ted240xs

Information

Base Station System

TechnicalDescription(TED:BSS)BS-240XS

A30808-X3247-M9-1-7618

2 A30808-X3247-M9-1-7618

Technical Description (TED:BSS)BS-240XS

InformationBase Station System

! Important Notice on Product Safety

DANGER - RISK OF ELECTRICAL SHOCK OR DEATH - FOLLOW ALL INSTALLATIONINSTRUCTIONS.

The system complies with the standard EN 60950 / IEC 60950. All equipment connected to thesystem must comply with the applicable safety standards.Hazardous voltages are present at the AC power supply lines in this electrical equipment. Somecomponents may also have high operating temperatures.Failure to observe and follow all installation and safety instructions can result in seriouspersonal injury or property damage.Therefore, only trained and qualified personnel may install and maintain the system.

The same text in German:

Wichtiger Hinweis zur Produktsicherheit

LEBENSGEFAHR - BEACHTEN SIE ALLE INSTALLATIONSHINWEISE.

Das System entspricht den Anforderungen der EN 60950 / IEC 60950. Alle an das System angeschlo-ssenen Geräte müssen die zutreffenden Sicherheitsbestimmungen erfüllen.In diesen Anlagen stehen die Netzversorgungsleitungen unter gefährlicher Spannung. EinigeKomponenten können auch eine hohe Betriebstemperatur aufweisen.Nichtbeachtung der Installations- und Sicherheitshinweise kann zu schweren Körperverlet-zungen oder Sachschäden führen.Deshalb darf nur geschultes und qualifiziertes Personal das System installieren und warten.

Caution:This equipment has been tested and found to comply with EN 301489. Its class of conformity isdefined in table A30808-X3247-X910-*-7618, which is shipped with each product. This class alsocorresponds to the limits for a Class B digital device, pursuant to part 15 of the FCC Rules.These limits are designed to provide reasonable protection against harmful interference when theequipment is operated in a commercial environment.This equipment generates, uses and can radiate radio frequency energy and, if not installed and usedin accordance with the relevant standards referenced in the manual “Guide to Documentation”, maycause harmful interference to radio communications.For system installations it is strictly required to choose all installation sites according to national andlocal requirements concerning construction rules and static load capacities of buildings and roofs.For all sites, in particular in residential areas it is mandatory to observe all respectively applicableelectromagnetic field / force (EMF) limits. Otherwise harmful personal interference is possible.

Trademarks:

All designations used in this document can be trademarks, the use of which by third parties for their own purposescould violate the rights of their owners.

Copyright (C) Siemens AG 2005.

Issued by the Communications GroupHofmannstraße 51D-81359 München

Technical modifications possible.Technical specifications and features are binding only insofar asthey are specifically and expressly agreed upon in a written contract.

A30808-X3247-M9-1-7618 3



Reason for UpdateSummary:

First Edition for New Release BR 8.0

Details:

Chapter/Section Reason for Update

All New Release BR 8.0

Issue HistoryIssue

Number

Date of Issue Reason for Update

1 01/2005 First Edition for New Release BR 8.0

4 A30808-X3247-M9-1-7618



A30808-X3247-M9-1-7618 5



This document consists of a total of 36 pages. All pages are issue 1.

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.1 Main Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.2 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2 Hardware Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.1 Core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.2 Rack Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3 Description of Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.1 Core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.1.1 Core Basis (COBA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.2 Carrier Unit (CU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.3 EDGE Carrier Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.4 GMSK Carrier Units (GCU). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.5 Flexible Carrier Unit (FlexCU). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.6 Carrier Unit Output Power Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.7 DC Panel (DCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.8 MSU:DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.9 Alarm Collection Terminal (ACT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.10 Overvoltage Protection and Tracer (OVPT) . . . . . . . . . . . . . . . . . . . . . . . . 263.11 Abis Connection Module (ABISCON) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.12 Abis Link Equipment (LE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.13 Cover Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.14 Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4 Combining Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284.1 BCOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284.1.1 Types of Basic Combiner Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294.1.2 Maximum Insertion Losses BCOM (TX path) . . . . . . . . . . . . . . . . . . . . . . . 294.1.3 BCOM GAIN (RX path) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304.1.4 Examples of Possible BTSE Configurations . . . . . . . . . . . . . . . . . . . . . . . . 304.2 Receiving Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324.2.1 Combining on Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324.2.1.1 Antenna System Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324.3 Transmission Diversity Time Delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324.3.2 Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344.4 FCC Issues (for US Market only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

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IllustrationsFig. 2.1 BS-240XS Base Rack. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Fig. 2.2 Block Diagram of the BS-240XS Base Rack . . . . . . . . . . . . . . . . . . . . . 13

Fig. 2.3 BS-240XS Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Fig. 3.1 Connections of Major Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Fig. 3.2 COBA internal architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Fig. 3.3 Internal Components of the Carrier Unit. . . . . . . . . . . . . . . . . . . . . . . . . 20

Fig. 3.4 FlexCU - Double ECU Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Fig. 3.5 FlexCU - Single ECU Mode - Fourfold Receive Diversity Mode . . . . . . 24

Fig. 4.1 BCOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Fig. 4.2 Single-Cell (2,0,0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Fig. 4.3 Multi-Cell (1,1,1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Fig. 4.4 Multi-Cell (2,2,2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Fig. 4.5 Capacity Downlink Improvements for TX Diversity . . . . . . . . . . . . . . . . . 33

Fig. 4.6 BTS Rack Cabling for Transmitter Diversity Operation. . . . . . . . . . . . . . 34

A30808-X3247-M9-1-7618 7



TablesTab. 1.1 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Tab. 1.2 Frequency Bands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Tab. 3.1 Units and Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Tab. 3.2 Carrier Unit Output Power Level (Typical and Guaranteed Values) per TRX25

Tab. 4.1 Insertion Loss of BCOM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Tab. 4.2 Parameters of BCOM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Tab. 4.3 Maximum RF Power Output Values at Antenna Port. . . . . . . . . . . . . . . 35

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A30808-X3247-M9-1-7618 9



1 IntroductionThe BS-240XS was introduced because some markets require a low capacity BTS opti-mized for small configurations.

