05 mn1780eu09mn 0001 enhanced microbts

Enhanced MicroBTS Siemens

MN1780EU09MN_0001 © 2001 Siemens AG

1

Contents

1 Main Features 3

2 Architecture 7

3 Mechanics 13

3.1 Shelter 14

3.2 Frame 14

3.3 Mounting Kits 16

3.4 Fan Unit 16

3.5 Cover Parts 16

4 Modules 19

4.1 Combining Modules 20

4.2 Antenna Diversity 20

4.3 On-Air Combining 20

4.4 Antenna Combining 22

4.5 Tower Mounted Amplifier 26

4.6 Dual Carrier Unit 28

4.7 Generic Modules 30

5 Example Configurations 35

5.1 Configurations with Full Diversity 37

5.2 Configurations with Partial Diversity 39

5.3 Configurations without Diversity 39

6 Exercises 41

7 Solutions 53

Enhanced MicroBTS

Siemens Enhanced MicroBTS

MN1780EU09MN_0001

© 2001 Siemens AG

2



3

1 Main Features

Fig. 1


MN1780EU09MN_0001

© 2001 Siemens AG

4

Base Cabinet

+ 3 Add-On

Modules (max 7)

+ 2 Add-On

Modules+ 1 Add-On

Module

Fig. 2 E-MicroBTS with add-on modules



5

��The e-MicroBTS is designed for max. 8 carriers (in max. 2 cabinets). The carriers are equipped in blocks of two. The same cabinet can be used both indoor and outdoor.

��The minimum/maximum configuration for the Master Base Unit is two/four carriers.

��Beside the Master Base Unit, an Extension Base Unit can be used.

��The e-MicroBTS is available for the frequency bands GSM900, GSM1800 and GSM1900.

��Dual-band configuration is possible for GSM900/GSM1800 and GSM900/GSM1900.

��Two types of cell configurations are available:

Single cell configuration: one e-MicroBTS is serving only one cell

Multi cell configuration: up to 4 cells per base unit and up to 8 cells per e-MicroBTS are supported

��4 combining options are supported:

combining on air with integrated antenna

combining on air with external antenna

2:1 duplex combining (external antennas)

4:1 duplex combining (external antennas)

��The core equipment is always located in the master base unit

��E-MicroBTS sensitivity at the cabinet input (� - 110 dBm) is better than required by GSM

��Antenna Diversity is supported in most standard configurations:

integrated antennas have polarization diversity,

no diversity for 4:1 DUAMCO combining

��DCU containing / not containing duplexers provide the following output power:

8 W / 14 W DCU (GSM1800)

8 W / 14 W DCU (R-GSM900)

8 W / 14 W DCU (GSM1900)

(The max output power at the antenna connectors is

12 W with DCUDUXx,

5 W with DCULGx and A:DXUAMCO2Mx equipment,

2.5 W with DCULGx and A:DUAMCO4Mx equipment)


MN1780EU09MN_0001

© 2001 Siemens AG

6

��Full-rate, enhanced full-rate and half-rate traffic channels are supported

��GPRS and HSCSD are supported

��Synthesizer and Baseband Frequency Hopping is available

��Hardware redundancy is not supported

��Different options for the Abis interface are available:

star, multidrop and loop configurations (changes are possible without interruption of service),

drop / insert feature on E1 and T1 links (for 16 kbit/s SSL and 64 kbit/s TS),

microwave and NTPM interfaces.

SBS Freq. Band Long Name Uplink (MHz) Downlink (MHz)

D900 P-GSM Primary GSM 890-915 935-960

D900 E-GSM Extended GSM 880-915 925-960

D900 R-GSM Railway GSM 876-915 921-960

D900 RE-GSM Railway Extension GSM 876-901 921-946

D900 PS-GSM Primary Shifted GSM 880-905 925-950

D1800 DCS Digital Com. System 1710-1785 1805-1880

D1900 PCS Personal Com. Service 1850-1910 1930-1990

The following module is currently not supported:

��Tower Mounted Amplifier TMA



7

2 Architecture


MN1780EU09MN_0001

© 2001 Siemens AG

8

The basic configuration of the e-MicroBTS consists of the master base unit only. In case of add-on-modules, e.g. A:DUAMCOM, A:DUXMEG, ..., the master base unit, together with the add-on-modules, which are placed on top of the master base unit, is called a master cabinet.

In order to expand the number of carriers from 4 to maximum 8, an extension cabinet can be connected to the master cabinet. The extension cabinet can comprise add-on modules as well. However, A:TIFx (terrestrial interface) are always part of the master cabinet.

The basic configuration with up to 4 carriers does not require any add-on modules: DCUDUX modules (DCU with duplexer) are used, which means that the BTS performs on-air-combining. Beside the integrated antenna (INTENNA), external antennas are available as well. In this case a dummy module replaces the INTENNA.

All connections between the different modules including RF cabling inside the e-MicroBTS are done via the backplane module. Like all other modules it consists of a closed metal box, which has only small openings to establish the connections to other modules. In these connector zones seals are used in order to prevent dirty air from penetrating the modules. The backplane can be accessed for service and maintenance purposes. Flat ribbon cables connect several boards, which are mounted inside the backplane module.

Via a cable inlet, which is integrated at the bottom side of the backplane, all communication to the outside world is achieved:

��power supply,

��Abis links,

��extension cabinet,

��synchronization input,

��external alarms.

An opening provides proper pressure balance.

If more than 4 carriers are required, one extension cabinet is added to the master cabinet. This combination offers up to 8 carriers.

All cabinets can be equipped with add-on-modules, which are placed on top of the respective base units. Add-on-modules are needed, if features are required which do not fit into the limited space of the base units, e.g. the A:DUAMCOM modules. The overall weight of add-on modules is limited to 35 kg, their number to 7 add-on modules (per base unit).

In the case of add-on modules the backplane module is appropriately extended.

Master and extension base units are equipped with add-on-modules independently.



