 109

Rx height 6m 154 150 136 124 147 109

Rx height 10m 150 147 135 121 142 109

ECC-33 COST-Hata ERICSSON SUI COST-WI FSPL

Figure 5. Analysis of simulation results for urban environment in different receiver antenna height.

B. Analysis of Simulation Results in Suburban Area In our calculation, we set 3 different antenna heights (i.e. 3

m, 6 m and 10 m) for receiver, distance varies from 250 m to 5 km and transmitter antenna height is 30 m. The numerical results for different models in urban area for different receiver antenna heights are shown in the Figure 6, 7 and 8.

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Figure 6. Path loss in suburban environment at 3 m receiver antenna height

Figure 7. Path loss in suburban environment at 6 m receiver antenna height.

Figure 8. Path loss in suburban environment at 10 m receiver antenna height.

The accumulated results for suburban environment are shown in figure 9. In following chart, it showed that the SUI model predict the lowest path loss (121 dB to 116 dB) in this terrain with little bit flections at changes of receiver antenna heights. Ericsson model showed the heights path loss (160 dB and 158 dB) prediction especially at 6 m and 10 m receiver antenna height. The COST-WI model showed the moderate result with remarkable fluctuations of path loss with-respect-to antenna heights changes. The ECC-33 model showed the same path loss as like as urban environment because of same parameters are used in the simulation.

Rural

154 154 148121 109 109

144 152 143121 109 109

132150 137

121 109 109

0

50

100

150

200

Distance at 2.5 km

Path

loss

dB

Rx height 3m 154 154 148 121 109 109

Rx height 6m 144 152 143 121 109 109

Rx height 10m 132 150 137 121 109 109

COST-Hata ERICSSON SUI COST-WI FSPL FSPL

Figure 9. Analysis of simulation results for suburban environment in different receiver antenna height.

C. Analysis of Simulation Results in Flat Area We set 3 different antenna heights (i.e. 3 m, 6 m and 10 m)

for receiver, distance varies from 250 m to 5 km and transmitter antenna height is 20 m. COST 231 W-I model has no specific parameters for rural area, we consider LOS equation provided by this model The numerical results for different models in urban area for different receiver antenna heights are shown in the Figure 10, 11, and 12.

Figure 10. Path loss in rural environment at 3 m receiver antenna height.



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The accumulated results for rural environment are shown in Figure 13. In this environment COST 231 Hata model showed the lowest path loss (132 dB) prediction especially in 10 m receiver antenna height. COST 231 W-I model showed the flat results in all changes of receiver antenna heights. There are no specific parameters for rural area. In our simulation, we considered LOS equation for this environment (the reason is we can expect line of sight signal if the area is flat enough with less vegetations). Ericsson model showed the heights path loss (154 dB to 150 dB).

Rural

154 154 148121 109 109

144 152 143121 109 109

132150 137

121 109 109

0

50

100

150

200

Distance at 2.5 km

Path

loss

dB

Rx height 3m 154 154 148 121 109 109

Rx height 6m 144 152 143 121 109 109

Rx height 10m 132 150 137 121 109 109

COST-Hata ERICSSON SUI COST-WI FSPL FSPL

Figure 13. Analysis of simulation results for rural environment in different receiver antenna height.

VII. CONCLUSION Our comparative analysis indicate that due to multipath

and NLOS environment in urban and suburban area, SUI models experiences lowest path losses compare to flat area. In flat area COST-Hata model provide lowest path loss than SUI model at 10 m receiver antenna height. Moreover, we did not find any single model that can be recommended for all environments.

We can see in urban area (data shown in Figure 5), the SUI model showed the lowest path loss (121 dB in 10 m receiver antenna height) as compared to other models. Alternatively, the ECC-33 model showed the heights path loss (156 dB in 3 m receiver antenna height).

