03 - Indoor System Design

1

Indoor System DesignIndoor System Design

Indoor System Design 2

TopicsTopics

1. Input Data for Design

2. System Design Considerations

3. Single and Multi-operator Cable System

4. RF Coverage Estimation and Design Goal

5. Other Coverage Considerations

6. Types of Signal Source

7. Antenna Placement Strategies

8. Uplink Amplifier Design Considerations

9. Active Antenna System

10.Uplink System Limitation in UMTS

11.Electromagnetic Radiation (EMR) Safety

2


Input Data and System Design ConsiderationInput Data and System Design Consideration

• Number of network operators and radio platforms to be supported

• Operating frequency and number of RF carriers

• Signal levels - downlink and uplink, % of coverage

• System capacity (no. of bands and carriers) and power handling

• Signal to (Noise + Intermodulation) level

• Threshold frame or bit error rates (if applicable)

• Plans of building and required coverage areas - public areas, private

areas (e.g. plant rooms, etc), lifts

• Active or passive system

• System maintainability and expandability

• Aesthetic consideration: antennas vs radiating cables

• System / component cost


Single Network, Single Cable SystemSingle Network, Single Cable System

BTS

1/F

2/F

Basement

Tx / Rx

DuplexedSignal

J J

Load

Coupler

Antenna

1/2" Coaxial Cable

7/8" Coaxial Cable

Leaky Cable

J Jumper

Legend:

Point of InterconnectionPOI

Tx / Rx

Tx / Rx

Tx / Rx

3


MultiMulti--Networks, Single Cable SystemNetworks, Single Cable System

1/F

2/F

Basement

J J

BTS

Tx / Rx

DuplexedSignal

BTSBTSBTS

POI

Load

Coupler

Antenna

1/2" Coaxial Cable

7/8" Coaxial Cable

Leaky Cable

J Jumper

Legend:


Tx / Rx

Tx / Rx

Tx / Rx


MultiMulti--Networks, Dual Cable SystemNetworks, Dual Cable System

J J

J J

1/F

2/F

Basement

BTS

Tx / Rx

BTSBTSBTS

POI

Load

Coupler

Antenna

1/2" Coaxial Cable

7/8" Coaxial Cable

Leaky Cable

J Jumper

Legend:


Tx

Rx

Rx

Rx

Rx

Tx

Tx

Tx

4


RF Coverage EstimationRF Coverage Estimation

• Estimating RF coverage starts with selection of a design goal, PDesignGoal, for minimum received signal strength over a coverage area with a specified reliability level.

• Design goal is based on air protocol, fade margins, body loss and receiver noise figure performance.

• Now, specify power level, PTX, expected from Antenna.

• Difference between the design goal and the transmitted power level represents the maximum allowable path loss, MAPL, for the link.

MAPL = PTX – PDesignGoal

• Lastly, path loss is translated to coverage radius.− Initially based on matching given site to one of the in-building

environment models, but may be replaced with those derived from actual site measurements.


TDMA GSM EDGE iDEN Units

Thermal Noise in Signal BW -129 -121 -121 -130 dBm

Mobile Noise Figure 7 7 7 7 dB

Minimum C/N (SNR) 15 9 19 16 dB

Multipath Fade Margin 6 6 6 6 dB

Rician K=6dB; 95% Confidence

Log-Normal Shadowing Margin 10 10 10 10 dB

Body Attenuation 3 3 3 3 dB

DL RSSI Design Goal (PDesignGoal) -88 -86 -76 -88 dBm

Signal level received by wireless handset at edge of coverage area

RF Coverage Design GoalRF Coverage Design Goal

Based on Downlink RSSI Analysis

• Customers typically specify an RF coverage design goal of about

-85dBm signal strength on the downlink with 95% area reliability.

• The table below lists, for several protocols, the components from

which the design goal is derived.

5


RF Coverage Design GoalRF Coverage Design Goal

Higher Power Design Goals

• In some cases, customer may require higher than -85dBm signal

strength coverage.

