Propagation Model Tuning For Wataniya Mobile GSM Network in Palestine [PDF]

Zitiervorschau

Graduation Project

Propagation Model Tuning for Wataniya Mobile GSM Network in Palestine Prepared by:

Mohammad Abu Eid Abd Al-Salam Saber Supervised by:

Dr. Ali Jamoos

6102-2017

‫اإلْذاء‬ ‫كهًاخ ‪ ،‬قهٍهح فً ػذدْا‪ ،‬ػظًٍح فً يضًَٕٓا‬ ‫إنى يٍ جشػٕا انكؤٔط فاسغح نٍغقَٕا قطشج دة‬ ‫إنى يٍ كهد أَايهٓى نٍقذيٕا نُا نذظح عؼادج‬ ‫إنى يٍ دصذٔا األشٕاك ػٍ دسٔتُا نًٍٓذٔا نُا طشٌق انؼهى‬ ‫إنى انقهٕب انكثٍشج ‪ ،،‬آبائنا‬ ‫إنى تغًح انذٍاج ٔعش انٕجٕد‬ ‫إنى يٍ كاٌ دػائٍٓ عش َجادُا ٔدُآٍَ تهغى جشادُا ‪ ،،‬أههاتنا‬ ‫إنى انشًٕع انرً ٔقفد يؼُا نرٍُش دسٔتُا ٔذغاَذَا‪ ،،‬أخىتنا وأخىاتنا‬ ‫اهداء خاص هن دمحم أتٕ ػٍذ‬ ‫إنى يٍ كاَد ػَٕا ً نً َٕٔسا ً ٌضًء انظهًح انرً كاَد ذقف أدٍاَا فً طشٌقُا ‪،،‬خطٍثرً عليا‬ ‫اهداء خاص هن ػثذ انغالو صاتش‬ ‫أْذي ْزا انؼًم أنى سٔح انشٍٓذٌٍ جذي خـالد الديـك ٔ خانً أبزاهين صابز‬ ‫ٔ أْهً فً انغشتح ٔانخاسج‬ ‫إنى انٕسٔد انرً ػطشخ أٌايُا ٔدٍاذُا تؼثٍش انصذاقح ‪ ،،‬أصدقائنا‬ ‫إنى يٍ ػهًَٕا دشٔفا ً يٍ رْة ٔكهًاخ يٍ دسس ٔػثاساخ يٍ أعًى ٔأجهى ػثاساخ فً انؼهى إنى يٍ صاغٕا نُا‬ ‫ػهًٓى دشٔفا ٔيٍ فكشْى يُاسج ذٍُش نُا يغٍشج انؼهى ٔانُجاح ‪ ،،‬أساتذتنا الكزام‬ ‫َرقذو تانشكش انجضٌم ٔااليرُاٌ انؼظٍى انى الدكتىر الفاضل علي جاهىس انزي قذو نُا كم انذػى ٔانُصخ ٔانًشٕسج ٔنى‬ ‫ٌثخم ػهٍُا ترٕجٍٓاذّ ٔاسشاداذىّ ‪،‬كاٌ نُا انًثم األػهى ٔانقذِٔ انذغُّ فً يغٍشذُا انرؼهًٍٍح‬ ‫فال أدذ ٌغرطٍغ أٌ ٌشكش انشًظ ألَٓا أضاءخ انذٍَا‪ٔ ،،‬نكٍ عُذأل سد جضء يٍ جًٍهكى تأٌ َكٌٕ كًا اسدذًَٕا أٌ‬ ‫َكٌٕ ‪.‬‬ ‫كًا َشكش كم يٍ عاْى فً إَجاص ْزا انؼًم انًرٕاضغ َٔخص تانزكش ششكح انٕطٍُح يٕتاٌم يرًثهح بـالوهندس أحود‬ ‫حىاشين‬

Contents Abstract……………………………………………………………………………………………………………………………………………………..…………..1 Chapter 1 ...................................................................................................................................................................... 3 Radio Wave Propagation ............................................................................................................................................. 3 1.1

Wave Propagation ........................................................................................................................................ 3

1.2

Radio Propagation Forms ............................................................................................................................. 4

1.2.1 Line of sight ..………………………..…………………..…………………………………………………………………………………………4 1.2.2 Ground Wave ………………..……………………………….…………………………………………………………………………………….4 1.2.3 Sky Wave ……………………………..….……………………….………………………………………………………………………………….5 1.3 Free-Space Loss .................................................................................................................................................. 5 1.4 Wave Behaviors .................................................................................................................................................. 6 1.4.1 Reflection ……………………………….……………………..………................................................................................6 1.4.2 Diffraction ………..……………….…………..………………………………………………………………………………………..............7 1.4.3 Scattering ……………………………………………..…………………………………………………………………………………………….7 Chapter 2 ...................................................................................................................................................................... 8 Loss Propagation Model ............................................................................................................................................... 8 2.1 Various Types Path-Loss Propagation Models .................................................................................................. 8 2.2 Empirical Model.................................................................................................................................................. 9 2.2.1 The Okumura Model …………………………..……………….……………………………………………………………………..….…..9 2.2.2 Hata Model …….…………………………………………………………………………………………………………………………………10 2.2.3 Cost Hata 231 Model ……….…………………………………………….…….…………………………………………….…………..…11 2.2.4 Ericsson Model …….………………………………................................................................................................12 2.2.5 Stanford University Interm (SUI) Model …………….…………….……………………………………………………..………..13 Chapter 3 .................................................................................................................................................................... 16 Wataniya Mobile Network Audit ............................................................................................................................... 16 3.1 Wataniya Mobile Network Technical Specification ………………………………………………………………….………….…….16 3.1.1 Frecuancy Band ………..……………….…………………………..…………………………………………………………………..…….16 3.1.2 Antennas Specification …………………………………………………………..………………………………………………………..18 3.1.2.1 Directional antenna ……………………………….……….……………………………………………………………….………18 3.1.2.2 Antenna Gain ……………………………………………………………………………………………………………………………19

