imt-advanced and fss interference area ratio...

IMT-Advanced and FSS Interference Area Ratio methodology

LWAY FAISAL ABDULRAZAK, ZAID A. SHAMSAN AND THAREK ABD. RAHMAN

Wireless Communication Center, Faculty of Electrical Engineering

Universiti Teknologi Malaysia

Skudai 81310, Johor,

MALAYSIA

[email protected] http://www.fke.utm.my/wcc/

Abstract: - This paper describes a new methodology to be utilized in assessing the level of coordination

difficulty on the basis of the actual terrain profile between IMT-Advanced (fixed and mobile users) and FSS

(Fixed satellite services) for a specific site. This methodology can be use to asses the effectiveness of

mitigation techniques based on the use of directional antennas, which takes into account the actual shielding

effect by terrain profile and clutter losses associated with the artificial objects. Considering a shielding effect

on the signal propagate within proper separation distance used to improve the current methodology.

Mathematical approach was simulated by Matlab and results confirmed by ICS Telecomm software for more

specifications. Eventually, the results had been summarized in planned methodology to serve regulators and

frequency management modulators.

Key-Words: - Interference, FSS, IMT-Advanced, different environments and area ratio methodology.

1 Introduction International protection of FSS earth stations and their

coordination are governed by the Radio Regulations,

which are applicable to specific FSS earth stations (those

whose geographical coordinates are known). The

thresholds/conditions to be used to trigger coordination

are those specified in most of the Radio regulations,

together with the calculation method of coordination

contours [1]. As specified in No 9.6 of the ITU Radio

Regulations, an administration intending to bring into use

terrestrial services, e.g., BWA network, whose territory

falls within the coordination contours of the earth stations

under the coordination or notification procedure or

notified under Articles 9 and 11 of the Radio Regulations,

shall effect coordination with other administrations

having these earth stations [2]. The Radio Regulations do

not provide any criteria or procedures for how this

bilateral coordination is to take place. It should be noted

that the coordination area is not an exclusion zone within

which the sharing of frequencies between the earth station

and terrestrial stations or other earth stations is prohibited,

but a means for determining the area within which more

detailed calculations need to be performed. In addition to

the coordination contours, these footnotes of the Radio

Regulations prescribe that before these administrations

bring into use a (base or mobile) station of the mobile

service in the specified band, it shall ensure that the pfd

produced at 3 m above ground does not exceed

−154.5 dB(W/(m2 ⋅ 4 kHz)) for more than 20 % of the

time at the border of the territory of any other

administration [3]. This limit may be exceeded on the

territory of any country whose administration has so

agreed. In order to quantitatively evaluate this shielding

effect, the methodology called interference area ratio, is

employed, to justify the method a complete study about

the shielding technique has taken a place in this article to

explain the conceptual figure which indicates that the

interference power level from an IMT-Advanced

transmitter which is non-uniformly decreased over the

360-degree area due to the shielding effect by terrain

profile and clutter losses which may be observed in a real

environment [4].

2. Shielding technique for fixed IMT-

Advanced It allows two-way protection from and to point-to-point

links in the fixed service, which reduce the separation

distance, and controls and reduces the interference. This

technique can be used for the FSS Earth station receive

antenna and can typically give 10-40dB of additional

protection. Fig.1 below illustrates the exact scenario of

protected satellite through the shielding.

Fig.1 different two different shielding types, natural and

artificial.

RECENT ADVANCES in CIRCUITS, SYSTEMS, ELECTRONICS, CONTROL and SIGNAL PROCESSING

ISSN: 1790-5117 15 ISBN: 978-960-474-139-7

On the other hand we should consider also the received

power versus distance; as a proposal for IMT-Advanced

we can consider the WiMAX because of its territorial

propagation nature which is quite similar to the scenario

we have in the IMT-Advanced [5] [6]. Fig.2 depicts the

received WiMAX power versus distance on flat territory.

