ATPC Related

PERFORMANCE STUDY OF AUTOMATIC TRANSMIT POWER CONTROL

(ATPC) IN POINT TO POINT MICROWAVE LINK FOR RAIN ATTENUATION

PROBLEM IN MALAYSIA

MUHAMAD MOKHTAR BIN SAAD

A project report submitted in partial fulfillment of the

requirements for the award of the degree of

Masters of Engineering (Electrical – Electronics & Telecommunication)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

NOVEMBER 2006

ii

I declare that this thesis entitled “Performance Study Of Automatic Transmit Power

Control (ATPC) In Point To Point Microwave Link For Rain Attenuation Problem

In Malaysia” is the result of my own research except as cited in the references. The

thesis has not been accepted for any degree and is not concurrently submitted in

candidature of any other degree.

Signature : ................................................................

Name : MUHAMAD MOKHTAR BIN SAAD

Date : 03 NOVEMBER 2006

iii

ACKNOWLEDGEMENTS

I would like to express my gratitude and appreciation to my supervisor, Prof.

Dr. Tharek bin Abd Rahman, for his guidance in the execution of the project and for

his kind understanding. I am especially grateful for all the help he provided and

resources he made available without which the project would not have reached its

current stage. I would also like to thank Dr Zaharuddin bin Mohamed, for being

most efficient in coordinating the project. My acknowledgement also goes out to the

project presentation assessors, Prof. Madya Dr. Jafri Din and Dr. Razali bin Ngah,

who have given me much advice and guidance during the project presentation. Last

but not least, I would like to thank my family especially my beloved wife Rodhiah

Ismail and all my children Ashraf, Afif, Azim and Husna Maisarah for just being

there, giving me the strength and much needed moral support.

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ABSTRACT

Point-to-point microwave system is the backbone link for mobile

communication industry as well as for other applications. In tropical region

particularly in Malaysia, rain attenuation is the major constraint for implementing

microwave system above 10GHz. The extreme of propagation channel environment

due to rain has brought to the research and development of an automatic transmit

power control (ATPC) in microwave transceiver. ATPC varies the transmit power

level in order to maintain the receive signal level (RSL) above the threshold for bit-

error-rate (BER) desired. This research project will cover three main scope of study.

First estimated calculation of rain attenuation on terrestrial point-to-point microwave

link based on rain data captured. This will involve the understanding and

computational of rain attenuation modeling equation by ITU-R recommendation

using the Matlab software. Second is the basic concept and operational of ATPC

applied in transceiver module of microwave link. Finally the experimental

performance analysis of ATPC on actual microwave link install in Celcom

microwave network. The performance will be measured on receive signal level on

the actual system with ATPC option enable and disable for a certain period of time

with realtime rain faded signal.

v

ABSTRAK

Sistem perhubungan microwave titik ke titik merupakan talian hubungan

utama bagi industri telekomunikasi mudah alih dan juga bagi aplikasi-aplikasi lain.

Walaubagaimanapun bagi negara-negara tropika faktor hadangan hujan keatas

perambatan gelombang microwave merupakan masalam utama bagi menggunakan

kemudahan system perhungan titik ke titik ini terutamanya bagi perambatan

gelombang microwave yang berfrekuensi melebihi 10GHz. Faktor hadangan hujan

keatas perambatan gelombang microwave telah membangunkan system perambatan

gelombang secara automatik (Automatic Transmit Power Control- ATPC). ATPC

akan mengubah kekuatan nilai perambatan gelombang bergantung kepada hadangan

hujan yang diterima oleh sistem. Projek penyelidikan ini akan merangkumi tiga

bidang kajian. Pertama menentukan nilai hadangan hujan ke atas sistem hubungan

microwave titik ke titik berdasarkan penerimaan jumlah hujan. Ini melibatkan

pemahaman dan pengiraan hadangan hujan yang dicadangkan oleh ITU-R. Kedua

mengkaji konsep pembinaan dan operasi ATPC didalam sistem hubungan

microwave titik ke titik. Akhirnya ujian prestasi ATPC ke atas satu sistem

hubungan microwave titik ke titik yang telah dipasang dalam rangkaian

perhubungan Celcom. Prestasi ATPC akan dinilai keatas gelombang penerimaan

sistem dengan optional ATPC dihidup dan dimatikan bagi satu tempoh masa yang

ditetapkan.

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TABLE OF CONTENT

CHAPTER TITLE PAGE

DECLARATION ii

ACKNOWLEDGEMENTS iii

ABSTRACT iv

ABSTRAK v

TABLE OF CONTENTS vi

LIST OF TABLES viii

LIST OF FIGURES ix

LIST OF APPENDICES x

1 INTRODUCTION 1

1.1 Objectives of the project 2

1.2 Scope of the project 3

1.3 Problem Statement 3

1.4 Methodology and Report Structure 4

2 DIGITAL MICROWAVE LINK AND PATH

PROPAGATION ATTENUATION 6

2.1 Transmission Lines 6

2.2 Radio Link System 7

2.3 Digital Point to Point Microwave Link 7

2.4 Introduction to Teresterial Link 9

2.5 Propagation Occurs Between Teresterial Link 9

2.5.1 Ground wave propagation 10

2.5.2 Space wave propagation 10

2.5.3 Sky wave propagation 11

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2.6 Path Propagation Attenuation 11

2.7 Effect of Atteneuation due to Hydrometeors 11

3 RAIN ATTENUATION MODEL FOR USE IN

PREDICTION METHOD 13

3.1 ITU-R Rain attenuation prediction model 13

4 ATPC DESIGN CONCEPT 18

4.1 Block Diagram and Operation 18

4.2 Design Consideration 20

4.3 Feedback Loop ATPC 21

5 RAIN ATTENUATION MODELLING BASED ON

ITU-R RECOMMENDATION 24

5.1 Design Flow Chart for Spesific Rain Attenuation Formula 24

6 RESULTS AND DISCUSSION 28

6.1 Calculation of estimated RSL on sample link 28

6.2 Calculated rain attenuation 30

6.3 Simulatin results on bench set up system 31

6.3.1 RSL response with ATPC enables 31

6.3.2 RSL response with ATPC disables 32

6.4 Results on the active system installed within Celcom

network 33

6.5 Summary of Results 34

7 CONCLUSIONS AND FURTHER WORK 35

7.1 Positive Conclusion 35

7.2 Further improvement for this Project 36

7.3 Future research 36

7.4 A Final Note 36

REFERENCES 37

Appendices A – E 39 - 63

viii

LIST OF TABLES

TABLE NO. TITLE PAGE

6.1 Calculated RSL Report with Pathloss 4 29

ix

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 Simplified block diagram of digital point to point microwave

system 8

2.2 Teresterial Link 9

2.3 Line of Sight Propagation 9

3.1 k coefficient for horizontal polarization as a function of frequency 15

3.2 α coefficient for horizontal polarization as a function of frequency 16

3.3 k coefficient for vertical polarization as a function of frequency 16

3.4 α coefficient for vertical polarization as a function of frequency 17

4.1 Block diagram of microwave transmitter with ATPC 19

4.2 A functional block diagram of feedback loop ATPC 21

6.1 Path profile plot 30

6.2 Matlab GUI for rain attenuation 31

6.3 RSL response with ATPC enables 32

6.4 RSL response with ATPC disables 33

6.5 The RSL response on the sample link with ATPC enables 34

x

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Timeline for Project 1 39

B Timeline for Project 2 40

C MATLAB Codes for Rain Attenuation Calculation 41

D Frequency dependant coefficient for estimating specific

attenuation 53

E Sample of system RSL response captured from the system 59

CHAPTER 1

INTRODUCTION

Moving forward to Third Generation Mobile Communication System (3G),

point-to-point microwave link will continue to serve as the backhaul link for

wireless systems. However, the heavy rain in tropical region country limits the full

implementation of the system in terms of installation distance and frequency usage.