The modular architecture and the flexible internal structure, enables the BS-240XS toprovide GSM features such as EDGE; this platform ensures that network evolution is assmooth as possible.

The BS-240XS variant of the BTS family is suitable for low capacity applications withlimited requirements for cell configuration.

The use of the latest technology reduces power consumption and improves reliability.Easy integration is possible in the already installed sites, for the backward compatibilitywith existing SIEMENS SBS systems. High Site efficiency is assured for compositetransmit power with minimal footprint requirements.

Homogenous service throughout the network is assured by common BTS SW runningon all the platforms.

The BS-240XS mainly consists of:• Carrier oriented boards called carrier unit CU, GCU, ECU, FCU• Core boards( COBA)• Combining equipment

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1.1 Main FeaturesThe BS-240XS can be configured for the GSM 900 or GSM 1800 systems.

The BS-240XSU can be configured for the GSM 850 or GSM 1900 systems.

The BS-240XS is designed for up to 6 carriers in a single Base Rack.• Two cell configurations are possible:

– Single cell configuration– Multi cell configurations

The BS-240XS can support a maximum of 3 cells with RX diversity:3 sectors / cells with up to 2 carrier frequencies each (Combining on Air)• One Basic Combining unit (BCOM) is supported.• Mixed Configurations of Cells/Sectors applying both EDGE Carrier Units (ECU),

FlexCU and normal Carrier Units CU.• Traffic Channels:

– Full-Rate (FR)– Half-Rate (HR)– Enhanced Full-Rate (EFR)– Adaptive Multi Rate Codec (AMR)

• Services:– GPRS– HSCSD– EDGE

• Abis interface configurations:– Star, loop, and multidrop configurations are possible– Change of PCM line configuration from star to multidrop or loop and vice versa is

possible without any interruption of service• BS-240XS Rack is designed for stacking of Compact Version of Node B at the top

(Co-location of UMTS / GSM Base Stations)

iBS-240XS and BS-240XSU support the same features.If not mentioned expressly the term BS-240XS is also related to the BS-240XSU appli-cation.

A30808-X3247-M9-1-7618 11



1.2 Technical DataThe BS-240XS with up to 6 transceivers can be supplied in the following configurationsfor indoor installation:– 1 Base Rack

Characteristics BS-240XS (indoor)

Maximum TRX per BTSE 6

Maximum TRX per cell 2

Dimensions (HxWxD)(Base Rack)

1050x600x450 mm

Volume net 283.5 l

Maximum power consumption about 997 W with CU1321 W with ECU

Weight of Rack full equipped ca.135 kg (298 Lbs)

Temperature range -5 °C to +45 °C

Tab. 1.1 Technical Data

Frequency-Band Uplink (MHz) Downlink (MHz)

P-GSM 900 (Primary) 890.2 - 914.8 935.2 - 959.8

GSM 1800 1710.2 -1784.8 1805.2 -1879.8

GSM 1900 1850.2 -1909.8 1930.2 -1989.8

Tab. 1.2 Frequency Bands

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2 Hardware ArchitectureThe BS-240XS is designed to achieve commonality of boards to serve GSM system.The goal is a full feature list and full output power with a small volume.

Fig. 2.1 BS-240XS Base Rack

A30808-X3247-M9-1-7618 13



Fig. 2.2 Block Diagram of the BS-240XS Base Rack

BCOM Basic Combiner ModuleCU Carrier UnitCOBA Core Basis (COBA2P8)ACTC Alarm Collection Terminal Connec-

tion moduleOVPT Over Voltage Protection and TracerABISCON Abis Connector InterfaceMSU Mains Supply Unit for ext. DC lineDCP DC PanelFAN Fan Unit

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2.1 CoreThe main communication between the modules is provided via of bi-directional seriallink between the carrier units (CU) and the Core board. The serial link also provides aneffective means to realize baseband frequency hopping. Despite the fact that synchro-nization information is also transported via the serial links, no differential lengthconstraints apply for the lines of the serial link.

All alarms, besides the alarms generated in the Core and in the CU boards, are trans-ported via the CAN bus. Alarms of the CU boards are transmitted via CC-Link. Coreboards use their interface bus.

The carrier unit(s) provide all analog and digital signal processing including an RF powerstage necessary to process a single carrier (e.g., GSM 8 TCHs). The carrier unit(s) inter-face with the combining equipment on the one side and with the Core module on theother. The Core board provide functions common to all carriers within the BS-240 XS(e.g., clock generation, O&M processing,...) as well as LAPD processing for the differentcarriers.