3.1.2.3 Wataniya Mobile Network Antennas ……………………………………………………………….………………….….19 3.1.3 Radio Frequency Power Transmission……………………………..……………………………………………………….…19 3.2 Ramallah City as a Case Study.......................................................................................................................... 20 3.3 TEMS Investigation as a Measuring Tool ......................................................................................................... 21 Chapter 4 .................................................................................................................................................................... 23 The Experimental Results and Discussion ………………………………………………………………..………………………………………….23 4.1 Experimental Results …….…….…….……………………………………………………………………………………………………………..23 4.2 Method of Measurements ………………………….…………………………….………………………………………………………………23 4.3 Software Tools ………………………………………………………………………….………………………………………………………………24 4.4 Root Mean Square Error (RMS Error) ……….………………………………………………………………………………………………24 4.5 Results and Discussion ……….…………………………………….………………………………………………………………………………25 Chapter 5 .................................................................................................................................................................... 30 The Optimized Model ……………………………………………………..…………………………………………………………………………………..30 5.1 Problem Formulation ……………………………………………………………………………………………………………………………….30 5.2 Linear least square method (LSM) ..………………………………………………………………………………………………..……….31 5.3 CONCLUSIONS ..……………………………………………………………………………………………………………………..…………………35 Appendix ……………………………………………………………………………………………………………..……………………………………………...36 References ……………………………………………………….………………………………………………………………………………………………….46

Abstract Radio signal path loss calculation is a particularly important element in the design of any radio communications system. The radio signal path loss will determine many elements of the radio communications system in particular the transmitter power, and the antennas, especially their gain, height and general location. For cellular operators radio coverage surveys are important because the investment in a base station is high. The Radio Wave Propagation Model is an empirical mathematical formulation for the characterization of radio wave propagation as a function of frequency, distance and other conditions. A single model is usually developed to predict the behavior of propagation for all similar links under similar constraints. Created with the goal of formalizing the way radio waves are propagated from one place to another, such models typically predict the path loss along a link or the effective coverage area of a transmitter. Radio propagation models are empirical in nature, which means, they are developed based on large collections of data collected for the specific scenario. Like all empirical models, radio propagation models do not point out the exact behavior of a link, rather, they predict the most likely behavior the link may exhibit under the specified conditions. Because each individual telecommunication link has to encounter different terrain, path, obstructions, atmospheric conditions and other phenomena, it is intractable to formulate the exact loss for all telecommunication systems in a single mathematical equation. As a result, different models exist for different types of radio links under different conditions. The models rely on computing the median path loss for a link under a certain probability that the considered conditions will occur. The available empirical formulae cannot be generalized to different environment, in general the suitability of these models differ for different environments. Extensive outdoor measurements for mobile phone base stations in Ramallah city, will be performed. In order to determine the model that can accurately predict the propagation in this environment, different well-known propagation models will be compared with our measurements. To further improve the prediction accuracy, we will propose a propagation model based on optimizing the most accurate model. 1

In this research we proposed an optimized path loss model for Urban/Suburban areas in Palestine. The optimization is based on the Linear least square Method (LSM) method in addition to measurements of the received signal power from many sites in Ramallah city, taking on to consideration the distances from the sites. The measurement was performed by Wataniya Mobile Company. We calculate the path loss from the measured results and compared it with the most famous path loss models applicable for urban areas. We found that Hata (for 900MHz) and Cost Hata (for 1800MHz) are the best models that can represent the nature of Urban/Suburban areas of Palestine. After that, we tried to optimize (Hata and Cost Hata) in order to get a new model close to our measurement in Ramallah City.

Finally, the optimized model is expected to be applicable and the most suitable model for other similar areas in Palestine. The proposed model can help the mobile operator companies in Palestine to make accurate predictions for future systems design.

2

Chapter 1 Radio Wave Propagation Radio waves are a type of electromagnetic waves which have frequencies from 3 THz to as low as 3 kHz. Like all other electromagnetic waves, they travel at the speed of light [1]. The idea that electromagnetic signals might propagate over considerable distances at the velocity of light was first proposed in 1865 by James Clerk Maxwell. Having added the “displacement current” term to the set of equations governing electromagnetic events (now termed Maxwell’s equations), he deduced that among their possible solutions wave solutions would exist. This prediction was verified experimentally by Heinrich Hertz in a series of experiments conducted in the late 1880s. Many of his experiments utilized waves of approximately 1 m wavelength, in what is now termed the ultra-high frequency (UHF) range, and transmission distances were usually on the order of only a few feet [2]. Electromagnetic waves are utilized in many engineering system: long-range-point-topoint communication, cellular communication, radio and television broadcasting, radar, global navigation satellite system such as the Global Position System (GPS), and so on [2]. The use of electromagnetic waves from this purpose is attractive, in part, because direct physical connection such as wires cables are not require. This advantage gave rise to the terms " wireless telegraphy " and " wireless telephony " that where commonly used for radio in the early part of the past century and have returned to popular usage with the widespread development " wireless" system for personal communication is resent decades [2]. Propagation model has traditionally focused on predicting the average received signal strength at a given distance from the transmitter, as well as the variability of the signal strength is closed spatial proximity to a particular location [1].

1.1

Wave Propagation

In general, waves are means of transporting energy or information [6]. Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere [3]. 3

Waves are easy to generate, it can travel long distances, and can penetrate buildings easily, so they are widely used for communication, both indoors and outdoors. Radio waves also are omnidirectional, meaning that they travel in all directions from the source, so the transmitter and receiver do not have to be carefully aligned physically. Sometimes omnidirectional radio is good, but sometimes it is bad [1].

