Passive Defense in Appropriate Location of Base Stations

Majlesi Journal of Electrical Engineering Vol. 8, No. 4, December 2014

83

Passive Defense in Appropriate Location of Base Stations in

Mobile Communication Networks

Ebrahim Shabanpour

1*, Hossein Emami

2, Seyed Ali Hashemi

3

Department of Electrical and Computer Engineering, Majlesi Branch, Islamic Azad University, Isfahan, Iran

1- Email: [email protected]*

2- Email: [email protected]

3- Email: [email protected]

Received: March 2014 Revised: July 2014 Accepted: October 2014

ABSTRACT

Passive defense in appropriate location of Base Transceiver Station (BTS) in Tehran is the main subject of this article.

According to the GSM network architecture and its components, BTS is the most vulnerable part of this network.

Under investigating current circumstances of Base Station Subsystems (BSCs) and BTSs in Tehran an optimization of

the deployment of these stations are examined regardless of the passive defense and with considering this issue. In

determining location of base transceiver stations in Tehran, according to different modes of sharing, a model is

designed in which the number of stations is causatively reduced. In addition, temporary base transceiver stations and

their variants are presented. Finally, a comparison of the results of the previous researches and this study shows that

the proposal plan is advanced in terms of beautifying the city, economical aspects and defensive schemes. Radio

Access Network (RAN) sharing is a kind of sharing in which operators share towers, antennas and Back Hall up to the

connecting dots of telecommunication core of operators’ network. This sharing has a particular importance both in

terms of reducing the number of base transceiver stations and also reducing operators' costs.

KEYWORDS: Passive Defense, BTS, Sharing Sites.

1. INTRODUCTION

Nowadays passive defense in antithetic to active

defense is an important factor on which human society

has focused. According to the Fourth Development

Plan Law in the government, one of the fundamental

pillars of national security is passive defense.

When we talk about passive defense in

telecommunications all attention will be attracted to

BTS which is the most accessible means of

telecommunication equipment. In this paper we intend

to study passive defense in appropriate location of base

transceiver station. Thus the current situation of Base

Transceiver Stations in Tehran are extracted by

utilizing GIS software at first and then the optimal

situation in appropriate the location of the base

transceiver stations is studied regardless of passive

defense. In the third stage by considering the principle

of passive defense we find a way to locate BTSs in

Tehran and then we compare these three cases.

2. CONTEXT

2.1. Working areas

Due to growth of cities and spread of technology in all

fields, naturally the system changes needed to

implement new technologies.

Considering these improvements can be made in all

fields, therefor coordination between them should be

inevitable. This is perceivable that urbanization process

and the communication station. The face of cities has

been changed due to the dynamic homespun over time.

The height of buildings and constructing of multi stages

buildings are increasing every day more and more.

Obviously, the base transceiver stations that service to

the users will be disappeared between buildings over

time. The component of BTS including of the mast

structure, Architecture and height in appropriate to the

changing face of the city will be changed.

Usually in major cities, committees are formed to

review these concerns and the only way to prevent

chaos, is defining standards in various areas. For

example, in urban areas defining corresponding

standards will prevent any problems. Unfortunately, in

Iran such standards have not been considered. In order

to study passive defense in BTSs we should first review

the existing structure and express its defects and then

Passive defense will be defined in the improved

network of BTSs . It doesn't exist any documentation

on installation of BTSs in the cities of Iran. Due to the

limited coverage of telecommunication towers, by

increasing the number of applicants,

mailto:[email protected]


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telecommunication office constructs new towers,

without considering any standard. By continuing this

process, many problems occur over time.

For example, the report of Subscriber Connection

Company in hundred and ninety-first session of the

City Council of Tehran's Environment Committee in

August 2013 indicated that the implementation of the

existing telecommunications tower has not been based

on any standard. For example, some of cases that were

discussed in this meeting are given below:

Reorganization of towers, antennas and radio

stations in Tehran.

Identifying and organizing adjacent Masts in the

site and constructing common sites in order to

remove redundant one.

Sharp increase in complaints from installing

antennas for radio communications

A variety of standards

The foregoing shows clearly that no standard was

considered in the installation of equipment and

telecommunication towers in Tehran [1].