• Some reasons for higher design goal include:

− For systems with non-hierarchical control channels, higher

downlink power is necessary to keep in-building mobiles locked on

to in-building signals (e.g. GSM).

− In WCDMA, higher level prevents pilot pollution and/or excessive

soft-handoff with outdoor networks.


Other Coverage ConsiderationsOther Coverage Considerations

• Using antennas to cover general open space

• Using leaky to cover (or pass through) a

number of rooms (in particular high loss

plant rooms)

BTS POI

1/F

2/F

Basement

Tx / Rx

DuplexedSignal

J J

Indoor

Outdoor

6


Other Coverage ConsiderationsOther Coverage Considerations

• How to cover inside lifts?

− Antennas at lift lobby of every floor

− Antennas inside cabin

− High gain antenna at lift shaft top emitting down, etc

• For last two solutions, need to co-ordinate with lift contractor, hard to

access and maintain

• For first solution, easy for access and maintenance


Types of Signal SourceTypes of Signal Source

7


BTS Signal SourceBTS Signal Source

• Stable and strong signal level

• Good signal quality

• Maximum dynamic range on uplink

• Theoretically no limits on traffic capacity

• Sector splitting possible

• Handover with outdoor site needed


OffOff--Air Repeater (OAR) SolutionAir Repeater (OAR) Solution

• Signal stability / strength / quality depends on location of donor antenna and LOS condition.

• Donor antenna may be blocked by nearby building development.

• Different operators have different preferred donor antenna location.

• Isolation between donor antenna and DAS to avoid oscillation.

• Multiple channels are required for multiple RF carriers.− Power back-off requirements

• Channel frequency needs retuning after network frequency changes (particularly for GSM).

• In multi-operator environment, different attenuators or gains are required to equalize the levels of different operators.

• Traffic capacity depends on donor cell.

• Outdoor frequency plan might put constraints on maximum numbers of channels assigned (for GSM).

• Handover with outdoor site for some entrances leading to areas covered by other outdoor cells.

8


Optical Repeater SolutionOptical Repeater Solution

• Stable signal level with good quality.

• Low to high (10W) power output is available.

• Lower dynamic range on uplink, typically < 80 dB.

• Coverage is uplink limited

− Lack of uplink diversity

− Increased uplink Noise Figure

• Sector splitting need another set of optical repeater.

• Handover with outdoor site need to consider.


Comparison of Signal Source SolutionsComparison of Signal Source Solutions

Advantages Disadvantages

BTS 1. High output power

2. High traffic capacity

1. Higher cost

2. Additional circuit (e.g. T1/E1 link)

Off-Air Repeater

1. Lower cost

2. High gain (up to 90dB)

1. Channel frequency needs to retune after change of frequency plan

2. Donor antenna may be blocked by nearby building development

Optical Repeater

1. Stable signal level with good quality

2. Suitable for long distance transmission

1. Higher cost than OAR

2. Relatively low output power

9


DAS and Active AntennaDAS and Active Antenna

Passive Distributed Antenna

System (DAS)

• Including coaxial & leaky cables,

POI, antennas and passive

devices

• All passive devices, no

maintenance is required

• Wide Dynamic Range

Active Antenna System (AAS)

• Including Main Hub, Expansion

Hub, Remote Antenna Unit

(RAU), optical fiber and twisted-

pair cable.

• Active devices

− DC or AC supply requires for each active antenna

• Maintenance required


Antenna Placement StrategiesAntenna Placement Strategies

10


Antenna PlacementAntenna Placement

• Antennas can be installed on each floor or only on some floors


Antenna Placement Antenna Placement

• Building geometry is the main determinant of where antennas are

installed and their frequency of placement.

