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Designing with Repeaters
RPT 9000 Repeater
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1. Introduction2. Why do we need repeaters. Why do we need repeaters3. Components of a repeater system4. Design objectives / criteria
Theory and basic concepts. Theory and basic concepts6. Deployment considerations7. Design examples8. Commissioning of a repeater
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Background THIS SHORT PRESENTATION IS A DETAILED TECHNICAL DISCUSSION ONREPEATER DESIGN. IT CONTAINS HIGH LEVEL MATHEMATICAL FORMULA FORENGINEERS AND DESIGNERSNGINEERS AND DESIGNERS.
The telecoms companies days of massive Base Station deployment are gone
Now its time to fine tune their networks and fill-in coverage holes andreduce dead cell zones and poor reception areas.
Ce u ar Repeaters can a ress some coverage issues in a cost-e ective way
This short discussion paper will cover a variety of technical considerationswhen desi nin re eaters.
Audience This discussion paper, will aid operations personnel involved with design and
deployment of RF repeaters. It will also help the layman understand thedesign needs when considering installing a cellular repeater
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2. Why Use Repeaters
Base stations
Cell Phone Base Stations, such as those ou will normall see in a cell tower willprovide cell phone Capacity ie the number of cell phones that can be used, andCoverage, ie the total area that a particular cell tower will cover.
Repeaters
Are an economical way of extending coverage to an underserved area
Extend the coverage
Have been proven a reliable means of extending coverage
Can be used to create a dominant pilot in an area of pilot pollution Telcosat RPT 9000 Repeater
Can handle numerous CDMA channels (band VS channel selective)( )
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3. Component s of a Repeater System
Signal to and from
distant Base Station
BTS
Donor Antenna
overage an enna a so ca e rea an ennaRepeater
New Service Area
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Area to cover STEP 1: define the area were coverage must be improved (create a map
based on, for example, the Received Signal Strength Indication RSSI)
STEP 2: run a prediction using Path Profile analysis tool to see if a repeatercould theoretically address the problem area. The precise Repeater sitelocation and area to cover are re uired.
STEP 3: analyze the results to qualify the candidate location based oncoverage objectives (STEP 1) and the ability of the signal transmission path
.
as required.
Distance between donor and repeater siteAssuming line of sight between both locations, here is the equation dictating
Free Space Loss:where: f = frequency (MHz)
= s ance m
Ideally, line of sight is preferred, but a repeater can sometimes be deployed inextreme conditions (obstructed path not recommended)
. 10 10
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Identify donor signalHere is a list of considerations for selecting a donor sector:a) Antennae azimuth discrimination: Adjust the donor antenna to peak in
the opposite direction from the serving antenna (ideally 180). Thisshould help achieve the required isolation
b) PN selection based on RSSI (Io) and Ec/Io. Ideally the donor signal shouldbe composed of one dominant PN (Ec/Io > -6 dB):
Ec = RSSI + Ec/Io [this value corresponds to the received Pilotpower from the donor base station and should not vary withtime exce t in extreme weather conditions
RSSI: This signal varies with traffic and will impact the Ec/Ioc) In general, site geometry dictates achievable antennae isolation, repeater
coverage area and received signal strength from the donor sector
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5. Theory and basic concepts
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5. Theory and basic concept s
High level link budgetWh t i it d f?hat is it composed of?