2.2. Materials and Methods

Currently the requirement for using of mobile

communication technology is using of BTSs. Spatial

organization of these stations has a complex network

and many considerations involved in determining the

appropriate location for the establishment of the

stations. The coverage and traffic capacity of each BTS

is limited. This reason, technical limitations and

servicing requirement to subscribers it is necessary to

install more commissioning stations for better

coverage. For installation equipment, every BTS

requires a space about 10 to 100 square meters

depending on the type of the station. Currently, there

are more than 2300 BTSs in Tehran that belong to the

three operators, Hamrah-e-Avval, MTN and Talia.

Having the areas varying between 10 to 100 square

meters, almost one-third of BTSs have been

constructed in urban spaces. However, these three

operators are developing and completing their networks

and the number of stations is constantly growing. In

addition, another operator whose name is Telecom

obtained its authorization and currently is designing

and operating its network. Undoubtedly, due to the

urgent need of using this technology, it is inevitable to

construct stations and install required equipment in

order to increase accountability to its users [1].

The data used in this study contains some information

on mobile phone antenna of three operators'

communication stations which are active in mobile

phone servicing in Tehran and are extracted in a format

of excel file. The purpose of this section is to review

the current situation of BSC and BTS in metropolitan

Tehran and in the second stage we extract the optimal

condition of determining BTS locations without

considering the passive defense and in the third stage

we consider a situation with considering passive

defense as a way of determining location of BTSs. First

and second stages are the results of researches that have

been already taken in this direction, and we use them

only as a reference.

2.3. Phase I: Evaluation of existing conditions More than 2,300 BTS are in Tehran:

From 2306 BTSs with 900 MHz as TX or transmission

frequency:

1791 BTS belong to MCCI . 428 BTS belong to TCT

or telecommunications Tehran province. 8 stations

belong to Nokia Siemens Networks or NSN. And with

1800 MHz as TX frequency:

36 BTSs belong to MCCI.27 BTSs belong to TCT or

Telecommunications Tehran Province.1 station belongs

to Nokia Siemens Networks or NSN.

Fig. 1.Pie-chart diagram of BTSs in Tehran

User distribution of BTSs in Tehran depicted in the

diagram above. The maximum percentage is allocated

to government agencies (25%), in the second rank

citizens (22%) and in the third level municipalities

(16%).

When capacity brings limitation, we use the GSM

1800. Existing masts can be used when GSM1800 is

the system for mobile communication, but their sectors

should be connected to BTS 1800. For this purpose, we

can use Dual Band antennas, which support both

frequencies 900 and 1800 MHz. By increasing

frequency, we have greater coverage but loss of power

is also increased, because of direct relationship between

increased permeability and loss of a signal [2].


85

2.4. Second Stage "optimal conditions without

considering passive defense"

In this regard, the City Site Sharing Co. did a study in

2009 and the main contents of it below:

Stating of BTSs is followed by a variety of adverse

effects. These effects are more visible in urban areas

and an addition in number of BTSs can increase the

severity of these effects. Creating visual nuisance and

pollution perspective, occupying the space, particularly

urban landscape, the impact on the economic value of

the adjacent properties to the existing station, and

concerns associated with electromagnetic radiation

harmfulness of these stations are the most important

adverse effects.

Table 1.User distribution and distributing percentage

of BTSs in Tehran

Access Type User

distribution Distribution

percentage

Governmental 581 25%

Residential 513 22%

Municipal 373 16%

Commercial 211 9%

Others 204 9%

Street 136 6%

Subway 77 3%

Park 44 2%

MCI-Center 29 1%

Mall 20 1%

Hospital 18 1%

Private 18 1%

University 16 1%

(blank) 15 1%

Bank 11 0

Hotel 10 0

Military 7 0

Green Field 4 0

Mosque 4 0

Mountain 3 0

MP 3 0

Sport Club 3 0

commercial/residential 1 0

No Data 1 0

No permission 1 0

parking 1 0

permission 1 0

Restaurant 1 0

In our country it has not done any useful activity in

regard of adverse effects received from the

establishment of these stations. Tehran Municipality

has recently consulted a company which is called City

Site Sharing Co. that started its activity to monitor

operators and organizing BTSs from the 2007. Tehran

is facing with this problem over than the other cities.

