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Functions of different entities of GSM Detailed desscription of 2G BTS
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Lesson objectives
After this lesson, you will be able to
• Define the main functions of a BTS
• Define the three functional parts of one BTS and their role
• Indicate the three different connection modes of a BTS and their benefits/drawbacks
• Describe the BCF module
• Describe the TRX
• Describe the coupling system.
BSS Architecture
TRAU(TCU)
BSCOMC-R
MSCRadio
InterfaceA Interface
Ater Interface
Abis Interface
NSS
BSS
OMN Interface
Public Switched Telephone Network
MS
MS
S8000Indoor
BTS
S8000Outdoor
BTS
Sun
StorEdge A5000
RadioInterface
e-CellBTS
PCUSN
GPRS Core NetworkInternet
Gb Interface
S2000H&LBTS
Agprs Interface
S12000Indoor
BTS
Traffic
Speech
Data Short messages
Transmission
Reception
Features of the radio interface
Signal processing
Coding Ciphering
D1
D2
D3
D4
D5
D6
D7
D8
D1
D2
D3
D4
D5
D6
D7
D8
Demodulation
1 2 3 4 5 6 7 8
Interleaving
Modulation
Coupling system
Frequencyhopping
PowerControl
Handover
L1M (Call sustaining)
Call clearing
002
104
017
113
002
104
017
113
Measurementpreprocessing
Q
0
I
3/4/4
/2
5/43/2
7/4
GMSK and/or 8-PSK
0
Capabilities of a BTS
Functions of BTS
• Modulation and demodulation, equalisation
• Ciphering /deciphering
• Coding/decoding, Interleaving/ de-interleaving
• Frequency hopping
• Radio measurements preprocessing
• Handover
• Power control
• Call clearing
• Coupling system
Capabilities of a BTS (continue)
Multi-cellsite
(Full multi-drop)
Drop and Insert techniques
LAPDconcentration
Link optimization
COM1
COM2
COM3
COM4 Time Slot
PCM
Control andSwitching
Unit A
Control andSwitching
Unit B
DSCDSC
DSC DSC+
n+1 redundancyAutomatic reconfiguration
Duplication
SynchroA
SynchroB
LAPD
LAPD
LAPD
Link and Site optimization Backup
Functional / BTS GENERIC Architecture
Antenna
Abis interface
RadioInterface
MS
Coupling System
TRX(Transceiver Equipment)
BCF(Base Common Functions)
BSC
BTS HARDWARE• SUBSYSTEM MOTOROLA NORTEL HUAWEI
• TRX CTU DRX DTRU
• BCF MCUF, NIU, ALARM cards
• COUPLER COMBINER / DUPLEXOR (DCF)
• POWER PSU
• CTU = COMPACT TRANSCEIVER UNIT
• DRX = DIGITAL TRANSCEIVER
• DTRU = DOUBLE TRANSCEIVER UNIT
• MCUF = MAIN CONTROL UNIT WITH FIBRE MUX
• NIU = NETWORK INTERFACE UNIT
• DCF= DUPLEX COMBINING FILTER
• PSU = POWER SUPPLY UNIT
• ANTENNA 4 PORTS
• DUAL BAND ANTENNA GSM 900 & GSM 1800 BANDS (MHZ)
• TRI-BAND ANTENNAS GSM 900 / 1800 & 3G UMTS-2GHz band or 2000MHzOne ANTENNA –> 2 RF CABLES = ONE MAIN CABLE (TX / RX)+ ONE RX DIVERSITY CABLEUMTS = UNIVERSAL MOBILE TELEPHONY SYSTEM
(7.6Mbps)GPRS = GENERAL PACKET RADIO SYSTEM(115kBPS)EDGE = ENHANCED DATA RATES FOR GSM
EVOLUTION(270Kbps)
• A Base Common Function Module performing all the common functions of the site.