D Donor port (repeater)
C Coverage port (repeater)
GDLB Radio Output Power
PD Received signal (Donor port)PC Output Power (Coverage port)
Radio
PB
PCPD
= -= - =
Path Loss (donor port & BTS) Repeater Output Power Repeater DownLink Gain
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5. Theory and basic concepts
What is Path Loss?The link budget between the output port of the radio located at the serving celland the received si nal stren th at the donor ort of the re eater. Path Loss isobtained as follows:
A Antenna gain
Az Antennae Azimuth Discriminationee er oss
FSL Free Space LossOb ObstructionPL Path Loss
B
ADAz
X Combining loss
FB FDFSL
XB
b
PLDB = PD - PB
,(donor port & BTS):
PLDB = Gains - Losses _Gains = AB + AD Losses = XB + FB + Az + FSL+ Ob + FD
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5. Theory and basic concepts
Breathing of a Repeater Coverage ZoneIn CDMA, breathing is a phenomenon that can be observed on the coverage of a cell site. Arepeater is an RF device that is meant to amplify its input signal by a fixed gain. An important
. ,limit invokes AGC to ensure the repeater does not exceed its maximum output power.Different options are to be considered when setting the gain of a repeater:
Breathing implies: - AGC kicks in as soon as traffic increases (G is reduced)p- Ec power out of the repeater is reduced as traffic grows, thus
reducing effective coverage area of the repeater
- Repeater operates at maximum output power 7/24
- Downlink gain is as follows:
Where: Pc = Max. Output Power
DR = Dynamic Range = 0 dB
GDL = [PC DR] - PB - PLDB
No breathing implies: - AGC should not be invoked- Ec power out of the repeater is fixed at any time, thus coverageis not changing
- Repeater output power grows with traffic
- Downlink gain remains fixed and is as follows:
DR = Dynamic Range
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5. Theory and basic concepts
Breathing of a Repeater Coverage ZoneAt all times, the repeater is transmitting at full PA power. Addition of traffic reduces the
. ,area BREATHES:
BTS PA
power
Repeater
Power= BTS wr + S stem ain
Repeater
Gain
Repeater
coverage area
Notraffic
RemainsFix
Tx Pwr =Max. PA Pwr
(No AGC)
Tx Pwr =Max. PA Pwr
Sometraffic
sinvoked andgain reduced
Full
Tx Pwr =Max. PA Pwr
AGC isinvoked and
Pilot
Traffic
Paginggain reduced
Sync
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5. Theory and basic concept s
No Breathing of a Repeater Coverage ZoneThe repeater is able to handle addition of traffic without changing the overhead output
. ,BREATH:
BTS PA
power
Repeater
Power= BTS wr + S stem ain
Repeater
Gain
Repeater
coverage area
Notraffic
RemainsFix
Max. PA Pwr
Tx Pwr
(No AGC)
Max. PA Pwr
Sometraffic
Tx Pwr ema nsFix
(No AGC)
Pilot
Traffic
PagingFull
Tx Pwr
RemainsFix
Sync(No AGC)
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5. Theory and basic concepts
Breathing or No Breathing ?o reat ng reat ng
Repeater
PA ower Grows with trafficRepeater is operating atmaximum PA ower 7/24
Coverage areaPilot / Paging / Sync remainfixed as traffic grows.
Pilot / Paging / Sync change astraffic grows. Coverage areavaries with traffic
Repeater gain Remains fix Changes as traffic grows
Dynamic range
Sufficient PA power headroomallows for addition of traffic
with changing the coverage
No PA power headroom impliescoverage area changes with theaddition of traffic
Grade of service Somewhat guaranteed Varies with traffic
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5. Theory and basic concept s
Noise
Noise consists of undesired, usually random, variations that interfere withdesired signals and inhibit communications
Noise cannot be avoided completely but its adverse effects can bereduced by various means
Generally noise can be broken into two main categories: internal andexternal
Internal noise originates within the communications equipment
External noise has many possible sources
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5. Theory and basic concepts
Thermal Noise (NTH)
Thermal noise power is produced by the random motion of electrons and exists
in all conductors and resistors at any temperature above absolute zero (0K)
Thermal noise power is calculated using temperature and bandwidth as shown by
the equation:
PN = k T B
ere: N = no se power n wa s
k = Boltzmanns constant = 1.38 x 10-23 J/o
T = Absolute temperature in Kelvin(ambient temperature = 25C = 298K)
B = Noise bandwidth in hertz (Hz)
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5. Theory and basic concepts
Thermal Noise (NTH) - formula
Practical formula for determining bandwidth noise power is:
=
Where 174 dBm = NTH for a bandwidth of 1 Hz (at room temperature)
Using this formula we can see that a CDMA channel and an AMPS channel have
uite different bandwidth noise owers:
Technology
Channel Bandwidth