As the frequency increasing, the rain attenuation will become worse [5-6]. The

installation distance could be reduced in order to have lower rain attenuation;

however the implementation cost will become higher since more microwave link is

required. Furthermore, frequency spectrum congestion unavoidable will force the

future system to operate in higher frequency band.

Numbers of researches have been conducted for measuring the rain

attenuation at point-to-point microwave link. However, research for the method to

overcome the problem is quite limited. Although power control system also

integrated in some of the point-to-point microwave communication system, the

discussions are limited to only the restrictions, applications and operations rather

than system design and performance analysis [6-8]. The research reported in this

paper therefore aims to give solution for rain attenuation problem at point-to-point

microwave link by introducing adaptive transmit power control (ATPC) in the front-

end of radio unit.

The response of ATPC to the receive signal level (RSL) decides how fast the

system can compensate for the fading and prevent the system from outage. The

design of radio system with ATPC needs to fulfill some regulations in the operating

country in order to install the equipment. European fixed radio systems

2

recommendations are taken as reference for determining the effect of ATPC to

transceiver system [7]. The ATPC is designed to provide sufficient power to

overcome the propagation path loss, without introducing excessive distortion and

spurious that will cause bit-error-rate (BER) performance degradation. Analysis of

transceiver system involves with harmonics and inter modulation that could not be

achieved with simple mathematical calculations. The system analysis will become

more complex when digital modulated signal is processed.

For terrestrial microwave links operating at frequencies higher than 10 GHz,

rain-induced degradations are significant. Major degradations caused by rain that

affect the reliability and availability of terrestrial links are rain attenuation and rain

fade. Besides attenuation, rain fade is another major factor affecting the

performance of microwave links. Rain fade is the dynamic fluctuation of receive

signal due to in homogeneities of the signal path, ranging from a few seconds to a

few minutes. Rain fade provides additional information on understanding the

characteristics of rain-induced degradations.

1.1 Objectives of the project

At the end of Project 1 and 2, I hope to achieve these 3 objectives:

* To calculate the estimation of rain attenuation on terrestrial point-to-point

microwave link based on rain data captured.

* To study the basic concept and operational of an Automatic Transmit Power

Control (ATPC) applied in point-to-point microwave link.

* To study the performance of ATPC to overcome rain attenuation for point-to-point

microwave link in Malaysia

3

1.2 Scope of the project

This project will focus on three main scope of study.

1) The estimated calculation of rain attenuation on terrestrial point-to-point

microwave link based on rain data captured. This will involve the

understanding and computational of rain attenuation equation using the

Matlab software.

2) Basic concept and operational of ATPC applied in transceiver module of

microwave link.

3) Performance of ATPC on actual microwave link install in Celcom

microwave network. The performance will be measured on receive signal

level on the actual system with ATPC option enable and disable for a certain

period of time.

MATLAB will be used in this project to calculate the estimated rain

attenuation based on rain rate data captured. I choose to use MATLAB as the

computer language to design the PSK based communications systems because it is

one of the most popular computer simulation languages in the world

1.3 Problem statement

Attenuation due to rainfall can severely degrade the radio wave propagation

at centimeter or millimeter wavelengths. It restricts the path length of radio

communication systems and limits the use of higher frequencies for line-of-sight

microwave links and satellite communications. The attenuation will pose a greater

problem to communication as the frequency of occurrence of heavy rain increases.

In a tropical region, like Malaysia, where excessive rainfall is a common

phenomenon throughout the year, the knowledge of the rain attenuation at the

frequency of operation is extremely required for the design of a reliable terrestrial

and earth space communication link at a particular location.

4

1.4 Methodology and Report Structure

This is a simulation project as well as life data captured from the system. To

achieve its objectives the following methodology are followed.

1) Select the experimental point to point microwave link for case study

2) Calculate the estimated RSL based on the path profile; transmit power and

gain of the system.

3) Calculate the estimated rain attenuation based on the planning path profile

and ITU-R recommendation.

4) Set up one experimental point to point microwave link at bench to simulate

the ATPC performance by capturing the RSL with ATPC enable and disable

using the results calculated on the above. Plot the graph RSL vs time and

compare the results.

5) Capture the RSL on the experimental link with ATPC enable and compare

the result with the link without ATPC.

Prior to the actual modeling and simulation of ATPC performance of the

systems, objectives, scope, motivations and problem statements are identified. This

is documented in Chapter 1 together with the overview of the project. The timelines

for Project 1 and Project 2 are attached in Appendix A and B.

The second chapter delves deeper into the subject matter which is digital

point to point microwave link and propagation attenuation due to rain. Extensive

research is carried out on the existing point to point microwave communications

system and its underlying siganal propoagation restrictions.

The third chapter outlines the modeling and calculation of rain attenuation

prediction based on ITU-R recommendations. This chapter illustrates the

mathematical models used to in writing the MATLAB codes

5

Subsequently, the next chapter, Chapter 4, writes about the ATPC design

concept. Two type of design consideration is introduced and basic operation of

ATPC module loopback type was clearly explained.

The fifth chapter puts together all the flow chart in writing the MATLAB

script to calculate the rain attenuation predictions.

The final section of this report gives all the results obtained throughout the

project. Discussions and analysis on the results are included in this section.

CHAPTER 2

DIGITAL MICROWAVE LINK AND PATH PROPAGATION

ATTENUATION

Focus of this project is on digital microwave link. As such basic

understanding on digital microwave transmission is necessary.

2.1 Transmission Lines

A transmission line is a device that transfers energy (information) from one

point to another with minimum amount of loss. Information can take the form of

voice, video and data signals. In other words, the transmission line must be

efficient. Efficiency is the real key to a transmission.

Transmission media can be classified as either:

cabled

• twisted pair

• coaxial cable

fiber optic cable

non-cabled

• cellular radio systems

• radio link systems

• satellite system

7

2.2 Radio Link System

Radio link systems operate in the MHz to GHz range (microwaves). A

microwave system consists of a number of ground base stations. Transmitting and

receiving antennas must be in direct line of sight of each other.

Radio link systems were introduced as an alternative to coaxial cable on

long haul routes. They are. also used for links to islands and difficult rural

situations.

Advantages of radio link systems include:

• high bandwidth

• low level of signal attenuation

• can be used over rough terrain which would be unsuitable

for cabled media

Disadvantages of radio link systems include:

• expensive over short distances

• there can be no obstacles between the transmitting and

receiving antennas

• can suffer from interference due to climatic conditions and

other microwave sources

2.3 Digital Point-to-Point Microwave Link [8]

The term digital communications covers a broad area of communications

techniques, including digital transmission and digital radio. Digital transmission is

the transmittal of digital pulses between two points in a communications system.