A30808-X3247-M9-1-7618 15



2.2 Rack ConfigurationThe BS-240XS with 6 transceivers per Rack, is supplied for indoor installation.There is one type of Rack:– Base Rack (with Core module)– The BS-240XS Rack has a total height of 1050 mm, a total width of 600 mm, and

provides space inside the Rack for one double Frame, one Frame for Fan units, andone mounting panel for the ACTC board

– The EMI panel is integrated in the top of the Rack. The EMI Panel is used to feed-through the cabling on top of the Rack and contains the space to install the OVPTand MSU

– Types of Rack: One type of the Rack R:BS60XSVx is available for the BS-240XSRacks

Fig. 2.3 BS-240XS Rack

The Rack satisfies various applications depending on the number of CU units configuredand/or the number and kind of Network termination equipment provided.

iUp to three Flexible Carrier Units FCU may be installed in to BS-240XS Base Rack. OneFCU is used instead of one CU pair ( 0/1 - 2/3 - 4/5 ).

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3 Description of Modules

Name Freq.Var.

Remarks

Core modules:COBA Core basis

no Up to 2 PCM lines with COBA

Carrier related modules:CUxECUxGCUFlexCU

Carrier unit yes Carrier unit can be equipped in theBS-240XS

Antenna system modules:BCOM Combiner 6:6

yesThe BCOM unit support one frequencyband. (Dual band configuration is notpossible).

Alarm collection modules:ACTC-3Vx Alarm collection terminals

noACTC is equipped in BS-240XS Rack.

Power supply modules:DCP DC Panel

noThe DCP is used for distribution of the-48V DC.

DC Mains Supply UnitMSU:DC-2VxMSU:LPDC-2Vx

Mains supply DC for 50AUpgrade Kit lightningprotection

no The MSU:DC-2Vx module doesn’tprovide any lightning protection function.Upgrade kit lightning protection for MSUDC 50 A (optional)

OVPTV2OVPTCOAX

Over voltage protectionand tracer

no The OVTP is an optional feature.100 Ω / 120 Ω balanced line75 Ω coaxial line.

ABISCON

Abis connection module no An ABISCON shall be installed when theOVPT is not applied.100 Ω / 120 Ω balanced line75 Ω coaxial line.

Abis Link Equipment:LE

Link Equipment no Link Equipment is to be considered asexternal Equipment.

Cover Parts:CP:AIRFLOWV1CP:CUVx

Cover Parts have to beinserted if the respectiveactive module is notneeded in a configuration

no The air flow inside the Frame is notaffected

BATTERY Backup battery systems no Not applicable.

FAN Central Fan unit no For forced convection cooling

RACK compact Rack no Only Base Rack is available for theBS240XS

Tab. 3.1 Units and Modules

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3.1 CoreThe Core has the following tasks inside of the BTSE:– local controlling of the entire BTSE– generation of system clocks– providing of up to 4 Abis-interfaces to BSC or other BTSEs– routing of Abis-data to up to 6 CUs– providing an interface to the LMT Evolution/OMT– handling and processing of O&M-messages

The Core module is the COBA board. The following illustration provides an idea of theslot-configurations:

Fig. 3.1 Connections of Major Modules

2/4 Abis

COBA Abis

6 other

interfaces

CUs

CUOVPT

CC-Link

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3.1.1 Core Basis (COBA)Two COBA boards are developed:• COBA2P8• COBA4P12

The first digit gives the number of Abis-Interfaces, the following letter the kind ofAbis-interface (e.g. P for PCM30/24), and the following digit the number of CU-inter-faces, e.g., COBA2P8 (2 PCM30/24 Abis-interfaces, 8 CU interfaces).

The COBA4P12 board permit to optimise the split of CU-links and Abis interfaces.

The primarily concepts of the COBA2P8 / COBA4P12 cards are:– Low impact on O&M software– Pin compatibility– Maintenance of the current functionality (same feature, same redundanvy concept)– Maintenance of the current LEDs signalling philosophy

The COBA is the central board of the Core. The main components of this board are theBase Core Controller, the Advanced CLock Generation, the SErial Link InterfaceController (SELIC) that manages the external interface towards the Carrier Units, andthe PCM30/24 Abis interfaces.

The most important functionalities of the COBA are the local controlling of the BTSE-plus, the generation of the system’s clocks, the management of all the internal/externalinterfaces and the routing of data to the CU. In addition the COBA handles all the O&Mmessages and it manages the SW download functionality.

Only one COBA board is available, redundant Core board doesn’t supported.

In the next "Fig. 3.2 COBA internal architecture." the internal components of the COBAare represented.

iA mixed configuration with COBA2P8 and COBA4P12 in the same BTSE is notsupported.

A30808-X3247-M9-1-7618 19



Fig. 3.2 COBA internal architecture.

The Advanced CLock Generation generates also the system specific timing signals thatare distributed to the external Carrier Units (CU).