(BW)
Thermal Noise
Power (NTH)
CDMA 1.23 MHz -113.1 dBm
AMPS 30 kHz -129.2 dBm
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5. Theory and basic concepts
Thermal Noise ()
There are other relevant noise sources that are part of the design considerations
Repeater manufacturers are governed as to the maximum amount of actively
generated spurious noise the device can generate
This s urious noise is enerall caused b inter-modulation distortion IMD
Passive inter-modulation distortion is the effect that applying multiple tones to apass ve e emen e a sp er or an enna w ave
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5. Theory and basic concepts
Inter-Modulation Distortion
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5. Theory and basic concepts
Inter-Modulation Distortion and IP3
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5. Theory and basic concepts
AGCIMD, IP3 and P1dB
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5. Theory and basic concept s
Noise contribution
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5. Theory and basic concept s
-45 dBc (30 kHz)
-45 dBc (30 kHz)
or
1
2
IS-2000 spectral mask
-9 dBm (30 kHz)
-55 dBc (30 kHz)P
out 33dBm
or
2
1
2
1
1.23 MHz
-22 dBm (30 kHz)
28 dBm Pout
< 33 dBm
or
-50 dBc (30 kHz)P
out< 28 dBm
3
4
3 3
4
-13 dBm (1 MHz)
-13 dBm (1 kHz)9 kHz < f < 150 kHz
4
-13 dBm (10 kHz)
150 kHz < f < 30 MHz
-13 dBm (100 kHz)
30 MHz < f < 1 GHz
5
f (MHz)
-13 dBm (1 MHz)1 GHz < f < 5 GHz
fc
0.8
85
1.2
50
1.9
80
2.2
50
0.8
85
1.2
50
1.9
80
2.2
50
4.0
00
4.0
00
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5. Theory and basic concepts
Calculating Noise contributions from multiple sources
Adding power values can be done in Watts (or mW) only
Therefore, to calculate the summed amplitude of unequal noise contributors wemust convert dBm values in mW for each contributor
P[mW] = 10(P[dBm]/10)
Next add all of the values together in mW:
PN-Tot [mW] = Ni[mW] Return this Total Noise value in dBm:
=- o m - o m
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5. Theory and basic concepts
Desensitization
,
signals
Desensitization can be caused b man factors from s urious noise within the receiver to
interfering signals
To understand the effect that desensitization will have on our system we should know
what our initial or benchmark sensitivity is
Transceiver manufacturers generally state the sensitivity of their radio equipment
Sensitivity specifications usually state the smallest signal amplitude that could be
demodulated as received at the input of the receiver
Any signal received from just below the sensitivity of the receiver to many times the
amplitude of the initial sensitivity will affect the sensitivity of the receiver
Usually in-band signals are the concern but strong out-of-band signals can reduce the
receivers sensitivity as well
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5. Theory and basic concept s
Desensitization ()
traffic within the coverage zone designed for the BTS
If the Re eater is causin desensitization at the BTS then the re eater could have a better
sensitivity than the BTS
The amount of BTS desensitization that a Repeater will contribute can be minimized
through design methodology
There is a direct relationship between Repeater sensitivity and BTS sensitivity
Repeaters, if engineered and configured properly, should not be major contributors to
desensitization
Repeaters, if not engineered and configured properly, can cause a great deal of BTS
desensitization and shrink the effective coverage zone of the BTS considerably
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5. Theory and basic concepts
Desensitization()
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5. Theory and basic concepts
Base Station Sensitivity Before a Repeater
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5. Theory and basic concepts
An Engineered Repeater Site
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5. Theory and basic concepts
BTS Sensitivity is Degraded
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5. Theory and basic concepts
Repeater Sensitivity is Reduced
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6. Deployment considerat ions
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6. Deployment considerat ions
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6. Deployment considerat ions
Isolation
For CDMA 15 dB Isolation Margin Recommended
For AMPS 12 dB Isolation Margin Recommended
Isolation Required = GDL + Isolation margin
TechnologyRecommended
Isolation margin
CDMA 15 dB
AMPS 12 dB
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6. Deployment considerat ions
How can antenna isolation be achieved?
Use Narrow Beam Antennas
Install Antennas 180 degrees apart
Use the Antenna nulls to assist in maximizing Isolation.