• Two generalized but very distinct building geometries to consider:

− High-rise office building with vertically stacked floor plans:� Many floors to cover = more antennas to place

� May require antennas on every floor

� Longer vertical cable runs and shorter horizontal cable runs

− Arena or mall style buildings with horizontally spaced open floor

plans:� Fewer floors to cover, more open areas = fewer antennas to place

� May not require antennas on every floor

� Longer horizontal cable runs and shorter vertical cable runs

• Number of antennas also depends on other related factors:

− Size of the building

− Coverage reliability requirements

− System specifications, such as noise figure, antenna gain, etc

− Path loss slope and standard deviation

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Antennas Placement on Each Floor

• Coverage is much more reliable than when antennas are not

mounted on every floor

• If many antennas are installed on the same floor, a line-of-sight

condition can be maintained for most areas

• Signal path loss is affected by the following factors:

− Wall penetration loss (1 to 10 dB),

depending on material

− Signal standard deviation can be

from 3 to 13 dB

− Different signal incidence angles

can produce >15 dB difference in

path loss (normal incidence vs.

grazing incidence)

− Received signal level when

turning a corner (up to 15 dB

difference)



Antennas Installed Only on Some Floors

• Coverage is much less predictable with fewer antennas

• More coverage is in non line-of-sight condition

• Signal path loss is affected by the following factors:

− Floor penetration loss (6 to 30 dB), depending on material

− Signal standard deviation can be >17 dB

− Different signal incident angle can produce >15 dB difference in

path loss (normal incidence vs. grazing incidence)

− Due to reflected signal,

signal loss is not proportional

to number of floors after

signal penetrates two or

three floors

12


Recommendations for Antenna PlacementRecommendations for Antenna Placement

• Proper antenna distribution can improve coverage quality and

diversity gain, and reduce interference from (to) outdoor network

• Install antennas on every floor to reduce

signal uncertainty

• On each floor, install multiple low gain

antennas to ensure coverage reliability

and to produce significant diversity gain.

− This increases probability that most

areas have line-of-sight conditions

• Use a timing delay component in an indoor antenna system, to

produce artificial timing delay between overlapping signals from

different antennas.

− This can solve reduced multipath diversity problem and

significantly improve downlink capacity for WCDMA

• Consider locating antennas at building entry/exit points to ensure

reliable handover to outdoor network and prevent dropped calls


• On each floor, place antennas at building perimeters and pointed

inwards – toward desired coverage areas

• Increase indoor signal level near building edge, reducing amount of

soft handover between indoor and outdoor Node Bs

• Reduce interference to and from outside of building - UE will

transmit lower power near building edge


13


Uplink Amplifier Design Uplink Amplifier Design ConsiderationsConsiderations


Receiver Sensitivity and Noise FigureReceiver Sensitivity and Noise Figure

• System sensitivity can be calculated as

where

k = Boltzmann’s constant (1.38 x 10-23 W/K)

T = Resistor temp in Kelvin (K)

BIF = noise bandwidth (Hz)

NF0 = system noise figure (dB)

• When amplifiers are used to amplify signals

− uplink noise is increased

− receiver sensitivity threshold must be increased by same amount

(sensitivity degradation).

0( ) (10log 30)sens IFP dBm kTB NF SNR= + + +

14


Amplifier Gain and Noise LevelAmplifier Gain and Noise Level

• Noise level at the output of an amplifier is:

• If an amplifier is used in a DAS (i.e., booster amplifier), there is NO

advantage to increase amplifier UL gain above the level of the

network losses.

• Raising gain might degrade system intermodulation performance

because both received signal and input noise are amplified equally

− No improvement in output SNR.

( ) ( ) GNFkTBdBmPno +++= 30log10

BTS

DPX Loss

-1.5dB

Splitter Loss

-3.5dB

Cable Loss

-35dB DPX Loss-1.5dB

TX RX

UL Amp Gain= 41.5dB

(1.5+3.5+35+1.5)

noP

For optimum gain and noise performanceUL Amp Gain <= Network Losses


Uplink Noise SummingUplink Noise Summing

• When N amplifiers are used in parallel within a network, the noise

power from each amplifier adds together.