9

Master

Base

Unit

ADD-ON

Module 1

ADD-ON

Module 2

Exten-

sion

Base

Unit

ADD-ON

Module 1

CC - Link4

CAN Bus

2

Abis

InterfaceT

Interface

LMT

Power

Supply

Power

Supply

Antenna/e

1 ... 4

Air Interface

1 ... 4

Air Interface

Antenna/e

Fig. 3 E-MicroBTS Architecture


MN1780EU09MN_0001

© 2001 Siemens AG

10

ADUAMCO

CAN

A:DUAMCOM

CAN

ATIF

CAN

A:TIFx

CAN

A:OVP16AM

Add-On-Modules

ATIF

CAN

A:DUXMEG

Antennas

1..4

LMT

Ethernet

CC-Links

4 AMCO-

alarms

PCM30

CAN Bus

ACPSC/DCPSC

M:TIFx

CAN Node

CAN Node

M:COBAM

CAN Node

Power -48V DC

BISON

Bus

Fan

Temp

RDO

CC-Links

230V AC

Master Base Unit

M:OVPTM

alarm

External

alarms

DCU0

DCU1

Rx

Tx

DUX

DUX

2 Abis-Links

BATTERYM

CC-Links

4 AMCO-

alarms

CAN BusCAN Node

Power -48V DC

Fan

Temp

RDO

230V AC

Extension Base Unit

alarmDCU0

DCU1

DUX

DUX

BATTERYM

Rx Tx

Master Cabinet

ADUAMCO

CAN

A:DUAMCOM

CANATIF

CAN

A:DUXMEG

Rx Tx

Rx

Tx

Extension CabinetAdd-On-Modules

Antennas

1..4

ACPSC/DCPSC

A:OVP16AM

-48V DC

-48V DC

Fig. 4 Building Blocks of E-MicroBTS



11

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HEATERM

FANM

BATTERYM

ACPSC / DCPSC

BAPM

TCU

DCUX

AntennaCOBA

COBAM

TIF

OVPT

Terrestrial

Interface

( Abis )

OVPTM

(ext. / integr.)

Fig. 5 Building Blocks for Master Base Unit (1)


MN1780EU09MN_0001

© 2001 Siemens AG

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13

3 Mechanics


MN1780EU09MN_0001

© 2001 Siemens AG

14

3.1 Shelter

The shelter is the overall housing for the modules mounted in the frame, the fan and the add-on modules. For outdoor applications it provides protection against rain and solar radiation.

For wall or pole mounting, the frame is fixed at mounting plates. The shelter itself has no carrying functions. It protects against the sun by shielding the radiation and isolating roughly against rain (a strict IP54 protection is performed at the module level).

The shelter consists of several parts covering all functional units. Add-on modules have their own covers.

Types of shelter

A standard type of shelter is used for master and extension cabinets in both indoor and outdoor applications. Two variants are available (with and without antenna). Add-on modules have their own sheltering.

3.2 Frame

The frame houses all the HW units representing a fully working e-MicroBTS system according to ETS 300 019-1-3, class 4.1E. The frame consists of the frame mount for modules and frame backplane as well as the frame with door.

The frame mount forms a compatible environment for the electronic boards and components housed inside. The frame consists of an aluminum structure, a module-entering unit shaped as a U-profile for all units. It is designed in such a way that the requirements regarding EMI, Product Safety, IP and the other environmental requirements (e.g. mechanical vibration and shock) are fulfilled.

Types of cabinet

A standard type of frame is used for master and extension cabinets. The frame is independent of frequency bands or power supply used. All unequipped slots of a cabinet must be equipped with cover parts to achieve a balanced airflow.



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Battery

Fan

(Terrestrial InterFace)TIF

Core BAse

Add-On Module

Mounting Kit

Backplane

module

Heater

Overvolt. Prot. &

TracerPower Supply

Dual Carrier Unit 0

Dual Carrier Unit 1

Cover removed

Fig. 6 Building Blocks for Master Base Unit (Front View)


MN1780EU09MN_0001

© 2001 Siemens AG

16

3.3 Mounting Kits

There are mounting kits for electrical parts and for lightning protection duct (for outdoor use together with A:OVP16M and A:TIFMW).

There are two different modules used for wall and pole assembly of the e-MicroBTS:

��rigid assembly (standard),

��swiveling assembly (for locations where mounting space is very restricted).

The e-MicroBTS must not be placed directly on the floor.

Kits for mounting a 150 mm diameter flexible tube as air outlet (non-standard) are also available.

Other mounting kits provide a mechanical lock for protecting e-MicroBTS from unauthorized access.

3.4 Fan Unit

The fan generates the airflow necessary for cooling the base station. Due to the high thermal losses per volume, the fan unit consists of one radially blowing fan.

A standard type of fan is used for master and extension cabinets. It is independent of the configuration of the e-MicroBTS.

The fan module is an easily replaceable unit fixed with a snap-in technique. A sealed pair of connectors between the fan and the backplane provides the electrical connection.

3.5 Cover Parts

Cover Parts have to be inserted, if the respective active module is not equipped in a configuration, so that the airflow inside the frame or shelter is not affected.

Cover parts are available for the modules

��DCU

��COBA

��OVPT

��TIF

��Battery



17

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Connection Zone

Add-On Module

Backplane

module

Mounting Kit

Cover removed

Fig. 7 Building Blocks for Master Base Unit (Rear View)


MN1780EU09MN_0001

© 2001 Siemens AG

18



19

4 Modules

FANM

A

C

P

S

C

CP:

TIF

C

O

B

A

M

D

C

U

0

D

C

U

1

I

N

T

E

N

N

A

A :DUAM CO 2M

O

V

P

T

M

D

C

P

S

C

BATT-

ERYM

M

O

U

N

T

I

N

G

P

L

A

T

E

A :DUAM CO 4M

A:OVP16A

A:TIFNTPM

A: t. b. d.

HEATERM

Fig. 8 Building Blocks for Master Base Unit (2)


MN1780EU09MN_0001

© 2001 Siemens AG

20

4.1 Combining Modules

The term “Antenna Combining” is used, if several transmitter outputs are fed to the TX antenna, and "Multicoupling” for splitting the RX signal for several receiver inputs. “Duplexing” uses both methods to connect the TX- and the RX-path to one and the same antenna.