Polarization (donor and Repeater site) Main beam
Always measure the Isolation / never assume isolation is adequate
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6 D l t id t i
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6. Deployment considerat ions
Free Space Loss32.4 + 20 log (d [km]) + 20 log (f [MHz])
90.0
Free Space Loss32.4 + 20 log ( d [km]) + 20 log (f [MHz])
130.0
80.0
85.0 125.0
75.0
L
o
ss
(d
B
)
115.0
.
o
ss
(d
B
)
65.0
.
F
ree
S
pa
ce
105.0
110.0
ree
S
p
ac
e
L
55.0
60.0
95.0
100.0F
50.0
10 30 50 70 90 110
130
150
170
190
Cellular
90.0
1 3 5 7 911 13 15 17 19
Cellular
Distance (m )PCS
PCS
6 D l t id t i
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6. Deployment considerat ions
Beginning of oscillation caused by
lack of antenna isolation
(signal integrity is altered)
Proper Isolation is achieved
(signal integrity is maintained)
6 Deployment considerat ions
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6. Deployment considerat ions
Keep in mind
Negative Link Gain is required between the Repeater and the BTS
Always check the affect the Repeater Install has on the BTS
Sensitivity can be transferred to the Repeater and that means from the BTS
Calculate the actual Path Loss between the Repeater and the BTS
Determine if you require an Attenuator
Test Your Results
6 Deployment considerat ions
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6. Deployment considerat ions
Typical C/I per technology
6 Deployment considerat ions
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6. Deployment considerat ions
Propagation delay
,
Those signals encounter delay traveling toward the mobile and through a Repeater there is
additional dela due to the shar filterin characteristics of the Re eater
Propagation delay through free space is approx. 4.1 chips per kilometer
The propagation delay of the repeater is approximately 7 chips
These additional delays must be accounted for in the Search Window settings
Possible adjustments may be required for
SRCH_WIN_A
SRCH WIN N_ _SRCH_WIN_R
6 Deployment considerat ions
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6. Deployment considerat ions
Propagation delay (formula)
6 Deployment considerat ions
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6. Deployment considerat ions
Propagation delay (rules of thumb)
delay including the delay through the Repeater (not too wide as that would slow down the
mobile overall pilot searching speed)
Set the Remaining list search window one or two steps above the Neighbor list search
window setting
Set the Active list search window according to measured results from your drive test
1 chip = 0.814 s
n -> . cps
c = d / t c = 3 x 108 m/s
= .= .
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PCS repeaterempirical example
PCS example
Type Monopole Type Roof top
Band PCS Band PCS
# channel 1 # channel 1
Distance 3.2 km Donor Ant. Gain 17.0 dBiSector Beta Donor Feeder Loss -2 dB
PN 204
RSSI -61 dBm
Ec 31.26 dBm Ec/Io (PN = 44) -12 dB
FRM output power
Mobile readings at repeater site
Design assumptions:1. Repeater should operate without coverage breathing; thus Dynamic Range will
Full traffic 41.34 dBm Ec/Io (PN = 108) -11 dB
Dynamic Range 10.08 dB Ec/Io (PN = 204) -8 dBEc/Io (PN = 320) -10 dB
Selected donor Line of sight with PN 204an e a t on o tra c: = etween p ot on y to u tra c
2. Area to cover is suffering from pilot pollution (6 PNs with Ec/Io ~ -13 dB,
RSSI ~ -90dBm): We need to bring one dominant PN (Ec/Io > -6 dB, RSSI > -
3. Our repeater donor antenna has a gain AD = +17 dBi and a feeder loss of FD= 2 dB.
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PCS repeater example Path Loss calculations RSSI varies with traffic
Pilot Power (Ec) is fixed at all times
Lets base our calculation on constant power (i.e. Ec (PN 204))
Ec (PN 204) = RSSI + Ec/Io (PN 204)
= -61 + -8Ec (PN 204) = - 69 dBm = PM = Pilot 204 signal strength at the mobile
(from the repeater location)
The Path Loss between the donor site and the mobile is as follows:
PLMB = PM - PB= -69 - 31.26100 3 dB 100 dB-100.3 dB ~ - 100 dB
Now, lets try to obtain the Path Loss between the donor site and at the donor port of therepeater (going through the donor antenna system):
PLDB = PD - PB= [PM + AD FD] - PB= [-69 + 17 2] - 31.26= -85.3 dB ~ -85 dB
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PCS repeater example Downlink Gain Downlink Gain of the repeater should be set as follows:
=GDL
Rqd
Ant. PC (PILOT)PC (FULL
TRAFFIC)
Repeater Output Power
Down Link
Thus:
GDL = PC - PD - DR
.
