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Huawei Technologies Co., Ltd. Huawei Confidential
Coverage and Capacity
of GSM System
GSM&UMTS Pre-sales RNP Department
Page 2Huawei Technologies Co., Ltd.
The planning for the radio network mainly involves
coverage and capacity. The coverage planning
involves radio propagation and hardware model.
The capacity planning involves channel
configuration and location area planning. This
course describes the preceding contents.
Foreword
Page 3Huawei Technologies Co., Ltd.
Cell Radius
No. of BTS TRX
Configuration
Subs. per BTS
Abis Configuration
…
Inputs
Coverage Related
-Coverage Region
- Area Type Information
-Propagation Condition
-Location Probability
Capacity Related
-Spectrum Available
-Subscriber Growth Forecast
-Traffic Density
-Blocking Probability
BTS Quantity
Capacity Requirement
Configuration
per BTS
Outputs
Overview
C3Q
� Coverage, Capacity, Quality & Cost
GSM Dimensioning Flow
Capacity
Quality Coverage
COST
Page 4Huawei Technologies Co., Ltd.
Capacity DimensioningCapacity Dimensioning
Coverage DimensioningCoverage Dimensioning
• Max Path Loss
• Propagation Model
• Coverage Dimensioning
Page 5Huawei Technologies Co., Ltd.
Link Budget
Cell radius
EIRP
Receive Sensitivity
Max. Path Loss
Propagation Model
Cell Radius
Page 6Huawei Technologies Co., Ltd.
Max Path Loss
MS Transmit Power
MS Antenna Gain
BTS Antenna Diversity Gain
Slow fading margin
Interference margin
Body Loss
Feeder Loss
Penetration Loss
Maximumallowable path
loss
UPLINK BUDGET
BTS Rx sensitivity
Gain
Margin
Loss
TMA Gain (optional)
BTS Antenna Gain
Path Loss
BTS
Sensitivity
MS Transmit power
Uplink Budget
Page 7Huawei Technologies Co., Ltd.
Max Path Loss
BTS Transmit Power
MS Antenna Gain
BTS Antenna Gain Slow fading margin
Interference margin
Body Loss
Feeder Loss
Penetration Loss
Maximum
allowable pathloss
DOWNLINK BUDGET
MS Rx sensitivity
Gain
Margin
Loss
Combiner Loss
TMA Insertion Loss (optional)
Path Loss
BTS
Transmit power
MS Sensitivity
Downlink Budget
Page 8Huawei Technologies Co., Ltd.
Max Path Loss
Path Loss - Loss between BTS antenna and MS antenna
Max. allowable P-loss
MS Rx sensitivity
BTS Rx sensitivity
Body loss
Slow fading margin
Penetration loss
TMA gain
Name
JCBTS antenna gain
KDMS antenna gain
LEBTS antenna div. gain
MFBTS combiner loss
NGBTS Feeder loss
IBMS Tx Power
HABTS Tx Power
ItemItemName
Uplink:
B + D – K – I – J – N + E + C (+ H) – G = L
Uplink:
B + D – K – I – J – N + E + C (+ H) – G = LDownlink:
A – F – G + C – N – I – J – K = M
Downlink:
A – F – G + C – N – I – J – K = M
Page 9Huawei Technologies Co., Ltd.
MS/BTS Tx Power & Rx Sensitivity
MS
� Typical Tx Power: 2w (33dBm)@900MHz; 1w(30dBm)@1800MHz
� Typical Rx Sensitivity: -102dBm (for planning)
BTS
Max Path Loss
http://3ms.huawei.com/mm/docMaintain/mmMaintain.do?m
ethod=showMMDetail&f_id=GSM200810200035
45W(GMSK)/30W(8PSK)60W(GMSK)/40W(8PSK)Transmitter power
-113dBm-112.5dBmReceive Sensitivity
BTS3900(DRFU 900M)BTS3012(DTRU 900M)
Page 10Huawei Technologies Co., Ltd.