The operators in most parts of the city established their

stations. They have almost constructed these stations

wherever they need to. However, according to direct

and indirect effects on urban environments these

mentioned stations are the main subject of urban

planning but Iranian planners and city managers do not

play any role in designing and implementation of

network stations and urban plans have not addressed

this issue. Each day the number of stations and the

result of the range of adverse effects are increasing.

Hence, it is necessary to consider this issue seriously

[1].

In organizing network of BTSs, a fundamental pursued

aim is detracting from the visual appearance of stations

and hiding them from the public views. These aims

generally follow by two ways: first, by reducing

stations in minimum level and using techniques such as

camouflage and concealment [3].

Optimal coverage of an area with minimum number of

BTSs is essentially a concept of allocation and

optimization of resources. Researches have been done

to optimize the approach of BTS location in local and

global levels. According to the requirements and

economical considerations the operators try to do their

best for network designing but when several operators

are working in a specific geographic area the best

option to reduce the total number of stations is

constructing and sharing.

2.4.1. Checking network stations status of three

operators in compare with each other

MCCI has been working more than 10 years before

MTN and Talia in Tehran hence its network is more

complete and greater. A close look at the maps of three

operators' network stations indicates that there is a

similarity in establishment of the network stations.

Although each operator has its own plan and its design

has been done separately in many cases. The design of

operators' networks is very close together, for example

it looks that MTN and Talia's networks designs are

partly comply with MCCI. The number of nearby MTN

and Talia stations to MCCI stations are so closely that

seems far away to happen randomly. Designing spatial

layout of stations in a mobile telecommunication

network in a city (especially in a city that has many ups

and downs) are so complicated, expensive, time

consuming, and require a lot of calculations and field

surveys. So it seems there is a possibility that network

designers of MTN Irancell and Talia have taken

advantage of MCCI experience in this field and their

network designs are similar to some extent.


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Fig. 2. A significant correlation network design of

MTN Irancell and Talia with MCCI

According to the obtained results [1] the possibility of

moving a macro station is approximately 50 m in the

current network station of Tehran with regard to

technical constraints and frequency. Though it is not

impossible but it is unlikely to move a Marco station

more than 200m. Therefore, the data are analyzed

assuming displacement stations in 50, 100, 150 and 200

m distances from each other.

The results of data analysis show that the strategy of

sharing the site can be useful in organizing the

establishment of networks of stations in Tehran.

Thus, according to the results of this study [1], in the

present state, 998 of 2282 BTSs in Tehran, which are,

included more than 43% of the stations are located in

places with less than 200 meters distance from the

nearest other operator's BTS.

In 24 cases, three stations of three different operators

and in other cases two stations of two different

operators are in the same situation.

If we assume that is possible to use one station by

sharing for all of these cases, we can reduce 998 to 487

stations. 24 stations are shared via three operators and

the rest shared between two operators. The operators

can eliminate a large number of stations by using site

sharing in Tehran.

2.5. The third stage, "Investigation of optimal

conditions with regard to the issue of passive

defense"

In the previous section, regardless of passive defense,

BTSs' locations were assessed in Tehran. Although in

this study we only focused on the site sharing, but there

are also some objections we discuss them during this

section.

The topics of passive defense are:

2.5.1 Concealment

Concealment or hiding is one of the methods widely

used in the field of passive defense. Of course, this

strategy should be used caution so that concealment

does not define as an obstacle for BTSs. However there

are examples of concealment in different countries for

telecommunication stations. However, the number of

BTSs is increasing because of increasing the number of

users and different services, and the urban

beautification is discussable.

Today one of the main concerns of municipalities is to

maintain the scenic of the cities with existing BTSs.

The concealment and camouflage techniques in this

field help to keep the beauty of the cities.

In many countries with the purpose of beautification

the face of cities or passive defense proposition, the

concealment and camouflage are used for deploying

BTSs. In Malaysia, for example, different approaches

are used for this purpose, such as:

mono pole structures like trees

Multi-purpose structures

Ad

Minarets

Lighting Tower

According to the standard installation of telecom

towers in each country, "any structure which is

designed according to the aesthetic of the building

should not degrade the quality of telecommunication

services. Therefore, the technical requirements for

installing masts according to aesthetic urban basis

should be in accordance with national and international

standards [4].