90 dB 105 dB 36.0 dBm 46.0 dBm
89 dB 104 dB 35.0 dBm 45.0 dBm
88 dB 103 dB 34.0 dBm 44.0 dBm
Repeater selection Based on our coverage objectives, lets assume a
Standard Power repeater (AR-3400) is adequate.Therefore:
87 dB 102 dB 33.0 dBm 43.0 dBm
86 dB 101 dB 32.0 dBm 42.0 dBm
85 dB 100 dB 31.0 dBm 41.0 dBm
84 dB 99 dB 30.0 dBm 40.0 dBm
83 dB 98 dB 29.0 dBm 39.0 dBm
DL =
PC = Repeater Average Output Power for the numberof carriers you design your system with (+33dBm for 1 channel, +28 dBm / channel for 2channels with and AR-3400)
82 dB 97 dB 28.0 dBm 38.0 dBm
81 dB 96 dB 27.0 dBm 37.0 dBm80 dB 95 dB 26.0 dBm 36.0 dBm
79 dB 94 dB 25.0 dBm 35.0 dBm
78 dB 93 dB 24.0 dBm 34.0 dBm
77 dB 92 dB 23.0 dBm 33.0 dBm
PC (PILOT) = +23 dBm
As traffic increases on the system, Pc (FULL TRAFFIC) willreach +33 dBm = Maximum output power of therepeater.
76 dB 91 dB 22.0 dBm 32.0 dBm
75 dB 90 dB 21.0 dBm 31.0 dBm
74 dB 89 dB 20.0 dBm 30.0 dBm
73 dB 88 dB 19.0 dBm 29.0 dBm
72 dB 87 dB 18.0 dBm 28.0 dBm
71 dB 86 dB 17.0 dBm 27.0 dBm
70 dB 85 dB 16.0 dBm 26.0 dBm
Next step Now we need to set the GUL and ensure our repeater does
not desensitize the BTS
69 dB 84 dB 15.0 dBm 25.0 dBm
68 dB 83 dB 14.0 dBm 24.0 dBm
67 dB 82 dB 13.0 dBm 23.0 dBm
66 dB 81 dB 12.0 dBm 22.0 dBm
65 dB 80 dB 11.0 dBm 21.0 dBm
64 dB 79 dB 10.0 dBm 20.0 dBm
63 dB 78 dB 9.0 dBm 19.0 dBm
62 dB 77 dB 8.0 dBm 18.0 dBm
61 dB 76 dB 7.0 dBm 17.0 dBm
60 dB 75 dB 6.0 dBm 16.0 dBm
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PCS repeater example Uplink Gain Uplink Gain of the repeater should be set to
minimize Noise Contribution from the GUL dBm mW mW dBmBTS
Desens.
NIN(from repeater) N (total)
p n
NIN (rep) = NTH + NF + GUL PLDB
90 dB -103.4 4.6E-11 5.1E-11 -102.9 -10.2 dB
89 dB -104.4 3.7E-11 4.2E-11 -103.8 -9.3 dB
88 dB -105.4 2.9E-11 3.4E-11 -104.7 -8.4 dB
Thus:GUL = NIN (rep) - NTH - NF + PLDB
87 dB -106.4 2.3E-11 2.8E-11 -105.5 -7.6 dB
86 dB -107.4 1.8E-11 2.3E-11 -106.3 -6.8 dB
85 dB -108.4 1.5E-11 1.9E-11 -107.1 -6.0 dB
84 dB -109.4 1.2E-11 1.6E-11 -107.8 -5.3 dB
83 dB -110.4 9.2E-12 1.4E-11 -108.5 -4.6 dB.
