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Transcript of GSM Radio Network Planning_LEGEND
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Introduction
RF people work in eitherRF people work in either
ResponsibilitiesResponsibilities
Nominal Plan Design
Sites Survey
Validation from field
Set RF design (Structure, Azimuth,
Height, Tilt, Cables type)
Fre uenc Plan
ResponsibilitiesResponsibilities
Maintain the Networks Accessibility KPIs
Maintain the Networks Retain ability KPIs
Maintain the Networks Service Integrity KPIs
Study and Apply new features
Try to think of innovative solutions to
maximize the Network ca acit
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Sites Acceptance
They have to provide the coverage eitheroutdoor or indoor.
They have to maintain the performance ofthe Network as good as possible.
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Course OutlinesCourse Outlines
Planning Process and Procedures.
mens on ng rocess.
Site Tuning.
Technical Site Survey.
Neighbors and Frequency Planning.
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GSM System Survey Revision
GSMGSM stands for Global System for Mobile Communication
.
Digital System.
Efficient Use of the Spectrum.
Speech privacy and security.
Better resistance to interference (Introducing the frequency Hopping)
Efficient use of the power battery (Introducing the power control)
GSM Networks are called PLMN: Public Land Mobile Networks i.e. the
Radio Sites are located on land not usin satellites.
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GSM System Survey Revision
GSM System can work in different bands as follows:GSM System can work in different bands as follows:
Frequency Band-Down Link Frequency Band-Up Link
GSM 800 869 894 MHz 824 849 MHz
DCS: Digital Cellular System PCS: Personal Communication Services.
E-GSM (Extended GSM) 925 935 MHz 880 890 MHz
P-GSM 900 935 960 MHz 890 915 MHz
GSM 1800 (DCS) 1805 1880 MHz 1710 1785 MHz
GSM 1900 (PCS) 1930 1990 MHz 1850 1910 MHz
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But what do we mean by frequency Band?
What is the DL and UL? Why DL is higher than UL band?
GSM System Survey Revision
Frequency BandFrequency Band
The range of frequencies which the operator is allowed to use for transmission
and reception.
Down Link and Up link bandsDown Link and Up link bands
DL band is the range of frequencies used by the Base station when
transmitting to the MS while the UL band is the range of frequencies used by
the Mobile station when transmitting to the Base Station.
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GSM System Survey Revision
Why DL band is higher than the UL band?Why DL band is higher than the UL band?
As freq then attenuation with air
> ase taton o e tat on
frequencies that will be attenuated fast to the side that is using higher power.
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GSM System Survey Revision
Access TechniquesAccess Techniques What do we mean by Access techniques?
These are the Techniques through which many MSs can access the shared media
.
i.i. FDMA ( Frequency Division Multiple Access)FDMA ( Frequency Division Multiple Access)
Each MS is assigned a dedicated frequency through which he can talk.
ii.ii. TDMA (Time Division Multiple Access)TDMA (Time Division Multiple Access)
All MSs are using the same frequency but each of them will be utilizing
it only over a certain period of time called Time Slot (TS)
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In GSM System were using TDMA over FDMA where the frequency band
is divided into no. of frequencies each of which is shared among no. of
MSs, where each MS will be assigned a certain TS on certain
frequency.
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GSM System Survey Revision
For PFor P--GSM (GSMGSM (GSM 900900))
UL Band 890MHz 915MHz, DL Band 935MHz 960MHz
Each Band is 25 MHz
Duplex Distance = 45 MHz
Carrier separation = 200 KHz
No. of frequencies = 124
200 KHz
Downlink 935 960 MHz
Uplink 890 915 MHz
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GSM 900 Frequency Allocation
F (MHz)915890
Uplink1 2 3 4 121 122 123 124
F (MHz)
Downlink
960935
1 2 3 4 121 122 123 124
.
890.4
.
935.2
935.4
935.6
1
1
121
121
GSM System Survey Revision
For the all GSM BandsFor the all GSM Bands
System P-GSM 900 E-GSM 900GSM(DCS)
1800
GSM(PCS)
1900
Uplink (MS BS)
Downlink(BSMS)890 915 MHz
935 960 MHz
880 915 MHz
925 - 960 MHz
1710 1785 MHz
1805 - 1880 MHz
1850 1910 MHz
1930 -1990 MHz
Wavelength 33 cm 33 cm 17 cm 16 cm
Bandwidth 25 MHz 35 MHz 75 MHz 60 MHz
Duplex distance 45 MHz 45 MHz 95 MHz 80 MHz
Carrier separation 200 kHz 200 kHz 200 kHz 200 kHz
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No. of carriers 124 174 374 299
Channel rate 270.8 kbps 270.8 kbps 270.8 kbps 270.8 kbps
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GSM System Survey Revision
GSM Network ArchitectureGSM Network Architecture
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GSM System Survey Revision
Core NetworkCore Network (NSS: Network Switching SystemNSS: Network Switching System)
MSC (Mobile Switching Center)MSC (Mobile Switching Center)
ou ng w c ng o ca s e ween en users w n e e wor .
Charging & Billing.
Service Provision.
Access to PSTN (Public Switched Telephone Network)
Act as a Gateway for other networks
Controls no. of BSCs connected to it.
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GSM System Survey Revision
HLR (Home Location Register)HLR (Home Location Register)
Centralized Network data base stores and manages all mobile subscriptions.
Example: IMSI, MSISDN, MSRN, Services subscribed/restricted for that user.
VLR (Visitor Location Register)VLR (Visitor Location Register)
It is co-located with the MSC.
Stored in it a copy of the users profile on temporary basis.
AUC (Authentication Center)AUC (Authentication Center)
Provides the HLR with the authentication parameters and ciphering Keys used
b the MSC/VLR to authenticate center user. Tri lets: RAND SRES Kc
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EIR (Equipment Identification Register)EIR (Equipment Identification Register)
Used to authenticate the user equipment through the IMEI.
IMEI = International Mobile Equipment Identification
GSM System Survey Revision
BSS (Base Station System)BSS (Base Station System) BSC (Base Station Controller)BSC (Base Station Controller)
It controls the air interface, it takes the decisions based on the reports came
.
Channel Allocation.
Controls the Handover Process.
Dynamic Power Control.
Frequency Hopping.
BTS (Base Transceiver Station)BTS (Base Transceiver Station)
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.
Speech Coding/Channel Coding/Interleaving/Ciphering/Burst
formatting/Modulation all these are done within the BTS (RBS=Radio Base
Station)
Equipment: Cabinet, jumpers, feeders, combiners, antennas.
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GSM System Survey Revision
MS (Mobile Station)MS (Mobile Station) Mobile EquipmentMobile Equipment
Transmit the radio waves.
peec co ng an eco ng.
Call control.
Performance measurement of radio link.
SIM card (Subscriber Identification Module)SIM card (Subscriber Identification Module)
Stores user addresses (IMSI, MSISDN, TMSI).
Stores authentication key Ki, authentication algorithm A3 and ciphering
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Stores the subscribed services.
GSM System Survey Revision
Over the Air InterfaceOver the Air Interface Frequency Band is divided into no. of frequencies.
Each frequency is divided into 8 Time slots (TS)
ac user w e ass gne .