Referring to our data about Tehran (Table 1) it can be

seen that 44 BTSs, which are 2% of the BTSs, are

located in the parks. Therefore, we can implement

passive defense strategy. However, in user weighting of

BTSs, data communications located in the park are in a

much lower level in compare with other users in the

system.

2.5.2. Camouflage

The concept of camouflage is getting isochromatic and

conformal with the environment.

The most effective and common defense in classical

world military is camouflage.


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Fig. 3.Camouflage BTS in the form of minaret

Although maintaining BTS by user’s servicing

responsibility is in a low level in passive defensive

aspect, but it has a specific booth in beautification and

preservation of the urban landscape.

Table 2. Passive defense arranges the BTSs of Tehran

in order of priority

Access Type Value No. of BTSs

Bank 1 11

Governmental 1 581

Hospital 1 18

MCI-Center 1 29

Military 1 7

Municipal 1 373

Commercial 2 211

Street 2 136

Subway 2 77

University 2 16

Residential 3 513

Hotel 4 10

Mosque 4 4

Sport Club 4 3

Mall 5 20

Mountain 5 3

Others 5 204

Park 5 44

Private 5 18

According to Table 2, 22% of BTSs in Tehran are

dedicated to citizens or other public users.

In the left column of the table, based on local access

and location of the BTSs which are in service, a name

assigned to them, in the middle column based on the

priority and importance in regard of passive defense the

number 1 to 5 are dedicated that 1 represents the

highest priority or most important and 5 is indicating

the lowest priority or least important. The right column

shows the number of BTSs belonging to each group.

Definitely, there is no coordination between values and

the third column (column of BTSs).

For example, although the number of BTSs in

residential group is considerable (513 pieces), but these

stations are in the third class of importance in passive

defensive category.The only criterion for evaluation of

a location is being strategic in passive defensive point

of view.

2.5.3. Fortifications

Regarding fortifications it is noteworthy that BTS shall

be made in accordance with standards of installation.

Further details can be obtained from the relevant

references that are not the purpose of this essay [5].

2.5.4. Coverage

The coverage is possible in two ways:

1. Security coverage is an action that is used mainly

for fixed installations.

2. Physical coverage which is termed as temporary

action that physically prevents from detecting the

goal. These actions can be included of creating

smoke screens or thick vapor.

Due to the nature of electromagnetic waves in this way

we can not cover the BTSs. Of course we can consider

coverage, camouflage and concealment similar to each

other. Today, many countries have used the structure of

Tree Coverage or Roof Top type antennas by using of

the height of buildings.

2.5.5. Creating safe structures by using of

strengthening patterns

It should be done according to telecommunication

standards of tower installation.

2.5.6. Scattering

Scattering is one of the things that needs to be

addressed. Today, countries have done many

designations regarding to distribution of passive

defense and strategic infrastructure. North Korea is the

perfect example of the decentralization policy and

strategy in this regard that its essence and core is

passive defense actions, serious considerations of

defense, security, economic in building and

constructing crucial institutions. Pyongyang Metro,

with a depth of 95 to 105 meters, is resistant to


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conventional and non-conventional weapons, refrain

from constructing large complex buildings and critical

and massive infrastructures and pay attention to

construct critical and sensitive centers in small and

scattered situations in all over country, constructing of

huge undergrounding tunnels, creating hundreds of

small ports with a capacity of loading one or two ships

along beaches of country, building high ways with

underground tunnels along it to facilitate transferring

military systems, constructing of large Nampo dam

near the margin of the coastal estuaries Dedong Kong

North Korea's western are examples of using passive

defense [6].

For example, by Mast sharing [1], 24 stations are

shared between three operators. It means that three

operators, mount their antennas on a mast. Now

imagine that the mast with regard to the above

requirements, covering an area that is belonging to one

or more governmental organization. If for any reason

(such as a war or an act of non-offensive military

action, such as repairs, wind or earthquake), the tower

is lost, then all three telecom operators lose their

servicing ability to that area. Therefore, site sharing

complies with the concept of mast sharing or

subscribing masts acts as a violation of passive defense

purposes. It is the same issue for stations that are

shared between two operators. This is one of the

objections to the results [1]. So according to the above

points it is required to design a proper model which can

locate BTSs according to passive defense criteria.