Max Path Loss
Combiner Loss
TOC Output Power =
Transmitter Output Power – Combiner Loss – Duplexer Loss – Connector Loss
DPX
RXDI
DPX
RXDI
TR
X1
TR
X2
CO
M
ANTA ANTB
DPX
RXDI
DPX
RXDI
TR
X1
TR
X2
CO
M
TR
X3
TR
X4
CO
M
ANTA ANTB
BTS3012
Output 47.8dBm@900M
DCOM 3.3dBm@900M
DDPU 0.8dBm@900M
Connector 0.2dBm
Page 11Huawei Technologies Co., Ltd.
Max Path Loss
Feeder Loss in Link Budget includes:
--- Feeder loss b/w BTS and antenna
--- Jumper Loss b/w BTS and antenna
--- Connectors loss b/w BTS and antenna
Feeder Loss
4.31dB/100m5.87dB/100m16.1dB/100m1800M
2.98dB/100m4.03dB/100m11.2dB/100m900M
5/4 inch7/8 inch1/2 inch
lightening arrester
Jumper between
Antenna
TTA
Antenna stand
Jumper between antenna and TTA
Jumper between TTA and feeder
Feeder
Lightening arrester
and cabinet
Page 12Huawei Technologies Co., Ltd.
Max Path Loss
� Typical gain:
� Omni: 11dB
� Directional: 18 dB
� In-building: 2dB
Antenna Gain
� Receive diversity gain:
� 2 way receive diversity: 3dB
� 4 way receive diversity: 6dB
Page 13Huawei Technologies Co., Ltd.
Max Path Loss
Technical Theory of TMA
� TMA is to reduce the noise figure of BTS, so as to improve the
sensitivity of BTS.
TMA Affect link budget
� Improve uplink
� Generally, the TMA gain can be calculated as to against feeder loss
between BTS and TMA.
� Worsen downlink
� Introduce insertion loss (0.5~1
dB) to downlink
Affect the Stability of network
TMA
Page 14Huawei Technologies Co., Ltd.
Slow fading (long term fading)
Fast fading (short term fading)
� Caused by multi-path propagation
� Fast fading margin: 3dB
Max Path LossFading Margin
Page 15Huawei Technologies Co., Ltd.
Max Path Loss
Slow Fading
� Signal levels obey Log-Normal distribution
Slow Fading Margin depends on:
� Area Coverage Probability
– The higher coverage probability is, the more SFM required
� Standard Deviation
– The higher standard deviation is, the more SFM required
Received Signal Level [dBm]
Pro
ba
bili
ty D
en
sity
Fmedian (x)Fthreshold
Coverage Probability:
P COVERAGE (x) = P [ F(x) > Fthreshold ]
Coverage Probability:
P COVERAGE (x) = P [ F(x) > Fthreshold ]σσσσ
SFM required
Fading Margin
Page 16Huawei Technologies Co., Ltd.
Max Path Loss
Building Penetration Loss
� Relate to frequency and building character
� Frequency ↑ � Penetration loss ↑
� Wall: 5~30 dB (concrete / brick / wood / …)
� Glass / Car: 6~10 dB
� Elevator: ~30dB
� ……
X dBmW dBm
Penetration Loss=X - WPenetration Loss=X - W
888Highway
10~1814~2016~23Urban
8~1410~1611~19Suburban
2~3Body loss
6~1288Rural
14~2218~2518~28Dense urban
450 MHz800/900
MHz1.8/1.9/2.1
GHzScenario
Frequency
� Typical penetration loss value (dB)
E1
θ
θ
DW1 W2
E2Penetration Loss & Body Loss
Page 17Huawei Technologies Co., Ltd.
Max Path Loss
Path Loss
Max. allowable P-loss
MS Rx sensitivity
BTS Rx sensitivity
Body loss
Slow fading margin
Penetration loss
TMA gain
Name
JCBTS antenna gain
KDMS antenna gain
LEBTS antenna div. gain
MFBTS combiner loss
NGBTS Feeder loss
IBMS Tx Power
HABTS Tx Power
ItemItemName
Uplink:
B + D – K – I – J – N + E + C (+ H) – G = L
Uplink:
B + D – K – I – J – N + E + C (+ H) – G = LDownlink:
A – F – G + C – N – I – J – K = M
Downlink:
A – F – G + C – N – I – J – K = M
� EiRP: Equivalent isotropic Radiation Power
� (BTS) EiRP = A – F – G + C
� (MS) EiRP = B + D
Page 18Huawei Technologies Co., Ltd.