One time slot =156.25 bits
1 Bit duration=3.69 sec
Time slot duration =156.25x3.69 sec= 0.577 msec
1 Frame = 8 TSs
Frame duration=0.577x8= 4.615 msec
Bit rate on the air interface is 270 Kbps, but for each user it is 33.8 Kbps
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GSM System Survey Revision
Physical ChannelsPhysical Channels vs.vs. Logical ChannelsLogical Channels
Physical channel:Physical channel: Time slot is called the physical channel.
og ca c anne :og ca c anne : s e con en a w e sen over e p ys ca c anne .
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GSM System Survey Revision
Logical ChannelsLogical Channels
Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Frequency Correction Control Channel Fast Associated Control Channel
Broadcast Dedicated
Common
Paging Channel
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Synchronization ChannelBroadcast Control Channel
Standalone Dedicated Control Channel
Slow Associated Control Channel
e roa cas onro anne
Random Access Channelccess ran anne
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GSM System Survey Revision
Traffic ChannelsTraffic Channels
Full Rate Channels (FR)Full Rate Channels (FR)
Carries users speech traffic or user data DL and UL.
.
Transmission rate is 13 Kbit/s.
Half Rate Channels (HR)Half Rate Channels (HR)
Carries users speech traffic or user data DL and UL.
2 users will share 1 TS (physical channel), each of them will be utilizing it
each frame.
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Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Synchronization Channel
BroadcastControlChannel
Frequency Correction ControlCh annel
Standalone Dedicated ControlCha nnel
Slow Associated Control Channel
FastAssoc iated Control Channel
CellBroadcastControlChannel
Broadcast Dedicated
Random Access Channel
Access Grant Channel
Common
Paging Channel
GSM System Survey Revision
Control ChannelsControl Channels
These are used to carry signaling or synchronization data, theyre divided into
three types:
Common Control Channels (CCCH)
Dedicated Control Channels (DCCH)
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Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Synchronization Channel
BroadcastControlChannel
Frequency Correction ControlCh annel
Standalone Dedicated ControlCha nnel
Slow Associated Control Channel
FastAssoc iated Control Channel
CellBroadcastControlChannel
Broadcast Dedicated
Random Access Channel
Access Grant Channel
Common
Paging Channel
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GSM System Survey Revision
BCH (Broad Cast Control Channels)BCH (Broad Cast Control Channels)
i.i. Frequency Correction Channel (FCCH)Frequency Correction Channel (FCCH)
Pure signal is transmitted to help the MS to lock on the frequency of the BTS
and s nchronize to its fre uenc . DL channel
ii.ii. Synchronization Channel (SCH)Synchronization Channel (SCH)
Carries the TDMA frame number.
BSIC (Base Station Identification Code) of the cell. (DL Channel)
iii.iii. BCCH (Broad Cast Control Channel)BCCH (Broad Cast Control Channel)
LAI (Location Area Identity)
Cell parameters (used power, Idle mode parameters,..etc)
List of BCCH carries of the nei hbor cells. DL Channel
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Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Synchronization Channel
BroadcastControlChannel
Frequency Correction ControlCh annel
Standalone Dedicated ControlC hannel
Slow Associated Control Channel
FastAssoc iated Control Channel
CellBroadcastControlChannel
Broadcast Dedicated
Random Access Channel
Access Grant Channel
Common
Paging Channel
GSM System Survey Revision
CCCH (Common Control Channels)CCCH (Common Control Channels)
i.i. Paging Channel (PCH)Paging Channel (PCH)
Used to inform the MS of an incoming call or sms, where the MSs IMSI/TMSI
will be sent over it. DL channel
ii.ii. Random Access Channel (RACH)Random Access Channel (RACH)
Used by the MS to ask for an SDCCH to respond to the request send on the
paging channel /initiate a call/location update/IMSI attach-detach. (UL
Channel)
iii.iii. AGCH (Access Grant Channel)AGCH (Access Grant Channel)
Used by the network to assign an SDCCH sub-channel for the MS. (DL
channel)
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Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Synchronization Channel
BroadcastControlChannel
Frequency Correction ControlCh annel
Standalone Dedicated ControlCha nnel
Slow Associated Control Channel
FastAssoc iated Control Channel
CellBroadcastControlChannel
Broadcast Dedicated
Random Access Channel
Access Grant Channel
Common
Paging Channel
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GSM System Survey Revision
DCCH (Dedicated Control Channels)DCCH (Dedicated Control Channels)
i.i. Standalone Dedicated Control Channel (SDCCH)Standalone Dedicated Control Channel (SDCCH)
Used for signaling purposes: call setup, location update, IMSI attach-detach.
. .
ii.ii. Slow Associated Control Channel (SACCH)Slow Associated Control Channel (SACCH)
Always allocated in conjunction with traffic channel/SDCCH channel to
transmit measurement reports.
DL measurement reports will include commands from the network to the MS
to adjust its power level and info about the Time Advance.
UL measurement reports will include information about the MS own power,
received SS & Quality from serving cell and SS from neighbor cells.
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Used to send SMSs in active mode
(DL/UL channel).Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Synchronization Channel
BroadcastControlChannel
Frequency Correction ControlCh annel
Standalone Dedicated ControlC hannel
Slow Associated Control Channel
FastAssoc iated Control Channel
CellBroadcastControlChannel
Broadcast Dedicated
Random Access Channel
Access Grant Channel
Common
Paging Channel
GSM System Survey Revision
iii.iii. Fast Associated Control Channel (FACCH)Fast Associated Control Channel (FACCH)
Used to send necessary Handover information . (DL/UL channel)
..
It is sent point to multi point i.e. from the cell to the mobiles attached to it, this
channel may carry information about the traffic, weather reports,etc. (DL
channel)
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Logical ChannelsLogical Channels
Control ChannelsControl ChannelsTraffic ChannelsTraffic Channels
Half Rate Full Rate
Synchronization Channel
BroadcastControlChannel
Frequency Correction ControlCh annel
Standalone Dedicated ControlCha nnel
Slow Associated Control Channel
FastAssoc iated Control Channel
CellBroadcastControlChannel
Broadcast Dedicated
Random Access Channel
Access Grant Channel
Common
Paging Channel
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GSM System Survey Revision
Mapping of Logical Channels on the Physical channels
Mapping on TS0/BCCH carrier (DL)
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51 consecutive control frames = 1 Control multi frame
GSM System Survey Revision
Mapping of Logical Channels on the Physical channels
Mapping on TS0/BCCH carrier (UL)
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TS0 in UL is reserved for the RACH, for the MS to access the system.
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GSM System Survey Revision
Mapping of Logical Channels on the Physical channels
Mapping on TS1/BCCH carrier (DL)
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GSM System Survey Revision
Mapping of Logical Channels on the Physical channels
Mapping on TS1/BCCH carrier (UL)
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GSM System Survey Revision
Mapping of Logical Channels on the Physical channels
Mapping on TS2/BCCH carrier (DL/UL) if it will be used by certain MS in active
mode
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26 consecutive Traffic frames = 1 Traffic multi frame
GSM System Survey Revision
TDMA Multi Frames StructureTDMA Multi Frames Structure Traffic Multi FramesTraffic Multi Frames
Traffic Multi Frame = 26 consecutive traffic frames (4.61msec x 26 =120msec)
on ro u rameson ro u rames
Control Multi Frame = 51 consecutive Control frames (4.61msec x 51
=235msec)
Super FrameSuper Frame
51 consecutive Traffic Multi Frames or 26 consecutive Control Multi Frames
Super Frame = 6.12 seconds
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Hyper FrameHyper Frame
2048 consecutive super Frames
Hyper Frame = 3 hours and 29 minutes nearly.