Note that, in contrast to the BTSplus combining, the term “Multi”coupling in connection with the e-MicroBTS might be slightly misleading, since the combination of the RX paths is rather a simple diversity coupling within one DCU (see below), but for the sake of compatibility the term “multicoupling” is used here as well.

The technology of the e-MicroBTS features duplexer (DUX) and TX/RX combiner (A:DUAMCOM). The A:DUAMCOM uses Low Noise Amplifier (LNA) in the RX path. Additionally the A:DUAMCOM has power supply and supervision functionality for a Tower Mounted Amplifier (TMA).

4.2 Antenna Diversity

Antenna diversity means that a second receive path is available improving the receive quality and the grade of service. It is important that the diversity path is configured in the same way as the normal path, that means either with or without TMA using the same combining equipment.

4.3 On-Air Combining

The basic configuration of antenna combining and multicoupling is the configuration with two TX/RX-antennas and two duplex combining modules (DUXMx). In the e-MicroBTS the duplex modules are integrated into the DCU.

If the E-GSM frequency band is used, the duplexers are not part of the DCU modules. Due to their large volume, the E-GSM duplexers are realized as add-on modules (A:DUXMEG) on top of the base unit.

Type of duplex module

Location Frequency band

DUXMPG integrated into the DCUDUXPG P-GSM900

A:DUXMEG placed on top of base cabinet as part of add-on module, contains two duplex filters

E-GSM

DUXMD integrated into the DCUDUXD GSM1800

DUXMP integrated into the DCUDUXP GSM1900



21

ANTENNA

M:SIPROx

CC

M:PWRSTMx

M:AMCO2xRXFIL

TXFILM:TXAx M

:SIPROx

M:RXAx

CC

ANTENNA

M:PSUM (DC/DC Converter)

Heat Sink

DUXMx

RXFIL

TXFIL

DUXMx

DCUDUXx

M:PWRSTMx

M:AMCO2x

M:TXAx

M:RXAx

M:COBAM

M:COBAM

Fig. 9 Block diagram of a DCU (DCUDUXx) in full on-air combining configuration (x = PG (P-GSM), D (GSM1800), P (GSM1900))

ANTENNA

CC

CC

ANTENNA


Heat Sink

A:DUXMEG

RXFIL

TXFIL

RXFIL

TXFIL

DCURG

M:SIPROG

M:PWRSTMR

M:AMCO2R

M:TXAG M:SIPROG

M:RXAG

M:PWRSTMR

M:AMCO2R

M:TXAG

M:RXAG

M:COBAM

M:COBAM

Fig. 10 Block diagram of a DCU (DCUR) in full on-air combining configuration but with the duplexer configured as an add-on module (A:DUXMEG)


MN1780EU09MN_0001

© 2001 Siemens AG

22

On-air combining of the GSM1800, P-GSM900 and GSM1900 frequency bands is performed by using the DCUDUXx (x= D, PG and P) modules containing two DUXMx modules each. The DCURG module (R-GSM) together with the external duplexer A:DUXMEG (add-on-module) performs on-air combining of the E-GSM900 band. The DCURG module does not contain any duplexing device.

For DUAMCO (i.e. antenna) combining, the DCULGx modules are used. They do not contain any duplexing device. The add-on modules A:DUAMCOM perform the filtering.

Dual band configuration is possible, but only in units of one entire DCU. That means, that every DCU supports only one frequency band. Since there are up to two DCU within one cabinet, dual band configuration is possible within one cabinet, too.

On-air combining is possible either via integrated or external antenna.

4.4 Antenna Combining

Antenna combining is used to feed several transmitters to the antenna system. In the e-MicroBTS duplex combining solely performs antenna combining. DUAMCO combining can be done with combiners for 2 or 4 carriers. The insertion loss of the A:DUAMCO4Mx is (3 dB) higher than for the A:DUAMCO2Mx.

The number of antennas used is a function of the TX combining equipment. If A:DUAMCO2Mx is used, two antennas per cabinet can be installed, in case of the A:DUAMCO4Mx only one.

The TX path of an A:DUAMCOM has an isolator and a supervision unit (ASU) for monitoring the mismatch of the antenna. If two carriers are combined to the antenna system the TX output of each DCU is fed to a TX input of the A:DUAMCOM.

In case more than 2 carriers have to be combined to the antenna system, an A:DUAMCO4Mx is used, which contains, beside an isolator for each TX input, a hybrid coupler to feed up to 4 TX inputs together to the TX path.

Every RX path runs through low noise amplifiers (LNA) with two stages and a splitter. The RX path is split to drive 2 receiver inputs.

The A:DUAMCOM has a mode switch, where every module can be set independently to work in the AMCO or the MUCO mode. The high amplifying AMCO mode is used if the antenna is directly connected to the A:DUAMCOM. The MUCO mode is used if a tower-mounted amplifier TMA is present. The DC power for the TMA is delivered by the A:DUAMCOM via antenna feeder cable.

Note: For some (non-standard) configurations with more than 4 TRX per cell, diversity is supported with DUAMCO4M (requiring inter-cabinet RF cabling, indoor).

In connection with the A:DUAMCOM modules a different DCU unit, called DCULGx, is used. In contrast to the DCUDUXx unit of, the DCULGx does not contain any duplex filtering and M:AMCO2LGx modules comprising only simple splitter functions replace the M:AMCO2x modules.

External antennas should perform DUAMCO combining only.



23

Antenna

Control

CAN bus

DC interf .

to/ from corefrom

TX

RX TX

LNA

ASU

Coupler

to RX

Triplexer

TMA

DC/DC

TMA

Signal.

ESN

Fig. 11 Block diagram of the A:DUAMCO2M

Control

CAN bus

DC interf .

Antenna

to/ from corefrom

TX

RX TX

LNA

ASU

Coupler

to RX

TMADC/DC

TMASignal.