Noise contribution from the repeater must bekept to a minimum to optimize BTS sensitivity.The art of controlling injected noise from arepeater is tied into the success of your
82 dB -111.4 7.3E-12 1.2E-11 -109.1 -4.0 dB
81 dB -112.4 5.8E-12 1.1E-11 -109.7 -3.4 dB80 dB -113.4 4.6E-12 9.5E-12 -110.2 -2.9 dB
79 dB -114.4 3.7E-12 8.6E-12 -110.7 -2.4 dB
78 dB -115.4 2.9E-12 7.8E-12 -111.1 -2.0 dB
77 dB -116.4 2.3E-12 7.2E-12 -111.4 -1.7 dB
repeater deployment.
Total Noise at the BTS is obtained as follows:
N = N + N (adding power is in W)
76 dB -117.4 1.8E-12 6.7E-12 -111.7 -1.4 dB
75 dB -118.4 1.5E-12 6.4E-12 -112.0 -1.1 dB
74 dB -119.4 1.2E-12 6.1E-12 -112.2 -0.9 dB
73 dB -120.4 9.2E-13 5.8E-12 -112.4 -0.7 dB
72 dB -121.4 7.3E-13 5.6E-12 -112.5 -0.6 dB
71 dB -122.4 5.8E-13 5.5E-12 -112.6 -0.5 dB
70 dB -123.4 4.6E-13 5.4E-12 -112.7 -0.4 dB
BTS desensitization is:Desensitization = NTOT - NTH (dB)
69 dB -124.4 3.7E-13 5.3E-12 -112.8 -0.3 dB
68 dB -125.4 2.9E-13 5.2E-12 -112.9 -0.3 dB
67 dB -126.4 2.3E-13 5.1E-12 -112.9 -0.2 dB
66 dB -127.4 1.8E-13 5.1E-12 -112.9 -0.2 dB
65 dB -128.4 1.5E-13 5.0E-12 -113.0 -0.1 dB
64 dB -129.4 1.2E-13 5.0E-12 -113.0 -0.1 dB
63 dB -130.4 9.2E-14 5.0E-12 -113.0 -0.1 dB
62 dB -131.4 7.3E-14 5.0E-12 -113.0 -0.1 dB
61 dB -132.4 5.8E-14 5.0E-12 -113.0 -0.1 dB
60 dB -133.4 4.6E-14 4.9E-12 -113.1 0.0 dB
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PCS repeater example Uplink Gain Typically, we should aim for: GUL dBm mW mW dBm
BTS
Desens.
NIN(from repeater) N (total)
p n
Desensitization < 1 B w ic correspon s to:NIN (rep) < -119 dBm
In this example, the noise contribution of the
90 dB -103.4 4.6E-11 5.1E-11 -102.9 -10.2 dB
89 dB -104.4 3.7E-11 4.2E-11 -103.8 -9.3 dB
88 dB -105.4 2.9E-11 3.4E-11 -104.7 -8.4 dB
repeater will affect the sensitivity of the basestation by 1 dB. Thus reducing the Reverse Linkcoverage by 1 dB
87 dB -106.4 2.3E-11 2.8E-11 -105.5 -7.6 dB
86 dB -107.4 1.8E-11 2.3E-11 -106.3 -6.8 dB
85 dB -108.4 1.5E-11 1.9E-11 -107.1 -6.0 dB
84 dB -109.4 1.2E-11 1.6E-11 -107.8 -5.3 dB
83 dB -110.4 9.2E-12 1.4E-11 -108.5 -4.6 dB
n ur an env ronments, t e ase tat on stypically Down-Link limited
In rural environments, the Base Station is
82 dB -111.4 7.3E-12 1.2E-11 -109.1 -4.0 dB
81 dB -112.4 5.8E-12 1.1E-11 -109.7 -3.4 dB80 dB -113.4 4.6E-12 9.5E-12 -110.2 -2.9 dB
79 dB -114.4 3.7E-12 8.6E-12 -110.7 -2.4 dB
78 dB -115.4 2.9E-12 7.8E-12 -111.1 -2.0 dB
77 dB -116.4 2.3E-12 7.2E-12 -111.4 -1.7 dB-
Desensitization will be observed to a greaterscale
76 dB -117.4 1.8E-12 6.7E-12 -111.7 -1.4 dB
75 dB -118.4 1.5E-12 6.4E-12 -112.0 -1.1 dB
74 dB -119.4 1.2E-12 6.1E-12 -112.2 -0.9 dB
73 dB -120.4 9.2E-13 5.8E-12 -112.4 -0.7 dB
72 dB -121.4 7.3E-13 5.6E-12 -112.5 -0.6 dB
71 dB -122.4 5.8E-13 5.5E-12 -112.6 -0.5 dB
70 dB -123.4 4.6E-13 5.4E-12 -112.7 -0.4 dB
It is the role of any repeater system designer toevaluate how much noise can the Base Stationtolerate from the repeater without adverselyaffecting its sensitivity
69 dB -124.4 3.7E-13 5.3E-12 -112.8 -0.3 dB
68 dB -125.4 2.9E-13 5.2E-12 -112.9 -0.3 dB
67 dB -126.4 2.3E-13 5.1E-12 -112.9 -0.2 dB
66 dB -127.4 1.8E-13 5.1E-12 -112.9 -0.2 dB
65 dB -128.4 1.5E-13 5.0E-12 -113.0 -0.1 dB
64 dB -129.4 1.2E-13 5.0E-12 -113.0 -0.1 dB
63 dB -130.4 9.2E-14 5.0E-12 -113.0 -0.1 dB
62 dB -131.4 7.3E-14 5.0E-12 -113.0 -0.1 dB
61 dB -132.4 5.8E-14 5.0E-12 -113.0 -0.1 dB