Fig. 4.Tower sharing between two networks A and B

In order to create a tailored plan for passive defense

criteria, the following algorithm is proposed. It is

notable for implementation of this algorithm; the

following points are taken into consideration.

1. According to order of Table 2, operators must

separately establish sites for places which their

values are 1 (such as governmental agencies,

hospitals, banks, military facilities, etc.) and these

sites should have the capability of RAN sharing. In

other words, for such situations sharing should not

be Mast sharing type. If the operators act

individually, distinct routes from the BTSs to the

BSCs have been created which are complementary

to each other and as a result a redundancy is

created.

2. Places that have a lower value (i.e. stations which

service general users, hotels, mosques, sports, and

clubs) are subjected Mast sharing. Through Mast

sharing, two or three operators' antennas should

install on a mast. However, if the shared mast

ruined by any circumstances, the easiest method is

to use a temporary BTS. It should be noted that in

cases with lower value we could also use RAN

sharing. But in term of operators' cost and

maintenance and contracting discussion get some

problems. Therefore it is not recommended.

3. In various combinations of sharing, potential

capacity of users and predicting to service must be

considered for the future.

4. It is considerable that the only way of sharing in

communication is not Mast sharing but this is one

of the ways of sharing which brings briefly:

Site sharing.

Mast (Tower) sharing.

RAN sharing.

Network roaming.

Core network sharing [2].

Passive sharing is usually defined as the sharing of

space or physical supporting infrastructure, which does

not require active operational co-ordination between

network operators. Site and mast sharing are considered

forms of passive sharing. The remaining categories,

listed above, are considered to be forms of active

sharing as they require operators to share elements of

the active network layer including, for example, radio

access nodes and transmission. For RAN sharing,

MNOs continue to keep separate logical networks and

the degree of operational co-ordination is less than for

other types of active sharing.

2.5.6.1. Site sharing Site sharing, involving co-location or sites, is perhaps

the easiest and most commonly implemented form of

sharing. Operators share the same physical compound

but install separate site masts, antennas, cabinets,

backhaul.


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Fig. 5. Site sharing between two networks A and B

In the figure 5, the solid line around the equipment and

masts represents the fenced-off compound that the

operators will either own or lease. Within this

compound each operator usually installs their own

infrastructure separately from that of other operators.

However, they may decide to share support equipment,

including shelters, power supply and air conditioning.

This form of sharing is often favored in urban and

suburban areas where there is a shortage of available

sites or complex planning requirements [2], [7].

2.5.6.2. Mast (tower) sharing: Mast, or tower, sharing is a step up from operators

simply co-locating their sites and involves sharing the

same mast, antenna frame or rooftop.

Fig. 6. Mast sharing between two networks A and B

Figure 6 shows a single fenced-off compound within

which operators will install their own access

infrastructure, ranging from antennas to base

transceiver station (BTS) cabinets. However, operators

will install their own antennas onto a shared physical

mast or other structure. The mast may need to be

strengthened or made taller to support several sets of

antenna. As for site sharing, operators may share

support equipment. Operator coverage remains

completely separate.

2.5.6.3. RAN Sharing:

RAN sharing is the most comprehensive form of access

network sharing. It involves the sharing of all access

network equipment, including the antenna, mast and

backhaul equipment. Each of the RAN access networks

is incorporated into a single network, which is then

split into separate networks at the point of connection

to the core. MNOs continue to keep separate logical

networks and spectrum and the degree of operational

coordination is less than for other types of active

sharing [2].

Fig. 7. RAN sharing between two networks A and B

Figure 7 illustrates how RAN sharing might work

between two partner networks. In this scenario both

operators share all the access network elements to the

point of connection with the core network. At this

interconnect point each operator then splits out the

traffic from its respective customers on its own core

network ring for processing by its own core network

elements and infrastructure. The exact implementation

may vary between different operators depending on the

local implementation.

2.5.6.4. Core network sharing:

At a basic level, the core network consists of:

• Core transmission ring.

• Switching center (with the home location register

(HLR)).

• Billing platform.

• Value Added Systems (VAS) that represent logical

entities and may also form part of the core

network.

The core network may be shared at one of two basic

levels, namely the:

• Transmission ring.

• Core network logical entities.