In suburban area (data shown in Figure 9) the SUI model showed quite less path loss (116 dB) compared to other models. On the other hand, ECC-33 model showed heights path loss as showed in urban area. Moreover, Ericsson model showed remarkable higher path loss for 6 m and 10 m receiver antenna heights (i.e.160 dB and 158 dB respectively).

In rural area (data shown in Figure 13), we can choose different models for different perspectives. If the area is flat enough with less vegetation, where the LOS signal probability is high, in that case, we may consider LOS calculation. Alternatively, if there is less probability to get LOS signal, in that situation, we can see COST-Hata model showed the less path loss (132 dB) compare to SUI model (137 dB) and Ericsson model (150 dB) especially in 10 m receiver antenna height. But considering all receiver antenna heights SUI model showed less path loss (148 dB in 3 m and 143 dB in 6 m) whereas COST-Hata showed higher path loss (154 dB in 3m and 144 dB in 6 m).

If we consider the worst case scenario for deploying a coverage area, we can serve the maximum coverage by using more transmission power, but it will increase the probability of interference with the adjacent area with the same frequency blocks. On the other hand, if we consider less path loss model for deploying a cellular region, it may be inadequate to serve the whole coverage area. Some users may be out of signal in the operating cell especially during mobile condition. So, we have to trade-off between transmission power and adjacent frequency blocks interference while choosing a path loss model for initial deployment.

VIII. FEATURE WORKS This is a formal ending of very small stage of a never

ending process. Nowadays the Worldwide Interoperability of Microwave Access (WiMAX) technology becomes popular and receives growing acceptance as a Broadband Wireless Access (BWA) system. In future, our simulated results can be tested and verified in practical field. We may also derive a suitable path loss model for all terrain. Future study can be made for finding more suitable parameters for Ericsson and COST 231 W-I models in rural area.

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AUTHORS PROFILE

MD. SIPON MIAH has Completed his M. Sc. degree in the Department of Information and Communication Engineering from the Islamic University, Kushtia-7003, Bangladesh in 2008 and in 2010 he has been joined as a lecturer in the same department. His interested research areas are data mining, Wireless Sensor Networks, Optical fiber and Mobile communication.

M MAHBUBUR RAHMAN received the Bachelor’s and Master‘s Degree in Physics, Rajshahi University, in 1983, 1994 and PhD degree in Computer Science & Engineering in 1997. He is courrently Professor in the department of ICE, Islamic University, Kushtia-7003, Bangladesh. He has twenty four published papers in international and national journals. His areas of interest include internetworking, AI & mobile communication.

PARESH CHANDRA BARMAN has Completed his M. Sc. degree from the department of Applied Physics and Electronics, The University of Rajshahi-Bangladesh in 1995 and Ph. D. degree in Bio & Brain Engineering , from Korea Advanced Institute of Science & Technology (KAIST), Republic of Korea in

2008. He has been joined as a lecturer in the Department of Information and Communication Engineering, Islamic University, Kushtia-7003, Bangladesh. Currently he is an Associate Professor and Chairman of the same department. His interested research areas are Artificial Neural Networks and Bioinformatics.

BIKASH CHANDRAN SINGH received the Bachelor’s and Master‘s Degree in Information and Communication Engineering from Islamic University, Kushtia, in 2005 and 2007, respectively. He is courrently Lecturer in the department of ICE, Islamic University, Kushtia-7003, Bangladesh. His areas of interest including database, optical fiber communication & multimedia.

ASHRAFUL ISLAM received the Bachelor’s Degree and M.SC in Information and Communication Engineering from Islamic University, Kushtia, in 2008 and 2009 respectively. He was completed M.Sc student in the department of ICE, Islamic University, Kushtia-7003, Bangladesh. He is currently Assistant Programmer in Bangladesh Computer Council, Dhaka.

ISSN: 2250-3501 60

http://www.wimax.com/commentary/wimax_weekly/2-6-reference-network-architecturecontin

http://www.wimax.com/commentary/wimax_weekly/2-6-reference-network-architecturecontin

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Evaluation and Performance Analysis of Propagation Models for WiMAX

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