• A coupling System (one per Cell)
• One or Several Tranceivers TRX( one per TDMA frame)
Generic Architecture
BSC
TRX n
TRX n-1
TRX 2
TRX 1
TRX n
TRX n-1
TRX 2
TRX 1
TRX n
TRX n-1
TRX 2
TRX 1
BCF
Co
up
sys
t
Co
up
sys
t
Co
up
sys
t
Co
up
sys
t
Co
up
sys
t
Co
up
sys
t
BTS (site)
Extension cabinetsBase cabinet
• A BTS may consists of one or more cabinets:
• The cabinet that contains the BCF (plus TRXs and Coupling
systems) is called a Base cabinet.
• The other cabinet containing the TRXs and coupling system
is called an Extension cabinet.
BCF
Backup
Switch A
SynchroA
SynchroB
GSM time
Signalingconcentration
Alarm management
Fans
Powersupply
Tempe-rature
Audiblealarm
Warning
Abis interfacemanagement
BSC
BTS
Out of order
In service
Operation and Maintenance
Switch B
• The purpose of the BCF is:
• Abis interface management
• GSM time distribution
• External alarms
• Operation & Maintenance
• Backup by redundancy of its main units
• Signalling concentration/deconcentration
TRXGeneric Architecture
PATX
RX
FP(Frame Processor)
TRX
BCF Couplingsystem
TX Coupler (Hybrid or Cavity)
RX Splitter
RX1 RX2 RX3
Four TRX
TX2TX1 TX3 TX4 RX4
Duplexer
-1 dB
-1 dB
TXDownlink
RXUplink
RX bandfilter
TX bandfilter
Duplexshift
Coupling System
• There are two types of Transmission coupler but only one type can be ussed in the same BTS. Hybrid or Cavity couplers.
• The Hybrid combiner is a broad band coupler enabling the combination of two RF signals generated by two transmitters into one signal, with high flexibility in frequency management.
• The minimum frequency separation required between TXs connnected to one coupler is 200 Khz.
• The receive coupling is achieved by means of two components LNA and the RX splitter.
• RX splitter is aimed at at pre-amplifying the signal received from the duplexer, and splitting it into several outputs to drive the receivers. For diversity purposes, the RX Splitters are duplicated onto the diversity receive path.
• The duplexer allows the connection of the transmission and reception paths onto a single antenna.
• The device mainly consists of two pass band filters tuned on the transmit and receive frequency bands.
Airinterface
Abisinterface
STAR Connection
CHAIN Connection
LOOP Connection
(single multi-drop)
MS (full multi-drop)
BSC
BTS Connection Modes
Nominal power at TX (PA) outputO1E = O1 Extendible with two DRX2O2_2 = dual band 900_1800
BTS Configuration TableMaximum Configurations and Transmission Power (1/3)
BTStype
Band
S4000Indoor
S4000Outdoor
S4000Smart
S2000EIndoor
S2000E Outdoor
S8002Outdoor
S8003Indoor
S8006Outdoor S2000L S2000H e-cell
900
25 / 35 W 25 W 25 W 25 W 30 W 30 W 2.5 W 20 W 1 W
2O82S3233S4446S888
O32S2222S34
O12O2 2O2 O2
O3S21
S111
O22O4
2O2_2
O1EO2
2O42O2_2
S112S22
2S2_2
O22O4
2O2_2
1800
20 / 30 W 20 W 20 W 20 W 30 W 30 W 2.5 W 20 W 1 W
2O83S4446S888
O32S2222S34
O12O2 2O2
O3S21
S111
O6S42S33
S222
O22O4
2O2_2
O1EO2
2O42O2_2
S112S22
2S2_2
O22O4
2O2_2
190020 W 20 W 20 W 20 W 20 W 2.5 W 20 W 1 W
2O83S444
O32S2222S34
1S1112S222
O12O2 2O2 O2
O1EO2S11
O22O4
30 W / 45 W / 60 W
O12
2O24
S66
S444
3S121212 (1)
30 W / 45 W / 60 W
O12
2O24
S66
S444
3S121212 (1)
30 W / 45 W / 60 W
O8
2O16
S44
S422
3S888
30 W / 45 W / 60 W
O8
2O16
S44
S422
3S888
1900
30W/30 W45 W 60W/30W
O12
2O24
S66
S444
3S121212 (1)
30W/30 W45 W 60W/30W
O12
2O24
S66
S444
3S121212 (1)
30W/30 W45 W 60W/30W
O8
2O16
S44
S422
3S888
30W/30 W45 W 60W/30W
O8
2O16
S44
S422
3S888)
850
/
900
/
1800
S12000
Outdoor
S12000
Indoor
S8000
Outdoor
S8000
Indoor
BTS type
Band
BTS Configuration tableMaximum Configurations and Transmission Power (2/3)
Coverage Solution
S8006
Coverage
Capacity
S8002
S8000 OutdoorS8000 Indoor
e-cell S2000HS2000L
S8000
S12000 Indoor
S12000 Outdoor
S12000
Coverage Solution
S8003
BTS 18000
18000 Indoor
18000 Outdoor
ABM
IFM ICM SPM ABM
ABM
BTS 18000 Indoor+ MCPA
CMCFboards
CPCMIboards
BCFICO board
300 mm
100 mmEnhanced Performances
Rapid installation into both S8000 Indoor and Outdoor cabinets.