1.2 Radio Propagation Forms 1.2.1 Line of Sight Line-of-sight is the direct propagation of radio waves between antennas that are visible to each other. This is probably the most common of the radio propagation modes at VHF and higher frequencies. Because radio signals can travel through many non-metallic objects, radio can be picked up through walls. This is still line-of-sight propagation. Examples would include propagation between a satellite and a ground antenna or reception of television signals from a local TV transmitter [3].

Figure 1: Line of Sight Propagation

1.2.2 Ground Wave This form of propagation fits most frequencies but the distance between the transmitter and receiver will vary with geography and composition of “ground” *1+. Ground Wave propagation is a method of radio frequency propagation that uses the area between the surface of the earth and the ionosphere for transmission. The ground wave can propagate a considerable distance over the earth's surface particularly in the low 4

frequency and medium frequency portion of the radio spectrum. Ground wave radio propagation is used to provide relatively local radio communications coverage [3].

Figure 2: Ground Wave Propagation

1.2.3 Sky-Wave In radio communication, sky wave refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvature of the Earth, sky wave propagation can be used to communicate beyond the horizon, at intercontinental distances. It is mostly used in the long wave frequency bands [3].

Figure 3: Sky-Wave Propagation

1.3 Free-Space Loss Free-space is an ideal condition without any energy absorption or adverse propagation effects. When radio waves are radiated in the space by an isotropic antenna, they will propagate identically in all directions [1]. The free space propagation model is used to predict received signal strength when the transmitter and receiver have a clear, unobstructed line of sight path between them [1]. Satellite communication systems and microwaves line of sight radio links typically under 5

go free space propagation [1]. As with most large scale radio waves propagation model, the free space model predicts that received power decayed as a function of the T-R separation distance raised to some power [1]. In free-space optical communication links, atmospheric turbulence causes fluctuations in both the intensity and the phase of the received light signal, impairing link performance [4].

1.4 Wave Behaviors As electromagnetic waves, and in our case, radio signals travel, they interact with objects and the media in which they travel. As they do this the radio signals can be reflected, refracted or diffracted. These interactions cause the radio signals to change their direction, and to reach areas which would not be possible if the radio signals travelled in a direct line [1].

1.4.1 Reflection Reflection occurs when a propagating electromagnetic wave impinges upon an object which has very large dimensions when compared to the wavelength of the propagating wave. Reflections occur from the surface of the earth and from buildings and walls [1]. The most obvious effect of the presence of the ground on RF and microwave propagation is reflection from Earth’s surface (land or sea). A receiver antenna may be illuminated by both a direct wave from the transmitter and a wave reflected from the ground. The reflected wave is generally smaller in amplitude than the direct wave because of the larger distance it travels, the fact that it usually radiates from the side lobe region of the transmit antenna, and the fact that the ground is not a perfect reflector. Nevertheless, the received signal at the target or receiver will be the vector sum of the two wave components and, depending on the relative phases of the two waves, may be greater or less than the direct wave alone. Because the distances involved are usually very large in terms of the electrical wavelength, even a small variation in the permittivity of the atmosphere can cause fading (long-term fluctuations) or scintillation (short-term fluctuations) in the signal strength. These effects can also be caused by reflections from in homogeneities in the atmosphere [5]. 6

Figure 4: Reflection

1.4.2 Diffraction Diffraction occurs when the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities (edges) such as hills, mountains, or buildings are in the path of propagation, diffraction effects can be stronger [5].

Figure 5: Diffraction

1.4.3 Scattering Scattering occurs when the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength, and where the number of obstacles per unit volume is large [1].

Figure 6: Scattering 7

Chapter 2 Loss Propagation Model A radio propagation model is a mathematical formulation for the characterization of radio wave propagation as a function of frequency, distance and other conditions. A single model is usually developed to predict the behavior of propagation for all similar links under similar constraints. Created with the goal of formalizing the way radio waves are propagated from one place to another, such models typically predict the path loss along a link or the effective coverage area of a transmitter. Propagation models are used extensively in network planning, particularly for conducting feasibility studies and during initial deployment. They are also very useful for performing interference studies as the deployment proceeds.

2.1 Various Types Path-Loss Propagation Models Radio transmission in mobile communication system often takes place over irregular terrain. A number of propagation models are available to predict path loss over different types of terrain [7] [2]. The models dealt with are applicable for GSM bands (900 MHz, 1800 MHz). These models can be broadly categorized into three types; empirical, deterministic and stochastic. Empirical models are those based on observations and measurements alone [10]. The deterministic models make use of the laws governing electromagnetic wave propagation to determine the received signal power at a particular location. Deterministic models often require a complete 3-D map of the propagation environment. An example of a deterministic model is a Ray-tracing model [11]. Stochastic models, on the other hand, model the environment as a series of random variables. These models are the least accurate but require the least information about the environment and use much less processing power to generate predictions. Empirical models can be split into two subcategories namely, time dispersive and nontime dispersive [12]. The former type is designed to provide information relating to the time dispersive characteristics of the channel i.e., the multipath delay spread of the channel. An example of this type are the Stanford University Interim (SUI) channel 8

models developed under the Institute of Electrical and Electronic Engineers (IEEE) 802.16 working group . Examples of non-time dispersive empirical models are , Hata [13] and the COST-231 Hata model [9]. All these models predict mean path loss as a function of various parameters, for example distance, antenna heights etc. Several existing path loss models such as Hata’s Model *14+, Stanford University Interim (SUI) model *15+, Lee’s Model and Egli’s Model are chosen for comparison with measurement data.

2.2 Empirical Model It is derived from in-depth field measurements. It is efficient and simple to use. The input data for the empirical models are generally qualitative, also not very correct, for instance like dense urban area, rural area and so on.