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Cell Planning Process
Cell Planning ProcessCell Planning Process
Cell Planning can be described briefly as all the activities involved in
determining the number of sites that shall be used, type of equipments and
their confi uration in order to ensure continuous covera e and ood ualit .
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Cell Planning Process
Traffic and Coverage AnalysisTraffic and Coverage Analysis
The cell planning process starts with a traffic and coverage analysis. The
analysis should produce information about the geographical area and the
ex ected ca acit needed.
The types of data collected are:
Cost, Coverage, Traffic demand and its distribution, GoS, Available Frequencies.
The traffic distribution can be estimated based on:
Population distribution, car usage distribution, income level distribution,
Telephone usage.
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Cell Planning Process
Nominal Cell PlanNominal Cell Plan
After compilation of the data received from the traffic and coverage analysis, a
coverage and capacity dimensioning will be done to produce the nominal cell
lan.
The Nominal Cell Plan is a graphical representation of the network which
simply looks like a cell pattern on a map.
Sites SurveysSites Surveys
The sites where the radio equipment will be placed are visited, it is necessary
to assess the real environment to determine whether it is a suitable location or
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not.
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Cell Planning Process
System DesignSystem Design
After the surveys from field are performed the design for each site is done
including: Site Structure, Height, Azimuth, Tilts, Types of Cabinets, Antennas
and Feeders.
ImplementationImplementation
This includes sites installation, commissioning testing the hardware and drive
testing to ensure that the sites are behaving well.
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Cell Planning Process
System TuningSystem Tuning
After the system has been installed it is continuously monitored and evaluated
to determine how well it meets the demand. This is called System Tuning and
it involves:
Checking that the final plan has been successfully implemented.
Evaluating the customer complaints.
Checking the network performance and parameters settings.
The system needs constant retuning due to the fact that the traffic and the
number of subscribers continuously increase.
The network may reach the point where it must be expanded so that it can
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manage the increasing load and new traffic and now the coverage and trafficanalysis is performed and the cell planning cycle is repeated.
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RF Sites and Hardware Equipments
Site Types and Hardware EquipmentSite Types and Hardware Equipment
We have many types for RF sites having different structures and design.
The choice of the RF site used will be during the validation phase, where the
planner will be responsible to choose the proper site type and structure based
on his target for coverage.
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RF Sites and Hardware Equipments
Site TypesSite TypesSite Types
Micro Site
Street LevelIndoor
Macro Site
COW Green FieldRoof Top
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MonopolePolesStup tower Tower
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RF Sites and Hardware Equipments
Site TypesSite TypesMacro SitesMacro Sites
Macro Sites are those which utilize cabinets that generates high power
~ m = an use o prov e ou oor an n oor coverage over
relatively medium and large distances in cities and on roads.
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Micro Site
Site Types
Street LevelIndoor
Macro Site
COW Green FieldRoof Top
MonopolePolesStup tower Tower
RF Sites and Hardware Equipments
Site TypesSite Types
Macro SitesMacro Sites
Roof Top SitesRoof Top Sites:: The antennas are placed on the roof of the buildings, used in
ur an an ense ur an c u ers ex: ns e e c es.
Stub Tower Poles
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Micro Site
Site Types
Street LevelIndoor
Macro Site
COW Green FieldRoof Top
MonopolePolesStup tower Tower
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RF Sites and Hardware Equipments
Site TypesSite TypesMacro SitesMacro Sites
COWCOW SitesSites:: COW stands for a Cell On Wheel, these are temporary sites
use n even s o max m ze e capac y ex: ex ons a ums.
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Micro Site
Site Types
Street LevelIndoor
Macro Site
COW Green FieldRoof Top
MonopolePolesStuptower Tower
RF Sites and Hardware Equipments
Site TypesSite Types
Macro SitesMacro Sites
Green Field SitesGreen Field Sites:: These sites are standalone sites used mainly on roads
an g ways o prov e coverage or ong s ances.
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reen e ower onopo e a m rees
Micro Site
Site Types
Street LevelIndoor
Macro Site
COW Green FieldRoof Top
MonopolePolesStuptower Tower
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RF Sites and Hardware Equipments
Site TypesSite TypesMicro SitesMicro Sites
Micro Sites are those which utilize cabinets that generate low power (~ 34
m = use n ou oor s ree s or capac y ssues n e o spo areas
(ex: Abdel Aziz St.) and used in Indoor buildings for both coverage and
capacity issues (Malls, Hotels)
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Street Level-Micro Outdoor Micro Indoor
Micro Site
Site Types
Street LevelIndoor
Macro Site
COW Green FieldRoof Top
MonopolePolesStuptower Tower
RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments The Hardware Equipments of the RF sites are those used to provide the radio
coverage over the air interface and can be seen as below:
BTS Cabinet ( Including DTRUs, Duplexers and Combiners)
Feeders, Jumpers and Connectors
Diplexers (In some cases)
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BTS Antenna
Repeaters
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsBTS (Cabinet)BTS (Cabinet)
Outdoor CabinetOutdoor Cabinet
Typical Macro Outdoor CabinetFrequency Band P-GSM 900, E-GSM 900, GSM 1800
Tx 935-960MHz, 925-960MHz, 1805-1880MHz
Rx 890-915MHz, 880-915MHz, 1710-1785MHz
Number of Transceivers 12
Dimension (WxDxH) 650x888x1380 mm
Weight 270 Kg
Output PowerCombined, Uncombined)
900MHz: 42.5/46 dBm
1800MHz: 42.0/45.5 dBm
DW
H
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This type of cabinets is used with Macro sites, it has built-in air conditions, it
doesnt need shelters and able to resist the different environmental conditions.
.Cabinet
RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
BTS (Cabinet)BTS (Cabinet)
Indoor CabinetIndoor Cabinet
Cabinet
Typical Macro Indoor CabinetFrequency Band P-GSM 900, E-GSM 900, GSM 1800
Tx 935-960MHz, 925-960MHz, 1805-1880MHz
Rx 890-915MHz, 880-915MHz, 1710-1785MHz
Number of Transceivers 12
Dimension (WxDxH) 600x400x900 mm
Weight 150 Kg
Output Power
Combined, Uncombined)
900MHz: 42.5/46 dBm
1800MHz: 42.0/45.5 dBm
Shelter
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This type of cabinets is used with Macro sites,
external air conditions should be used,
it needs a shelter to prevent the equipment from
the different environmental conditions (rain, heat,)
.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsBTS (Cabinet)BTS (Cabinet)
Typical Micro CabinetFrequency Band P-GSM 900, E-GSM 900, GSM 1800
Tx 935-960MHz, 925-960MHz, 1805-1880MHz
Rx 890-915MHz, 880-915MHz, 1710-1785MHz
Number of Transceivers 4
Dimension (WxDxH) 433x270x610 mm
Weight 41 Kg
Output PowerCombined, Uncombined)
900MHz: 34/32 dBm
1800MHz: 33.5/31.5 dBm
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This type of cabinets is used with Micro sites.
RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
DuplexerDuplexer
Duplexers are devices make us able to transmit and receive on the same
ca e.
External Duplexers have typical losses = 0.5 dBs
DTRUs have internal Duplexers that have nearly zero losses.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsDTRU (Dual Transceiver Unit)DTRU (Dual Transceiver Unit)
It is the hardware unit on which the frequencies are configured.