− System noise floor is raised by 10 log N.

• When several LNAs are placed close to antenna, improvements in

system noise figure is offset by increased noise floor.

− Attenuator is used to pad the noise before entering BTS.

• Furthermore, LNA is prone to desensitization.

RX

RX

NFA

NFA

RXNFA

BTS

Path 1

Path 2

Path 3

NFB

Noise

Noise

Noise

noP

noP

noP

15


Uplink Noise Impact on WCDMAUplink Noise Impact on WCDMA

• Interfering power introduced from noise or spurious emissions will

result in decreased sensitivity level in the WCDMA Node B.

• Total noise rise is equal to

• Pnr is the receiver noise floor

• The second term in equation is noise rise (or sensitivity degradation)

caused by external source.

• UL noise from optical amplifiers must be well below BTS receiver

noise floor.

− Noise at 11dB below BTS receiver noise floor will cause a 0.3dB

noise rise, and reduces cell area by ~4% for same capacity, or

reduces capacity for same cell radius.

[ ] [ ]int10log 1nr

PNoiseRise dB dB

P

= +


Optimum Amplifier PlacementOptimum Amplifier Placement

• Best results when amplifier is placed near to antenna.

− DL losses between amplifier and antenna is minimized

− UL NF is minimized, i.e. better sensitivity

• Trade-off between how close amplifier is placed to the antenna, and

number of amplifiers needed.

Configuration 1

Configuration 2

Splitter

Uplink

Splitter

Uplink

16



• Scenario 1: No Amplifier

− System noise figure is simply BTS NF plus cable loss

• Scenario 2: Amplifier Near the Antenna

− Uplink amplifier placed near antenna.

− Improves uplink NF from 50 to 16dB.

− Improvement is almost equal to loss

between BTS and amplifier.

System Noise Figure = 50 dB

System Noise Figure = 16.2 dB

RXNF = 10dBGain = 40dB

-5dB

BTS

NF = 5dBB

-40dB

Gain = 0dB forAmplifier + Network

RX

-45dB

BTS

NF = 5dBB

Stage 1 Stage 2 Stage 3 Stage 4

dB dB dB dB

Stage Gain -5 40 -40

Stage NF 5 10 40 5

Overall Gain -5 dB

Overall NF 16.19 dB


• Scenario 3: Amplifier Far from Antenna

− Uplink amplifier too close to BTS

− No improvement in system

noise figure

− No advantage in using UL amplifier

too close to BTS.

• Placing UL amplifier close to antenna is analogous to using TMAs in

macro-cellular system.

• Amplifier gain compensates for feeder loss and thereby increasing

performance.


System Noise Figure = 50 dB

RXNF = 10dBGain = 40dB

-40dB

BTS

NF = 5dBB

-5dB

Gain = 0dB forAmplifier + Network

Stage 1 Stage 2 Stage 3 Stage 4

dB dB dB dB

Stage Gain -40 40 -5

Stage NF 40 10 5 5

Overall Gain -5 dB

Overall NF 50 dB

17


Active Antenna SystemsActive Antenna Systems


Active Antenna SystemActive Antenna System

• Components of an Active Antenna System

− Main Hub (MHub)

− Expansion Hub (EHub)

− Remote Antenna Unit (RAU)

BTS MainHub

ExpHub

RAU

RAU

PL

PTX

PDesignGoal

RAU Coverage

Radius

18


Main Hub

SMF: up to 6 km

MMF: up to 1.5 km

Up to 4 Expansion Hubs per Main Hub

Up to 8 RAUs per Expansion Hubfor a possible total of 32 RAUs per Main Hub

RemoteAccess

Unit

Cat-5/6 ScTP:

100 m (no loss); up to 150 m

Active Antenna SystemActive Antenna System


EHub

EHub

Floor 1

EHub

RAU S/C

MHubMHub

BTS A

BTS B

BTS C

EHub

RAU S/C

A

A

Floor 2

Floor 3

Floor 4

Floor 5

Floor 6

EHub

Floor N-2

Floor N-1

Floor N

EHub

Attn

Attn

Attn

S/C

RAURAU A

Active Antenna SystemActive Antenna System -- Network ArchitectureNetwork Architecture

• Active Antenna Systems are typically implemented with a double star

architecture: MHub connected to multiple EHubs, which in are in turn

connected to multiple RAUs.