2.2.1 The Okumura model The Okumura model [16] [17]is a Radio propagation model that was built using the data collected in the city of Tokyo, Japan. The model is ideal for using in cities with many urban structures but not many tall blocking structures. The model served as a base for the Hata Model. Okumura model was built into three modes. The ones for urban, suburban and open areas. The model for urban areas was built first and used as the base for others.

Mathematical formulation The Okumura model is formally expressed as:

PL[dB]  LF  Amu ( f , d )  G(hte )  G(hre )  GAREA Where, LF : Free space propagation loss

Amu ( f , d ) : Median attenuation relative to free space 9

(2-1)

G(hte )  20 log10 (hte / 200) : Base station antenna height gain factor hre  3m 10 log10 (hre / 3), G(hre )   : Mobile antenna height gain factor 20 log10 (hre / 3), 10m  hre  3m GAREA : : Gain due type of environment

And to take on consideration the following assumption:    

Frequency = 150 - 1920 MHz Mobile station antenna height: between 1 m and 3 m Base station antenna height: between 30 m and 1000 m Link distance: between 1 km and 100 km

2.2.2 Hata model Hata Model is an empirical formulation of graphical path loss data provided by Okumura model. The Hata model gives prediction of the median path loss [18] [1]. Also known as the Okumura–Hata model for being a developed version of the Okumura model, is the most widely used radio frequency propagation model for predicting the behavior of cellular transmissions in built up areas. This model incorporates the graphical information from Okumura model and develops it further to realize the effects of diffraction, reflection and scattering caused by city structures. This model also has two more varieties for transmission in suburban areas and open areas. Hata Model predicts the total path loss along a link of terrestrial microwave or other type of cellular communications

Mathematical formulation The Hata model for urban areas is formulated as following: PL(urban)[dB]  69.55  26.16 log10 f  13.82 log10 hte  a(hre )  (44.9  6.55 log10 hte ) log10 d

For small or medium-sized city, a(hre )  (1.1log10 f  0.7)hre  (1.56 log10 f  0.8)

dB

And for large cities, 10

(2-2)

2  8.29(log10 1.54hre )  1.1 dB, a(hre )   2  3.2(log10 11.75hre )  4.97 dB,

f  300 MHz f  300 MHz

Where, PL(urban)[ dB]

= Path loss in urban areas. Unit: decibel (dB)

hte = Height of base station antenna. Unit: meter (m)

hre = Height of mobile station antenna. Unit: meter (m) f

= Frequency of transmission. Unit: Megahertz (MHz).

a(hre ) = Antenna height correction factor

d = Distance between the base and mobile stations. Unit: kilometer (km). And to take on consideration the following assumption:    

Frequency: 150–1500 MHz Mobile Station Antenna Height: 1–10 m Base station Antenna Height: 30–200 m Link distance: 1–10 km.

Though based on the Okumura model, the Hata model does not provide coverage to the whole range of frequencies covered by Okumura model. Hata model does not go beyond 1500 MHz while Okumura provides support for up to 1920 MHz.

2.2.3 Cost Hata 231 model The COST Hata model is a radio propagation model that extends the urban Hata model (which in turn is based on the Okumura model) to cover a more elaborated range of frequencies. It is the most often cited of the COST 231 also called the Hata Model PCS Extension [14]. This model is applicable to urban areas. To further evaluate Path Loss in Suburban or Rural Quasi-open/Open Areas, this path loss has to be substituted into Urban to Rural/Urban to Suburban Conversions.

11

Mathematical formulation The COST Hata model is formulated as[9], PL(urban)[dB]  46.3  33.9 log10 f  13.82 log10 hte  a(hre )  (44.9  6.55 log10 hte ) log10 d  CM

(2-3)

For suburban or rural environment [12]: a(hre )  (1.1log10 f  0.7)hre  (1.56 log10 f  0.8)

dB

0 dB, for medium sized city and suburban areas CM   for metropolit an centers 3 dB,

Where,      

= Median path loss. Unit: decibel (dB) f = Frequency of Transmission. Unit: megahertz (MHz) hte = Base station antenna effective height. Unit: meter (m) d = Link distance. Unit: Kilometer (km) hre = Mobile station antenna effective height. Unit: meter (m) a(hre ) = Mobile station antenna height correction factor as described in the Hata model for urban areas. PL(urban)[ dB]

And to take on consideration the following assumption:    

Frequency: 1500–2000 MHz Mobile station antenna height: 1–10 m Base station Antenna height: 30–200 m Link distance: 1–20 km

2.2.4 Ericsson model

Model 9999 is the Ericsson's implementation of Hata model [19][20]. In this model parameter is possible according to propagation environment. The path loss PL is given as: PL[dB]  a0  a1 log10 d  a2 log10 hb  a3 log10 hb log10 d  3.2(log10 (11.75hm )) 2  g ( f ) g ( f )  44.49 log( f )  4.78(log( f ))

2

12

(2-4)

And parameters f is the Frequency in (MHz), hb :is the transmission antenna height in (m), hm :is the Receiver antenna height in (m).