Fig.2 received WiMAX power versus distance

3. Separation distance results for

different shields

Considering the harmful interference power level is any

ataced signal exceeded -166db was calculated and

explained in [7] as a worst case scenario. Shielding

effects power reduction (R) counted as a most effective

parameter in [8] [9] according to that we did a calculation

for different values of shielding and results appeared

through the Matlab simulation as illustrated in fig.3, 4, 5,

6, and 7 when R varied from 0 to 40 dB.

Fig.3 shows that D =13.766 km when R = 0

Fig.4 shows that D = 5.0644 km when R=10

Fig.5 shows that D =1.8631 when R=20

Fig.6 shows that D = 0.6854 when R=30


ISSN: 1790-5117 16 ISBN: 978-960-474-139-7

Fig.7 shows that D = 0.2521when R = 40

We can conclude the previous graphs in a table of

comparison to show the real effect of shielding; when we

increase the shielding we are reducing the terrestrial

transmitted power from surrounding base stations.

Therefore a different level of immunity we gain for

different wall sizes as clarified in table 1.

Table 1: summarized results of different separation

distance base on different shielding

EIRP(dB) I(dB) G(dB) F(GHz) Ah(dB) R(dB) D(KM)

30 -166 -10 3.5 16 0 13.7665

30 -166 -10 3.5 16 10 5.0644

30 -166 -10 3.5 16 20 1.8631

30 -166 -10 3.5 16 30 0.6854

4. ICS Telecomm simulation results As we went farther in this research we recognized that in

feasible experiment can cost a lot of resources to deploy

different walls heights widths, so we used the ICS

telecom software to simulate different walls base on

specific geographic area. However, we depend on

different maps to illustrate the effect of different

environments. For dense urban area we could get an

amazing separation which is about 3km while the

Shielding height by ATDI for was five meters. When we

used an eight meters height wall we got a separation

distance about only 1km and 0.5km separation distance

for ten meters height. Fig.8, 9 and 10 shows the

simulation scenarios.

Fig.8 with 5m height shielding we got 3km separation

distance.

Fig.9 with 8m height shielding we got 1km separation

distance.

Fig.10 with 10m height shielding we got 0.5km

separation distance.

For urban area the ICS telecom shows completely

different results from the first simulation as clarified in

table 2. However, the buildings heights are less and more

scattered. Table 3, 4, and 5 Shows the magnificent

separation which may use as a reference for

telecommunication regulatory, according to there own

environments.


ISSN: 1790-5117 17 ISBN: 978-960-474-139-7

Table 2: Results of sub urban area:

Separation

distance

(km)

PRx

before

shielding

Shielding

height

Shielding

thickness

PRX after

shielding

20 -165 dB 0 m 0 ________

10 -112 dB 4m 0.3m -186dB

5 -103dB 7m 0.3m -186dB

3 -90dB 10m 0.3m -186dB

Table 3: Results of rural area:

Separation

distance

(km)

PRx

before

shielding

Shielding

height

Shielding

thickness

PRx after

shielding

40 -165 dB 0 m 0 ________

30 -115 dB 3m 0.2m -150dB

15 -100dB 5m 0.2m -156dB

7 -95dB 7m 0.2m -158dB

Table 4: Results of urban area:

Separation

distance

(km)

PRx

before

shielding

Shielding

height

Shielding

thickness

PRx after

shielding

15 -165 dB 0 m 0 ________

7 -108 dB 5m 0.3m -186dB

3 -100dB 10m 0.3m -186dB

1 -95dB 10m 0.3m -186dB

Table 5: Results of dense urban area:

Separation

distance

PRx

before

shielding

Shielding

height

Shielding

thickness

PRx after

shielding

9 -165 dB 0 m 0 ________

3 -108 dB 5m 0.3m -186dB

1 -100dB 10m 0.3m -186dB

0.5 -95dB 10m 0.3m -186dB

5. Interference area methodology

Fig.11 shows the conceptual figure which indicates that

the interference power level from an IMT-Advanced

transmitter is non-uniformly decreased over the 360-

degree area due to the shielding effect by terrain profile

and clutter losses which may be observed in a real

environment. Due to the feature of non-uniformly

distributed interference power level over the 360-degree

area, the required minimum separation distance can be

reduced by using the additional mitigation technique

based on directional-beam antenna.