• Attenuators (Attns) are used to adjust

levels at base station (BTS) interface.

• Fiber (SMF or MMF) is used for vertical run.

• CAT-5 cabling is used for horizontal runs.

• One or more RAUs provide coverage

across a floor.

• RAU can either be split or connected

directly to the antenna.

• Generally used for mid-high capacity/

mid-high coverage area applications.

•

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Using Active Antenna SystemsUsing Active Antenna Systems

This is standard cascaded amplifier noise calculations

� This is why most 3G operators uses

tower LNA/TMA

� To increase coverage (UL limited)

� To reduce rollout costs

� To increase revenue

� This can also be used indoors

In this example, NF is improved 11.55 dB

Cascaded noise calculation (Noise Factor)

Fs = F1+ G1

F2 -1

G1 G2

F3 -1+ +........+

G1 G2 G3...... G(n-1)

Fn -1

BS

T/R Rx

Sek-1

2dBi

Passive Loss = 25dB

NF4dB

Stage 1Stage 2

P (2dB loss /

2dB gain)

Stage 1Stage 2Stage 3

Passive System

Active Antenna added


Heavy 7/8” Coax

CAT5

Non controlled mobile (on other operators cell)

� Uniform coverage

� Easy to Optimise

� Distributed Remotes

� Distributed UL LNA (Lower NF)

� Distributed DL PA (High DL PWR)

� Higher risk of desensitisation

ActivePassive

� Uneven coverage

� Adjacent I/f problems

� Hard to Optimise

� High losses

� DL Power degradation

� UL NF degradation

Performance of Active Antenna SystemsPerformance of Active Antenna Systems

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Amplifier Gain and Noise LevelAmplifier Gain and Noise Level

• Higher risks of amplifier desensitization if placed near antenna.

• Channel-selective amplifier minimizes the risk of desensitization

from un-controlled mobiles (on other operators cell)

• Trade-off between how close amplifier is placed to antenna, and

number of amplifiers needed.

• In retrofitting 2G systems, a combination of high power amplifiers

and low power active antennas may be the best option


Uplink System Limitation in UMTS Uplink System Limitation in UMTS

21


Uplink System Limitation in UMTSUplink System Limitation in UMTS

• Since all users in UMTS share the same spectrum, all uplink signals

must be received with exactly the desired level

− Any user received at higher power will cause all other users to

increase their power level.

• This is also the reason for difference in range of emitted power

available for mobiles in GSM and UMTS:

− GSM: 5 to 33dBm

− UMTS: -50 to 24dBm (Class 3)

− LTE: -40 to 23dBm (Class 3)

• In UMTS, care has been to be taken to avoid mobiles with low path

loss creating too much interference in the Node B, reducing its

capacity

− In indoor cell, mobiles emitting at -50dBm can create problems in

the cell if it is located very close to antennas and the cell has few

antennas (small DAS losses).


Uplink System Limitation in UMTS Uplink System Limitation in UMTS

• Minimum Coupling Loss

− Defines the minimum uplink loss between UE and Node B.

− 3GPP states 70 dB as lowest acceptable value on minimum

coupling loss for a macro cell.

− GSM benefits from the same value

• How do we arrive at MCL=70dB?