The default values of these parameters ( a0 , a1 , a2 and a3 ) for different terrain are given in Table 2.1 Table 2.1: Values of parameters for Ericsson model [4, 9]

Environment

a0

a1

a2

a3

Urban

36.2

30.2

12

0.1

Suburban

43.2

68.93

12

0.1

Rural

45.95

100.6

12

0.1

2.2.5 Stanford University Interm (SUI) Model The proposed standards for the frequency bands below 11 GHz contain the channel models developed by Stanford University, namely the SUI models. Note that these models are defined for the Multipoint Microwave Distribution System (MMDS) frequency band Their applicability to the 3.5 GHz frequency band that is in use in the UK has so far not been clearly established [4]. The SUI models are divided into three types of terrains1, namely A, B and C. Type A is associated with maximum path loss and is appropriate for hilly terrain with moderate to heavy foliage densities. Type C is associated with minimum path loss and applies to flat terrain with light tree densities. Type B is characterized with either mostly flat terrains with moderate to heavy tree densities or hilly terrains with light tree densities. The basic path loss equation with correction factors is presented in[2] [3]

PL[dB]  A  10 log10 (d / d0 )  X f  X h  S

13

(2-5)

Where: d is the distance between the base station and the receiving antenna, d=100m, S is the lognormal distributed factor that is used to account for the shadow fading due to trees and other clutter and has a value between 8.2 dB and 10.6 dB. The remaining parameters are defined as: A = 20 log( 4  d 0 /)

 = a - bh b + c/h b

Where the parameter hb is the base station height above ground in meters and between 10m-80m. The constant used for a, b and c are given in table 1. The parameters ϒ in equation (13) is the path loss exponent. For a given terrain type the path loss exponent is determined by hb .

Table 2.2 SUI model numerical values for different terrain categories

Model Parameter

Terrain A

Terrain B

Terrain C

A

4.6

4

3.6

b(m-1)

0.0075

0.0065

0.005

c(m)

12.6

17.1

20

The correction factor for the operation frequency for the receiver antenna height for the model is: Xf = 6 log( f/ 2000) X h = - 10.8 log( hr / 2000)

For terrain type A and B

X h = - 20.0log( hr / 2000)

For terrain type C

f is the frequency in MHz and hm is the receiver antenna height above ground in m. The

SUI model is used to predict the path loss in all three environments namely urban.

14

Table 2.3 : Comparative for Propagation Path loss Models

Mobile Base station Antenna height station antenna height

Link distance

model

Frequency

Hata

150– 1500 MHz

1–10 m

30–200 m

1–10 km.

Cost hata

1500– 2000 MHz

1–10 m

30–200 m

1–20 km

Okumura

150– 1920 MHz

1m–3m

30 m – 1000 m

1 km – 100 km

SUI

500– 2100 MHz

1m–8m

10 m-80 m

1 km – 160 km

Ericsson

740– 1900 MHz

1m–6m

30 m-400m

1 km – 110 km

15

Chapter 3 Wataniya Mobile Network Audit Wataniya Mobile Palestine a member of Ooredoo group was first established as a partnership between the Wataniya Group (head quartered in Kuwait and majority owned by Ooredoo) and the Palestine Investment Fund (PIF) with ownership stakes of 57% and 43% respectively. In 1 November 2009, Wataniya Mobile launched its commercial services across the West Bank. Wataniya Mobile serves their customers through GSM technology “2G”.

3.1 Wataniya Mobile Network Technical Specification

3.1.1 Frequency band Networks in different geographical locations work on different bands - GSM networks in the Americas use the 850 MHz and 1900 MHz bands while networks in Europe, Brazil, Asia and Africa use the 900/1800 MHz bands.

Figure 7: GSM World Coverage Map

Wataniya Mobile is a GSM dual band Network which use 900/1800 bands together. They allocate 1.8 MHz on 900-band and 2.8 MHz on 1800-band. Wataniya Mobile frequency’s in details is shown below. 16

Table 3.1: Wataniya Mobile 900-band Frequencies Band 900 900 900 900 900 900 900 900 900

ARFCN 51 52 53 54 55 56 57 58 59

Downlink (MHz) 945.2 945.4 945.6 945.8 946.0 946.2 946.4 946.6 946.8

Uplink (MHz) 900.2 900.4 900.6 900.8 901.0 901.2 901.4 901.6 901.8

Table 3.2: Wataniya Mobile 1800-band Frequencies Band 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800

ARFCN 871 872 873 874 875 876 877 878 879 880 881 882 883 884

Downlink (MHz) 1877.0 1877.2 1877.4 1877.6 1877.8 1878.0 1878.2 1878.4 1878.6 1878.8 1879.0 1879.2 1879.4 1879.6

17

Uplink (MHz) 1782.0 1782.2 1782.4 1782.6 1782.8 1783.0 1783.2 1783.4 1783.6 1783.8 1784.0 1784.2 1784.4 1784.6

3.1.2 Antennas Specification Antenna is that part of a transmitting or receiving system which is designed to radiate or to receive electromagnetic waves. An important property of an antenna is the ability to focus and shape the radiated power in space, it enhances the power in some wanted directions and suppresses the power in other directions. Many different types and mechanical forms of antennas exist, each type is specifically designed for special purposes.

3.1.2.1 Directional antenna In mobile communications there are two main categories of antennas used, Omni directional antenna, radiate in all horizontal directions with equal power, and Directional antenna which is used in Wataniya Mobile Network. Directional antennas are used to get higher gain compared to Omni-directional antenna and to minimize interference effects in the network.

Figure 8: Directional Antenna

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3.1.2.2 Antenna Gain

Antenna gain is a measure for antennas efficiency. Gain is the ratio of the maximum radiation in a given direction to that of a reference antenna for equal input power. Antenna gain depends on the mechanical size, the effective aperture area, the frequency band and the antenna configuration.

3.1.2.3 Wataniya Mobile Network Antennas

In the table below, we can find the Wataniya mobile network used antennas.

Table 3.3: Antennas Specifications

Antenna ID

Antenna Gain (dBi)

Horizontal Beam Width

Vertical Beam Width

Antenna-01

17

65°

7°

Antenna-02

15

65°

14°

Antenna-03

16

90°

10°

3.1.3 Radio Frequency Power Transmission Radio frequency power transmission is the transmission of the output power of a transmitter to an antenna. When the antenna is not situated close to the transmitter, special transmission lines are required. The most common type of transmission line for this purpose is large-diameter coaxial cable. In radio communication systems, equivalent isotropically radiated power (EIRP) is the amount of power that a theoretical isotropic antenna (which evenly distributes power in all directions) would emit to produce the peak power density observed in the direction of maximum antenna gain. EIRP can take into account the losses in transmission line and connectors and includes the gain of the antenna. Where, 19

Figure 9: EIRP In Wataniya Mobile Case, the transmitted power is 41 dBm.