Duplexer
TX1
RX1
TX1/RX1
RXD1
RXD2
TX2
Hybrid
CombinerCombined
Mode
TX1/RX1
Un Combined
Mode
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If the internal combiner is used then this will result in 3dB losses in the output
signal.
RX2 TX2/RX2TX2/RX2Duplexer
RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
CombinerCombiner
The internal combiner in the DTRU is used to combine two signals from the
same an o e ransm e on e same ca e.
The combiner is a broadband one that doesnt need tuning.
The combining stage will result in 3 dB loss in the output signal.
If we need to make expansion ( connect 2 DTRUs = 4 frequencies to be
connected to the same antenna) then the combiner should be used.
DuplexerTX1RX1 TX1/RX1
RXD1 Hybrid
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DuplexerTX3RX3 TX1/RX1
RXD1
RXD2TX4RX4 TX2/RX2
Duplexer
RXD2TX2RX2 TX2/RX2
DTRU2
Duplexer
Hybrid
Combiner
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsFeeders, Jumpers and ConnectorsFeeders, Jumpers and Connectors
Feeders, jumpers and connectors are responsible
to carry the electrical signal from the BTS to the antenna.
Jumpers are flexible and used as a connection between Feeder-BTS
and Feeder-Antenna.
Typically, Jumper losses=0.5dB while connector losses=0.1dB
BTSjumper jumper
Feeder
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Feeder losses will differ based on the feeders diameter as below.
Feeder Type 800/900 (dB/100m) 1800/1900 (dB/100m)LCF 1/2" 7.0/7.2 10.5LCF 7/8" 4 6.5
LCF 1-1/4" 3.3 5.3
LCF 1-5/8" 2.6 4.2
RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
DiplexersDiplexers
Diplexers are used to combine two signals from different bands.
Typically, Diplexer losses=0.3dB
Typically with 4 port antennas, the output from the 1800-DTRU is mixed with
the output from the 3G cabinet via the diplexers.
DTRU-900
2G Cabinet
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3G Cabinet
DTRU-1800
Diplexer
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsTMA (Tower Mounted Amplifier)TMA (Tower Mounted Amplifier)
The TMA is installed direct after the BTS antenna.
It is used to enhance the uplink signal received by the antenna before being
deteriorated through the feeders.
The use of TMAs is important due to the fact that the output signal from the
MSs are transmitting in the uplink with low power.
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through the cables it will reach the BTS with acceptable level.
In the downlink, the TMA will add 0.3 dB losses, while in the uplink it will add
gain nearly = 24 dB.
RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
AntennaAntenna
It is the device used to convert the electrical signal from the cables to an
e ec romagne c ra a ons propaga ng on e a r n er ace.
Isotropic Antenna: Is a theoretical/reference model for an antenna propagating
equally in all directions.
Omni Antennas: Propagates equally in one plan.
Directive Antennas: Propagates in certain direction.
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Isotropic Antenna Omni Antenna Directive Antenna
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsAntennaAntenna
Antenna Gain:Antenna Gain:
Since Antennas are passive elements, then the only way to have gain in
any direction is to increase the directivity by concentrating the radiations
in the desired direction.
Now the Antenna gain can be defined as the ratio between the power of
the max direction of the antenna to the power obtained by an isotropic
antenna in the same direction.
Gain for Typical directive antennas = 18 dBi and for Omni antennas = 11
dBi
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
AntennaAntenna
Beam Width:Beam Width:
Defined as the angel between the max direction to the direction where the
power is reduced to the half in the max direction.
Direction of
the max
power
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Horizontal Beam
width =65
3dB
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsAntennaAntenna
Beam Width:Beam Width:
The standard antenna has a horizontal beam width of 65deg, this means
that the gain at 32.5deg is 3 dB less than the maximum gain ( i.e. half the
power)
Typically the vertical beam width is 7 degrees.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
AntennaAntenna
Tilting:Tilting:
Normally when the antenna is correctly mounted, then the vertical beam
of the antenna is pointing towards the horizon.
Lowering the beam below the horizon is known as Down tilt, and when
the beam is directed above the horizon then it is called Up tilt
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsAntennaAntenna
Tilting:Tilting:
According to how the tilt is implemented; we have two types: Mechanical
tilting and Electrical tilting.
Mechanical tilting: the physical body of the antenna is tilted, which cause
tilting in the main beam.
Electrical titling: we change the phase of the current fed the internal
dipoles which will result in tilting the main beam.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
AntennaAntenna
Tilting:Tilting:
With mechanical down tilting the main beam will be down tilted which is
useful but this will result in up tilting the back lobe which may interfere on
another cells.
With antennas support mechanical tilting only, we wont be able to have
different tilting for different bands if needed.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsAntennaAntenna
Diversity:Diversity:
Defined as the redundancy in receiving or transmitting the signal.
The purpose is to overcome the attenuation and fading that may
encounter the signal while propagating in air.
Typically the antenna diversity results in a 3.5 dB gain.
We have two types of diversity: Space Diversity and Polarization Diversity.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
AntennaAntenna
Diversity:Diversity:
With Space diversity well use 2 antennas that should have separation =
12-18
(=0.33m for GSM900 and =0.17m for GSM1800) in order to obtain the
desired gain.
S ace
SS1 2 1 2
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Diversity
Time
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsAntennaAntenna
Diversity:Diversity:
With Polarization diversity, the antenna will be manufactured with internal
arrays have dual polarizations, either Horizontal & Vertical or +45/-45
Dual Polarized
Antenna
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
AntennaAntenna
Diversity:Diversity:
The polarization is the direction of oscillation of the electric field with
respect to ground.
Vertically polarized antennas: Transmit electromagnetic waves where the
electric field component oscillate in direction perpendicular to the ground.
Horizontal polarized antennas: Transmit electromagnetic waves where the
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.
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsAntenna DiversityAntenna Diversity::
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware Equipments
RepeatersRepeaters
A repeater can cover areas that otherwise would have been blocked by
o s ac es.
Fields of application are roads in hilly terrain, tunnels or other obstructed low
capacity areas.
The signal is typically amplified by 50-80 dB.
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Road
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RF Sites and Hardware Equipments
Hardware EquipmentsHardware EquipmentsRepeatersRepeaters
Repeaters can also been used for indoor applications, like offices and
un ergroun s.
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Sites Surveys and Validation
The cell planning process results in a cell plan with nominal site positions.
If the operator has access to existing locations (ex: deal with TE, Police,..etc)
then it is necessar to ada t the cell lan accordin to these locations.
The proposed network design shows only approximate site locations but the
exact site position depends on the possibilities of constructing a site on the
suggested location.
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Sites Surveys and Validation
Non technical issues may contribute in preferring one location than the otherNon technical issues may contribute in preferring one location than the other
provided that both of them verify the radio requirements:provided that both of them verify the radio requirements:
Obtainin the ermits from the different authorities like civil aviation and
military authorities.
Lease contract should be agreed upon with the owner of the site.
Access roads: the site must be accessible for material transport and
installation.
Space requirements for the shelter and passes for the feeders.
Space to construct the antenna supports.
AC power Source.
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Sites Surveys and Validation
Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Distance from the nominal.
.
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Technical requirements based on which we select the best candidate:Technical requirements based on which we select the best candidate:
Distance from the nominal:Distance from the nominal:
The initial study of a cell system often results in a theoretical cell pattern
.
The existing buildings must then be adapted in such a way that the real
positions are established and replace the nominal positions.