Abis1

Abis2

SA

T-I

nter

face

DC/DC Converter

SRAM

RDLLOGIC

WATCHDOG

EEPROMsA/D-Conv. Mux

CAN-BUS, ALARMS LEDs, Redundancy Control,

Route clock

external CLK sync

CONTROLLER

BASE CORE ADVANCED

CLOCK

GENERATOR

Links to

LMT Interface

to

COSA

AlarmInterface

Flash Memory Input/Output PCM Switch

Internal Core Controller Bus

CUs

SERIALLINK

INTERFACECONTROLLER

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3.2 Carrier Unit (CU)The Carrier Unit (CU) is composed by an analogue receive and transmit part with aSynthesiser and Power Amplifier (PA), by a SIgnal PROcessing unit (SIPRO) as well asa Power Supply Unit (PSU). It has two receive inputs, one for the normal path, the otherfor the diversity path. The CU contains all the functions that make up one carrier andinclude synthesiser hopping and advanced equalizer functions for high speed applica-tions.Besides it takes care for all carrier oriented tasks. In the uplink (UL) direction twoRF signals (diversity) are received and finally converted into TRAU frames ( PCU forGPRS) and signalling data. In the downlink (DL) direction, TRAU frames and signallingdata are received and converted into a GMSK modulated RF signal, which is amplifiedto the desired power level.

There are four variants of the CU for the different frequency bands P-GSM 900, GSM1800 and GSM 1900. The differences of the variants arise mainly on the Power Ampli-fier.

Fig. 3.3 Internal Components of the Carrier Unit.

Power Amplifier and Transceiver Unit (PATRX)

The Power Amplifier and Transceiver Unit provides the main analog functions of theCU:– It receives the two (diversity) RF signals from the antenna combining equipment and

converts them down to IF. The downconverted RF signals are then transmitted toSignal Processing Unit where they are sampled and digitally downconverted tobaseband.

– It receives the GMSK modulated signal from the Signal Processing Unit. The signalis then I/Q modulated, upconverted, levelled, power amplified, and transmitted to theantenna combining equipment.

– It supports the synthesizer frequency hopping.– It provides an RF loop between downlink and uplink path for the unit test of the CU.

The power control loop implements 6 static power steps (each 2 dB) and an additional15 dynamic power levels (each 2 dB). For low output power versions of the CU, a furtherreduction of 2 dB is provided.

cc-link

-48V DC

Rx inputs

Tx output

PowerAmplifier

SignalProcessingUnit

Power Supply Unit

A30808-X3247-M9-1-7618 21



Signal Processing Unit (SIPRO)

The Signal Processing Unit contains all the digital functions of the carrier unit, includingthe following:• Signal Processing in uplink and downlink.• Control of RF on the Power Amplifier.• Baseband and synthesizer hopping.• Channel Control.• Radio Link Control.• O&M parts relevant for the carrier unit.• Link to the Core Board (COBA) via the CC link.

Additionally, also the following analog functions are managed:• Analog to digital conversion (IF).• Digital to analog conversion (baseband).• Management of CU local clock.

Due to the analog functions, the Signal Processing Unit is specific for the differentfrequency variants. (one type for the GSM 850, GSM 900, and one for the GSM 1800,GSM 1900).

Power Supply Unit (PSU)

The Power Supply Unit is the DC/DC converter for the CU for all applications. It gener-ates the voltages +26/28V, +6V (only GSM 1800, GSM 1900), +12V, +5.3V and -5.3Vfor the analog circuitry and +3.35V for the digital circuitry from a -48V primary inputvoltage. The PSU is mechanically incorporated in the CU.

3.3 EDGE Carrier UnitThe EDGE Carrier Unit (ECU) is a modified CU that uses the same interfaces as theCU but supporting the EDGE functionality in uplink and downlink. In downlink direction,the signalling and traffic data are received from the Core and converted into GMSK or8-PSK modulated signal, which is amplified to the desired power level.With the ECU it is possible to mix EDGE and non EDGE timeslots on the same carrier.

The ECU carries two independent receivers (normal and diversity channel) to providethe antenna diversity function. In uplink direction, the received signal is converted to theIF-band. The IF-band is then converted to a digital GMSK/8PSK-signal.

The mechanical design of ECU is identical to that of CU versions.

The ECU and CU modules may be installed in any kind of mixed configurationsconcerning BS-240/241 hardware (Base/Extension Racks). Further, any cell/sectorconfiguration with a mixture of EDGE CU and “normal CUs” can be implemented.

The EDGE Carrier Unit (ECU) takes care for all carrier oriented tasks of the BTS. Inuplink (UL) direction, two RF signals (diversity) are received and finally converted intoTRAU frames and signalling data. In downlink (DL) direction, TRAU (or PCU) framesand signalling data are received and converted into a GMSK or 8-PSK modulated RFsignal, which is amplified to the desired power level.

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Functional Structure of the EDGE Carrier Unit

The ECU unit is a new developed and enhanced CU unit which supports the GMSK and8PSK Modulation in uplink and downlink. It is a HW compatible to the CU unit and fitsinto the BTSplus Rack. A functional description of the whole receive and transmit pathincluding the EDGE Carrier Unit and the antenna combining equipment can be foundbelow.

The ECU consists of following functional subunits:

EDGE Power Amplifier and Transceiver Unit (EPATRX).

EDGE Signal Processing Unit (ESIPRO).

EDGE Power Supply Unit (EPSU).

EDGE Power Amplifier and Transceiver Unit ( EPATRX)

The EDGE Power Amplifier and Transceiver UNit provides the main analogic functionsof the CU. In uplink direction, two (diversity) preamplified and filtered RF signals arereceived from the antenna combining equipment. These signals are down converted toIF and channel filtered in the RXFE stage. The IF signals are then transmitted toESIPRO, where they are sampled and digitally down converted to baseband. In down-link direction, the GMSK or 8PSK modulated signal is received from the ESIPRO, I/Qmodulated and up converted by the MODUP stage, which also provides the levelling ofthe output power.