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2.5.6.5. Network roaming

Network roaming can be considered a form of

infrastructure sharing although traffic from one

operator’s subscriber is actually being carried and

routed on another operator’s network. However, there

are no requirements for any common network elements

for this type of sharing to occur. As long as a roaming

agreement between the two operators exists then

roaming can take place. For this reason operators may

not classify roaming as a form of sharing as it does not

require any shared investment in infrastructure. When

roaming agreements come to an end they can be

renegotiated either with the existing host network or

another operator with minimal effort and transitional

impact [1], [7], [8].

The proposed algorithm for locating BTSs based on the

theme of passive defense and with regard to the

beautification of the city is given below. This algorithm

is intended so that it is compatible with existing

conditions of BTSs in Tehran.

2.6. Connecting BTSs to each other

A very important point that must be considered is how

BTSs connect to each other, but in this case, there was

no information for BTSs in Tehran. However, there are

four methods of connecting BTSs to each other and to

BSC. For each one a brief description is given below:

1- Chain method

In this way, the BTSs connected to each other like a

chain and cutting off via two BTSs disconnects the

other connections.

Fig. 8.Chain connection

2- Star method

Fig. 9.Star connection

3- Ring method

Fig. 10. Ring connection

4- Hybrid Method

A Hybrid of Star and Circle connections

Fig. 11.The Hybrid Connection

2.7. Temporary Base Transceiver Station:

Temporary base stations, usually use for covering or

releasing the capacity fast. One application for a

temporary base station is temporary cellular covering

of residential places that are waiting for installing

permanent telecommunication stations or mobile sites

that have been prepared for special events.

There are two types of temporary BTSs:

1- Mobile BTS

2- Portable BTS

Mobile BTSs can be installed on moving platforms

such as trucks or vans but portable BTSs are

immovable temporary structures, which are easily

assembled and disassembled.

The structure of portable BTS in Mobile BTS is bigger

and higher. Temporary BTS is a retractable mast,

which its height is up to 10 meters, which is used for

installing antennas and microwave dishes [2], [8].


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Fig. 12.Temporary Telecommunication Base Station

3. RESULTS AND DISCUSSION

As previously mentioned, locating of BTSs in Tehran

carried out according to customer requirements and

therefore there is no specific design for these stations.

Since MCI has more experiences than the other active

operators, designed location of its stations is a model

for other operators that want to locate their new

stations. Therefore, the location of stations belonging to

MTN and Talia to some extent is similar to MCI. This

leads to compressed installation of stations in Tehran.

Researches were done to find a way to regulate the

establishment of these stations. In this regard, some

studies have been done with City Common

Communication Co. But, these studies have been done

based on the site sharing. Three active mobile operators

in covered areas use shared towers. For example, three

operators install their antennas on one mast for

telecommunication services to Tehran Pars subscribers.

However, one important factor in the passive defense is

dispersion.

The compression of BTSs according to the obtained

information (based on engineering standards or not) is

beneficial in passive defensive aspects. Because in

valuable places by missing a station, other adjacent

stations belonging to other operators can be used

instead. Of course, in this regard there are some

technical requirements that should be followed. In other

words, BTS should be usable by all operators.

However, there is not this possibility in Tehran. Now,

respect for the matters mentioned in passive defense,

we want to investigate BTSs’ location in Tehran.

3.1. Passive defense for existing location of BTSs in

Tehran

By using the available data, we can derive the number

of BTSs in each rated group. (Note: 1 is the maximum

value of stations and 5 is the lowest one.)

Table 3. The number of BTSs in each Rated group

Rating BTSs The number BTS in

each rated group

1 1020

2 441

3 514

4 37

5 294

Total of BTSs 2306

3.1.1. Implementation of passive defense model on

valuable BTSs

Only in 23 of 965 locations of BTSs they are located 2,

3 or 6 BTSs of three operators for servicing only one

special place (Table 3).

3.1.1.1. Locations with more than one station with

value 1

Although increasing the number of BTSs in these areas

has taken because of increasing the number of users,

but with some modification in the backbone of

communication network, it is possible to provide a

situation in which all operators can take advantage of

this communication network. Also in this category, the

possession of BTS is not important because

communication devices are shared up to the connection

point of the core of each operator’s own network.

So in this regard, changes in implementation of passive

defense are:

- Physical changes that include retrofitting and

increasing in the height of masts.