Fig.11 Shielding effect by terrain profile and clutter

losses

When applying the interference area ratio of x%, we

exclude the x% of area that has the larger separation

distance over d + ∆d. Then, the required separation

distance becomes d + ∆d. When x > 0%, the additional

mitigation technique is adopted in order to protect the

FSS earth stations located in the x% of the area. A

possible mitigation technique is to employ directional-

beam antenna, such as sectorized- or adaptive-

beamforming antenna at an IMT-Advanced transmitter.

In order to quantitatively evaluate this shielding effect,

Fig.12 shows a conceptual figure to explain the definition

of “interference area ratio”, where an IMT-Advanced

transmitter is located at the center of the calculation area.

When using the interference area ratio, at each grid of the

calculation area, we calculate the interference power level

caused by the IMT-Advanced transmitter and decide

whether its interference power level exceeds the

protection criteria of the FSS earth station based on

Recommendation ITU-R SF.1006. If the interference

power level exceeds the protection criteria, this grid is

judged as the interfered area. Consequently, the

interference area ratio as a function of distance, d, from

the interferer, i.e., IMT-Advanced transmitter, is defined

as the portion of the interfered area between the distance

of d and d + ∆d from the interferer divided by the ring-

shaped area between the distance of d and d + ∆d from

the interferer. It should be noted that the analyses using

the interference area ratio are also applicable to the

aggregated interference case from multiple IMT-

Advanced transmitters.

Fig.12 shows the required minimum distance as a


ISSN: 1790-5117 18 ISBN: 978-960-474-139-7

function of the interference area ratio.

As shown in this figure, according to increase in the

interference area ratio value, the required minimum

separation distance can be reduced. When we derive the

required separation distance for the interference area ratio

of x%, we exclude the x% of area that has the larger

separation distance over d + ∆d. Then, the required

separation distance becomes d + ∆d. It should be noted

that the additional mitigation technique based on

directional-beam antenna, such as the sectorized-antenna

and adaptive-beamforming antenna at the IMT-Advanced

transmitters, is adopted in order to protect the FSS earth

stations located in the x% of the area. Figure 13 shows an

example employing sectorized-antenna as a mitigation

technique. In this example, the transmission signal from

the sector #6 of the IMT-Advanced transmitter #1 facing

to the front direction of an FSS earth station antenna is

stopped using a sectorized-antenna, while other base

station #2, which is not facing to the front direction of an

FSS earth station antenna, provides the services. It should

be noted that the sectorized-antenna has been already

implemented in the current cellular mobile

communication technologies. Furthermore, the adaptive-

beamforming has been also implemented in some cellular

mobile communication systems. Therefore, these

mitigation techniques can be applied to the IMT-

Advanced systems.

Figure 13 Mitigation technique by utilizing sectorization

In Table 6, the required minimum distance is summarized

for an assumed interference area ratio of 10%, as an

example. For the comparison, the required minimum

distance is also shown in the case of the interference area

ratio of 0%, which is equivalent to the separation distance

without considering the interference area ratio. As shown

in this table, by introducing the measure “interference

area ratio” associated with the mitigation technique using

the directional beam antenna, the required minimum

distance is reduced by about 5% to 60% depending on the

scenarios in IMT-Advanced systems.

Table 6: required minimum distance for interference area

ratio of 10% (urban area, single-entry, FSS earth station

elevation angle =5degrees)

6 Conclusions In the absence of any coordination, IMT-Advanced

systems planned to operate in the 3.5 GHz band will

cause unacceptable interference to FSS stations in

the extended C band (3.4 – 3.6 GHz) if the two

systems operate on the same frequency channels.