The obtained RF signal is then power amplified by the module EPWRST and transmittedto the antenna combining equipment. A part of the transmitted power is fed to themodule PWRDET, which performs the power detection. This signal is used to close thedigital power loop.

The Predistortion Receiver (PDRX) down converts the transmit signal to the TX-IF forthe I/Q-Demodulation and adjusting the predistortion values. The transmitter is linear-ized by means of an adaptive digital predistortion which is applied to the basebandsignals. For the introduction of the ECU,a static predistortion was choosen for lineariza-tion of the transmit path. The HW is able to do adaptive predistortion, which can beinstalled by SW update. EPATRX is able to support synthesizer frequency hopping bythe implementation of the synthesizer modules RXLO and TXLO. The unit test of theECU is supported by the module LTL, which provides an RF loop between downlink anduplink path.

EDGE Signal Processing Unit (ESIPRO)

The Signal Processing Unit board of the BTSPLUS is a part of the EDGE Carrier Unit.It contains the following functions of the EDGE Carrier Unit:– Signal Processing in uplink and downlink– Control of RF on EPATRX– Baseband and synthesizer frequency hopping– Channel Control– Radio Link Control– O&M parts relevant for carrier unit– Link to Core via ASIC SELIC– Digital Modulation– Predistortion signal processing– Digital part of Power control– Analog to digital conversion (RXIF)

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– Digital to analog conversion (TX-baseband, TX-ramping)– Analog to digital conversion (PDRX)– Analog to digital conversion of Diode voltage– Analog to digital conversion of temperature– Local clock of CU

EDGE Power Supply Unit (EPSU)

The EPSU is the DC/DC converter for the ECU for all applications. The EPSU generatesthe voltages +26V/+28V, +12V, +5,3V and -5,3V for the analog circuitry and +3.3V forthe digital circuitry from a -48V primary input voltage. The only interface relevant changewas the change of the analog bias voltage for the EPWRSTD to +12V. The EPSU ismechanically incorporated in the ECU.

The EPSU is a slightly modified version of the PSU of the GSM CU. In this document,not all Interface names are changed to EPSU. Therefore, PSU can be seen as asynchronym for EPSU in this document.

3.4 GMSK Carrier Units (GCU)The GCU is a resembled ECU (the main sub-units are similar) which supports GMSKmodulation only, like the CU.

GCUs and CUs differ in the RF output power value for the GSM 1800 frequency band:

GCU: 53,7 W; CU: 37,1 W.

There are different variants of GCUs for the frequency bands GSM 900 and GSM 1800.

The types of GCU are the following:• GCUGV2 GMSK Carrier Unit for GSM 900 MHz• GCUDV2 GMSK Carrier Unit for GSM 1800 MHz

3.5 Flexible Carrier Unit (FlexCU)

The FlexCU is a complete two-carrier unit with the same dimension and based on theECU. Its two TRX can be configured independently, e.g. into different sectors. TheFlexCU either acts as two ECUs or as one carrier unit with so called “fourfold receivediversity”, if “Transmission Diversity Time Delay” is enabled (for operation modes seebelow).

In uplink direction four RF signals are received and converted into traffic and signallingdata. In downlink direction traffic and signalling data are received and converted into twoGMSK or 8PSK modulated signals which are amplified to the desired power level.

By using FlexCUs instead of other carrier units the number of carriers within the existingshelter(s) can be doubled. This is an ideal solution to double the capacity of BTSEs, anadvantage not only for footprint restricted BTS sites.

A working FlexCU requires about 33 % less power than two ECUs.As soon as a TRX is idle, it is switched off. With this enhanced power saving mode theoverall power consumption of an idle FlexCU (both TRX in idle state) is only 40 Watt.

The FlexCU supports all the frequency bands: GSM 850, GSM 900, GSM 1800 andGSM 1900. There exists one type for each frequency band.

iFlexCU modules are available from BR 8.0 onwards.

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These types of FlexCU are available:• FCU850V1 Flexible carrier unit for GSM 850• FCUGV1 Flexible carrier unit for (R-) GSM 900• FCUDV1 Flexible carrier unit for GSM 1800• FCUPV1 Flexible carrier unit for GSM 1900

FlexCU Operation Modes

FlexCUs may operate in two different modes: the double and the single ECU mode.

The double ECU mode is the default configuration of a FlexCU, with full support ofMCS-1 to MCS-9 in uplink and downlink. It functions like two independent ECUs withcomplete twofold EDGE TRX functionality: Each of both transceivers shows afull-equipped main receiver and diversity receiver.

Fig. 3.4 FlexCU - Double ECU Mode

Together with a FDUAMCO (and its possibility to switch from 2:2 to 4:2 and reverse viajumper cable) it is easy to increase the capacity.

The so called fourfold receive diversity mode is the single ECU mode in which theFlexCU functions as one carrier unit with four receivers. Only one TX path is used. Whentransmit diversity is enabled, this mode is automatically activated.

The four receivers of the FlexCU are fed by four independent antennas via two(F)DUAMCOs.

The TX path is fed via the (F)DUAMCO to two of the four antennas.

The fourfold receive diversity mode enhances the receiver sensitivity of the BTSE. Thedoubled number of the RX paths leads to an enhanced diversity gain (additionally up to2.5 dB).