3.2 Ramallah City as a Case Study Wataniya Mobile Network spreads all around the west bank, in Cities, Villages and roads between there. In this research, we take Ramallah as an example of urban areas. Surly, we can take the results of this research as a reference to all urban areas in Palestine.

20

To get accurate results, we will make a measurements on some sites around Ramallah city as shown below.

Figure 10: some of WM sites locations around Ramallah

After taking the measurements on above proposed sites, we will compare the results with the propagation models introduced in Chapter 2, to determine the most accurate model should be used in Palestine Urban/Suburban areas.

3.3 TEMS Investigation as a Measuring Tool TEMS Investigation is an air interface test tool for cellular networks. It enables monitoring of voice and video telephony as well as a variety of data services over packetswitched and circuit-switched connections. TEMS Investigation is primarily a tool for data collection and real-time analysis. It interfaces with phones, data cards, scanners, and 21

other measurement devices; it collects data and records it in log files. The application also boasts a vast array of windows for presentation of log file data.

Figure 11: The Drive Test Tools

We will use TEMS Investigation to collect data around the proposed sites in order to measure the path loss according to distance from the site. The results can be shown on a table or on maps as shown below.

Figure 12: TEMS Log file shown in a map 22

Chapter 4 The Experimental Results and Discussion 4.1 Experimental Results We chose the below sites in Ramallah city (Urban and Suburban Areas) to find the mobile receiving power (Rx). The base station transmitting sites specifications and the effective testing data numbers are shown in below table. Table 4.1: Specifications of Base Stations Sites Antenna Name Type No. Freq Band (MHz) PTX GTX EIRP Azimuth Height Total down tilt (Mech. + Elec.) Effective Testing Data Number

BS-01 Antenna-02 900MHz Band 41 dB 15 dB 53.5 dB 20° 18 6° 815

BS-02 Antenna-02 900MHz Band 41 dB 15 dB 53.5 dB 280° 18 6° 888

BS-03 Antenna-02 900MHz Band 41 dB 15 dB 53.5 dB 150° 18 6° 536

BS-04 Antenna-02 1800MHz Band 41 dB 15 dB 53.5 dB 120° 18 6° 679

BS-05 Antenna-02 1800MHz Band 41 dB 15 dB 53.5 dB 40° 18 6° 791

4.2 Method of Measurements The technique of measurement was using consisted of using a car containing a Sonny Ericsson mobile which is a measurement equipment that can detect and record a wide variety of the physical and virtual parameters of mobile cellular service in a given geographical area. By measuring what a wireless network subscriber would experience in any specific area, wireless carriers can make directed changes to their networks that provide better coverage and service to their customers. We have used a car outfitted with drive testing measurement equipment “Idle Mode Mobile” and a GPS. We drive the car slowly to take Accurate measurements after that we saved them in log file in our laptop using TEMS investigation tool. 23

Figure 13: TEMS Log file shown in a map and Effective Testing Data Number for BS-01

4.3 Software Tool’s We used MATLAB v7.8 to simulate the collected results, the program was written as m file formed. The complete information of the areas under consideration are entered to the program and stored in the file, information such as transmitter antenna (base station) height, receiver antenna (mobile unit) height, terrain information, operating frequency, etc. When the simulation is run, the mobile starts to move on the same direction of the actual mobile measurements path. According to the path loss model used, the path loss of each location is calculated and stored in the program. Four path loss models are used in this study for the 900MHz frequency and the 1800MHz frequency, they are, okumara model, SUI model , Ericsson model and Cost -231 Hata. For each model, the simulation is run for the two frequencies bands 900 MHz and 1800 MHz, and for each frequency, two types of terrain, urban and suburban are considered.

4.4 Root Mean Square Error (RMS Error) The Root Mean Square Error (RMSE) is a frequently used measure of the difference between values predicted by a model and the values actually observed from the environment that is being modeled (dB), in our work we use RMSE to find the error between the measured path loss and estimated path loss. 24

These individual differences are also called residuals, and the RMSE serves to aggregate them into a single measure of predictive power. The RMSE of a model prediction with respect to the estimated variable X model is defined as the square root of the mean squared error:



n

RMSE 

i 1

(4-1)

( X measur pathloss  X model,i ) 2 n

Where X measurements path loss and X model is modelled values at time/place i. The calculated RMSE values will have units, and RMSE for phosphorus concentrations can for this reason not be directly compared to RMSE values for chlorophyll a concentrations etc. However, the RMSE values can be used to distinguish model performance in a calibration period with that of a validation period as well as to compare the individual model performance to that of other predictive models.

4.5 Results and Discussion Figures 13 ,14 and 15 show the results of path loss estimation using the path loss models of Hata, SUI, Ericsson and OKUMARA for three different areas in Ramallah city which are BS-01, BS-02 and BS-03 they are measured results are estimated at 900 MHz frequency. Figures 16 and 17 show the at 1800 MHz, the areas are BS-04 and BS-05 using Cost-231 Hata model, Hate, Ericsson , OKUMARA and SUI. The mean square error of the four graphics is calculated using equation (4-1) and the results are in table 4.2 and table 4.3. Table 4.2: RMS Error for propagation models

Frequency (MHz)

900

Site

Models RMS Error (dB) Hata

Ericsson

SUI

OKUMARA

BS-01

10.9

32.8

19.4

17.5

BS-02

12.9

23.8

15.2

16.9

BS-03

13.9

32.1

15.4

14.7

25

Table 4.3: RMS Error for propagation models

Frequency (MHz)

1800

Models RMS Error (dB) Site

OKUMARA

SUI

Ericsson

COST HATA

Hata

BS-04

14.4

23.0

19.2

12.7

11.0

BS-05

16.3

29.1

16.6

14.9

17.1

Figure 14: BS-01at 900MHz

26

Figure 15: BS-02 at 900 MHz

Figure 16: BS-03 at 900 MHz

27

Figure 17: BS-04 at 1800MHz

Figure 18: BS-05 at 1800MHz

28

The applicable path loss models are compared with measured path loss for base stations in Ramallah city for two frequency bands of 900 MHz and 1800 MHz. At 900 MHz frequency the best fit models for BS-1, BS-2 and BS-3 is first Hata model and the second is the OKUMARA model then sui model and at least Ericsson model . For 1800MHz frequency, the best fit for BS-4 and BS-5 is first Cost-Hata model .