RR
ASK
PB
IST
+5 V
RD
YLF
A
NO
S
RST
RL0
LP0
XL0
RL1
LP1
XL1
CPC
MI E
1
0 1
CM
CF
+5
VR
DY
RU
N
AB
ISO
NB
IST
CL
K0
CL
K1
CL
K2
HL
DV
RL
OC
KE
DO
VE
NT
XL
NK
CO
LR
X
TEST
ET
H
Compact BCF Module
• The Compact Base Common Function module is composed of six boards
• One BCF Interconnection
• Three Compact PCM Interface
• Two compactMain commonfunction
• The CBCF module manages Abis PCM interfaces,Signalling concentration (Lap D ) and Routing functions
• BTS synchronisation
• The RECAL board is incharge of collecting and managing internal and external alarms.
BCF View/Shelf/Placement
BCF
(e)DRX(e)DRX Radio(e)DRX digital
CouplingSystem
(e)TRX
((H)e)PA
Frame Processor
TX Driver
RX Main
RX Diversity
TXLogic
Where :• For DRX:
DRX digital part = DRX Logic board + Power Supply board, DRX Radio part = DRX Radio board + Power Supply board.
• For eDRX eDRX digital part = e-LDRX Digital board, eDRX Radio part = e-RDRX Radio board.
S8000E TRXFunctional view
• The e-DRX is designed to work in one of the frequency range used by the BTS (GSM 850,GSM900,E-GSM 900,GSM 1800 and GSM 1900), the personalisation is done by the radio board. The (e) DRX is split into.
• a DRX digital part including a frame processor, a TX logic (GMSK and 8-PSK or only GMSK modulation) and a local time base, working for all frequency bands.
• A DRX Radio part including a low power driver and dual receiver
• The use of DRX by separating the TX power Amplifier (PA) from the rest of the transmit chain, allows different power classes of transmission to be envisaged.
DRX
TRX
PA
Non EDGE capable TRX
Characteristics of the ePA:• Available in GSM 850, 900, 1800 and 1900 MHz frequency bands.• RF Output power: 30 W
Characteristics of the HePA:• Only available in GSM 1900 MHz frequency band.• RF Output power:
60W for GMSK modulation. 45W for 8-PSK modulation.
eDRX: EDGE DRXePA: EDGE PAHePA: High Power ePA
eDRX
TRX
ePA orHePA
EDGE capable TRX
S8000/S12000 EDGE TRXFrom HW point of view
• The introduction of EDGE requires two new boards:
• An Edge driver+Receiver+Frame processor(eDRX) board.
• An Edge power Amplifier (e PA ) board
• The e DRX is fully backward and forward compatible with the current DRX versions.
• A combination of DRX, eDRX,PA and ePA (or HePA) can co-exist in a single BTS configuration (same cabinet and / or same cell)The association of both eDRX +e PA or HePA) enables the EDGE capability of the TRX.