Digital radio is the transmittal of digitally modulated analog carriers between two

8

points in a communications system. Digital transmission systems require physical

facility between the transmitter and receiver, such as a metallic wire pair, a coaxial

cable or a fiber optic cable. In digital radio systems, the transmission medium is free

space or the earth's atmosphere.

Figure 2.1 shows simplified block diagrams of digital transmission point-to-

point microwave system. In a digital transmission system, the original source

information may be in digital or analog form. If it is in analog form, it must be

converted to digital pulses prior to transmission and converted back to analog form

at the receive end. In a digital radio system, the modulating input signal and the

demodulated output signal are digital pulses. The digital pulses could originate from

a digital transmission system, from a digital source such as a mainframe computer or

from the binary encoding of an analog signal.

Figure 2.1 Simplified block diagram of digital point to point microwave system

Digital Input

Digital Output

Digital Interface

Digital Interface D

em

Mux Modulator

Demodulator

Crystal Oscillator

Crystal Oscillator

Independence Crystal Or

Synthesizer Bord

Upconverter

Down Converter

Power Am

LNA

Transmit Filter

Receive Filter

Circulator

Waveguide

RF Oscillator

Interface

Interface

Multiplexing

De multiplexing

Modulation

Demodulation

RF

RF

9

2.4 Introduction to Terrestrial Link

Terrestrial link is a link between the transmitter and the receiver bounded by

the earth surface or ground plane. It also can be interpreted as a path of wave

propagate between two base station.

Figure 2.2 Terrestrial Link

2.5 Propagation Occurs Between Terrestrial Link

Propagation is the study of how radio waves travel from one point to another.

Its most important practical results for telecommunications are predictions of the

transmission impairment characteristics of radio links as loss, fading, interference,

dispersion, distortion and so on. These strongly influence the choice of transmitting

and receiving antennas, transmitter powers, and modulation techniques.

Figure 2.3 Line of Site Propagation

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In microwave communications system, there are several ways in which

waves can be propagated, depending on the type of system and the environment.

Electromagnetic waves travel in straight lines except when the earth and its

atmosphere alter their path. There are three ways of propagating electromagnetic

waves; ground wave, space wave (includes both direct and ground-reflected

waves), and sky wave propagation.

2.5.1 Ground wave propagation A ground wave is an electromagnetic wave that travels along the surface of

the earth. Ground waves are sometimes called surface wave. Ground wave must be

vertically polarized. This is because the electric field in a horizontally polarized

wave would be parallel to the earth’s surface and such waves would be short

circuited by the conductivity of the ground. The earth’s surface also has resistance

and dielectric losses. Therefore ground waves are attenuated as they propagate.

2.5.2 Space wave propagation Space wave propagation includes radiated energy that travels in the lower

few miles of the earth atmosphere. Space waves include both direct and ground

reflected waves. Direct waves are waves that travel essentially in a straight line

between the transmit and receive antennas. Space wave propagation with direct

waves is commonly called line-of-sight (LOS) transmission. Thefore space wave is

limited by the curvature of the earth. Ground reflected waves are those waves that

are reflected by the earth’s surface as they propogate between the transmit and

receive antennas.

11

2.5.3 Sky wave propagation Electromagnetic waves that are directed above horizon levels are called sky

waves. Sky waves are radiated in a direction that produces a relatively large angle

with reference to the earth. Sky waves are radiated toward the sky, where they are

either reflected or refracted back to the earth by ionosphere.

2.6 Path Propagation Attenuation

Basically, microwave path propagation can be categorized into 3 main

categories – clear atmosphere, rain and ice depolarization. Through these main

types of path, microwave signal may experience attenuation, which is one of

propagation effect. The other propagation effects are include diffraction fading due

to obstruction of the path by terrain obstacles under adverse propagation condition,

attenuation due to atmospheric gases, fading due atmospheric multi-path or beam

spreading, and fading due to multi-path arising from surface reflection, and many

more.

2.7 Effect of Attenuation due to Hydrometeors

Absorption and scattering by hydrometeors cause attenuation. Hydrometeors

meant here are such as rain, snow, hail, and fog. Above 5GHz, rain attenuation must

take into consideration unlikely for the case of below 5GHz, rain attenuation can be

ignored. In order to design a communication system that reliable, certain

characteristic may consider. For a line-of-sight system, terrestrial, maximum

attenuation is a crucial characteristic to know. From here, systems are designed to

work above attenuation level so that it can maintain at required strength level.

Predictions method is used to model the attenuation can be occurred. Rain

attenuation can be interpreted as a function of rain rate. Thus it can be meant the

12

rate at which rainwater would accumulate in a rain gauge situated at the ground in

the region of interest. Rain rate is measured in millimeters per hour. As we know

rain attenuation occurs due to the absorption of radio waves by the rain drops, and to

the scattering effect, both resulting in diminished receive signal power. Scattering

occurs when the medium through which the wave travels consists of object with

dimension that are small compared to the wavelength, and when the number of

obstacles per unit volume is large.

Attenuation results in a poorer S/N [ 3 ]. When the S/N is seriously impaired

by attenuation, communication becomes difficult; errors appear in the received

signal. If the fade is deep enough, the signal is entirely lost in the noise.

CHAPTER 3

RAIN ATTENUATION MODEL FOR USE IN PREDICTION METHOD

Attenuation due to rainfall can severely degrade the radiowave propagation

at centimeter or millimeter wavelengths. It restricts the path length of radio

communication systems and limits the use of higher frequencies for line-of-sight

microwave links and satellite communications. The attenuation will pose a greater

problem to communication system as the frequency of occurrence of heavy rain

increases. In a tropical region, like Malaysia, where excessive rainfall is a common

phenomenon throughout the year, the knowledge of the rain attenuation at the

frequency of operation is extremely required for the design of a reliable terrestrial

and earth space communication link at a particular location.

3.1 ITU-R Rain attenuation prediction model

The accurate prediction of rain attenuation in line of sight terrestrial links is

essential for planning and designing point-to-point and point-to-multipoint radio

systems for frequency bands above 10 GHz. Several empirical and semi-empirical

rain attenuation prediction methods that have been proposed over the years are

based, mainly, on experimental data obtained in temperate climates. Currently, the

ITU-R model [1-2] and the Crane model are among the most widely used.

Rain attenuation model is based on the knowledge of rain rates. By using the

power-law relationship, specific attenuation,γR (dB/km), is obtained from the rain

rate, R (mm/h).

14

γR = kRα (1)

The frequency-dependent coefficient, k and α , for linear polarizations

(horizontal:H, and vertical:V) and horizontal paths is supplied by ITU-R as shown in

Table 1, in Appendix section.

Table 1 in Appendix D supplies tested and sufficient accurate values for attenuation

prediction upto frequencies of 55GHz. The value of k and α, are determined from

the following equation:-

where : f: frequency (GHz)

k: either kH or kV

α: either αΗ or αV

From equation (2) and (3), there are the others values contribute to the

prediction value of k and α , from calculation. The values are given in the Table 2

and 3, in Appendix D. Prediction frequency-dependent coefficient, k and α ,for

linear and circular polarization can be calculated by using the following equations:

k =[kH+ kV+ (kH-- kV ) cos2 θ cos 2 τ]/ 2 (4)

α =[kH αH kV αV kH αH – kV αV cos2 θ cos 2 τ] / 2k (5)

15

where θ is the path elevation angle and τ is the polarization tilt angle relative to the

horizontal (τ = 45° for circular polarization).