Triplexer

ESN

Fig. 12 Block diagram of the A:DUAMCO4M


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24

Types of A:DUAMCOM

For each system GSM900, GSM1800 and GSM1900 two types of A:DUAMCOM are available, one to combine 2 carriers (A:DUAMCO2Mx) and the second to combine 4 carriers (A:DUAMCO4Mx). Due to their mechanical dimensions, all A:DUAMCOM modules are configured as add-on modules on top of the master cabinet.

Type of DUAMCO Frequency Band

A:DUAMCO2/4MD GSM1800

A:DUAMCO2/4MPG P-GSM900

A:DUAMCO2/4MRE RE-GSM900

A:DUAMCO2/4MP GSM1900

Note: Whereas the entire E-GSM band can be used with combining on-air, with DUAMCO combining only the P-GSM and RE-GSM bands are available.

One A:DUAMCOM is one Least Replaceable Unit (LRU). The A:DUAMCOM modules are always used in connection with the DCULGx (x= D, PG and P) modules. The DCULGx do not comprise any duplex filter and have only a low gain amplifier. The A:DUAMCOM module performs the main amplification.

The number and the type of A:DUAMCOM required depend on the number of carriers to be combined to the antenna system. The frequency band of the A:DUAMCOM must correspond to the corresponding DCU frequency:

��A:DUAMCO2Mx is needed to combine 2 carriers to the antenna system.

��A:DUAMCO4Mx is needed to combine up to 4 carriers to the antenna system.

To combine 4 carriers and to reach lower insertion loss, e.g. two A:DUAMCO2Mx can be used instead of a single A:DUAMCO4Mx, with twice the antennas needed as in the latter case.

At the time of installation before the startup of the e-MicroBTS the RX path must be switched into the AMCO or into the MUCO mode. The AMCO mode (highest gain) is set, if no preamplifier TMA is used. The MUCO mode is set, if a TMA is used. For MUCO mode only, to compensate for the antenna cable loss, the attenuator in the A:DUAMCOM has to be set to an appropriate value to adjust the correct gain.

Fault propagation through dependent modules

Each TX path of the A:DUAMCOM is supervised by an ASU. The ASU measures the VSWR and generates an alarm message towards the O&M (CAN bus interface):

��VSWR< 2 neither warning nor alarm

��2 � VSWR � 3 Generation of minor alarm "Antenna not Adjusted"

��VSWR > 3 Generation of major VSWR alarm "Antenna Faulty".



25

M:SIPROx

CC

M:PWRSTMx

M:AMCO2LGx

M:TXAx M:SIPROx

M:RXAx

CC


Heat Sink

DCULGx

CC

CC


Heat Sink

DCULGx

RXFIL

TXFIL

Coupler

ANTENNA

A:DUAMCO2Mx

RXFIL

TXFIL

Coupler

ANTENNA

A:DUAMCO2Mx

M:TXAx

M:RXAx

M:PWRSTMx

M:AMCO2LGx

M:SIPROx

M:PWRSTMx

M:AMCO2LGx

M:TXAx M:SIPROx

M:RXAx

M:TXAx

M:RXAx

M:PWRSTMx

M:AMCO2LGx

M:COBAM

M:COBAM

M:COBAM

M:COBAM

Fig. 13 Block diagram of DCULGx and its integration into the 2:1 DUAMCO combining option using A:DUAMCO2Mx, (x = PG (P-GSM900), D (GSM1800), P (GSM1900))

RXFIL

TXFIL

Coupler

ANTENNA

A:DUAMCO4Mx

M:SIPROx

CC

M:PWRSTMx

M:AMCO2LGx

M:TXAx M:SIPROx

M:RXAx

CC


Heat Sink

DCULGx

CC

CC


Heat Sink

DCULGx

M:TXAx

M:RXAx

M:PWRSTMx

M:AMCO2LGx

M:SIPROx

M:PWRSTMx

M:AMCO2LGx

M:TXAx M:SIPROx

M:RXAx

M:TXAx

M:RXAx

M:PWRSTMx

M:AMCO2LGx

M:COBAM

M:COBAM

M:COBAM

M:COBAM

Fig. 14 Block diagram of DCULGx and its integration into the 4:1 DUAMCO combining option using A:DUAMCO4Mx, (x = PG (P-GSM900), D (GSM1800), P (GSM1900))


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26

"Antenna Faulty" leads to the switch-on of a red Alarm LED in this module, and all DCU connected to this antenna port are turned off within one minute.

Each amplifier of the A:DUAMCOM RX path (LNA) consists of two parallel branches. If only one branch of one amplifier fails, the amplifier reaches lower sensitivity and generates a warning. Operation continues with performance degradation.

If more than one branch of the whole amplifier chain is faulty, the corresponding path of the receiver is not ready for operation. The connected DCU lose one of their RX paths (normal or diversity path). The operation continues without diversity. If one carrier unit loses both RX paths, it is taken out of operation.

If a TMA is installed, the A:DUAMCOM works in MUCO mode and only the second amplifier of the RX chain is active. If both branches of the TMA fail, "Fail Save Compensation" takes effect. The TMA connects the antenna directly to the A:DUAMCOM and the A:DUAMCOM receives a message to switchover into AMCO mode. In AMCO mode both amplifiers are active and the attenuation switches off. The connected DCU continue their operation with minor performance degradation. The state of "Fail Save Compensation" is left only by a Power On/Reset or SW reset.

4.5 Tower Mounted Amplifier

The TMA is located near the antenna (no module or add-on for e-MicroBTS). Its function is to amplify the received signal and pass through the transmit signal.

The TMA contains two duplex filters, each on one RF connector, to separate and combine receive and transmit path inside the TMA.

The transmit path only consists of two TX parts of the duplex filters. The receive path consists of two RX parts of duplex filters, a Low Noise Amplifier (LNA) between them and a fail save switch. The LNA features a low noise figure and contains two parallel branches.