Fig. 3.5 FlexCU - Single ECU Mode - Fourfold Receive Diversity Mode

TX0

TX1

RX-N0RX-Div0

RX-N1RX-Div1

SignalProcessing

Combiner(s) TX0

TX1

RX-a

TX0RX-b

RX-cRX-dRX-d

RX-bRX-b

cell 1

cell 1

cell 2

TX0

TX0

RX-NRX-Div0

RX-Div1RX-Div2

SignalProcessing

Combiner(s) TX0

TX1

RX-a

TX0RX-b

RX-cRX-dRX-d

RX-bRX-bcell 1

1 carrier ofa cell

A30808-X3247-M9-1-7618 25



3.6 Carrier Unit Output Power LevelThe typical and guaranteed values of RF output power level are listed below for CUs,GCUs, ECUs and FCUs, dependent on its frequency bands and modulation types(GMSK and 8PSK).

3.7 DC Panel (DCP)The DC Panel is used for distribution of the 48 V supply voltage to the modules withinthe BS-240XS Rack and integrates the required DC breakers for the different circuits.

In addition, the LMT connector and Ethernet connector are integrated into the frontcover of the DC panel. These connectors are linked to the COBA module.

3.8 MSU:DCThe DC Mains Supply Unit is located at the EMI Panel of the BS-240XS.

The DC Mains Supply Unit comprises the lightning protection (optional feature), the EMIfilter, and the terminal clamps for the external cable DC (-48 Volts, 0 Volt).

FrequencyBand

Carrier Unit Type TypicalRF Output Power

GuaranteedRF Output Power

GMSK 8PSK GMSK 8PSK

dBm Watt dBm Watt dBm Watt dBm Watt

CU/GCU GSM 900 CUGV3 / V4 47.3 54 -- -- 47.0 50 -- --

GCUGV2 47.3 54 -- -- 47.0 50 -- --

GSM 1800 CUDV3 / V4 45.7 37 -- -- 45.4 35 -- --

GCUDV2 47.3 54 -- -- 47.0 50 -- --

GSM 1900 CUPV4 45.7 37 -- -- 45.4 35 -- --

ECU

GSM 900 ECUGV3 / V3A 48.3 68 46.3 43 48.0 63 46.0 40

GSM 1800 ECUDV2 47.3 54 45.3 34 47.0 50 45.0 32

ECUDHPV3 / V3A 48.3 68 45.3 34 48.0 63 45.0 32

GSM 1900 ECUPV2 47.3 54 45.3 34 47.0 50 45.0 32

ECUPHPV2 48.3 68 45.3 34 48.0 63 45.0 32

ECUPHPV3 / V3A 48.3 68 45.3 34 48.0 63 45.0 32

FlexCU

GSM 900 FCUGV1 47.0 50 44.0 25 46.7 47 43.7 23

GSM 1800 FCUDV1 47.0 50 44.0 25 46.7 47 43.7 23

GSM 1900 FCUPV1 47.0 50 44.0 25 46.7 47 43.7 23

Tab. 3.2 Carrier Unit Output Power Level (Typical and Guaranteed Values) per TRX

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The lightning protection element indicates fault conditions on an alarm output, lightningProtection Alarm-LPA that is linked to the Alarm Collection Terminal .

3.9 Alarm Collection Terminal (ACT)The physical function of the ACT is to transfer the alarm and command signals from thealarm command connectors of the BTSE subsystem via the CAN BUS to the CoreController.

ACTC is installed in each Rack to collect all internal alarms.

The ACTC board provides connectors for DC supply (-48 V) and alarm interface tofollowing units:– Fan units– Smoke sensor– Rack Door Open sensor– Temperature sensor– Lightning Protection Alarm (LPA, also called Over Voltage Protection - OVP).

3.10 Overvoltage Protection and Tracer (OVPT)The OVPT is responsible for coarse protection of the PCM24/PCM30 ports of the Abisinterface and the external synchronization clock input of the BS-240XS against overvoltage. Additionally the OVPT provides interfaces to connect PCM tracers without inter-ruption for monitoring the Abis lines. The OVPT is located outside the EMI shield toterminate possible over voltages before they enter of the EMI protected area inside ofthe Rack.

The board performs the following tasks:– lightning protection of PCM lines– provision to connect external monitoring equipment without interruption. The lines

are de-coupled by resistors to prevent distortions– supporting 75 Ω coax or 100 Ω/120 Ω balanced lines– provides grounding facility for the external cable shielding– provides stress relief for the external cables

Type of OVPT:• up to 4 balanced PCM30/24 lines (100 Ω/120 Ω impedance)• Up to 4 coaxial PCM30/24 lines (75 Ω impedance)

Optional module, the OVPT module can be installed only as alternative to the ABISCONmodule.

3.11 Abis Connection Module (ABISCON)The Abis Connection module provides the interface between the base Rack and theperipheral Abis-cables. The Abis Connection module also provides the feature for moni-toring the Abis lines. The module is located outside the EMI shielding.

Type of ABISCON:• Up to 2 Abis symmetrical lines with 100 Ω/120 Ω impedance• Up to 2 Abis coaxial lines 75 Ω impedance

A30808-X3247-M9-1-7618 27



The ABISCON module can be installed only as alternative to the Over Voltage protec-tion and Trace module (OVPT).