From these equations, curve of k and α, coefficients vs. frequency,

respectively, for each type polarization can be plotted to have clearer relationship

between them. The Figure 3.1 to figure 3.4 shows these characteristics.

Figure 3.1 k coefficient for horizontal polarization as a function of frequency

16

Figure 3.2 α coefficient for horizontal polarization as a function of frequency

Figure 3.3 k coefficient for vertical polarization as a function of frequency

17

Figure 3.4 α coefficient for vertical polarization as a function of frequency

The next step is to determine distance factor , r ,which this value will allow

us to calculate effective path length, deff. Effective path length can be determine by

multiplying actual path length and distance factor. The following are the equations

involve:

where actual path length, d = √(H2 + D2)

H = height

D = distance

and d0 = 35 e-0.015R0.01

ITU has recommended that, for the case R0.01 > 100 mm/h, use the value 100 mm/h

in place of R0.01.

Lastly, the rain attenuation in general case is a product of specific attenuation and

effective path length.

A0.01 = γRdeff =γ R dr

CHAPTER 4

ATPC DESIGN CONCEPT

The extreme of propagation channel environment due to rain has brought to

the research and development of adaptive transmit power control (ATPC) in

microwave transceiver. ATPC varies the transmit power level in order to maintain

the receive signal level (RSL) above the threshold for bit-error-rate (BER) desired.

4.1 Block diagram and operation

ATPC refers to the process of varying the transmit power in a microwave link

with the presence of rain attenuation, in order to maintain the desired RSL. The

provision of this function allows to obtain the following effects.

• Reduction of interference to neighbouring systems

• Improvement in up fading characteristics

• Improvement in residual BER characteristics

• Savings on power consumption

The ATPC system implemented in microwave transceiver is an open loop power

control system. Consequently, the transmit power level is adjusted by operation on

a radio frequency signal, which itself undergoes rain attenuation, and is used to infer

the rain attenuation on the other link. It is suitable to be used against propagation

19

fading, with the environment is free from interference [7]. Furthermore, this

mechanism is the less complexity. Good accuracy could be obtained since the

receiving frequency is close to the transmit frequency in microwave radio unit. In

microwave transceiver, ATPC system is integrated in the front end of the transmitter

as shown in figure 4.1. The power control can be achieved by using a

programmable attenuator where the attenuation level is varied by a driving signal.

The control range of programmable attenuator is 11 dB, with 1 dB step. Since the

power control is performed by refer to the RSL in receiver, an automatic gain

control (AGC) voltage signal that proportional to the RSL is required for

determining the attenuation level. The driver circuit processes appropriate control

signal for programmable attenuator based on the level of AGC voltage. Due to the

deep fading cause by the rainfall, ATPC with wide operation range is required.

When the RSL drop below threshold level for BER 10-6, the ATPC is activated. The

ATPC will be in inactive region when the RSL is above threshold level.

Figure 4.1 Block diagram of microwave transmitter with ATPC

20

4.2 Design Consideration

With ATPC, the transmission power will be varied according to the propagation

channel condition external to the transceiver. It is essential to ensure that the system

fulfills the performance requirement within the transmission power range. There are

two situations that require consideration in ATPC design: the nominal power

transmission and maximum power transmission. The transceiver cannot introduce

excessive distortion and spurious to adjacent channels when operating in maximum

transmission power. The minimum performance parameters for point-to-point

equipment in terrestrial digital fixed service radio communications systems

operating at have been specified in European Telecommunications Standards

Institute (ETSI) recommendations, which is one of the popular regulations that

follows by the commercial products. In [7], the requirements that need to be

followed when applying ATPC include:

• Transmitter maximum mean output power before the feeder shall not exceed

+30 dBm

• Transmit spectrum mask

The spectrum mask is an important feature since it defines the limitation of

spectrum for a digital modulation in order to avoid interference to adjacent channel.

The interference is majority cause by the nonlinear of the operating components,

which cause the spectrum spreading due to the increasing level of higher order inter

modulation product. Increasing the transmit power level from nominal to maximum

level might drive the system to compression mode.

Basically there are two popular types of ATPC system widely implemented in

microwave link transceiver.

1) Local Sense of RSL(Open loop) – transmit power is varies according to RSL

detected at local station. (Assumption there is attenuation in between two terminal)

2) Feedback Loop – transmit power is varies according to the RSL detected at

remote station feedback to local transmit station.

21

4.3 Feedback Loop ATPC [4]

Figure 4.2 A functional block diagram of feedback loop ATPC

A functional block diagram is shown in figure 4.2. First, at the receiving end,

the RX IN level is detected by the RX UNIT of the equipment and the input signal

is passed on to the central processing unit (CPU) circuit on the ATPC module.

The CPU circuit determines whether or not the TX output power of the opposite

station should be controlled, according to the hysteresis characteristics . The

information concerning this control is sent through the RFCOH INTFC circuit to

reach the RFCOH INS circuit on the MODULATOR module of the equipment,

where it is inserted. This inserted control information is then transmitted to the

opposite station by the TX UNIT. At the transmitting end, the control information

received is detected by the RFCOH EXTRACTOR on the DEMODULATOR

module of the equipment, and passed on to the RFCOH INTFC circuit on the

ATPC module. The ATPC module produces a control signal through the CPU

circuit of the ATPC module in accordance with the control information received,

in order to hold the TX output power constant or to raise it or lower it. The control

signal thus produced is converted into an analog signal by the D/A CONV circuit.

This control signal finally varies the TX output power of the FET AMP. To activate

this ATPC function in the dynamic range for the specified transmitter output power,

the system needs to establish the following settings:

22

a) Minimum TX Power level setting:To be set to the lowest TX power level.

b) Threshold level setting:Level to initiate the TX Power control.

c) Hysteresis level setting:Range within which the minimum TX power can be

raised till reaching maximum dB.

The control conditions of the ATPC are as follows;

1) The TX power control is performed by 1 dB steps within preset control range

at 100 dB/sec. tracking speed since receiver input level variation is detected

at the receive section of the opposite ATPC module.

2) The TX power minimum control (POWER MIN CTRL) function is

performed on the AUTO CTRL mode. When the situation of the Maximum

TX output power control continues over the preset period, the TX output

power is adjusted to the preset MIN level by 1 dB steps.

3) The TX power reset control (TX POWER RESET CTRL) function is

performed by the manual switch on the AUTO CONT mode. Under pushing

the MIN CONT switch, the TX output power is adjusted to the preset MIN

level by 1 dB steps.

4) The power on reset control (POWER ON RESET CONT) function is

performed when power is supplied initially. When power is supplied

initially, the TX output power is emitted at the limit minimum level without

ATPC control for the preset period, and over the preset period, the TX output

power is adjusted to the preset MIN level by 1 dB steps in advance and then

the ATPC operation is proceeded.

5) The TX power control answerably (ANSWERBACK) function is performed

for the ATPC control confirmation. Controlled TX output power level is

feedback by the TX output power monitor (T PWR MON) signal and is

compared with control command signal and if the receipt level is deviated

more than 5 dB, TX PWR ALM signal is generated.