The DC power for the TMA is delivered by the A:DUAMCOM via the antenna feeder cable. The TMA modules are taken without changes from the BTSplus platform. There are three types of TMA for each of the three available frequency bands: TMAG (P-GSM900), TMAD (GSM1800), and TMAP (GSM1900).

One TMA represents one Least Replaceable Unit (LRU). It consists of only one module. The TMA operates in conjunction with an A:DUAMCOM set to MUCO mode. The configuration with TMA offers the highest sensitivity of the RX path.

TMA is needed once per A:DUAMCOM.

Note: The TMA is currently not supported (SW limitation). However, the A:DUAMCOM hardware is already prepared to work together with TMA.



27

T M A

T XR X

T o A :D U A M C O M

F a i l

S a v e

S w it c h

R XR X T X

T o a n te n n a

Fig. 15 TMA Structure


The TMA supervises the DC current of its LNA and generates an alarm message towards A:DUAMCOM in case of malfunction which is passed on to O&M. LED on the front panel of the A:DUAMCOM show the state of each TMA. Each green LED indicates that the DC for the TMA is OK and each red LED gives notice of a faulty TMA if the BTS is configured for TMA.

The LNA consists of two parallel branches. If only one branch fails, the amplifier reaches lower gain and the connected A:DUAMCOM generates a warning towards O&M. Operation continues with performance degradation.

In case both branches fail, the amplifier is bypassed by the "fail save switch". The connected A:DUAMCOM generates an alarm message towards O&M. The red LED in the A:DUAMCOM of the concerned TMA is switched on, and the multicoupler switches over into AMCO mode automatically. Operation continues with minor performance degradation.


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28

4.6 Dual Carrier Unit

The DCU modules of the e-MicroBTS contain the functionality of two CU (c.f. BTSplus) in a single module. The DCU consists of two analog receive and transmit parts with synthesizer and power amplifier, two signal processing units as well as one power supply unit. The DCU has two receive inputs. The DCU contains all functions that make up two carriers as a diversity pair including synthesizer hopping and advanced equalizer functions for high-speed applications. In addition to the BTSplus carrier units, LNA, splitter and filtering functions are integrated in the DCU module.

Note: A DCU is not simply a combination of 2 CU. It also contains amplifiers and splitters (as well as, for DCUDUXx, a duplexer).

Types of DCU

Because of the variety of combining options and different frequency bands several types of DCU are provided:

Name Frequency band

Remarks

DCUDUXD GSM1800 Dual Carrier Unit with duplexer module (DUXMD)

DCULGD GSM1800 Dual Carrier Unit without duplexer module but with low gain amplifier (AMCO2)

DCUDUXPG P-GSM Dual Carrier Unit with duplexer module (DUXMPG)

DCURG R-GSM Dual Carrier Unit without duplexer module

DCULGRG R-GSM Dual Carrier Unit without duplexer module but with low gain amplifier (AMCO2)

DCUDUXP GSM1900 Dual Carrier Unit with duplexer module (DUXMP)

DCULGP GSM1900 Dual Carrier Unit without duplexer module but with low gain amplifier (AMCO2)

CP:DCU "dummy" DCU (metal box for thermal reasons, IP54 conform)

The DCU provides two carriers in the same frequency band.

2 DCU can be installed in one frame or shelter. These DCU may be assigned to different frequency ranges (dual band operation).

One e-MicroBTS can handle up to 4 DCU (Master and Extension Unit, 2x4 carriers).

For DUAMCO combining it is required that the A:DUAMCOM and the corresponding DCULGx modules support the same frequency range.

Note: Within one cell it is not allowed to have a mix of DCU types.



29


Every DCU has a connection to the core via CC-Link. Traffic data, signaling data as well as timing information and a carrier unit on/off signal are transferred here.

In case of a DCU failure an alarm message is sent to the COBA. If the failure is originated in a single carrier unit, the respective power stage is switched off separately, so that one carrier of the DCU remains operative (at full diversity if the RX path is not affected by the failure). If the failure affects the PSU of the DCU, the whole DCU will be switched off. If possible, BCCH reconfiguration is performed.

If both carrier units fail and only one DCU is equipped, no further operation of the e-MicroBTS is possible. If more than one DCU is installed in a cell, performance degrades in case of carrier unit failure.

4.6.1 DCU and Duplexers

The following table contains all available DCU and their internal or external duplexers:

Name Frequency band

Add-on Required

Remark

DCUDUXD GSM1800 No Duplexer module DUXMD integrated

DCULGD GSM1800 Yes Add-on modules A:DUAMCO2/4MD

DCUDUXPG P-GSM900 No Duplexer module DUXMPG integrated

DCURG R-GSM900 Yes Add-on module A:DUXMEG as external duplexer

DCULGRG R-GSM900 Yes Add-on modules A:DUAMCO2/4MRE or A:DUAMCO2/4MPG

DCUDUXP GSM1900 No Duplexer module DUXMP integrated

DCULGP GSM1900 Yes Add-on modules A:DUAMCO2/4MP


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30

4.7 Generic Modules

4.7.1 Core Base

The central core board comprises the COBA module (M:COBA2P8Vx), and a PID connector board (M:PIDCON). The COBA is adopted from BTSplus. The PID connector board routes the PID port of COBA to the outside of its mechanical housing. The COBA and the PIDCON module are properly encapsulated. The whole module is called M:COBAM.

The essential components are the

��base core controller (BCC),

��advanced clock generation (ACLK),

��PCM30/24 Abis-interfaces,

��DCU interfaces (CC-Link) and

��internal system alarm interface.

The priority tasks of COBA are

��local controlling of e-MicroBTS,

��generating of system clock,

��providing all interfaces,

��routing data to the DCU and

��handling O&M messages.

M:COBAM features two PCM30/24 interfaces and eight carrier unit (4 DCU) interfaces.

For the e-MicroBTS no core redundancy is supported.

The M:COBAM is needed to support up to two DCU in the Master Base Unit and an additional two DCU in Extension Base Unit. The M:COBAM of the Master Base Unit serves both the DCU of the Master as well as the Extension Base Unit. The extension cabinet does not comprise a M:COBAM module. Instead, a simple metal box without electrical functions (CP:COBAM) is used to maintain the original airflow.