For each nominal point the RF planner will choose a search area such
that the nominal shouldnt be moved out of it.
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Search Area, ex: 50m
Nominal Cell Location
Sites Surveys and Validation
Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Strategic location to fulfill coverage objects:Strategic location to fulfill coverage objects:
Clear of present and upcoming obstructions.
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Sites Surveys and Validation
Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Strategic location to fulfill coverage objects:Strategic location to fulfill coverage objects:
The proper designed height can be achieved with the used tower
.
Typically the common structures are Poles: 6/9m poles, Stub towers:
9/12/15/18/21m Green Field Towers: 30/40/60 m
If the required antennas height as per the design is 35m and the
buildings height is 25m then the proper structure is 12m stub tower.
12 m
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25 m
Sites Surveys and Validation
Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Strategic location to fulfill coverage objects:Strategic location to fulfill coverage objects:
The proper tilting as per the design and simulation can be implemented
.
H
= tilt angle
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D=Cell Range
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Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Strategic location to fulfill coverage objects:Strategic location to fulfill coverage objects:
Ex: If H=35m and we need theoretical Cell range=500 m what will be the
Tilt angle = 90 = 90 ( tan-1 (D/H)) = 90 ( tan-1 (500/35)) = 90 86
= 4 degrees, then the proper tilting = 4 degrees
= tilt angle
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D=Cell Range
H
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Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Strategic location to fulfill coverage objects:Strategic location to fulfill coverage objects:
It is better to install the antennas on the edges of the roof.
calculate the minimum height of the antenna in order to not have any
shadowing on the roof edge.
= tilt angle
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D=Cell Range
H
V/2h
d
Half the verticalbeam width
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Technical RF requirements based on which we select the best candidate:Technical RF requirements based on which we select the best candidate:
Strategic location to fulfill coverage objects:Strategic location to fulfill coverage objects:
If the distance to the roof d = 50m and were going to apply tilt = 4
,
shadowing on the roof.
=90 - (+V/2) = 90 (4+3.5) = 90 - 7.5 = 82.5 degrees
Tan = ( d/h), then Tan (82.5) = (50/h) = 7.5
then h = 50/7.5 = 6.7meters (min. tower height to not have shadowing with 4
deg down tilt)
= tilt angle
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D=Cell Range
H
V/2h
d
Half the verticalbeam width
Sites Surveys and Validation
Some Planning TipsSome Planning Tips The First Fresnel zone:The First Fresnel zone: The area around the visual line-of-sight that radio
waves spread out into after they leave the antenna. This area must be
clear or else si nal stren th will weaken. .
Double Structure sites.
Roads coverage.
Obstacles like Bill Boards.
Terrain difference.
Sites near water.
Tunnels coverage.
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Coverage Dimensioning
The sensitivity of the BTS and MS is defined as the minimum required
received input level in order to decode the signal correctly.
However, when lannin a s stem it is not sufficient to use this sensitivit level
as a planning criterion.
Various margins must be added to compensate for the degradation in the
signal level during its propagation in air.
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Coverage Dimensioning
These margins will include:These margins will include:
Rayleigh Fading Margin (Fast Fading Margin) RFmargin Interference Margin IFmargin
Outdoor Log Normal Fading Margin LNFmarg(o)
Outdoor + Indoor Log Normal Fading Margin LNFmarg(o+i)Car Penetration Loss CPL
Mean Building Penetration Loss BPLmean
Now the design level can be calculated as follows:Now the design level can be calculated as follows:
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SSdesign = MSsens + RFmargin + IFmargin + BLmargin + LNFmarg(o) (MS Outdoor)
SSdesign = MSsens + RFmargin + IFmargin + BLmargin + LNFmarg(o) + CPL (MS in Car)
SSdesign = MSsens + RFmargin + IFmargin + BLmargin + LNFmarg(o+i) + BPLmean (MS Indoor)
Coverage Dimensioning
Rayleigh Fading Margin (Fast Fading Margin)Rayleigh Fading Margin (Fast Fading Margin)::
Due to multipath reflection from the surrounding buildings some fading
dips may occur.
Based on measurements a Ra lei h Fadin Mar in of 3dB is ade uate
i.e. RFmargin = 3dB
Interference MarginInterference Margin::
Since the frequencies are reused, then the received carrier power must be
large enough in order to compensate for the interference from
surroundings.
The interference margin depends on the frequency reuse, traffic load and
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.normal system an Interference Margin of 2dB is adequate i.e. IFmargin =
2dB
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Coverage Dimensioning
Body LossBody Loss::
Since the humans body absorbs some of the energy, then a body loss
margin is used to compensate for this power dissipation
The recommended Bod Loss b the GSM standards is:
BL = 5dB (800/900 MHz Band) , BL = 3dB (1800/1900 MHz Band)
Car Penetration LossCar Penetration Loss::
When the MS is situated in a car without an external antenna (which is the
typical case) an extra margin should be added to cope with the
penetration loss of the car body.
The recommended Body Loss by the standard is: CPL = 6dB
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Coverage Dimensioning
Log Normal Fading (Slow Fading)Log Normal Fading (Slow Fading)::
The signal strength fluctuates around a mean value while the MS is
moving.
This t e of fadin is due to the terrain structure and the obstacles like
hills and trees in the path between the BTS and MS.
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Coverage Dimensioning
Log Normal Fading (Slow Fading)Log Normal Fading (Slow Fading)::
The log normal fading LNFmarg will differ based on the environment and
the coverage area.
LNF will be calculated from a ra h relates environment Standard
Deviation:LNF ) with the coverage percentage needed.
These values were
obtained from field
measurements
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N.B: (LNF marg(o+i) )2 = (LNF marg(o))
2 +(LNF marg(i) )2
Coverage Dimensioning
Log Normal Fading (Slow Fading)Log Normal Fading (Slow Fading)::
LNFmarg will be calculated from a graph relates environment (LNF ) with
the coverage.
Exam leExam le::
For an Urban area Outdoor,
then LNF =8 dB and with
98% coverage, then we can get
from the graph LNFmarg(o) = 8 dB
LNF
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Coverage Dimensioning
ExampleExample:
Get SSdesign for a MS-Outdoor in different
clutters with different required percentage
o coverage.
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SSdesign = MSsens + RFmargin + IFmargin + BLmargin + LNFmarg(o) (MS Outdoor)Then SSdesign = -104 + 3 + 2 + 5 + LNFmarg(o) = -94 dBm + LNFmarg(o) (MS Outdoor)
Coverage Dimensioning
ExampleExample::
then we can calculate SSdesign for
MS-Outdoor in different clutters as follows:
SSdesign = -94 dBm + LNFmarg(o)
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Coverage Dimensioning
ExampleExample::
Get SSdesign for a MS-In Car in different
clutters with different required percentage
o coverage.
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SSdesign = MSsens + RFmargin + IFmargin + BLmargin + CPL+ LNFmarg(o) (MS in Car)Then SSdesign = -104 + 3 + 2 + 5+ 6 + LNFmarg(o) = -88 dBm + LNFmarg(o) (MS in Car)
Coverage Dimensioning
ExampleExample::
Get SSdesign for a MS-Indoor in different
clutters with different required percentage
o coverage.