• Node B sensitivity can be approximated by

• For speech RAB and a load of 50%,

• Minimum Coupling Loss

( ) margin

bRAB

bBnsr I

R

W

N

ENFPdBmP +

−

++= log10)(

0

dBm 1203255103 −=+−+−=srP

( ) dB 7012050min__ =−−−=−= srUEtUL PPMCL

22


Minimum Coupling Loss (MCL)Minimum Coupling Loss (MCL)

• Minimum uplink coupling loss will dictate maximum usable antenna

EIRP, and thereby cell radius!

• Typically, for indoor systems, too much attention is put on the ”far”

performance and too little on the ”near” situation.

• If the minimum coupling loss is too low, the BTS will be affected by

very strong input signals (bad quality) and in 3G terminate calls

trough the admission control!

• 3GPP Specs:

− UE Rx input power level: max -25 dBm

− Node B Rx input power level: max -73 dBm



• Minimum coupling loss depends mainly on antenna type and

distance to the antenna.

• Path loss can be estimated by the Free Space Loss (FSL)

• Below are a few examples of FSL

Distance between

Antenna and UE

Path Loss between

Antenna to UE (approx.)

0.3 m 29 dB

1 m 39 dB

2 m 45 dB

3 m 49 dB

10 m 59 dB

30 m 69 dB

=

λ

πddBPL

4log20)(

23



• Assume 1 meter minimum distance between antenna and UE

− we will get 40 dB of worst case coupling loss.

• To provide 70 dB of total minimum path loss, we need another

30 dB of DAS losses between antenna and Node B input.

• On downlink,

− Antenna total EIRP = 43 – 30 = 13 dBm for 3G

− EIRP for pilot level (10% CPICH allocation) = 3 dBm

− Total EIRP of 13 dBm and 40 dB downlink path loss means

13-40 = -27 dBm maximum input power to UE

− 3GPP states < -25, so downlink is also OK

DAS

DAS LossPath Loss

1mNode B

UE

40 dB30 dB



• Of course, this low EIRP of 3 dBm will have an impact on maximum

cell radius and number of antennas needed to achieve the minimum

RSCP or Ec/Io requirement.

• But it will provide a very robust system that performs well and

handles the near far dynamics of indoor environments!

DAS

DAS LossPath Loss

1mNode B

UE

40 dB30 dB

24


Electromagnetic Radiation (EMR) Electromagnetic Radiation (EMR) SafetySafety


The Electromagnetic SpectrumThe Electromagnetic Spectrum

Frequency in Hz

0 102 104 106 108 1010 1012 1014 1016 1018 1020 1022

Directcurrent

Non-ionizing radiation

Visiblelight

Extremely low frequency (ELF) Very low

frequency (VLF)

Radio waves(100 kHz - 300 GHz)

Microwaves(1 GHz - 300 GHz)

Infraredradiation

Ultravioletradiation

X-rays

Gammarays

Ionizing radiation

450 - 2200 MHz

Ionizing radiation can penetratethe human body and damageinner organs and tissues bybreaking down molecules

25


• Radio signal intensity or power density is

− proportional to the transmitter’s output power;

− inversely proportional to the distance from the antenna.

• The power density is defined

simply as

• The power density at a distance

r (m) away from a point source is

Power DensityPower Density

][4

2

2mW

r

EIRPPd

π=

][ 2mW

Area

Powerr

Pd at distance raway from source

Sphere enclosinga point source



• For antennas with a directive gain , the maximum occurs

when measuring at the beam axis

• The unit for power density is

( )dBiGa

2

2

2

max

4

][4

r

GP

mWr

EIRPP

aout

d

π

×=

π=

2

2

1.0

100100

10001 1

cmmW

mW

=

×

×=

dP

22or cmmWmW

26



Example 1

• The power at the input of an antenna is 38 dBm. If the antenna gain

is 7.7 dBd, determine the maximum power density at a distance of

20m.

Solution

( ) ( )dBiGdBmPEIRP aout +=max( )15.27.738 ++=

dBm85.47=

mW1085.4710=

W 95.60=

( )2(max)204

95.6020

π=matPd mW 2 012.0=

cmmW2

0012.0=


ICNIRP MPE StandardICNIRP MPE Standard

• The most important organization to give guidance regarding EMF

exposure is the International Commission on Non-ionizing Radiation

Protection (ICNIRP).