If a failure occurs in the M:COBAM, the entire e-MicroBTS is out of operation. In case of an M:COBAM failure all active calls are lost.

A relay between the two Abis ports maintains the PCM connection to other base stations (in a multidrop chain or loop) even in case of complete COBA failure.



31

4.7.2 Over Voltage Protection and Tracer

The M:OVPTM is responsible for coarse protection of the PCM24 / PCM30 or TIF interface ports of the Abis interface against over voltage. Additionally the M:OVPTM provides interfaces to connect PCM tracers without interruption for monitoring the Abis lines. In support of two units of microwave link equipment two RS232 interfaces are located in the EMI section of the M:OVPTM. They also have lightning protection for the configuration equipment connected to RS232.

There are three types of over voltage protection modules available:

��M:OVPTM supporting 100/120 � symmetrical lines, offering ports and monitoring

��M:OVPTKOAXM supporting 75 � asymmetrical line, restricted to PCM24/30 Abis interface ports

��A:OVP16AM protecting 16 external site alarms (ENVA) against over voltage

An over voltage protection module is needed once in the Master Base Unit (not with A:TIFNTPM). The extension cabinet does not comprise an over voltage protection module. Instead, a simple metal box without electrical functions (CP:OVPTM) is used to maintain the original airflow.

For protecting environmental alarm lines against over voltage, the add-on module A:OVP16AM is available.

4.7.3 Power Supply and Control Unit

ACPSC/DCPSC are the power supply modules for the e-MicroBTS. The ACPSC/ DCPSC module provides a –48 V power supply to all –48 V consumers within the e-MicroBTS and performs central control and alarm collection functions. Particularly the DC control is incorporated in the ACPSC/DCPSC module.

All heaters (incl. battery heater) are directly connected to mains (115 V / 230 V) and are, thus, no load on ACPSC/DCPSC.

Three different types of modules are available:

��ACPSC for 50 Hz AC power supply (220 V or 230 V)

��ACPSC/U for 60 Hz AC power supply (115 V)

��DCPSC for DC power supply (- 48 V)

Max power consumption is 860 W / 730 W for ACPSC / DCPSC.

Every Base Unit (Master / Extension) is equipped with one ACPSC/DCPSC module. Whether the ACPSC or the DCPSC module is used depends on the power supply available.

Additional AC-line surge protection is available with an additional ACPROTECT module (outside of e-MicroBTS in separate housing).

Note: The max DC current to supply the equipment is limited to 35 A (excl. heaters).


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32

4.7.4 Backup Battery

The backup battery guarantees continuous operation for a certain time in case the mains AC power supply is interrupted. In case of a – 48 V DC power supply no backup battery is provided. The unit ACPSC for charging, switching on/off, warming up and alarming, controls the BATTERYM. In case the input power supply is interrupted, the battery unit is switched on and provides – 48 V DC to ensure normal operation for at least 5 minutes (at 720 W load, typical backup times are between 10 min and 60 min).

Only one type of Backup Battery with a nominal capacity of 4.5 Ah is available.

Each base cabinet of the e-MicroBTS can be equipped with one BATTERYM module for AC power supply.


If the backup battery fails, operation continues as long as the AC/DCPSC units are available.

4.7.5 Heater

The heater heats up the e-MicroBTS, if the temperature inside the shelter is below the operating temperature range.

There are four different types of heaters depending on the power supply available. They are connected directly to the mains (115 V / 230 V).

Each base cabinet of the e-MicroBTS can be equipped with one HEATERM module.


If the heater is faulty, the e-MicroBTS operates as long as the temperature inside the shelter is within the defined operating range. If the temperature falls below the lower threshold of the defined range, all AC/DC converters are switched off and the e-MicroBTS goes down. If the internal temperature returns to the defined operating range again, the e-MicroBTS goes automatically back into operation.

If the maximum allowed temperature is exceeded the heater is automatically switched off.



33

4.7.6 Abis Link Equipment

The link equipment acts as a front end for connection of PCMB lines. Different equipment is available for wired, optical fiber or radio transmission.

PCM24/30 connectivity is always available on the M:COBAM module. Any other link equipment is available as M:TIFx or A:TIFx modules. The ‘x’ attached to the module name indicates possible future Abis interface types, e.g. S0 or xDSL.

The M:TIFx is an optional module for the master base unit, only. The extension cabinet does not comprise an M:TIFx module. If a cabinet is not equipped with an M:TIFx module, a simple metal box without electrical functions (CP:TIF) is used to maintain the original airflow.

The following types of add-on TIF are available

��A:TIFMW supporting SRA-L operation and

��A:TIFNTPM supporting NTPM (wired) and

��A:NTPMFG (optical fiber) network terminating equipment.

The A:TIFMW has special lightning protection for a microwave Abis link via SRA-L (exclusively). If a base cabinet is equipped with A:TIFMW, it must also contain M:OVPTM (M:OVPTCOAXM is not allowed in this case).

The A:TIFNTPM is the network termination for wired (NTPM) or optical fiber (NTPMFG) terrestrial interface.

A:TIFNTPM must not be placed directly on top of A:DUAMCOM. The cooling device A:COOLING is required in this case between A:TIFNTPM (bottom) and A:DUAMCOM (top). A:COOLING contains a radially-blowing fan in an add-on enclosure.


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34

4.7.7 Integrated Antenna

The integrated antenna (INTENNA) is composed of dual slanted patch antennas. This type of antenna complies with the mechanical dimensions of the e-MicroBTS even in the "long wave" GSM900 frequency range. Furthermore its flat shape makes it possible to integrate it into the overall mechanical concept.

Nevertheless, the INTENNA may be used in a stand-alone configuration separated from the e-MicroBTS.

The INTENNA consists of two subunits. Each subunit is able to support two carriers and consists of one dual slanted patch antenna for R-GSM and two in case of GSM1800 or GSM1900.

One of the advantages of the INTENNA is that no antennas are visible.