• SW updation required in the BCF
Combiner Type
Insertion Loss
Dp -1 dB
H2D -4.5 dB
H4D -8 dB
2 antennas per cell
5 - 8 TRXH4D
PA
5
PA
6
PA
7
PA
8
H4D
PA
1
PA
2
PA
3
PA
4
LNA
Splitter Splitter
LNA
SplitterSplitter
Main Div.
1 TRX
PA
1 SplitterSplitter
H2D
LNA LNA
PA
3
4 TRXH2D
PA
1
PA
2 Splitter SplitterPA
4
Main Div.H2D
LNA LNA
PA
3
3 TRXH2D
PA
1PA2 Splitter Splitter
Main Div.
Main Div.2 TRX
PA
1
PA
2
Main Div.Duplex. Duplex.
LNALNA
Duplex. Duplex.
LNALNA
SplitterSplitter
S8000 Coupling1 - Standard Coupling
• Hybrid couplers 2 ways and Duplexer (H2D):up to 2 TRXs
• Hybrid couplers 4ways and Duplexer (H4D):up to 4 TRXs (8 TRXs per cell)
• Duplexer only (Dp) 1 TRX ( 2 TRX s per cell)
• Reception multicoupling is aimed at preamplifying the signal received from the duplexer and splitting it into several outputs to drive the DRX receivers.
Combiner Type
InsertionLoss
Dp -1 dB
CC8 -5 dB*
2 antennas per cell
5 - 8 TRX
CC8
PA
5
PA
6
PA
7
PA
8
PA
1
PA
2
PA
3
PA
4
Splitter Splitter
Main
SplitterSplitter
Div.
.
Max. Config. =
O8, 2O16 or 3S888* 4.8 dB for a 1200 kHz spacing, 5.3 dB for a 600 kHz spacing
S8000 Coupling2 - Cavity Coupling: Two Antenna per Cell
Duplex Duplex
LNALNA
5 - 8 TRX
H2D
PA
3
H2D
PA
5
PA
6
PA
4
LNA
H2D
PA
1
PA
2Splitter Splitter
MainH2D
LNAPA
7
PA
8Splitter Splitter
Div.
5 - 8 TRX
CC8
PA
5
PA
6
PA
7
PA
8
PA
1
PA
2
PA
3
PA
4LNA
Splitter Splitter
Main
LNA
SplitterSplitter
Div.
Duplex.Duplex.
1st cabinet
2nd cabinet
S8000 Coupling3 - Mixed Coupling: H2D and CC8
Compact packaging: 8 TRXs (DRX + PA) in each cabinet Compact BCF integrated in the first cabinet
Optimized ratio size versus capacity: Floorspace: 2 x 0.90 m2
Cabinet size = 170 x 75 x 45 cm (72 l / TRX)
Power Supply: -48 V dc
PA TX Power: 30 W
RX sensitivity: -110 dBm
Extended operating temperature range:
-5 °C to +45 °C
Cabinet weight: Fully equipped = 250 kg Empty (pre-cabled) = 110 kg
BTS S8000 Indoor1 - Characteristics
Control,Signal.Concentr. Synchronization
Management
CMCF
CBCF
PrivatePCM bus
Switching
CMCF
CPCMI
CPCMI
CPCMIPCM
Interface
DRX
DRX Radio
DRX Logic CouplingSystem
PATX Driver
TXLogic
CTRL_PA
RECALAlarms
Concentration
To/fromBSC
Frame Processor
COMICOCOMbiner InterCOnection
Split
Split
S8000 Downlink
RX Main
RX Diversity
RFCombiner
Control,Signal.Concentr. Synchronization
Management
CMCF
CBCF
PrivatePCM bus
Switching
CMCF
CPCMI
CPCMI
CPCMIPCM
Interface
DRX
DRX Radio
DRX Logic
RFCombiner
CouplingSystem
PATX Driver
RX Main
RX Diversity
TXLogic
CTRL_PA
RECALAlarms
Concentration
To/fromBSC
Frame Processor
Split
Split
COMICOCOMbiner InterCOnection
S8000 Uplink