• ICNIRP is formally recognized by the World Health Organization

(WHO) as the non-governmental organization for EMF protection.

• In 1998, ICNIRP published guidelines for maximum permissible

exposure (MPE) to electromagnetic fields in the frequency range 0

Hz to 300 GHz.

• Limits have been set with wide margins and protect all persons from

established adverse effects from short and long-term exposure.

• The ICNIRP standard is used in most European countries and is

gaining acceptance in many other countries throughout the world

outside of North America.

27



• ICNIRP standard has set 2 MPE limits:

− Public exposure (uncontrolled environment)

− Occupational exposure (controlled environment)

610

510

410

310

100

10

0.1

1.0

01.0

2mW/cm

3 10 30 100 300 3 10 30 100 300 3 10 30 100 3001 1

kHz MHz GHz

E

H

Reference LevelsTime and Whole Body Averaged

f in MHZ

= Occupational= General Public

100 / f 2

20 / f 2

2 / f f / 2000

f / 400



• From the ICNIRP graph, the levels of power density for General

Public are:

System Power Density

(mW/cm2)

Power Density

(W/m2)

GSM900 0.45 4.5

GSM1800 0.9 9.0

WCDMA2100 1.05 10.5

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Theoretical Safe DistanceTheoretical Safe Distance

• The theoretical minimum safe distance for an N-carrier transmitter

can be derived from the free space power density expression

• The ERP and EIRP are related by

• Expressing Pd in terms of ERP

24 r

EIRPNPd

π

⋅=

ERPdBERPEIRP ⋅=+= 64.115.2

222

41.0

4

64.1

4 r

ERPN

r

ERPN

r

EIRPNPd

π

⋅=

π

⋅⋅=

π

⋅=

mP

ERPNr

d

41.0

π

⋅=⇒


Practical Safe Distance for Hazard AnalysisPractical Safe Distance for Hazard Analysis

• Tests conducted by AT&T Bell Laboratories [1] reveals much lower

power density levels near the antenna.

− Near field values decrease approx. linear with distance

(~ 3dB/octave or 11dB/decade).

− Far field values decrease

inversely with the square

of distance (~ 6dB/octave

or 20dB/decade).

− Transition from near to

far field occurs at ~ 9m.

[1] Peterson, R.C. and Testagrossa, P.A., ‘Radio-Frequency Electromagnetic Fields Associated with

Cellular-Radio Cell-Site Antennas’, Bioelectromagnetics, 13, pp 527-542 (1992).

Broadband Measurements

Narrowband Measurements

16 Transmitters, 100 W ERP Each

Distance from Antenna (m)

Pow

er

Density (

W/m

)

2

0.011 10 100

0.1

1

10

slope α 1/r 4

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Practical Safe Distance for Hazard AnalysisPractical Safe Distance for Hazard Analysis

• For distances between 1 and 10m, the maximum power density can

be estimated from the empirical equation,

where

• For distances >10m, the following formula (suggested by FCC and

approved by EPA) can be used,

][64.0 2

2mW

r

ERPNPd

π

⋅=

][02.0 2

mWr

ERPNPd

⋅=

metresin Distance

dipole 2 toref.power radiated Effective

carriers ofnumber

=

=

=

r

ERP

N

λ

• FCC: Federal Communications Commission

• EPA: Environmental Protection Agency


SummarySummary

• Input Data for Design

• System Design Considerations

• Single and Multi-operator Cable System

• RF Coverage Estimation and Design Goal

• Other Coverage Considerations

• Types of Signal Source

• Antenna Placement Strategies

• Uplink Amplifier Design Considerations

• Active Antenna Systems

• Electromagnetic Radiation (EMR) Safety

03 - Indoor System Design

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Transcript of 03 - Indoor System Design