3.12 Abis Link Equipment (LE)The link equipment (LE) acts as a front end to provide the Abis interface. Different equip-ment can be used for wire or radio transmission depending on customer requirements.If a link equipment is available at the telecommunications site, no additional link equip-ment is necessary. If the BS-240XS is installed away from a telecommunications site,the link equipment can be installed inside of the Service Rack. If radio transmission isrequired, microwave equipment can be used. Direct connections of the PCM24/30 linksare also possible.

3.13 Cover PartsAll unequipped slots in the Frames of a Rack must be equipped with Cover Parts, toreach a balanced airflow.

3.14 FanThe Fan Unit is responsible for creating a sufficient airflow to cool the inner electronicsusing all of the effects of forced convection cooling.

The Fans used are able to overcome the pressure drop caused by the system resistancetaking into account additional losses caused by adequate filters or Heat Exchangersused to establish an airflow that limits the ∆T (Temperature difference between criticalhotspots inside the Rack and the ambient temperature) caused by the specific powerdissipation of that hotspot.

In order to keep both the acoustic noise and the power consumption of all Fans at thelowest level possible, the Fan speeds are (independent of each other) temperaturecontrolled via integrated sensors (NTC) that monitor the critical hotspots to keep themin an acceptable range.

Furthermore, each Fan delivers a Fan good/Fan bad signal that is processed by theCOBA board.

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4 Combining Module

4.1 BCOMThe BCOMs consist of six identical Modules (0/.../5), with a transmit and a receive pathwith one Antenna.The Basic Combining unit BCOM 6:6 supports 6 antenna interfaces with 6 carrier unitsin total. The BCOM unit supports one frequency band only (Dual band configuration isnot possible).

The BS-240XS can support maximal 3 cells with RX diversity:– 3 sectors / cells with up to 2 carrier frequencies each (combining on Air).

Each of these Modules provides:– Trasmit path with a single TX input port– Receive path with two RF output ports– TX/RX duplex filter– Low Noise Amplifier (LNA) for the receive signal– Single antenna port (TX/RX)

The BCOM serves as a duplexer Unit, which provides filtering functions for both RX andTX paths and low noise amplification for the RX path. The following illustration showsthe configuration of the BCOM:

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Fig. 4.1 BCOM

4.1.1 Types of Basic Combiner UnitsThe types of basic combiner are the following:• BCOMPGVx Antenna Combining module for the GSM 900 MHz• BCOMDVx Antenna Combining module for the GSM 1800 MHz• BCOMPVx Antenna Combining module for the GSM 1900 MHz

4.1.2 Maximum Insertion Losses BCOM (TX path)

Type GSM 900 (dB) GSM 1800 (dB)

typical guaranteed typical guaranteed

BCOM 1,5 2,0 1,5 2,0

Tab. 4.1 Insertion Loss of BCOM

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4.1.3 BCOM GAIN (RX path)

4.1.4 Examples of Possible BTSE ConfigurationsA solution of antenna combining and multicoupling is the configuration with two TX-RXantennas and two duplex combining modules.Both Antennas belong to the same cell. One Antenna is used for transmission andreception, the other for transmission and diversity reception. Therefore, two transmitpaths exist, one normal receive path and one diversity receive path. The combining ofthe two transmit paths happens 'on air'.

Most frequently used configurations:– Configuration 2/0/0 (Fig. 4.2)– Configuration 1/1/1 (Fig. 4.3)– Configuration 2/2/2 (Fig. 4.4)

Fig. 4.2 Single-Cell (2,0,0)

BCOM gain

BCOM gain GSM 900 GSM 1800, GSM 1900

Gain (ANT-RX) 20 dB +/-1.5 dB 22 dB +/-1.5 dB

Tab. 4.2 Parameters of BCOM

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Fig. 4.3 Multi-Cell (1,1,1)

Fig. 4.4 Multi-Cell (2,2,2)

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4.2 Receiving Paths

4.2.1 Combining on AirBasically, there are two different diversity combining techniques:• Switched Combining• Maximum Ratio Combining

Switched Combining

Switched Combining simply selects one of the two receiver paths according to a givenquality criterion, such as maximum receiver gain.

Thus, in the case of correlated signals from receiver paths (and comparable gain),Switched Combining cannot improve receiver performance. A decision is usually madefor one full Um burst.

Maximum Ratio Combining

Maximum Ratio Combining, used by Siemens, provides bitwise combining of all avail-able information from both receiver paths.

4.2.1.1 Antenna System ModulesDifferent Antennas are provided which are connected to the combining modules in orderto serve cells with different carrier numbers. These combining modules have to providethe necessary performance by using the following methods:– Antenna Combining

to feed several transmitter outputs to the TX Antenna– Multicoupling

for splitting the RX signal for several receiver inputs– Duplexing

both Antenna Combining and Multicoupling methods are used in order to connectthe TX- and the RX-path to one Antenna

The technology of the new BTSE (BCOM), use a Low Noise Amplifier (LNA) in the RXpath, which can be set to different gain to establish the various configurations of theBS-240XS.

Antenna diversity is a second receive path to improve the receive quality and the gradeof service.

Both Antennas belong to the same cell. One Antenna is used for transmission andreception, the other for transmission and diversity reception. Therefore exist twotransmit paths, one normal receive path and one diversity receive path. The combiningof the two transmit paths happens 'on air'. Supervision of the two Antennas will be doneseparately for each one.

4.3 Transmission Diversity Time Delay

4.3.1 GeneralThis feature combines the output signals of 2 standard carrier units (fed with the samebaseband signal) to increase the available output power. To allow the parallel CU oper-ation, their transmit signal must be de-correlated.

