RGM TTC CHENNAI-27

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.

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• Modulation and demodulation, equalisation

• Ciphering /deciphering

• Coding/decoding, Interleaving/ de-interleaving

• Frequency hopping

• Radio measurements preprocessing

• Handover

• Power control

• Call clearing

• Coupling system

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

Functional Architecture

Antenna

Abis interface

RadioInterface

MS

Coupling System

TRX(Transceiver Equipment)

BCF(Base Common Functions)

BSC

RGM TTC CHENNAI-27

• 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)

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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.

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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

RGM TTC CHENNAI-27

TRXGeneric Architecture

PATX

RX

FP(Frame Processor)

TRX

BCF Couplingsystem

RGM TTC CHENNAI-27

Transmission Chain

FrameProcessor

Modul.Synchro(GMSK

or8-PSK)

Low powerAmplifiers

and IFTranspos.

PA

RFTranspos.

RFTranspos.

Odd TS

Even TS

TXLogic IF

RFBCF

FH bus

Couplingsystem

RGM TTC CHENNAI-27

• Conversion of bit stream (I&Q) to be transmitted into an IF

• Transposition of GMSK signals on to the frequency band

• Frequency hopping management, acording to the coupling mode hybrid or cavity.

• Final amplification of the Radio signal according to the level of each TS

RGM TTC CHENNAI-27

RX orDRX Radio

Diversity Path

Main Path

A

A

Amplifi-cation even TS

odd TS

FrequencyTransposition

A/D Conversion

Amplifi-cation even TS

odd TS

FrequencyTransposition

A/D Conversion

Coupling

system

FrameProcessor

Main

Diversity

Reception Chain

RGM TTC CHENNAI-27

• Filtering of the RF signal coming from the RX multicoupler (splitter) to limit the noise level in the mixer.

• Pre-amplification of the filtered signals from the frequency band (GSM 900 Mhz band)

• To allow frequency hopping (at Time slot level), the frequency transposition needs two identical stages (one for odd TS and one for even TS) thus avoiding overlap delay when changing the frequency.

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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.

RGM TTC CHENNAI-27

• 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.

RGM TTC CHENNAI-27

Airinterface

Abisinterface

STAR Connection

CHAIN Connection

LOOP Connection

(single multi-drop)

MS (full multi-drop)

BSC

BTS Connection Modes

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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)

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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.

RGM TTC CHENNAI-27

BCF View/Shelf/Placement

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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.

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

• 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.

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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

RGM TTC CHENNAI-27

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