Capacity DimensioningCapacity Dimensioning
Coverage DimensioningCoverage Dimensioning
• Max Path Loss
• Propagation Model
• Coverage Dimensioning
Page 19Huawei Technologies Co., Ltd.
Propagation Model
� Tradition model is an empirical mathematical formulation
� describe radio wave propagation as a function of frequency, distance,
antenna height and other conditions.
– Path Loss = f (frequency, distance, antenna height, etc.)
� The model is usually used to predict the behavior of propagation
for all similar links under similar constraints.
� Predict the path loss along a link or effective coverage area of a transmitter.
What is Propagation Model
Page 20Huawei Technologies Co., Ltd.
Propagation Model
� Okumura/Hata
� Frequency: 150~1500 MHz
� Distance: 1~20 Km
� Tx antenna height: 30~200m
Lp = 69.55 + 26.16*lg(f) − 13.82*lg(Hb) + [44.9 − 6.55*lg(Hb)]*lg(d) − a(Hm) − Cm
• a(Hm) = [1.1*lg(f) – 0.7]*Hm – [1.56*lg(f) – 0.8] (for city)
• Cm = 0 (for urban area)
= 2*[lg(f/28)]2 + 5.4 (for suburban area)
= 4.78*[lg(f)]2 – 18.33*lg(f) + 40.94 (for open area)
Lp = 69.55 + 26.16*lg(f) − 13.82*lg(Hb) + [44.9 − 6.55*lg(Hb)]*lg(d) − a(Hm) − Cm
• a(Hm) = [1.1*lg(f) – 0.7]*Hm – [1.56*lg(f) – 0.8] (for city)
• Cm = 0 (for urban area)
= 2*[lg(f/28)]2 + 5.4 (for suburban area)
= 4.78*[lg(f)]2 – 18.33*lg(f) + 40.94 (for open area)
� Cost231/Hata
� Frequency: 1500~2000 MHz
� Distance: 1~20 Km
� Tx antenna height: 30~200m
Common Models
Page 21Huawei Technologies Co., Ltd.
Propagation Model
� U-Net SPM model
� Based on Hata model
� Suitable for more macro cell scenarios
� Be used to do coverage prediction and simulation by software
Lp = K1 + K2 * lg(d) + K3 * lg(Hb) + K4 * Diffraction_loss + K5 * lg(d) * lg(Hb)
+ K6 * Hm + Kclutter * f(clutter)
• K1, constant, relate to frequency
• K2, distance factor, show the speed of signal fading along with distance
• K3, affect the relation between path-loss and transmitter antenna height
• Diffraction_loss, according to the selected diffraction algorithm
• f(clutter), avg. clutter loss according to the digital map
Lp = K1 + K2 * lg(d) + K3 * lg(Hb) + K4 * Diffraction_loss + K5 * lg(d) * lg(Hb)
+ K6 * Hm + Kclutter * f(clutter)
• K1, constant, relate to frequency
• K2, distance factor, show the speed of signal fading along with distance
• K3, affect the relation between path-loss and transmitter antenna height
• Diffraction_loss, according to the selected diffraction algorithm
• f(clutter), avg. clutter loss according to the digital map
Typical Propagation Models
Page 22Huawei Technologies Co., Ltd.
Propagation Model
Why
� Propagation environment is very complicated
� No universal model
� It’s necessary to calibrate the model based on the on-site test
How
� On-siteTest
� CW (Continuous Wave) test
– Accurate but high cost (money and workload)
� Existing telecommunication network DT
� Calibrate the model by software (U-Net)
Model Tuning
Page 23Huawei Technologies Co., Ltd.
Capacity DimensioningCapacity Dimensioning
Coverage DimensioningCoverage Dimensioning
• Max Path Loss
• Propagation Model
• Coverage Dimensioning
Page 24Huawei Technologies Co., Ltd.
Coverage Dimensioning
� Path Loss = f (frequency, distance, BTS antenna height)
� Allowable max. path loss, calculated through link budget
� Frequency, confirmed
� BTS antenna height, designed according to:
� Distance, i.e. cell radius, can be figured out
Cell Radius
UL/DL Balance
� Balance or Not?