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The parallel CU operation with de-correlated signals establish a diversity down-link path.Using down-link diversity significantly reduces the influence of signal fading.The codingschemes CS3, CS4, MCS8, and MCS9 particularly profit from such transmission diver-sity operation.

The mobile station (MS) receives an increased signal level. Applying downlink transmis-sion diversity time delay enables serving large cells, e.g., in rural areas.

By using Transmission Diversity, the downlink budget of the BTS can be significantlyimproved. This helps to balance the cell ranges of 850/900 MHz and 1800/1900 MHz inco-location scenarios.

The illustration of the downlink budget in relation to the downlink capacity is shown inthe next figure, which compares several possibilities of statically allocated CU combina-tions in one sector.

Fig. 4.5 Capacity Downlink Improvements for TX Diversity

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4.3.2 FunctionalityThe fully equipped BTS site with combined CU to apply transmission diversity keeps upwith later capacity requirements and helps operate the BTS sites in temporarily adjust-able modes of operation. The Transmission Diversity mode provides the BTS sites withdouble power and half capacity, and it performs using a CU of master and slave. Later,in case additional BTS sites get installed, the BTS sites of combined CU can switch overto normal capacity and normal power mode and release their slave CUs from no longerneeded halves to make them the single CU of an additional BTS site.

Parallel CU Operation

A parallel operation of two CUs required for the parallel transmission of de-correlatedsignals is feasible and compatible with baseband hopping. The CU processes data simi-larly to baseband hopping. The CU operates at the same carrier frequency. The CUsare assigned to the same cell antenna sector, and the CUs use separate antennas. Adistance higher than ten lambdas preferably separates the antennas when combiningon-air transmissions.

The following example illustrates CU co-location in an extended circular cell thatprovides an increased cell capacity by using several different carrier frequency bands(e.g. GSM 900; GSM 1800, GSM 1900). CUs consisting of master and slave CU, applytransmission diversity time delay operation. One CU transmits on one frequency band,and the other CU transmits on another frequency band.

Fig. 4.6 BTS Rack Cabling for Transmitter Diversity Operation

The transmission diversity time delay feature raises an additional inaccuracy caused bythe actual timing deviation of the two transmitting CUs, due to the different length of thefeeding cables and the antenna positions. The transmission diversity time delay opera-tion can be disabled for certain burst types that are timing-sensitive, e.g., the synchroni-zation channel (SCH) for Location Services (LCS). The transmission of the slave CU isdisabled when such a burst type is going to be transmitted. The operator is allowed to

A30808-X3247-M9-1-7618 35



exclude time slots or logical channels from applying the transmission diversity timedelay.

4.4 FCC Issues (for US Market only)In this chapter you find the maximum output power at the antenna connector of theBTS.These values are only relevant for the US market.

Revised FCC Certification for ECU 1900

For ECUs with 1930.2 and 1989.8 MHz frequencies, in order to fulfil the FCC require-ments in the USA, the maximum transmitting power of the corner frequencies of theGSM 1900 band (channel numbers 512 and 810, i.e. 1930.2 MHz and 1989.8 MHz,respectively) is decreased for all carrier units available for the U.S. market. This featureis realized per software.The BTS evaluates the mobile country code (MCC) provided by the BSC via the attribute"cellGlobalIdentity". If the MCC indicates “USA“, the BTS reduces the output power ofthe corner frequencies dependent on the hardware type of the carrier unit. The followingtable represents the maximum RF power output values for GMSK and 8PSK modula-tion.

CU Type CarrierFrequency

[MHz]

ChannelNo.

Maximum RFPower Output

GMSK

Maximum RFPower Output

8PSK

ECUPHPV3(A) 1930.2 512 39.9 dBm = 9.8 W 43.3 dBm = 21.4 W

ECUPHPV3(A) 1989.8 810 42.1 dBm = 16.2 W 45.7 dBm = 37.2 W

ECUPHPV2 1930.2 512 39.3 dBm = 8.5 W 42.2 dBm = 16.6 W

ECUPHPV2 1989.8 810 41.6 dBm = 14.5 W 44.3 dBm = 26.9 W

ECUPV2 1930.2 512 42.1 dBm = 16.2 W 44.7 dBm = 29.5 W

ECUPV2 1989.8 810 44.4 dBm = 27.5 W 47.1 dBm = 51.3 W

Tab. 4.3 Maximum RF Power Output Values at Antenna Port

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5 AbbreviationsAMR Adaptive Multi Rate Codec

COBA Core Basis

DL Downlink

ECU EDGE Carrier Unit

EDGE Enhanced Data Rates for the GSM Evolution

EFR Enhanced Full-Rate

EMI Electromagnetic Interference

FR Full-Rate

GCU GSMK Carrier Unit

GPRS General Packed Radio System

GSMK Gaussian Minimum Shift Keying

HR Half-Rate

HSCSD High Speed Circuit Switched Data

LE Link Equipment

LMT Local Maintenance Terminal

LNA Low Noise Amplifier

NTC Negative Thermal Coefficient

O&M Operation and Maintenance

OMT Operation and Maintenance Terminal

OVPT Overvoltage Protection and Tracer

PCM Pulse Code Modulation

RF Radio Frequency

TRAU Transcoding and Rate Adaption Unit

UL Uplink

Documents

ted240xs