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SSdesign = MSsens + RFmargin + IFmargin + BLmargin + BPL+ LNFmarg(o+i) (MS Indoor)
Then SSdesign = -104+3+2+5+BPL+LNFmarg(o+i) = -94 dBm + BPL+ LNFmarg(o+i)
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Coverage Dimensioning
ExampleExample::
then we can calculate SSdesign for
MS-Indoor in different clutters as follows:
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Then SSdesign= -94 dBm + BPL+ LNFmarg(o+i)
Coverage Dimensioning
Down Link BudgetDown Link Budget
Now, were going to calculate the cell radius where the PinMS will be the
SSdesign which was computed previously based on the clutter type and
coverage percentage.
Pout : Output power from the Base Station Cabinet
Pout BTS PinMS =SSdesign
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Lf BTS : Losses in Feeders, Jumpers and connectors
Ga BTS : BTS antenna gain Gd BTS : BTS antenna diversity gain
Lp : Path Loss Pin MS : Input power at the MS Station
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Coverage Dimensioning
Down Link BudgetDown Link Budget
Example:Example:
for Urban clutter with required outdoor coverage= 95% (GSM900-Band) then
n MS = design= - . m an g ven a : ou BTS = m, BTS = .
Ga BTS = 18 dBi Gd BTS = 3.5 dB , then we can calculate the path loss as follows:
Lp = (Pout BTS - Lf BTS + Ga BTS + Gd BTS ) - Pin MS
Lp = 46-2.6+18+3.5-(-89.1)= 154 dB
Then the maximum allowed path loss is Lp is 154 dB and through which we are going to
calculate the cell range d
N.B:
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d= Cell Range
Inter Site-distance =1.5dArea 1.9 d2
d
d
Coverage Dimensioning
Path Loss LpPath Loss Lp
I.I. Free Space ModelFree Space Model::
Theoretical Model not commonly used, it assumed Line Of Sight (LOS)
direct ra between the Transmitter and Receiver.
The Path Loss will be calculated as follows:
Lp = 32.44 + 20 log f(MHz) + 20 log d (Km), where f: frequency and
d:cell range
II.II. Two Path ModelTwo Path Model::
Assumes two paths: direct path and a ground reflected path.
It suits the road sites.
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Lp = 20 log HBS + 20 log HMS +40 log d (Km) where d:cell range
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Coverage Dimensioning
Path Loss LpPath Loss Lp
III.III.Multi Path Propagation ModelMulti Path Propagation Model::
As stated before, the signal travelling in air will follow different paths
due to reflections from the surroundin s where each individual ath
affects the signal causing attenuation, delay and phase shift.
The received signals is therefore a result of direct rays, reflected rays
and shadowing or any combination of these signals.
Experimental measurements in different places led to the conclusion
that there is a necessity to make different models for different urban
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, ,
suburban and rural.
Coverage Dimensioning
Path Loss LpPath Loss Lp
III.III.Multi Path Propagation ModelMulti Path Propagation Model:: (A) Hata Okumura Model
Lp = A 13.82 log HBS + (44.9-6.55 log HBS ) log d(km) a (HMS )Clutter Type Frequency Value of A
HBS = Base Station antenna height
HMS = Mobile Station antenna height
d= Cell Range in Km
a(HMS)= 3.2(log 11.75HMS)2-4.97
Dense Urban and Urban Areas
800 146.2
900 146.8
1800 153.8
1900 154.3
Sub Urban Areas
800 136.4
900 136.9
1800 146.2
1900 146.9
800 127.1
900 127.5
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1800 134.11900 134.6
Open Areas
800 117.9
900 118.3
1800 124.3
1900 124.8
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Coverage Dimensioning
Path Loss LpPath Loss Lp
III.III.Multi Path Propagation ModelMulti Path Propagation Model:: (A) Hata Okumura Model
In our previous example for Urban clutter ( GSM 900MHz- band),
Assuming HBS=35m and HMS=1.5m
Lp = A 13.82 log HBS + (44.9-6.55 log HBS ) log d(km) a (HMS )
Lp = 146.8 13.82 log 35 + (44.9-6.55 log 35 ) log d(km) [ 3.2(log
11.75*1.5)2-4.97]
Lp = 146.8 21.34 + 34.786 log d(km) + ( 0.001)
Then log d(km) = 0.76 then d = 6.6 km
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Hata Okumuras mode doesnt give accurate values with Dense Urban
and Urban areas when the typical cell radius is less than 1 km, so it isused with rural and open areas only.
Coverage Dimensioning
Path Loss LpPath Loss Lp
III.III.Multi Path Propagation ModelMulti Path Propagation Model:: (B) Walfish-Ikegami Model
Lp = K +38 log d + 18 log (HBS -17)
HBS = Base Station antenna height
d= Cell Range in Km
Concerning our previous example, in Urban clutter (GSM 900-Band), Lp=154 dB
Assuming HBS =35m, then
L = 143.2 + 38 lo d + 18 lo 35-17 = 154
u er ype requency a ue o
Dense Urban, Urban and Sub
Urban Areas
800 142.4
900 143.2
1800 153.2
1900 154.1
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.
Log d = - 0.3 then d = 0.5 Km = 500 m
Walfish-Ikegami Model is more suitable for estimating the cell range in
Dense Urban and Urban clutters.
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Coverage Dimensioning
Up Link BudgetUp Link Budget
Now, were going to calculate the cell radius where the PinBTS will be
PinBTS = BTSsensitivity + RFmargin + IFmargin + BLmargin + LNFmarg(o)
Pout : Out ut ower from the Mobile Station.
Pin BTSPoutMS
TMA
GTMA-UL
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.
Lf BTS : Losses in Feeders, Jumpers and connectors
Ga BTS : BTS antenna gain Gd BTS : BTS antenna diversity gainLp : Path Loss Pin BTS : Input power at the Base Station
GTMA-UL : TMA UL gain
Coverage Dimensioning
Up Link BudgetUp Link Budget
Example:Example:
Given that: Pout MS = 33 dBm, Lf BTS = 2.6 dB, G TMA-UL = 4 dB ,
sensitivity= - m, a BTS = BTS = . , en we can cacu a e e
path loss as follows:
Lp = (Pout MS + G TMA-UL - Lf BTS + Ga BTS + Gd BTS ) PinBTS
PinBTS = BTSsensitivity+ RFmargin + IFmargin + BLmargin + LNFmarg(o)
= -110+3+2+5+4.9=-95.1
Lp = 33 + 4 2.6 + 18 + 3.5 (-95.1) = 151 dB
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Based on Walfish-Ikegami, we can calculate the maximum cell range on the
path loss calculated in the UL
Assuming HBS =35m, then
Lp = 143.2 + 38 log d + 18 log (35-17) = 151 dB
Log d = - 0.38 then d ~ 0.42 Km = 420 m
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Coverage Dimensioning
NowNow
from downlink budget calculationsdownlink budget calculations dDL = 500m
while
= UL ,
then were going to design on the lower valuelower value.
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Coverage Dimensioning
Power BalancePower Balance
Now in order to guarantee that there is a power balance between the DL and the ULpaths, weve to recalculate the BTS output power that will achieve this balance.
L = Pout - Lf + Ga + Gd - Pin
Lp = Pout BTS - 2.6+18+3.5-(-89.1) = Pout BTS + 108 = 151 dB
Pout BTS = 43 dBm and this is the BTS o/p power for power balance.
DL Coverage
If the DL and UL coverage are not balanced as in
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UL Coverage
figure, then in the shaded area in between, the MSswill receive a good DL signal but their UL signal wont
reach the BTS.