Name Patch 1 Patch 2 Application

INTENNARGRGV1 R-GSM900 R-GSM900 supports up to 4 R-GSM carriers

INTENNARGDPV1 R-GSM900 GSM1800 / GSM1900

supports up to 2 R-GSM and 2 GSM1800 / GSM1900 carriers

INTENNADPDPV1 GSM1800 / GSM1900

GSM1800 / GSM1900

supports up to 4 GSM1800 / GSM1900 carriers

The e-MicroBTS can be operated with the INTENNA or external antennas. The INTENNA can only be used in conjunction with on-air combining. External antennae can be used both for on-air or DUAMCO combining. DUAMCO combining should be performed with external antennas only.

If the e-MicroBTS covers more than one cell, also a mixed use of the INTENNA and external antennas is possible. However, within one cell only one type of antenna is allowed (integrated or external).



35

5 Example Configurations


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© 2001 Siemens AG

36

On the next pages, some examples are given how to combine the carriers to the antenna system.

The antenna configurations are subdivided into three configurations:

Configurations with complete receive diversity of all cells/carriers (full antenna diversity), configurations, where some cells/carriers do not comprise antenna diversity (partial antenna diversity), and configurations without antenna diversity.

Since diversity is a very important issue, emphasis is laid on the configurations with full antenna diversity. Nevertheless, there might be the need of saving antennae while accepting the lack of diversity. Therefore, configurations with partial and without diversity are presented as well.

The examples shown are dual-band configurations.

Note: For one DCU / add-on module frequency bands cannot be mixed.

For standard configurations, neither RX nor TX antenna combining is allowed between cabinet borders, i.e. there are no RF cables running between master and extension cabinets. Thus, some configurations are restricted to partial diversity or no diversity.

However, emphasis may be placed on having full diversity for all carriers. Example: 8 carriers in one cell with two cabinets and only two antennae available. For this case, the standard configurations exclude a full diversity scenario. However, full diversity can be achieved (in a non-standard configuration) if two additional cables (combined with two power splitters) are set up between master and extension cabinets. Due to lightning protection, such a configuration should only be used indoor.



37

5.1 Configurations with Full Diversity

RX TX RX TX RX TX RX TX

Cell 0

MasterCabinet

DCUDUXx0 DCUDUXx1

Cell 1

MasterCabinet ExtensionCabinet

Cabinet Border

CP:DCU

RX TX RX TXRX TX RX TX RX TX RX TX

Cell 0

DCUDUXx0 DCUDUXx1

Cell 1

RX TX RX TX

DCUDUXx2


Cabinet Border

Cell 1


Cell 0

DCUDUXx0 DCUDUXx1

RX TX RX TX

DCUDUXx2

RX TX RX TX

DCUDUXx3

a) b)

c)

Fig. 16 Standard Configuration a) 2 cells, 4 carriers with on-air combining, b) 2 cells, 4+1 carriers with on-air combining, c) 2 cells, 4+3 carriers with on-air-combining

MasterCabinet

Cell 0

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

ExtensionCabinet

Cell 1

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

Cabinet Border

MasterCabinet

Cell 0

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

ExtensionCabinet

Cell 1

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

Cabinet Border

DCULGx2

RX TX RX TX

CP:DCU

RX TX RX TX

a) b) DCULGx2

RX TX RX TX

CP:DCU

RX TX RX TX

Fig. 17 Standard Configuration for a) 2 cells, 4+1 carriers with DUAMCO2:1 combining, b) 2 cells, 4+2 carriers with DUAMCO2:1 combining


MN1780EU09MN_0001

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38

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

Master Cabinet Extension Cabinet

Cabinet Border


DCUDUXx0 DCUDUXx1


Cabinet Border

Cell 0

DCUDUXx0

RX TX RX TX

CP:DCU

RX TX RX TX

b)

Cell 0 Cell 1

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

Cell 1

a)

Fig. 18 Standard Configuration for a) 2 cells, 4+2 carriers with on-air and DUAMCO2:1 combining, b) 2 cells, 4+4 carriers with on-air and DUAMCO2:1 combining

Master Cabinet

Cell 2

Extension Cabinet

Cabinet Border

Cell 0 Cell 1

CP:DCU

RX TX RX TXRX TX RX TX

DCUDUXx2

RX TX RX TX

DCUDUXx1

RX TX RX TX

DCUDUXx0


Cabinet Border

Cell 2


Cell 0

DCUDUXx0 DCUDUXx1

RX TX RX TX

DCUDUXx2

Cell 1

RX TX RX TX

DCUDUXx3a) b)

Master Cabinet


Cell 2

Extension Cabinet

Cabinet Border


Cell 0

DCUDUXx0 DCUDUXx1 DCUDUXx2 DCUDUXx3

Cell 1 Cell 3

c)

Fig. 19 Standard Configuration for a) 3 cells, 3 carriers, b) 3 cells, 4+3 carriers with on-air combining, c) 4 cells, 4+4 carriers with on-air combining



39

5.2 Configurations with Partial Diversity

a)RX TX RX TX

DCUDUXx0

Cell 0 Cell 1

RX TX RX

DCUDUXx1


Cabinet Border

RX TX RX TXRX TX RX TX RX TX RX TX

Cell 0

DCUDUXx0 DCUDUXx1

RX TX RX TX

DCUDUXx2

Cell 1

b)

MasterCabinet

PD PD

DCUDUXx3

Fig. 20 Standard Configuration for a) 2 cells, 3 carriers with on-air combining, b) 2 cells, 4+3 carriers with on-air combining

5.3 Configurations without Diversity

a)

Cell 0

Master Cabinet

RX TX RX TX

CP:DCU

RX TX RX TX

Cell 1

TXRX

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

Cell 0

A:DUAMCO4M

Master Cabinet

TXRX

DCULGx2

RX TX RX TX

DCULGx3

RX TX RX TX

Cell 1

A:DUAMCO4M

Extension Cabinet

Cabinet Border

b)DCUDUXx0

Fig. 21 Standard Configuration for a) 2 cells, 2 carriers, b) 2 cells, 4+4 carriers with DUAMCO4:1 combining


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41

6 Exercises


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42



43

��How many carriers does e-MicroBTS support? How many cabinets are required? Which module limits TRX capacity?