6) ATPC RX CPU ALM control function is performed to reset the ATPC

23

control operation. The RX CPU ALM information is kept at the ACL

interface circuit by latching and is sent to the ACL serial bus. The transmitter

output power in the opposite station is controlled to any of MAX, MIN or

HOLD level by the ATPC module according to presetting mode with LCT.

7) ATPC TX CPU ALM control function is performed to reset the ATPC

control operation. The ATPC TX CPU ALM information is kept at the ACL

interface circuit by latching and is sent to the ACL serial bus. The TX output

power is controlled to either MAX or MIN level according to presetting mode

with ATPC module.

8) COMU ALM control function is performed to reset TX output power level to

the preset level. When communication from the ATPC of the opposite is lost,

the ATPC control operation is discontinued for a preset period and the TX

output power level is adjusted to the any of MAX, MIN or HOLD level by 1

dB steps according to presetting mode with LCT.

9) F ASYNC ALM control function is performed to reset TX output power

level to the preset level. When F ASYNC ALM is received from local

demodulator or opposite station, the ATPC control operation is discontinued

for a preset period and the TX output power level is adjusted to the any of

MAX, MIN or HOLD level by 1 dB steps according to presetting mode with

LCT.

When receiver input level of the receiving side is decreased above predetermined

threshold level, TX output power of the transmitting side is increased by 1 dB steps at

preset power control range. On the contrary, when receiver input level of the

receiving side is increased, the transmitter output power is decreased by 1 dB steps.

CHAPTER 5

RAIN ATTENUATION MODELLING BASED ON ITU-R

RECOMMENDATION

In calculating rain attenuation based on ITU-R prediction model it is best to

use computer for the accuracy and fast results. The following design flow charts

was developed as a guide in actual computer programming.

This project uses the MATLAB [9] high language computer software, which

is produced by MathWork Inc. MTALAB, a sophisticated language for matrix

calculation, stands for MATrix LABoratory. MATLAB used to calculate the

estimated rain attenuation according to ITU-R recommendations. A detail

MATLAB code is shown in Appendix C.

25

5.1 Design Flowchart for Specific Rain Attenuation Formula

26

27

CHAPTER 6

RESULTS AND DISCUSSION 6.1 Calculation of Estimated RSL on sample link. The following table 6.1 and path profile plot is a report generated by path

calculation tools (Pathloss 4.0) on the estimated RSL calculated based on the path

profile and technical specsifications of the system.

29

Table 6.1 Calculated RSL Report with Pathloss 4

DatoDagang_TR.pl4 Wisma Dato Dagang Menara Naluri

Elevation (m) 56.00 10.00Latitude 03 05 57.40 N 03 05 15.00 N

Longitude 101 43 28.00 E 101 43 15.00 ETrue azimuth (°) 197.13 17.13Vertical Angle (°) -3.51 3.50

Antenna Model VHP1-142(NEC) VHP1-142(NEC)Antenna Height (m) 76.00 30.00Antenna Gain (dBi) 32.00 32.00

TX Line Type QUASAR-FLEX QUASAR-FLEXTX Line Length (m) 1.00 1.00

TX Line Unit loss (dB /100 m) 80.00 80.00TX Line loss (dB) 0.80 0.80

Circ. Branching loss (dB) 1.50 1.50

Frequency (MHz) 15000.00Polarization Vertical

Path Length (km) 1.50Free Space loss (dB) 119.51

Atmospheric Absorption loss (dB) 0.04Net Path loss (dB) 60.15 60.15

Radio Model NEC PASOLINK NEC PASOLINKTX power (watts) 0.01 0.01TX power (dBm) 10.00 10.00

EIRP (dBm) 39.70 39.70RX Threshold Criteria BER 10^6 BER 10^6

RX Threshold Level (dBm) -60.00 -60.00Maximum Receive Signal (dBm) -15.00 15.00

RX Signal (dBm) -50.15 -50.15Thermal Fade Margin (dB) 9.85 9.85

C Factor 4.00Average Annual Temperature (°C) 32.00

Worst Month Multipath Outage (%) 99.99874 99.99874(sec) 33.07 33.07

Annual Multipath Outage (%) 99.99953 99.99953(sec) 148.80 148.80

(% - sec) 99.99906 - 297.59

Rain Region ITU Region P0.01% Rain Rate (mm/hr) 145.00

Rain Rate (mm/hr) 129.90Rain Attenuation (dB) 9.85

Annual Rain Outage (%-sec) 99.98486 - 4774.20Annual Multipath + Rain (%-sec) 99.98392 - 5071.79

30

Figure 6.1 Path profile plot

Discussion: The choosen link is between Wisma Dato Dagang and Menara Nuluri in

Kuala Lumpur. Based the report generated, the actual path length is 1.5 Km apart

and the estimated RSL for both site around -50 dBm. The threshold level of system

is set at -60dBm.

6.2 Calculated Rain Attenuation

The following figure from MATLAB GUI is a result for the rain attenuation

on the worse case scenario. The rain rate at 146 mm/hr was choosed.

Sep 19 06

C ELC O M ( M ) BH D

W isma D ato D ag angLati tude 03 05 57.40 NLong i tude 101 43 28.00 EA z imuth 197.13°E levation 56 m A SLA ntenna C L 76.0 m A G L

M enar a N alur iLati tude 03 05 15.00 NLong itude 101 43 15.00 EA z imuth 17.13°E levation 10 m AS LA ntenna C L 30.0 m AG L

F r eq uency ( M H z ) = 15000.0K = 1.33

% F 1 = 100.00, 60.00

Path Leng th ( 1.50 km)0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

Elev

atio

n (m

)

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

31

Figure 6.2 Matlab GUI for rain attenuation Discussion: Based on ITU-R recommendation worse case scenario was selected with

rain rate of 146 mm/hr choosen. With the actual path length of 1.5 Km and height

differences between two antennas around 46 meters the calculated specific rain

attenuation is 11 dB.

6.3 Simulation results on bench set up system 6.3.1 RSL Response with ATPC enables. The graph on the following figure 6.3 shows the response of RSL whenever

the ATPC module is enable in the system and the attenuation of rain is introduced at

11 dB as what is calculated. The attenuation is gradually increase another 11 dB to

22 dB to further analyse the ATPC performance.

146

15

1.5

0.046

3

11.26

32

Figure 6.3 RSL response with ATPC enables

Discussion: The initial RSL of the system is set to -50dBm as calculated. Once 11

dB rain attenution is introduced to the system the RSL is expected to drop by 11 dB

exceed the threshold level (-60 dBm). The attenuation is detected by the system and

ATPC automatically in increase the transmit power to maintain the RSL above the

threshold level. As susch the RSL is maintain around -59 dBm. Whenever another

11 dB attenuation is introduced (so total 22 dB) the system still capable to maintain

the RSL above the threshold level. The system manage to maintain the RSL above

the threshold level up to maximum 25 dB attenuation. Exceeding that value the RSL

will drop below the threshold. The transmit power level is varying according to the

atteneuation received by the system

6.3.2 The RSL response with ATPC disables. The graph on the following figure 6.4 shows the response of RSL whenever

the ATPC module is disable in the system and the attenuation of rain is introduced at

-70

-60

-50

-40

-30

-20

-10

0

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

RX(A1)RX(B1)TresholdTX(A)TX(B)

11 dB Attenuation

22 dB Attenuation 25 dB Attenuation

33

11 dB as what is calculated. The attenuation is gradually increase another 11 dB to

22 dB to further analyse the ATPC performance

Figure 6.4 RSL response with ATPC disables

Discussion: The initial RSL of the system is set to -50dBm as calculated. Once 11

dB rain attenution is introduced to the system the RSL is propotionally drop 11 dB

below the threshold level. Whenever another 11 dB attenuation is introduce (total 22

dB) the RSL keep dropping far below the tershold level. The transmit power is

maintain at the initial setting without any changes.