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Capacity Dimensioning
The Capacity in cellular system depends on:The Capacity in cellular system depends on:
The number of channels available.
system
Traffic TheoryTraffic Theory attempts to obtain useful estimates, for example the number of
channels needed in a cell these estimates will depend on the selected system
and the assumed or real behavior of the subscribers.
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Capacity Dimensioning
TrafficTraffic?? Traffic refers to the usage of channels and is usually thought of as
the holding time per time unit.
Traffic:Traffic: is measured in Erlan s Er , a traffic of 1 Er means that this channel
was busy for 1 complete hour.
TrafficTraffic (Er) =
How much traffic can one cell carry?
This will depend on:
Number of traffic channels available.
Number of calls/hr X Average call holding time (Sec)
3600
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Amount of congestion which is the GOS
Capacity Dimensioning
ErlangErlang--B table:B table: is used to calculate how much traffic a cell can bear given
certain no. of Traffic Channels and certain GOS.
The ErlanThe Erlan --B table:B table: was formed based on certain assum tions:
Poisson distribution (random) traffic
Blocked calls leave the call.
ExampleExample::
With a cell configured with 4 frequencies, then the number of available TCH
channels = 4*8 2 =30 TCHs, with GOS=2% then using Erlang-B we can
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ca cu ate t e max mum tra c on t s ce = . r
If the average traffic/user = 30 mEr (i.e. average call/user = 108 seconds= 1.8
minutes) then at peak (busy) hour this cell can support 21.932/30m = 730 users
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Capacity Dimensioning
Erlang BErlang B--TableTable
N.B:N.B:
The numerical
headin s indicate
blocking probability %
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Capacity Dimensioning
ExampleExample::
If we have input from the marketing team that in a certain city each 100meters well have
in the busy hour 150 users each will talk for 108 seconds = 1.8 minutes (i.e. each
,
frequencies.
Solution:Solution:
For each cell, no. of TCHs = 4*8 2 =30 TCHs, with GOS=2% then using Erlang-B
Table we can find that each cell can bear up to 21.932 Er
But each user generates 30mE, then this cell can serve (21.9/30e-3) = 732
subscriber.
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ccor ng o e user s s r u on, en eac m we ave su scr er, enfor each cell the 732 subscriber will be distributed on 100*(732/150) = 487 meters.
Distance
(meters)10
0
20
0
30
0
40
0
50
0
4.
5E
r
4.
5E
r
4.
5E
r
4.
5E
r
4.
5E
r0
d= 487m
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Capacity Dimensioning
SDCCH DimensioningSDCCH Dimensioning
Two models are used to estimate the SDCCH load
BASBAS11 Model:Model: Typical model for SDCCH load estimations in average
network.
ERAERA55 Model:Model: More aggressive model may be used when the subscribers
behavior in the network is not known.
The SDCCH load estimations, three types of cells are considered:
Border Cell (BC):Border Cell (BC): Cell lies on a location area border and will be subjected
to heavy location updating.
Inner Cell (IC):Inner Cell (IC): Cell lies in the core of the location area and will never
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subjected to location updating.
Average Cell (AC):Average Cell (AC): Cell having average no. of location updating.
Capacity Dimensioning
SDCCH DimensioningSDCCH Dimensioning
The SDCCH load estimations based on the two models can be seen as
below:
The 1st model:
BAS1 ModelEvent Average Cell Inner Cell Border Cell
Location Updating 0.5 0 1.5 mE/subscriber
IMSI Attach/detach 0.4 0.4 0.4 mE/subscriber
Periodic Registration 0.2 0.2 0.2 mE/subscriber
Call set-up 0.8 0.8 0.8 mE/subscriber
SMS 0.3 0.3 0.3 mE/subscriber
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. . .
20% Traffic Margin added 2.6 2 3.8 mE/subscriber
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Capacity Dimensioning
SDCCH DimensioningSDCCH Dimensioning
The SDCCH load estimations based on the two models can be seen as
below:
The 2nd model:
ERA5 ModelEvent Average Cell Inner Cell Border Cell
Location Updating 1 0 3 mE/subscriber
IMSI Attach/detach 1.8 1.8 1.8 mE/subscriber
Periodic Registration 0.5 0.5 0.5 mE/subscriber
Call set-up 0.9 0.9 0.9 mE/subscriber
SMS 1.7 1.7 1.7 mE/subscriber
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. . .
20% Traffic Margin added 7.1 5.9 9.5 mE/subscriber
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Frequency Planning
A Cellular system is based upon reuse of the same set of carriers
(frequencies).
The same set of frequencies will be reused every cluster, where the cluster is
formed of defined no. of cells.
When applying certain frequency plan strategy, some issues should be taken
into consideration like: Available frequency spectrum, Subscribers distribution,
required Carrier to Interference ratio (C/I) and Carrier to Adjacent ratio (C/A).
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It is recommended to keep I > 12 dB, while maintaining A > -3 dB
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I) Fixed Frequency Groups
(A)(A)
44//1212 ReuseReuse
PatternPattern
(B)(B)
33//99 ReuseReuse
PatternPattern
(II) Multiple Reuse Pattern
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
It is the traditional way of assigning frequencies, it is accomplished by dividing
the frequency spectrum into groups each of which has the same no. of
frequencies and each cell will be assigned a certain group.
The advantage with this method is that once the BCCH plan is finished, all
other frequencies will be mapped in the same way.
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the fact that not all cells have the same number of TRUs.
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
The Cluster will be formed of 4 Sites =12
cells on which the frequency spectrum
will be divided.
The cluster will be then repeated
every where all over the network.
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
Using this pattern then:
D= 3.46 R
D= Reuse distance
R= hexagon radius
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C/I = 10log(D/R) 4 = 21.58 dB
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
ExampleExample::
If the frequency spectrum is made up of 36 freq, then
whatll be the distribution of these frequencies/cluster?
Strategy#1: Block Distribution
The frequency band will be divided into blocks
formed of consecutive frequencies, block for the
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.
Then well form 12 groups each group will be
assigned to a cell within the cluster( 1 BCCH freq. + 2 TCHs frequencies)
BCCH Block TCH Block 1 TCH Block 2
f1 f2 f3 f4 f5 f6 f7 f8 f9f10f11f12f13f14f15f16f17f18f19 f20f21f22f23f24f25f26f27f28f29f30f31 f32f33f34f35f36
Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
Strategy#1: Block Distribution
Cell A1: Group1 = f1(BCCH), f13(TCH1), f25(TCH2)
Cell B1: Group2 = f2(BCCH), f14(TCH1), f26(TCH2)
Cell C1: Group3 = f3(BCCH), f15(TCH1), f27(TCH2)
Cell D3: Group12 = f12(BCCH), f24(TCH1), f36(TCH2)
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A1 B1 C1 D1 A2 B2 C2 D2 A3 B3 C3 D3
f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12
f13 f14 f15 f16 f17 f18 f19 f20 f21 f22 f23 f24
f25 f26 f27 f28 f29 f30 f31 f32 f33 f34 f35 f36
Frequencies from the BCCH Block
Frequencies from TCH Block 1
Frequencies from TCH Block 2
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
Strategy#2: Scattered Distribution
The frequencies assigned for both BCCH and TCH
bands will be chosen in a scattered manner and not as
block.