- RAN sharing

- Increasing the capacity of coverage by

increasing the number of TRX's

- Assign any location 2 BTSs with above

conditions.

Result 3.1: By applying the above conditions, the

number of BTSs is reduced from 55 to 46.


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Fig. 13. Passive defense in determining BTS location0

Determinig BTS location with

considering passive defense

Establishment of

new BTS

urban beautification and

reorganization of BTS

Determinig BTS location with

considering passive defense

The location

value of

BTS>2

The location

value of

BTS<2

BTS location is strategically and

defensively less important

Using MAST Sharing for regulating

operators' stations

The number of BTSs in this area decrease

and operators use adjacent BTS for

servicing

Breaking

down the BTS

Using TEMPORARY BASE TRANSCIEVER

STATION

Communication Data transmited to

the destination


defensively important

Because of the importance of these places

it's not possible to reduce the number of

BTS and operators must use MAST

Sharing

For passive defense, the number of BTSs

will not decrease in these areas And BTSs

have redundancy roles

Breaking

down the

BTS


defensively important

Installation of BTSs by RAN Sharing

possibility for any operator nearby the

location

Breaking

down the

BTS

Using

adjacent BTS


STATION

Using

adjacent BTS


STATION

YES

NO NO

YES

YES

NO

NO

YES

YES

YES

NO

NO YES

NO


93

Benefits:

1- Implementing the desired algorithm

2- Increasing the performance of BTSs in

such a way that all operators are able to

use each mast.

3- In case of losing one BTS, the second BTS

plays a supporting role.

4- In case of losing both BTSs, it is possible

to use the temporary BTS according to the

diagram 13.

The issue of passive defense is as a new subject that

will be recently addressed in various fields. Because

the establishment of BTS mobile operators have started

their activities almost 20 years ago, it is expected that it

targeted based on this fact. Then we examine this

structure and try to organize the locations of BTSs, we

have additional costs for changing the existing

conditions and adapting to any imposed conditions.

Examples of these costs are:

- Restructuring costs of telecommunication masts and

strengthen their bodies and increasing their height for

installing operators' mobile antennas on the mast.

- Increased cost of installing the panels of the towers

which requires more space next to the mast because of

mast sharing by operators.

- In regards to the areas where are important in terms of

defense, it is necessary to implement RAN sharing and

according to above, in this kind of sharing, all

accessible parts of network such as antenna, mast,

equipment of site, back haul will be shared up to the

connecting point of cores of operators' network or

mobile network. In regards to information that is

extracted of Iran’s network, these changes need lots of

investment, although it is necessary.

3.1.1.2. Locations with only one station, with value

of 1

70% of BTSs belongs to MCI, 28% of BTSs belongs to

MTN and the rest belongs to Talia and as we discussed

in previous parts, the situation of the locations of BTSs

for 3 operators are very similar to MCI. So for these

stations the locations of BTSs of MCI are accepted. 55

of 1020 stations with value 1 were examined. 675 of

965 stations belong to MCI. By using of RAN sharing

we can share these stations via 3 operators.

Result 3-2: 675 of 965 stations are shared via 3

operators. So we can reduce 290 stations which are

adjacent to MCI operators in this way.

3.1.1.3. The location of stations with values of 1,2, 3,

4, 5

1020 stations of 2306 were studied above. So it remains

only 1286 BTSs. 900 of BTSs belongs to MCI, 360 of

BTSs belong to MTN and 26 of BTSs belong to Talia.

70% stations belong to MCI so at least 70% of regions

of Tehran recovered by this operator. So consequently,

we also implement a pattern for passive defense of the

900 stations we use.

As previously mentioned, the areas that their values are

except 1, because of having less important, it is

possible to change the location of establishing these

stations in order to match for changes according to the

desired pattern.

Table 4. The number of BTSs used in optimization

plan after taking into account the issue of passive

defense

Rating BTSs

The number of BTSs

in each rated group

The number of BTSs

used in the

optimization plan

1 1020 730

2 441 310

3 514 359

4 37 26

5 294 205 TOTAL OF

BTSs 2306 1630

First, because of using Mast sharing, the tower height

should be increased and its body is also strengthened.

Secondly, to preserve the beauty of the city, which is

proportional to the occupied space for the mast, it is

possible to use camouflage techniques mentioned

before. For example, the towers are used in the parks,

are decorated with artificial foliage and in areas with a

high density of buildings, Top roof masts are used.

