Journal of Multidisciplinary Engineering Science Studies (JMESS) ISSN: 2458-925X Vol. 6 Issue 2, February - 2020 www.jmess.org JMESSP13420664 3384 COMPUTATION OF OPTIMAL TRANSMISSION RANGE OF LINE OF SIGHT LINK BASED ON WALFICSH-BERTONI PROPAGATION LOSS MODEL Isaac A. Ezenugu Department of Electrical/Electronic Engineering, Imo State University [email protected]Abstract— In this paper, computation of optimal transmission range of line of sight (LOS) link based on Walficsh-Bertoni propagation loss model is presented. The optimal transmission range differ from the maximum transmission range obtained using the propagation loss model along. At the optimal point, the fade margin is equal to the fade depth. Seeded Regular Falsi iteration method was adapted and used in the computation of the effective transmission range and the computation was implemented in Matlab software. A 4.5 GHz C-band microwave link with transmitter power of 20 dB, transmitter and receiver antenna gain of 30 dBi was used in the numerical example. The simulation was conducted for the microwave link two cases, namely, for a communication link located in ITU rain zone M with rain rate of 65 mm/hr and for a communication link located in ITU rain zone N with rain rate of 95 mm/hr. The results show that for the link located in rain zone M , it took 41 cycles before the Regular Falsi algorithm could converge and determine the optimal transmission range as 5.605388531 km whereas, for the link located in rain zone N it took 8 cycles before the Regular Falsi algorithm could converge and determine the optimal transmission range as 5.363387406 km. in all, the results showed that the optimal transmission range is inversely proportional to the rain rate. Keywords— Transmission Range , Propagation Model, Walficsh-Bertoni Propagation Model, Path Loss, Optimal Transmission Range, Line Of Sight (LOS) Link, Regular Falsi Algorithm I. INTRODUCTION In wireless communication industry, there are several propagation loss models that are used to estimate the expected propagation loss in different environments and frequency ranges [1,2,3,4,5]. Particularly, Walficsh- Bertoni propagation model is an empirical model that is used for estimating the expected path loss wireless signal will experience when it propagates in areas that have a good number of buildings [6,7,8,9,10]. It takes into account the building height and the space in-between buildings .As such it is suitable for cities, residential and industrial estates and market areas. In this paper, Walficsh-Bertoni model is used in the computation of optimal path transmission range of line of sight microwave communication link [11,12,13,14,15,16]. The paper adopted an iterative approach whereby; the transmission range was first computed using the link budget equation with the Walficsh-Bertoni model for computation of the path loss after which the fade margin is determined. The same transmission range (distance) used in computing the pathloss in the Walficsh-Bertoni propagation model was used to compute the fade depth based on rain fading. The transmission range was adjusted iteratively until the point at which the fade margin is the same value as the fade depth. At this point, the transmission range is said to be optimal because the available fade margin can accommodate the expected fade depth without any excess or deficit. This ensures that the design time quality of service is maintained in the operation time since the fade depth is adequately taken care of at the design time. Sample LOS link parameters are used to show how the ideas presented here can be employed in practice. II. METHODOLOGY A. THE WALFICSH-BERTONI PROPAGATION LOSS MODEL Propagation loss based on Walficsh-Bertoni model (which is denoted as LP WB (dB)) is given as [6,7,8,9,10]: () = 89.5 − 10 (log 10 ( 1 0.9 ( −ℎ ) 2 )) + 21log 10 () − 18log 10 (ℎ − ) + 38 log 10 ( ) (9) Where; 1 = √(( 2 ) 2 + ( −ℎ ) 2 ) (10) is the frequency in MHz; ℎ is the base station antenna height in meters; is the building height in meters, ℎ is the mobile height in meters; R: Space between buildings in meters and d: is the distance between base station transmitter and mobile station in Km. B. LINE OF SIGHT COMMUNICATION LINK OPTIMAL TRANSMISSION RANGE ANALYSIS BASED ON WALFICSH-BERTONI PROPAGATION LOSS MODEL Based on Walficsh-Bertoni Propagation loss model, the transmission range of a Line of Sight (LoS) link can be computed from the link budget formula as follows; P R = P T + (G T + G R ) – () (11) Therefore, propagation loss due to Walficsh-Bertoni model (denoted as ()) is; ()= P T + G T + G R - P R = 89.5 − 10 (log 10 ( 1 0.9 ( −ℎ ) 2 )) + 21log 10 ( )− 18log 10 (ℎ − ) + 38 log 10 () (12)
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Journal of Multidisciplinary Engineering Science Studies (JMESS)
ISSN: 2458-925X
Vol. 6 Issue 2, February - 2020
www.jmess.org
JMESSP13420664 3384
COMPUTATION OF OPTIMAL TRANSMISSION RANGE OF LINE OF SIGHT LINK BASED ON WALFICSH-BERTONI PROPAGATION LOSS MODEL
Isaac A. Ezenugu
Department of Electrical/Electronic Engineering, Imo State University [email protected]
Abstract— In this paper, computation of optimal transmission range of line of sight (LOS) link based on Walficsh-Bertoni propagation loss model is presented. The optimal transmission range differ from the maximum transmission range obtained using the propagation loss model along. At the optimal point, the fade margin is equal to the fade depth. Seeded Regular Falsi iteration method was adapted and used in the computation of the effective transmission range and the computation was implemented in Matlab software. A 4.5 GHz C-band microwave link with transmitter power of 20 dB, transmitter and receiver antenna gain of 30 dBi was used in the numerical example. The simulation was conducted for the microwave link two cases, namely, for a communication link located in ITU rain zone M with rain rate of 65 mm/hr and for a communication link located in ITU rain zone N with rain rate of 95 mm/hr. The results show that for the link located in rain zone M , it took 41 cycles before the Regular Falsi algorithm could converge and determine the optimal transmission range as 5.605388531 km whereas, for the link located in rain zone N it took 8 cycles before the Regular Falsi algorithm could converge and determine the optimal transmission range as 5.363387406 km. in all, the results showed that the optimal transmission range is inversely proportional to the rain rate.