6.4 Results on the active sytem install within Celcom network

The graph on the following figure 6.5 show the actual RSL response on the

selected link installed within Celcom network with the ATPC enables.

-80

-70

-60

-50

-40

-30

-20

-10

0

10

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

RX(A)RX(B)TresholdTX(B)TX(A)

11 dB Attenuation 22 dB Attenuation

34

Figure 6.5 The RSL response on the sample link with ATPC enables

Discussion: On the actual case study link the ATPC performance is hardly seen due

to a very small attenuation introduced by the rain even the sampled RSL response is

captured during a heavy raining period. The RSL is continuously maintained above

the threshold level.

6.5 Summary of results

With ATPC enables, the system will try to maintain the RSL respsonse

above the threshold level by aoutomatically varying the transmit power of the

system. The transmit power will vary propotionally with the attenuation received by

the system. However this function will not happened in system without ATPC

module.

RSL DURING RAINING PERIOD (22 AUG 2006 12:10-2.00 PM)

-56.5-56

-55.5-55

-54.5-54

-53.5-53

-52.5-52

-51.5-51

-50.5-50

-49.5-49

-48.5

RSL

CHAPTER 7

CONCLUSIONS AND FUTURE WORK

This report has outlined the work done on studying the performance of

ATPC in point to point microwave link for rain attenuation problem particularly in

Malaysia.

Firstly, one sample point to point microwace link within Celcom network

was selected. Based on the path profile and system specifications the expected RSL

is calculated with Pathloss 4.0 sofware. The rain attenuation models based on ITU-

R recommendation was developed and then implemented in Matlab. The expected

rain attenuation is calculated.

Following that, based on the RSL and rain attenuation calculated the system

bench simulation is set up to simulate the RSL response with the ATPC module

enable and disable. HP variable attenuator is used as rain attenuation between the

two sites of the system. The RSL response is captured from the system the graph

RSL against time with ATPC option enable and disable is plotted. At the same time

the RSL on the real link system is also captured and the graphs are plotted. All the

results are compared to determine the ATPC performance.

7.1 Positive Conclusion The project went rather well. An automatic transmit power control (ATPC)

is just a small module in microwave transceivers but undoubtedly plays significant

36

impact to overcome rain attenuation problem especially for frequency over 10GHz.

ATPC varies the transmit power level in order to maintain the receive signal level

(RSL) above the threshold for bit-error-rate (BER).

7.2 Further improvement for this Project

Satisfactory results were obtained. However, there is still room for

improvements. As this project is only focus on the system with 15GHz frequency

band, given more time, I would like to make a study at a higher frequency band. On

top of that I would recommend the selected sample link for study case should be

selectec within the worse case scenario (longer distance hop and higher operating

frequency) so that the impact of rain attenuation is more.

7.3 Future research

Further study on adaptive modulation and using the most suitable modulation

schemes under certain condition can enhance current wireless transmission. More

research can be carried out on realizing higher order PSK schemes with acceptable

bit error rate performance to provide better bandwidth efficiency.

7.4 A Final Note This project has been interesting and challenging for a newcomer in the

wireless communication field like me. I have achieved all the objectives stated but

most importantly, I have learnt more on wireless communications systems

particularly on the ATPC basic design concept and operational on an ATPC module.

This project is a stepping stone for me to embark in the R&D for the wireless

technologies.

37

REFERENCES

1. International Telecommunication Union Recommendation P.530-11

Propagation Data and Perediction Methods Required for the Design of

Teresterial Line of Sight System; 2005.

2. Inter national Telecommunication Union Recommendation P.838-3 Spesific

Attenuation Model for Rain for Use In Prediction Methods; 2005.

3. Prof Dr Tharek Rahman, Lecture Notes Wireless Communication, UTM; 2005.

4. N.Nagatomo, NEC Pasolink+ Technical Reference Manual, NEC Tokyo, 2003.

5. Robert K. Crane, Prediction of Attenuation by Rain, IEEE Transactions on

Communications, Vol. Com-28, No 29, September 1980. 1717 – 1733.

6. Rafiqul M.I & Tharek A.R, One Year Measurement of Rain Attenuation of

Microwave Signal at 23GHz and 38 GHz in Malaysia, The 4th CDMA

International Conference (CIC’99), Seoul, Korea, September 8-11, 1999.

7. Hsuan-Jung Su and Geraniotis, Adaptive Closed Loop Power Control with

Quantized Feedback and Looping Filtering. Wireless Communications, IEEE

Transaction on, Volume: 1 Issue 1. 2002; 76-86.

8. Mohd Nizam Asari, Basic Micowave Transmission, Celcom Academy, Kuala

Lumpur, 1998

9. Proakis, J.G. Digital Communications, 3rd ed., NY: Mcgraw-Hill, 1995.

38

10. http://www.mathworks.com

11. Sampei, S., Applications of Digital Wireless Technologies to Global Wireless

Communications, Upper Saddle River, NJ: Prentice Hall, 1997

12. Prasad, J. G., Digital Communications, 3rd Edition., New York: McGraw Hill,

1995

13. Jakes, W.C., Microwave Mobile Communications, NewYork:IEEE Press, 1994

39

APPENDIX A

TIMELINE FOR PROJECT 1

Task W1 W2 W3 W4 W5 W6 W7 W8 W9 W10W11 W12 W13 W14W15

Project proposal

Literature review

Internet research

Discussion with

supervisor

Matlab installation

Learning Matlab

Presentation draft

Presentation slide

preparation

Presentation

Report Writing

40

APPENDIX B

TIMELINE FOR PROJECT 2

Task W1 W2 W3 W4 W5 W6 W7 W8 W9 W10W11 W12 W13 W14W15

Select a case study

link

Calculate the

estimated RSL

with Pathloss

Model and

develop Matlab

script to calculate

rain attenuation

Set up bech

simulation link

Simulate ATPC

on bench link

Capture the RSL

on live link

Plot and compare

the RSL response

Presentation slide

preparation

Presentation

Report Writing

41

APPENDIX C

MATLAB CODES FOR BPSK TRANSMISSION SCHEME

42

Program Code (Version 1)

Calculate log10(freq)

function calculate_Callback(hObject, eventdata, handles)

lfreq = log10(handles.metricdata.frequency);

Calculate for horizontal polarization, kh and ah

jhoripolar =[ 0.3364 1.1274 0.2916;0.7520 1.6644 0.5175;

-0.9466 2.8496 0.4315];

ihoripolar =[0.5564 0.7741 0.4011; 0.2237 1.4023 0.3475;