29

Chapter 5 The Optimized Model 5.1 Problem Formulation The optimization process is intended to enhance the accuracy of the path loss model in order to suit the environmental area under consideration. To that end, the COST-231 Hata model consists of three parts: initial offset, initial system design parameter and slope of model curve, which are expressed as: HATA PLoffset = 69.55 PLsystem = (26.16 * log10 (f)) - (13.82 * log10 (hb)) PLslope = ((44.9 - 6.55 * log10 (hb)) * log10 (d))

Thus, Hata model can be written as follows: PL - HATA = [PLoffset + PLsystem ] + [PLslope ] * log10 (d)

COST-231 PLoffset  46.3 PLsystem  33.9 * log10 (f) - 13.82 * log10 (hb)

PLslope = (44.9 - 6.55 * log10 (hb)) * log10 (d)

Thus, COST-231 Hata model can be written as follows: PL - COST 231 = [PLoffset + PLsystem ] + [PLslope ] * log10 (d)

(5-2)

The role of the optimization process is to modify the expressions between the square brackets in equation (5-3) and (5-4) so that a better match will be created between the resulting optimized equation and the measured data. This can alternatively be done through introducing two coefficients, say A and M , associated with the square brackets. According to that, equation(5-1)and (5-2) becomes: 30

Tuned_PL_Hata = ( [PLoffset + PLsystem ]A) + ( [PLslope ] * log10 (d)  M * log10 (d) )

(5-3)

Tuned_PL_COST 231 = ( [PLoffset + PLsystem ]A) + ( [PLslope ] * log10 (d)  M * log10 (d) )

(5-4)

The Linear least square method , Method will be used to find the optimum values of A and M.

5.2 Linear least square method (LSM) Linear least square regression is by far the most widely used fitting method. It is what most people mean when they say they have used "regression", "linear regression" or "least squares" to fit a model to their data. Not only is linear least squares regression the most widely used fitting method, but it has been adapted to a broad range of situations that are outside its direct scope The Difference between path loss drive test and Path loss model is

PL1 = PL measured - PL model

(5-5)

Where, L measured is the measured values for path loss , L model is the modeled values for path loss. Assuming equation (5-5) where A and M are offset values will be added to the model after finding them:

PL = A + M log 12 (d)

(5-6)

And the error function is N

E(A, M) =  (PLi 2 - PLi1 ) 2 i 1

31

(5-7)

To make sure the error function is minimum (least)

E(A, M) / A = 0

(5-8)

E(A, M) / M = 0

(5-9)

By means of calculating equation group, the solution of parameters A and M are calculated as:

N

N

N

N

i1

i1

i1

A  {[  (log10 di ) ].[ (PL1 )]  [ (log10 di ) ].[ (log10 d i ) .PL1 ] 2

i1

N

N

} / N .[ (log10 di ) ]  [ (log10 di ) ]2

(5-10)

2

i1

i1

N

N

N

i 1

i 1

i 1

A  {N.[  (log10 d i ) .PL1 ]  [ (log10 d i )].[ PL1 ] N

N

} / N .[ (log10 d i ) ]  [ (log10 d i ) ]2 2

i 1

(5-11)

i 1

While the method of least squares often gives optimal estimates of the unknown parameters, it is very sensitive to the presence of unusual data points in the data used to fit a mode 32

Table 5.1:The root mean square error (RMSE) values and optimized coefficients for base stations: BS-01,BS-02 and BS-03. Frequency (MHz)

Site

Tuned Model

Hata

Ericsson

SUI

OKUMARA

8.7

10.9

32.8

19.4

17.5

BS-01 900

Optimized coefficient’s

Models RMS Error (dB)

BS-02

10.7

12.9

23.8

15.2

16.9

BS-03

10.1

13.9

32.1

15.4

14.7

A

M

-1.11

-8.03

5.04

-11.43

1.55

-3.31

AVG A

AVG M

1.83

-7.59

Table 5.2:The root mean square error (RMSE) values and optimized coefficients for base stations: BS-04 and BS-05 Frequency (MHz)

1800

Optimized coedfficients

Models RMS Erorr (dB) Site

Tuned Model

OKUMARA

SUI

Ericsson

COST HATA

Hata

BS-04

9.4

14.4

23.0

19.2

12.7

11.0

BS-05

12.0

16.3

29.1

16.6

14.9

17.1

A

M

1.54

3.72

-3.85

9.85

AVG A

AVG M

-1.16

6.79

.

Fig. 19: Path loss and optimized model vs. transmitter to receiver (Tx-Rx) distance in kilometres for different sectors of base station 01 (BS-01) site.

33

Fig. 20: Path loss and optimized model vs. transmitter to receiver (Tx-Rx) distance in kilometres for different sectors of base station 02 (BS-02) site.

Fig. 21: Path loss and optimized model vs. transmitter to receiver (Tx-Rx) distance in kilometres for different sectors of base station 03 (BS-03) site.

Fig. 22: Path loss and optimized model vs. transmitter to receiver (Tx-Rx) distance in kilometres for different sectors of base station 04(BS-04) site.