60 dB -133.4 4.6E-14 4.9E-12 -113.1 0.0 dB
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8. Repeater Conf igurat ion
a repeater
provides the basis for the settings that we will applyto the repeater
There are a number of tools available in therepeater to assist us in the configuration process
Remember to test your results after configuring a
re eater to ensure that our new covera e area aswell as the existing macro area are optimized toprovide the best possible result
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8. Repeater Conf igurat ion
Repeater Variants
Gain
A
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p g
Channel Selective Repeaters
Channel Selective repeaters are configured on a per
channel basis for uplink and downlink gain
Channel selective repeaters automatically tune to thechannel frequency and bandwidth
Channel selective repeaters offer RSSI based on theenergy seen at the input of the repeater relevant to that
Channel selective repeaters have a wider gain setting
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Band Selective Repeaters
Band Selective repeaters have a settable bandwidthinstead of a channel number input and as manychannels as you have can pass through it
Band Selective repeaters dont offer an RSSI becausethere could be many signals input into the repeater
Band selective repeaters have a lower gain settablerange for the lowest achievable noise figure
en ocate near a , a an se ect ve repeaterrequires some extra consideration in the uplink
the same successful results as a Channel Selectiveinstallation
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Calculate the actual path loss between the BTS site and the repeater site.
To do this simply, you must know the power level being transmitted from the BTS.the donor antenna connector where it attaches to the repeater. Please refer to thediagram. Take the power level transmitted from the BTS and subtract the powerreceived at the Repeater site through the donor antenna and you have the actual path
. .always vary.
Example: Pilot power from BTS radio is +31.26 dBm. c o
= -8 dB
Equation: Path Loss = BTS TX Power (Pilot power only)- R I (at the Repeater donor antenna) + Ec/Io (donor sector)
For this example: Path Loss = +31.26 [ -55 -8 ] = 94.26 dB
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[Step 2] Set your Uplink gain according to your path loss.
ou mus ave a nega ve n ga n e ween erepeater and the BTS to enable the noise powerof the repeater to arrive at the BTS somewherearoun t e sensitivity o t e BTS wit out t erepeater. The rule of thumb here is to have a 10dB ne ative link ain. Take the actual ath lossas calculated in step one and subtract 10 dB toestablish your uplink gain setting. In the
would be 84 dB.
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power from the repeater site at the base stationreceiver or call your Network and ask for the MTX
off and then with the repeater on. The noise valuesshould remain the same or have very little variance.
contribution in noise power received from therepeater attenuate the uplink of the repeater
attenuation to the uplink path.
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XPANDAcell - www.xpandacell.com Toll Free: 1-888-785-7393 - Int'l: 1-951-694-1173 [email protected]
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