-0.1961 0.5769 0.2372; -0.02219 2.2959 0.2801];

for j = 1:3

qk = (lfreq - jhoripolar(j,2))/ jhoripolar(j,3);

sk(j) = (jhoripolar(j,1) * exp(-(qk^2)));

end

kh = 10^(sum(sk) + ( 1.9925*lfreq ) -4.4123);

for i = 1:4

qa = (lfreq - ihoripolar(i,2))/ ihoripolar(i,3);

sa(i) = (ihoripolar(i,1) * exp(-(qa^2)));

end

ah = sum(sa) + ( -0.08016*lfreq ) + 0.8993;

Calculate for vertical polarization, kv and av

jvertpolar =[ 0.3023 1.1402 0.2826; 0.7790 1.6723 0.5694;

-1.0022 2.9400 0.4823];

ivertpolar =[0.5463 0.8017 0.3657; 0.2158 1.4080 0.3636;

-0.1693 0.6353 0.2155; -0.01895 2.3105 0.2938];

for j = 1:3

uk = (lfreq - jvertpolar(j,2))/ jvertpolar(j,3);

wk(j) = (jvertpolar(j,1) * exp(-(uk^2)));

end

kv = 10^(sum(wk) + ( 1.9710*lfreq ) -4.4535);

for i = 1:4

ua = (lfreq - ivertpolar(i,2))/ ivertpolar(i,3);

wa(i) = (ivertpolar(i,1) * exp(-(ua^2)));

- 18 -

end

43

av = sum(wa) + ( (-0.07059)*lfreq ) + 0.8756;

Calculate for circular polarization, kc and ac

elevangle = atand(handles.metricdata.height /

handles.metricdata.distance);

tau = 45;

kc = [ kh + kv + ( (kh - kv)*((cosd(elevangle))^2)*(cosd(2*tau)))] / 2;

ac = [ (kh*ah) + (kv*av) + ( ((kh*ah) -

(kv*av))*( (cosd(elevangle))^2)*(cosd(2*tau)))] / (2*kc);

Calculate special attenuation

polar = handles.metricdata.polarization;

switch polar

case 1

y = kc * (handles.metricdata.rainrate ^ ac);

case 2

y = kh * (handles.metricdata.rainrate ^ ah);

case 3

y = kv * (handles.metricdata.rainrate ^ av);

end

Calculate rain attenuation

d = sqrt( (handles.metricdata.distance ^2) + (handles.metricdata.height

^2) );

if (handles.metricdata.rainrate <= 100)

do = 35 * exp(-(0.015 * handles.metricdata.rainrate));

elseif (handles.metricdata.rainrate > 100)

do = 35 * exp(-(0.015 * 100));

end

r = 1 / ( 1 + (d / do) );

deff = r * d;

rainatt = y * deff;

- 19 -

Plot Rain Attenuation Vs. Frequency

open('RainAttenuationGraph.fig');

cla;

c=0;

44

jhoripolar =[ 0.3364 1.1274 0.2916;0.7520 1.6644 0.5175;

-0.9466 2.8496 0.4315];

ihoripolar =[0.5564 0.7741 0.4011; 0.2237 1.4023 0.3475;

-0.1961 0.5769 0.2372; -0.02219 2.2959 0.2801];

jvertpolar =[ 0.3023 1.1402 0.2826; 0.7790 1.6723

0.5694;

-1.0022 2.9400 0.4823];

ivertpolar =[0.5463 0.8017 0.3657; 0.2158 1.4080 0.3636;

-0.1693 0.6353 0.2155; -0.01895 2.3105

0.2938];



tau = 45;

d = sqrt( (handles.metricdata.distance ^2) +

(handles.metricdata.height ^2) );




do = 35 * exp(-(0.015 * 100));

end

r = 1 / ( 1 + (d / do) );

deff = r * d;

for lfreq = 1:1:400;

c=c+1;

x(c)=lfreq;

lfreq=log10(lfreq);

for j = 1:3



end

kh = 10^(sum(sk) + ( 1.9925*lfreq ) -4.4123);

for i = 1:4



45

end

ah = sum(sa) + ( (-0.08016)*lfreq ) + 0.8993;

for j = 1:3



end

kv = 10^(sum(wk) + ( 1.9710*lfreq ) -4.4535);

for i = 1:4



end

av = sum(wa) + ( (-0.07059)*lfreq ) + 0.8756;

kc = [ kh + kv + ( (kh -

kv)*((cosd(elevangle))^2)*(cosd(2*tau)))] / 2;

- 20 -

ac = [ (kh*ah) + (kv*av) + ( ((kh*ah) -



switch polar

case 1


case 2


case 3


end

rainatt(c) = y * deff;

end

varploty = handles.atten ;

varplotx = handles.metricdata.frequency ;

title('Rain Attenuation vs Frequency')

xlabel('Frequency in GHz');

ylabel('Rain Attenuation in dB');

plot(x,rainatt,'-');

46

text(varplotx,varploty,'\bullet \leftarrow','FontSize',12);

Plot Rain Attenuation Vs. Rain Rate


cla;

c=0;


jhoripolar =[ 0.3364 1.1274 0.2916;0.7520 1.6644 0.5175;

-0.9466 2.8496 0.4315];

ihoripolar =[0.5564 0.7741 0.4011; 0.2237 1.4023 0.3475;

-0.1961 0.5769 0.2372; -0.02219 2.2959 0.2801];

for j = 1:3



end

kh = 10^(sum(sk) + ( 1.9925*lfreq ) -4.4123);

for i = 1:4



end

ah = sum(sa) + ( -0.08016*lfreq ) + 0.8993;

jvertpolar =[ 0.3023 1.1402 0.2826; 0.7790 1.6723

0.5694;

-1.0022 2.9400 0.4823];

ivertpolar =[0.5463 0.8017 0.3657; 0.2158 1.4080 0.3636;

-0.1693 0.6353 0.2155; -0.01895 2.3105 0.2938];

for j = 1:3



end

kv = 10^(sum(wk) + ( 1.9710*lfreq ) -4.4535);

for i = 1:4



- 21 -

47

end

av = sum(wa) + ( (-0.07059)*lfreq ) + 0.8756;

tau = 45;



kc = [ kh + kv + ( (kh -


ac = [ (kh*ah) + (kv*av) + ( ((kh*ah) -


d = sqrt( (handles.metricdata.distance ^2) +

(handles.metricdata.height ^2) );

for rainrate = 1:1:400;

c=c+1;

x(c)=rainrate;

if (rainrate <= 100)

do = 35 * exp(-(0.015 * rainrate));

elseif (rainrate > 100)

do = 35 * exp(-(0.015 * 100));

end

r = 1 / ( 1 + (d / do) );

deff = r * d;


switch polar

case 1

y = kc * (rainrate ^ ac);

case 2

y = kh * (rainrate ^ ah);

case 3

y = kv * (rainrate ^ av);

end


end


varplotx = handles.metricdata.rainrate ;

48

title('Rain Attenuation vs Rain Rate')

xlabel('Rain Rate in mm/h');




Plot Rain Attenuation Vs. Distance


cla;

c=0;


jhoripolar =[ 0.3364 1.1274 0.2916;0.7520 1.6644 0.5175;