Thirdly, if we lost critical situations we can use

temporary base stations (section 2.7) in great detail.

3.2 Comparison between optimization BTSs,

regardless of and in regard to passive defense

At first in regard to the result of parts 3.1.1 and 3.1.2

we complete table 3. This column is added to the table

which shows the number of BTSs in each group that is

used to implement passive defense pattern.

As it shows, the implementation of defensive pattern,

reduced the number of BTSs about 28%. It helps

maintaining the beauty of the city and on the other

hand, provides more reliable services for urban

subscribers.

In compare with the earlier research on BTSs of Tehran

by using site sharing pattern the number of BTSs which

are at a distance of less than 200 meters from each

other, become less to 487 stations. It is 21% of whole

BTSs. But on that research there are no information of

changes on BTSs and type of sharing between

operators.

According to the results, the best type of BTS

connection is STAR. In this way if the connection

between BTSs and BSCs were cut off, it didn't affect

on the other BTSs and BSC connections.


94

4. CONCLUSION AND RECOMMENDATIONS

According to the survey, based on the evidence the lack

of coordination between the ministry of roads and

urban development and mobile telecommunication

companies for more than two decades now there is no

specific pattern for locating BTSs and their

establishment is based on the necessity of users. In

recent years by adding new operators to

telecommunication network, they desire to expand their

network coverage made the situation more complex.

However, researches on organizing these stations in

order to beautifying the city were carried and in this

study we also examined this issue with a view to

passive defense, both of these methods were progressed

toward reducing the number of the stations. Passive

defense is an issue, which is investigated recently.

Therefore, all of these researches are preliminary.

In order to increase the number of users and

miscellaneous communication services progressively,

we suggest that for installation of new BTSs, operators

share the BTS and its components by using different

type of sharing. In this way, the new mast of an

operator can use this feasibility for high quality

servicing to the users. This coordination helps us

resoundingly to attain to our defensive and beautifying

aims.

REFERENCES

[1] M., Rafieian, M., Farajzadeh and Z., Yousefi,

“Organizing BTS Sites Deployment Based on

Urban Planning Goals Using Site Sharing

Approach; Case Study: Tehran”;Urban

Management, No.28, pp.123-142, 2010.

[2] GSMA Head Office, Mobile Infrastructure Sharing,

2012.http://www.gsma.com/publicpolicy/wp-

content/uploads/2012/09/Mobile-Infrastructure-

sharing.pdf

[3] K., Torabi, A.; Mahdinezhad. “Investigating the

Vulnerability of Street Networks Against Air Rids

Using IHWP and GIS Case Study: 6th zone of

Tehran”; Journal of Passive Defense Science and Technology ISSN 2228-5865, No.4; pp.295-303, 2012.

[4] Malaysian Technical Standards Forum Bhd, Radio

communications Network Infrastructure (External),

http://www.inti.gob.ar/cirsoc/pdf/antenas/Guidelines_o

n_ Technical_ Specifications.pdf ,

http://www.mtsfb.org.my, 2009.

[5] -“Guidelines on technical specifications for the

installation of telecommunications masts and

towers”, 2009.

[6] M.R., Rajabi., et al. “TOPSIS-Based Model for

Hydropower Dam Site-Selection in Isfahan

Province”; Journal of Passive Defense Science and Technology, No.4; pp.315-324, 2011.

[7] N., Ahangarai, “The History of International

Telecommunication Union (ITU)”; the office of

improving study; pp.1-5, 2009.

[8] S., Maruyama, K., Tanahashi, and T., Higuchi, “Base

Transciver Station for W-CDMA,” FUJITSU Sci.

Tech. J., Vol.38, No. 2, pp.167-173, December 2002.

http://www.gsma.com/publicpolicy/wp-content/uploads/2012/09/Mobile-Infrastructure-sharing.pdf











http://www.inti.gob.ar/cirsoc/pdf/antenas/Guidelines_on_%20Technical_%20Specifications.pdf

http://www.inti.gob.ar/cirsoc/pdf/antenas/Guidelines_on_%20Technical_%20Specifications.pdf

http://www.mtsfb.org.my/

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Passive Defense in Appropriate Location of Base Stations