Fig. 23: Path loss and optimized model vs. transmitter to receiver (Tx-Rx) distance in kilometres for different sectors of base station 05(BS-05) site.

From Table 5.1 and Table 5.2, we can see that the proposed optimized model has the best RMSE values in all the base station sites compared with the other examined models. Substituting the average values of A and M from Table 5.1 and 5.2 into equation (5-3) and (5-4), the proposed optimized model can be written as follows: Tuned_PL_Hata  69.55  26.16 log10 f  13.82 log10 hte  a(hre )  1.83  (44.9  6.55 log10 hte ) log10 d  (7.59 * log10 d )

Tuned_PL_COST231  46.3  33.9 log10 f 13.82 log10 hte  a(hre )  1.16 (44.9  6.55 log10 hte ) log10 d   CM  (6.79 * log10 d ) 34

(5-12) (5-13)

5.3 CONCLUSIONS In this research we proposed an optimized path loss model for Urban/Suburban areas in Palestine. The optimization is based on the Linear least square Method (LSM) method in addition to measurements of the received signal power from many sites in Ramallah city, taking on to consideration the distances from the sites. The measurement was performed by Wataniya Mobile Company. We calculate the path loss from the measured results and compared it with the most famous path loss models applicable for urban areas. We found that Hata (for 900MHz) and Cost Hata (for 1800MHz) are the best models that can represent the nature of Urban/Suburban areas of Palestine. After that, we tried to optimize (Hata and Cost Hata) in order to get a new model close to our measurement in Ramallah City. Finally, the optimized model is expected to be applicable and the most suitable model for other similar areas in Palestine. The proposed model can help the mobile operator companies in Palestine to make accurate predictions for future systems design.

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APPENDIX Finding The RMSE For Model And Tuned Model At BS-01

36

Finding The RMSE For Model And Tuned Model At BS-02

37

Finding The RMSE For Model And Tuned Model At BS-03

38

Finding The RMSE For Model And Tuned Model At BS-04

39

Finding The RMSE For Model And Tuned Model At BS-05

40

About the Site

Compar Between Path Loss

Comparison Between Path Loss And Tuned Model

41

Finding A and M factors

42

MATLAB Code Written by author’s

43

44

TEMS Log file shown in a map and Effective Testing Data for BS-01 & BS-02

TEMS Log file shown in a map and Effective Testing Data for BS-03 & BS-04

45

References [1] Wireless Communications Principles and Practice 2nd Edition, T Rappaport, Prentice Hall-2001_2 [2] Radiowave Propagation: Physics and Applications [3]https://en.wikipedia.org/wiki/Radio_propagation [4] Free-Space Optical Communication Through Atmospheric Turbulence Channels Xiaoming Zhu and Joseph M. Kahn, Fellow, IEEE [5]Microwave_Engineering_David_M_Pozar_4ed_Wiley_2012 [6]Sadiku__Elements_of_electromagnetics2 [7] N. Shabbir, M. Saidq, T. Kashif, and R.Ullah, " Comparison of Radio Propagation Models For Long Term Evolution (LTE) Network", International Journal of Next generation networks, Vol. 3, No. 3, September 2011. [8] S. Ranviers, " Path loss Models", Finland Helsinki University of Technology 2004, Available at http//: www.comlabhut.fi/opetus/333/20042005-sides/path-loss-models.pdf. *9+ COST Action 231, “Digital mobile radio towards future generation systems, final report,” tech. rep., European Communities, EUR 18957, 1999 *10+ R. K. Crane, “Prediction of attenuation by rain,” IEEE Transactions on Communications, vol. COM-28, pp. 1727–1732, September 1980. *11+ G. E. Athanasiadou, A. R. Nix, and J. P. McGeehan, “A microcellular raytracing propagation model and evaluation of its narrowband and wideband predictions,” IEEE Journal on Selected Areas in Communications, Wireless Communications series, vol. 18, pp. 322–335, March [12] H. R. Anderson, Fixed Broadband Wireless System Design. John Wiley & Co., 2003. *13+ M. Hata, “Empirical formula for propagation loss in land mobile radio services,” IEEE Transactions on Vehicular Technology, vol. vol. VT-29, pp. 317–325, September 1981. 46

[14]Cotares Ltd., Cambridge Broadband Ltd. and Cambridge University, “A study on efficient dimensioning of broadband wireless access networks,” tech. rep., Ofcom, UK, 2003. See Ofcom website. *15+ V. Erceg, L. J. Greenstein, et al., “An empirically based path loss model for wireless channels in suburban environments,” IEEE Journal on Selected Areas of Communications, vol. 17, pp. 1205–1211, July 1999. *16+ . P. K. Sharma & R. K. Singh, “Comparative Analysis of Propagation Path loss Models with Field Measured Data”, International Journal of Engineering Science and Technology Vol. 2(6), 2010, pp 2008-2013. [17] . V. S. Abhayawardhana, I. J. Wassell, D. Crosby, M. P. Sellars & M. G. Brown,” Comparison of Empirical Propagation Path Loss Models for Fixed Wireless Access Systems”, IEEE , December 2003. [18] Hata M., "Empirical Formula For Propagation Loss in Land Mobile Radio Services", IEEE Transaction on Vechicular Technology Vol. 29, No. 3, 1980. [19] N. Shabbir, H. Kashif, " Radio Resource Management in WiMAX", Ms Thesis, Bleking Institute of Technology, Karlskrona Sweden, 2009. [20] J. Lanovic, S. Rimac, and K. Bejuk, " Comparison of Propagation Models Accuracy for WiMAX on 3.5 GHz, IEEE International Conference on Electronics, 2007. [21] http://www.itl.nist.gov/div898/handbook/pmd/section1/pmd141.htm [Accessed in November 2016].

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