-0.9466 2.8496 0.4315];

ihoripolar =[0.5564 0.7741 0.4011; 0.2237 1.4023 0.3475;

-0.1961 0.5769 0.2372; -0.02219 2.2959 0.2801];

for j = 1:3



end

- 22 -

kh = 10^(sum(sk) + ( 1.9925*lfreq ) -4.4123);

for i = 1:4



end

ah = sum(sa) + ( -0.08016*lfreq ) + 0.8993;

jvertpolar =[ 0.3023 1.1402 0.2826; 0.7790 1.6723

0.5694;

-1.0022 2.9400 0.4823];

ivertpolar =[0.5463 0.8017 0.3657; 0.2158 1.4080 0.3636;

-0.1693 0.6353 0.2155; -0.01895 2.3105 0.2938];

for j = 1:3



end

49

kv = 10^(sum(wk) + ( 1.9710*lfreq ) -4.4535);

for i = 1:4



end

av = sum(wa) + ( (-0.07059)*lfreq ) + 0.8756;

tau = 45;




do = 35 * exp(-(0.015 * 100));

end

for distance = 1:1:400;

c=c+1;

x(c)=distance;

elevangle = atand(handles.metricdata.height / distance);

d = sqrt( (distance ^2) + (handles.metricdata.height ^2) );

r = 1 / ( 1 + (do / d) );

deff = r * d;

kc = [ kh + kv + ( (kh -


ac = [ (kh*ah) + (kv*av) + ( ((kh*ah) -



switch polar

case 1


case 2


case 3


end


end

50

varploty = handles.atten

varplotx = handles.metricdata.distance

title('Rain Attenuation vs Distance')

xlabel('Distance in km');




- 23 -

Plot Rain Attenuation Vs. Height


cla;

c=0;


jhoripolar =[ 0.3364 1.1274 0.2916;0.7520 1.6644 0.5175;

-0.9466 2.8496 0.4315];

ihoripolar =[0.5564 0.7741 0.4011; 0.2237 1.4023 0.3475;

-0.1961 0.5769 0.2372; -0.02219 2.2959 0.2801];

for j = 1:3



end

kh = 10^(sum(sk) + ( 1.9925*lfreq ) -4.4123);

for i = 1:4



end

ah = sum(sa) + ( -0.08016*lfreq ) + 0.8993;

jvertpolar =[ 0.3023 1.1402 0.2826; 0.7790 1.6723

0.5694;

-1.0022 2.9400 0.4823];

ivertpolar =[0.5463 0.8017 0.3657; 0.2158 1.4080 0.3636;

-0.1693 0.6353 0.2155; -0.01895 2.3105 0.2938];

for j = 1:3


51


end

kv = 10^(sum(wk) + ( 1.9710*lfreq ) -4.4535);

for i = 1:4



end

av = sum(wa) + ( (-0.07059)*lfreq ) + 0.8756;

tau = 45;




do = 35 * exp(-(0.015 * 100));

end

for height = 0:1:400;

c=c+1;

x(c)=height;

elevangle = atand(height / handles.metricdata.distance);

d = sqrt( (handles.metricdata.distance ^2) + (height ^2) );

r = 1 / ( 1 + (d / do) );

deff = r * d;

kc = [ kh + kv + ( (kh -


ac = [ (kh*ah) + (kv*av) + ( ((kh*ah) -



switch polar

case 1


- 24 -

case 2


case 3


52

end


end


varplotx = handles.metricdata.height ;

title('Rain Attenuation vs Height Difference')

xlabel('Height Difference in km');




53

APPENDIX D

FREQUENCY DEPENDENT COEFFICIENTS FOR ESTIMATING SPESIFIC ATTENUATION

54

TABLE 1

55

56

57

58

59

APPENDIX E

SAMPLE OF SYSTEM RSL RESPONSE CAPTURED FROM THE SYSTEM

60

1. Setting

2. Maintenance

3. Monitoring

99. Exit

Select function No. :3

Monitoring

1. Monitoring voltage

2. Monitoring voltage(continuous mode)

3. Alarm/Status

4. Inventory

00. Menu

99. Exit

Select item No. :2

2. Monitoring voltage (continuous mode)

Time stamp (1min:0 / 1sec:1) :1

Press any key to start...

|----------RX LEV[ V/dBm ]---------| |----------TX PWR[ V/dB ]---------|

Time MAX(1) MIN(1) MAX(2) MIN(2) MAX(1) MIN(1) MAX(2)

MIN(2)

1 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

2 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

3 3.12/-42 3.12/-42 2.78/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

61

4 3.12/-42 3.12/-42 2.78/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

5 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

6 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

7 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

8 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

9 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

10 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

11 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

12 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

13 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

14 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

15 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

16 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

17 3.14/-42 3.12/-42 2.78/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

18 3.14/-42 3.12/-42 2.78/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

19 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

20 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

21 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

22 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

23 3.14/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

24 3.14/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

25 3.12/-42 2.73/-52 2.76/-51 1.57/-81 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

26 2.73/-52 2.73/-52 2.37/-61 1.57/-81 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

27 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

28 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

29 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

30 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

31 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

32 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

33 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

34 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

35 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

36 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

37 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

62

38 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

39 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

40 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

41 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

42 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

43 2.73/-52 2.73/-52 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

44 2.73/-52 2.73/-52 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

45 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

46 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

47 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

48 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

49 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

50 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

51 2.73/-52 2.71/-53 2.37/-61 1.96/-71 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

52 2.71/-53 2.33/-62 1.96/-71 1.96/-71 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

53 2.33/-62 2.31/-62 1.96/-71 1.96/-71 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

54 2.31/-62 2.31/-62 1.96/-71 1.96/-71 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

55 2.33/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

56 2.33/-62 2.31/-62 1.94/-72 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

57 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

58 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

59 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

60 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

61 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

62 2.31/-62 2.31/-62 1.96/-71 1.96/-71 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

63 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

64 2.31/-62 2.31/-62 1.94/-72 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

65 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

66 2.31/-62 2.31/-62 1.96/-71 1.94/-72 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

67 2.31/-62 2.31/-62 1.94/-72 0.98/-96 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

68 2.31/-62 1.71/-78 2.35/-61 0.98/-96 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

69 2.73/-52 1.71/-78 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

70 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

71 2.73/-52 2.73/-52 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

63

72 2.73/-52 2.71/-53 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

73 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

74 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

75 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

76 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

77 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

78 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

79 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

80 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

81 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

82 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

83 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

84 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

85 2.73/-52 2.73/-52 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

86 2.73/-52 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

87 2.71/-53 2.71/-53 2.37/-61 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

88 2.73/-52 2.71/-53 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

89 2.73/-52 2.73/-52 2.37/-61 2.35/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

90 2.73/-52 2.04/-69 2.76/-51 2.37/-61 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

91 3.12/-42 2.04/-69 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

92 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

93 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

94 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

95 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

96 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

97 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

98 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

99 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

100 3.12/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

101 3.14/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

102 3.14/-42 3.12/-42 2.76/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

103 3.14/-42 3.12/-42 2.76/-51 2.76/-51 4.47/ 0 4.47/ 0 0.00/*** 0.00/***

104 3.14/-42 3.12/-42 2.78/-51 2.76/-51 4.49/ 0 4.49/ 0 0.00/*** 0.00/***

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