Then well form 12 groups each group will be
assigned to a cell within the cluster
( 1 BCCH freq. + 2 TCHs frequencies)
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BCCH Frequencies
TCH Frequencies 1
TCH Frequencies 2
f1 f2 f3 f4 f5 f6 f7 f8 f9 f10f11f12f13f14f15f16f17f18f19f20f21f22f23f24f25f26f27f28f29f30f31f32f33f34f35f36
f1 f4 f7f10f13f16f19f22f25f28f31f34f35f2 f5 f8f11f14f17f20f23f26f29f32f33f36f3 f6 f9 f12f15f18f21f24f27f30
BCCH Frequencies TCH Frequencies 1 TCH Frequencies 2
Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
Strategy#2: Scattered Distribution
Cell A1: Group1 = f1(BCCH), f35(TCH1), f33(TCH2)
Cell B1: Group2 = f4(BCCH), f2(TCH1), f36(TCH2)
Cell C1: Group3 = f7(BCCH), f5(TCH1), f3(TCH2)
Cell D3: Group12 = f34(BCCH), f32(TCH1), f30(TCH2)
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A1 B1 C1 D1 A2 B2 C2 D2 A3 B3 C3 D3
f1 f4 f7 f10 f13 f16 f19 f22 f25 f28 f31 f34
f35 f2 f5 f8 f11 f14 f17 f20 f23 f26 f29 f32
f33 f36 f3 f6 f9 f12 f15 f18 f21 f24 f27 f30
BCCH Frequencies
TCH Frequencies 1
TCH Frequencies 2
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--A)A) 44//1212 Reuse PatternReuse Pattern
For this example whatever the strategy used either
Blocked or scattered, the no. of frequencies/cell = 3.
We can calculate the trunking efficiency as below:
No. of TCHs/Cell = (3*8 2 )= 22 Traffic channels,
with GOS=2% then Traffic = 14.9 Er
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T = 100* (14.9/ 22) = 66.72%
Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
The Cluster will be formed of 3 Sites = 9 cells
on which the frequency spectrum will be divided.
The cluster will be then repeated every where
all over the network.
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
Using this pattern then:
D= 3R
D= Reuse distance
R= hexagon radius
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C/I = 10log(D/R) 4 = 19.1 dB
Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
Example:
If the frequency spectrum is made up of 36 freq,
then whatll be the distribution of these frequencies/Cluster?
Strategy#1: Block Distribution
The frequency band will be divided into blocks
formed of consecutive frequencies, block for the BCCH
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.
Then well form 9 groups each group will be
assigned to a cell within the cluster
( 1 BCCH freq. + 3 TCHs frequencies)
BCCH Block TCH Block 1 TCH Block 2
f1 f2 f3 f4 f5 f6 f7 f8 f9f10f11f12f13f14f15f16f17f18f19 f20f21f22f23f24f25f26f27f28f29f30f31 f32f33f34f35f36
TCH Block 3
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
Strategy#1: Block Distribution
Cell A1: Group1 = f1(BCCH), f10TCH1), f19(TCH2), f28(TCH3)
Cell B1: Group2 = f2 (BCCH), f11(TCH1), f20(TCH2), f29(TCH3)
Cell C1: Group3 = f3(BCCH), f12(TCH1), f21(TCH2), f30(TCH3)
Cell C3: Group9 = f9 (BCCH), f18(TCH1), f27(TCH2), f36(TCH3)
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A1 B1 C1 A2 B2 C2 A3 B3 C3
1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18
19 20 21 22 23 24 25 26 27
28 29 30 31 32 33 34 35 36
Frequencies from the BCCH Block
Frequencies from TCH Block 1
Frequencies from TCH Block 2
Frequencies from TCH Block 3
Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
Strategy#2: Scattered Distribution
The frequencies assigned for both BCCH and TCH bands
will be chosen in a scattered manner and not as block.
Then well form 9 groups each group will be assigned to a
cell within the cluster ( 1 BCCH freq. + 3 TCHs frequencies)
BCCH Frequencies
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BCCH Block TCH Block 1 TCH Block 2
TCH Frequencies 2
TCH Frequencies 3
f1 f5 f9f13f17f21f25f29f33f34 f2 f6f10f14f18f22f26f30f31f35f3 f7f11f15f19f23f27f28f32f36f4 f8f12f16f20f24
TCH Block 3
f1 f2f3 f4 f5f6 f7 f8f9 f10f11f12f13f14f15f16f17f18f19f20f21f22f23f24f25f26f27f28f29f30f31f32f33f34f35f36
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
Strategy#2: Scattered Distribution
Cell A1: Group1 = f1(BCCH), f34(TCH1), f31(TCH2), f28(TCH3)
Cell B1: Group2 = f5(BCCH), f2(TCH1), f35(TCH2), f32(TCH3)
Cell C1: Group3 = f9(BCCH), f6(TCH1), f3(TCH2), f36(TCH3)
Cell C3: Group9 = f33(BCCH), f30(TCH1), f27(TCH2), f24(TCH3)
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A1 B1 C1 A2 B2 C2 A3 B3 C3
f1 f5 f9 f13 f17 f21 f25 f29 f33f34 f2 f6 f10 f14 f18 f22 f26 f30
f31 f35 f3 f7 f11 f15 f19 f23 f27
f28 f32 f36 f4 f8 f12 f16 f20 f24
BCCH FrequenciesTCH Frequencies 1
TCH Frequencies 2
TCH Frequencies 3
Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(I)(I) Fixed Frequency GroupsFixed Frequency Groups
(I(I--B)B) 33//99 Reuse PatternReuse Pattern
For this example whatever the strategy used either
Blocked or scattered, the no. of frequencies/cell = 4.
We can calculate the trunking efficiency as below:
No. of TCHs/Cell = (4*8 2 )= 30 Traffic channels,
with GOS=2% then Traffic = 21.93 Er
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T = 100* (21.93/ 30) = 73.1%
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(II)(II) Multiple Reuse PatternMultiple Reuse Pattern
It is more spectrum efficient than fixed frequency groups for non-uniform
configurations.
The frequency assignment is done according to layered frequency planning
where each band is individually planned.
That is due to the fact that the load on each cell differs according to the
serving area.
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies
(II)(II) Multiple Reuse PatternMultiple Reuse Pattern
Assume a frequency bandwidth of 7.2MHz (36 frequency) and configuration
w max mum requenc es per ce s a owe .
The frequencies are then divided into four bands, one band for the BCCH
frequencies and three bands for the TCH frequencies as below:
12 BCCH FrequenciesBCCHFrequencies
f1 f3 f5 f7 f9 f11 f13 f15 f17 f19 f21 f23
TCHFrequencies1
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TCHFrequencies2
f22 f24 f26 f28 f30 f32 f34 f368 TCH Frequencies in the 2nd TCH band
TCHFrequencies3
f25 f27 f29 f31 f33 f356 TCH Frequencies in the 3rd TCH band
f2 f4 f6 f8 f10 f12 f14 f16 f18 f20
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Frequency Planning
Frequency Assignment StrategiesFrequency Assignment Strategies(II)(II) Multiple Reuse PatternMultiple Reuse Pattern
Assume that cell A is serving in an area where high traffic is expected, while
ce s serv ng n a norma ra c area.
The frequency allocation for both cells may be as below:
Cell A: f1 (BCCH), f6 (1st TCH Band), f22 (2nd TCH Band), f25 (3rd TCH Band)
Cell B: f3 (BCCH), f8 (1st TCH Band)
A
CB
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can e seen a ce s won exper ence e same requency reuse pa ern
as each of which is configured with different no. of TRXs.