� Cell radius? UL or DL?
UL DL
Difference:
• BTS/MS Tx power
• Tx Combiner loss
• BTS/MS Rx
sensitivity
• Rx diversity gain
• UL/DL Frequency
• TMA gain
Page 25Huawei Technologies Co., Ltd.
Coverage area of single site
Distance between 2 sites
� Normal site: D = 1.5 * R
� Highway site: D = 2 * R
Coverage Dimensioning
RR
23
8
9RArea =
23
2
3RArea =
• 3-cell site with 65-degree H-BW antenna
• Omni site• 3-cell site with 90-
degree H-BW antenna
D
R
Coverage Area of Single Site
Page 26Huawei Technologies Co., Ltd.
Coverage Dimensioning
Coverage Requirement
� Total coverage area: XXX Km2
� Divided into several scenarios
� CBD, Dense urban, Urban, Suburban, Rural, Highway, etc.
� Area of each scenario
BTS Quantity Dimensioning
� Except for highway:
� Highway:
∑=Site Singleof AreaCoverage
Scenario Eachof AreaTotalQuantity BTS
∑=Site Singleof Radius Cell * 2
Highwayof Length TotalQuantity BTS
BTS Quantity Dimensioning
Page 27Huawei Technologies Co., Ltd.
Coverage Dimensioning
Shortcoming of Dimensioning
� Too simple, based on the theoretic calculation only
� Lack of consideration of actual situation
� Scrambling of coverage area
� Unnecessary area
� Possibility of sites acquisition
� ……
How to improvement
� Field survey
� Terrain, scenario division, buildings, population, existing networks, …
� Lay out BTS depends on both dimensioning and map
� Digital map, GoogleEarth, traditional map, photographs, …
BTS Layout
Page 28Huawei Technologies Co., Ltd.
Capacity DimensioningCapacity Dimensioning
Coverage DimensioningCoverage Dimensioning
• Max Path Loss
• Propagation Model
• Coverage Dimensioning
Page 29Huawei Technologies Co., Ltd.
Capacity Dimensioning
Capacity Planning Process
Coverage area per Site
Traffic model
Distribution of Subscribers
Traffic Load per Site
TRX/Channel/…Configuration
Limitation Judgment
Figure out the max. configuration
Frequency Planning
END
Coverage
limitation
BTS Quantity
Capacity
limitation
Coverage Dimensioning
GoS
Erlang-B
Page 30Huawei Technologies Co., Ltd.
Capacity Dimensioning
Traffic Model
Traffic refers to the usage of channels and is usually thought as the holding time per time unit for
one or several circuits.
Erlang
Erlang (E) is the unit of measurement for traffic intensity.
Measure of Traffic: 1 Erlang = 1 Call with duration 1 Hour
A = n x T / 3600 Erlang
where,
A = offered traffic from one or more users in the system
n = number of calls per hour
T = average call time in seconds
Key Factor: Traffic Model
Page 31Huawei Technologies Co., Ltd.
Capacity Dimensioning
GoS (Grade of Service)
It is the probability of a call in a circuit group being blocked or delayed for more than a specified
interval.
For a Lost Call system, the GoS can be measured using such equation:
calls offeredof Number
callslost of NumberServiceof Grade =
Key Factor: GoS
Page 32Huawei Technologies Co., Ltd.
Capacity Dimensioning
Key Factor: Erlang-B
Page 33Huawei Technologies Co., Ltd.
Capacity Dimensioning
How many 3 sectored sites needed for Area X if
Traffic per subscriber = 25mE
Number of Subscribers = 10,000
Max Configuration of BTS is S222
GoS = 2%
Answer:
Traffic channels per Cell = 2 x 8 –1 (Control Channels) = 15 TCH
Traffic per cell = 15 TCH with 2% GoS = 9.01Erlangs (from Erlang’s B Table)
The number of subscribers per cell = 9.01 E / 25 mE = 328
No of cells needed = 10,000 / 328 = 28 cells
No of 3 sector sites needed = 10
Example
Thank youwww.huawei.com
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