Over and above, IMT-Advanced systems in the 3.5

GHz band which are located nearby and with clear

line-of-sight to FSS stations will cause interference

to the latter operating in 3.6 – 4.2 GHz band if the

separation distance is less than about 300 meters and

there are protection measures like different shielding

and existing buildings blocks. For nomadic IMT-

Advanced a new methodologies should take a place

and turn to a technical methods govern all the

scenarios of interference for major use of wireless in

suburban and urban environments. The required minimum distance is summarized for an

assumed interference area ratio of 10%, by introducing

the measure “interference area ratio” associated with the

mitigation technique using the directional beam antenna,

the required minimum distance is reduced by about 5% to

60% depending on the scenarios in IMT-Advanced

systems. This assessment is done in response to IMT-

advanced threats to all the services work within

same frequency. However, the author advised the

regulators to consider the current results presented in

this paper to govern all companies transmitting a

signal in C-band range.

Acknowledgements The Author acknowledge the Malaysian commission

and multimedia commission for funding this project

in order to process a complete study for the

Environ

ment

IMT-

Advanced

station

antenna

downtilt

Interfere

nce area

ratio=10

%

without

considering

interference

area ratio

Suburba

n Macro

2 degree 36 38 km

Suburba

n Macro

7 degree 21 32 km

Urban

Micro

2 Degree 12 14 km

Urban

Micro

2 Degree 5.8 14 km


ISSN: 1790-5117 19 ISBN: 978-960-474-139-7

coexistence between current services and future

services in the lower portion of C-band.

References:

[1] Lway Faisal Abdulrazak, Tharek Abd Rahman,

“Review Ongoing Research of Several

Countries on the Interference between FSS and

BWA”, International Conference on

Communication Systems and Applications

(ICCSA'08) in China Hong Kong, conference

proceeding (ISBN: 978-988-98671-8-8), March

2008.

[2] ITU-R WP 8F/TEMP 432 rev.2, “Working

document towards a PND report on sharing

studies between IMT-ADVANCED and the

Fixed Satellite Service in the 3 400- 4 200 and 4

500-4 800 MHz bands”, ITU-R Working Party

8F, August 2006.

[3] ITU-R SF.1486, “Sharing methodology

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Fixed Service and Very Small Aperture

Terminals in the Fixed-Satellite Service in the 3

400-3 700 MHz Band,” ITU-R R WP4-9S,

Geneva, November 2000.

[4] Electronic Communications Committee (ECC),

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[5] ZAID A. SHAMASN, LWAY Faisal and

THAREK ABD. RAHMAN ” On Coexistence

and Spectrum Sharing between IMT-Advanced

and Existing Fixed Systems” International

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TRANSACTIONS on COMMUNICATIONS,

ISSN: 1109-2742, Issue 5, Volume 7, pp505-

515, May 2008.

[6] Lway Faisal Abdulrazak, Zaid A. Shamsan and

Tharek Abd. Rahman “Potential Penalty

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Malaysia” International Journal Publication in

WSEAS Transactions on COMMUNICATIONS,

ISSN: 1109-2742, Issue 6, Volume 7, pp637-

646, June 2008.

[7] Zaid A. Shamasn, Lway Faisal, S. K. Syed-

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WiMAX and Existing Fixed Wireless Access

Systems” International Journal Publication in

WSEAS Transactions on COMMUNICATIONS,

ISSN: 1109-2742, Issue 6, Volume 7, PP627-

636 June 2008.

[8] Lway Faisal Abdulrazak and Thaek Abd.

Rahman, “Potentiality of Interference

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in Istanbul, Turkey, May 27-30, 2008.

[9] Zaid A. Shamasn, Lway Faisal and Tharek Abd.

Rahman, ” Co-sited and Non Co-sited

Coexistence Analysis between IMT-Advanced

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INFORMATICS (TELE-INFO '08), Istanbul,

Turkey, May 27-30, 2008.


ISSN: 1790-5117 20 ISBN: 978-960-474-139-7

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