Keywords— Transmission Range , Propagation Model, Walficsh-Bertoni Propagation Model, Path Loss, Optimal Transmission Range, Line Of Sight (LOS) Link, Regular Falsi Algorithm
I. INTRODUCTION
In wireless communication industry, there are several
propagation loss models that are used to estimate the
expected propagation loss in different environments and
frequency ranges [1,2,3,4,5]. Particularly, Walficsh-
Bertoni propagation model is an empirical model that is
used for estimating the expected path loss wireless signal
will experience when it propagates in areas that have a
good number of buildings [6,7,8,9,10]. It takes into account
the building height and the space in-between buildings .As
such it is suitable for cities, residential and industrial estates
and market areas. In this paper, Walficsh-Bertoni model is
used in the computation of optimal path transmission range
of line of sight microwave communication link
[11,12,13,14,15,16].
The paper adopted an iterative approach whereby; the
transmission range was first computed using the link budget
equation with the Walficsh-Bertoni model for computation
of the path loss after which the fade margin is determined.
The same transmission range (distance) used in computing
the pathloss in the Walficsh-Bertoni propagation model was
used to compute the fade depth based on rain fading. The
transmission range was adjusted iteratively until the point at
which the fade margin is the same value as the fade depth.
At this point, the transmission range is said to be optimal
because the available fade margin can accommodate the
expected fade depth without any excess or deficit. This
ensures that the design time quality of service is maintained
in the operation time since the fade depth is adequately
taken care of at the design time. Sample LOS link
parameters are used to show how the ideas presented here
can be employed in practice.
II. METHODOLOGY
A. THE WALFICSH-BERTONI PROPAGATION LOSS
MODEL
Propagation loss based on Walficsh-Bertoni model (which
is denoted as LPWB(dB)) is given as [6,7,8,9,10]:
𝐿𝑃𝑊𝐵(𝑑𝐵) = 89.5 − 10 (log10 (𝜌1𝑅
0.9
(𝐻𝐵−ℎ𝑚)2)) +
21log10(𝑓) − 18log10(ℎ𝑏 −𝐻𝐵) + 38 log10(𝑑𝑘)
(9)
Where;
𝜌1 = √((𝑅
2)2
+ (𝐻𝐵 − ℎ𝑚)2) (10)
𝑓 is the frequency in MHz; ℎ𝑏 is the base station antenna
height in meters; 𝐻𝐵 is the building height in meters, ℎ𝑚 is
the mobile height in meters; R: Space between buildings in
meters and d: is the distance between base station
transmitter and mobile station in Km.
B. LINE OF SIGHT COMMUNICATION LINK
OPTIMAL TRANSMISSION RANGE ANALYSIS
BASED ON WALFICSH-BERTONI
PROPAGATION LOSS MODEL
Based on Walficsh-Bertoni Propagation loss model, the
transmission range of a Line of Sight (LoS) link can be
computed from the link budget formula as follows;
PR = PT + (GT + GR ) – 𝐿𝑃𝑊𝐵(𝑑𝐵) (11)
Therefore, propagation loss due to Walficsh-Bertoni model
Journal of Multidisciplinary Engineering Science Studies (JMESS)
ISSN: 2458-925X
Vol. 6 Issue 2, February - 2020
www.jmess.org
JMESSP13420664 3387
antenna gain of 30 dBi. The simulation results for the link
located in rain zone M with rain rate of 65 mm/hr is shown
in Table 2. The results show that it took 41 cycles before
the Regular Falsi algorithm could converge and determine
the optimal transmission range as 5.605388531 km, ( as shown in Table 2 and Figure 1).Similarly, the simulation
results for the link located in rain zone N with rain rate of
95 mm/hr is shown in Table 3. The results show that it took
8 cycles before the Regular Falsi algorithm could converge
and determine the optimal transmission range as
5.363387406 km, (as shown in Table 3 and Figure 1). Notably, the communication link in rain zone M has longer transmission range than the link that is located in rain zone N. The difference in the optimal transmission range is associated with the difference in the rain rates of the two rain zones. Essentially, the optimal transmission range is inversely proportional to the rain rate.
Table 1 The communication link parameters used for the numerical iteration for a microwave link located in rain zone M
Parameter Name and Unit Parameter Value Parameter Name and Unit Parameter Value
f (MHz) 4500 kh 0.000134
Transmitter power, PT(dB) 20 ah 1.6948
Transmitter antenna Gain, GT(dB) 30 kv 0.000235
Receiver antenna gain, GR(dB) 30 av 1.3987
Receiver sensitivity, Ps (dB) -85 Percentage Availability, Pa (%) 99.99