��Name the most important e-MicroBTS modules (and compare with BS24x)! Are there different types of e-MicroBTS for indoor and outdoor application?

��Compare e-MicroBTS with picoBTS (modules, typical features e.g. output power, diversity etc.)

��Which types of combining do e-MicroBTS support? What are the respective advantages? Does the choice of combining option influence the types of modules used?

��Which types of carrier units are available for e-MicroBTS? Do they support dual band operation? Are any combinations of carrier unit numbers in different bands available?

��Name three add-on modules! Are they optional or mandatory?

��Which antenna options does e-MicroBTS offer? What are the respective advantages? How does the choice of antenna relate to the combining equipment?



45

Exercise 1

Title: Standard Configurations with Single Cells at Full Diversity

Objectives: Getting familiar with e-MicroBTS configurations

Task

Complete the configurations!

Cell 0

Master Cabinet

DCUDUXx0

RX TX RX TX

CP:DCU

RX TX RX TX

Master Cabinet

RX TX RX TX

Extension Cabinet

Cabinet Border


Cell 0

DCUDUXx0 DCUDUXx1 DCUDUXx2 CP:DCU

RX TX RX TX

a) b)

d)

Cell 0

Master Cabinet

CP:DCU


DCUDUXx0 c)RX TX RX TX

Master Cabinet

DCUDUXx0

Cell 0

RX TX RX TX

DCUDUXx1

Fig. 22 Standard configuration for a) 1 cell, 1 carrier, b) 1 cell, 2 carriers, c) 1 cell, 3 carriers



47

Exercise 2

Title: Standard Configurations with 2 Cells at Full Diversity

Objectives Getting familiar with e-MicroBTS configurations

Task


Master Cabinet

Cell 0

A:DUAMCO2M

TXRX TXRX

DCULGx0

RXTX RXTX

DCULGx1

RXTX RXTX

Extension Cabinet

Cell 1

A:DUAMCO2M

TXRX TXRX

Cabinet Border

Master Cabinet

Cell 0

A:DUAMCO2M

TXRX TXRX

DCULGx0

RX TX RXTX

DCULGx1

RXTX RXTX

Extension Cabinet

Cell 1

A:DUAMCO2M

TXRX TXRX

Cabinet Border

DCULGx2

RXTX RXTX

CP:DCU

RXTX RXTX

a) b) DCULGx2

RXTX RXTX

CP:DCU

RXTX RXTX

Fig. 23 Standard Configurations with a) 2 cells, 4+1 carriers, b) 2 cells, 4+2 carriers



49

Exercise 3

Title: Configurations with Partial Diversity

Objectives: Getting familiar with e-MicroBTS Configurations

Task

Complete the configuration!

a) b)

c)

RX TX RXTX

Master Cabinet

DCUDUXx0

Cell 0

RX TX RXTX

DCUDUXx1


Cabinet Border

RX TX RXTX

CP:DCU

RX TX RXTX

DCUDUXx2

RX TX RXTX RX TX RX TX

Cell 0

DCUDUXx0 DCUDUXx1

RX TX RXTX

DCUDUXx0

Cell 0 Cell 1

RX TX RX

DCUDUXx1


Cabinet Border

Cell 2

RX TX RXTX

DCUDUXx3

RX TX RXTX RX TX RX TX

Cell 0

DCUDUXx0 DCUDUXx1

RX TX RXTX

DCUDUXx2

Cell 1

d)

PD PD

PD PD

Fig. 24 Standard configurations for a) 1 cell, 3 carriers, b) 1 cell, 4+1 carriers, c) 2 cells, 3 carriers, d) 3 cells, 4+3 carriers



51

Exercise 4

Title: Configuration without Diversity


Pre-requisite:

Task


a) b)

c)

Cell 0

Master Cabinet

DCUDUXx0

RX TX RX TX

CP:DCU

RX TX RX TX

Cell 1

Master Cabinet

RX TX RX TX

CP:DCU

RX TX RX TX

Extension Cabinet

Cabinet Border


DCUDUXx0 DCUDUXx1 DCUDUXx2

Cell 0 Cell 1 Cell 2 Cell 3 Cell 4 Cell 5

Cell 0

Master Cabinet

RX TX RX TX

CP:DCU

RX TX RX TX

DCUDUXx0

Fig. 25 Standard configurations for a) 1 cell, 1 carrier, b) 2 cells, 2 carriers, c) 6 cells, 4+2 carriers



53

7 Solutions



55

Solution 1

Title: Standard Configurations with Single Cells at Full Diversity


Task


Cell 0

Master Cabinet

DCUDUXx0

RX TX RX TX

CP:DCU

RX TX RX TX

Master Cabinet

RX TX RX TX

Extension Cabinet

Cabinet Border


Cell 0

DCUDUXx0 DCUDUXx1 DCUDUXx2 CP:DCU

RX TX RX TX

a) b)

d)

Cell 0

Master Cabinet

CP:DCU


DCUDUXx0 c)RX TX RX TX

Master Cabinet

DCUDUXx0

Cell 0

RX TX RX TX

DCUDUXx1

Fig. 26 Standard configuration for a) 1 cell, 1 carrier, b) 1 cell, 2 carriers, c) 1 cell, 3 carriers



57

Solution 2

Title: Standard Configurations with 2 Cells at Full Diversity


Task


Master Cabinet

Cell 0

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

Extension Ca

Cell 1

A:DUAMCO2M

TXRX

A:DUAMC

Cabinet Border

Master Cabinet

Cell 0

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

DCULGx0

RX TX RX TX

DCULGx1

RX TX RX TX

Extension Cabinet

Cell 1

A:DUAMCO2M

TXRX TXRX

A:DUAMCO2M

Cabinet Border

DCULGx2

RX TX RX TX

CP:DCU

RX TX RX TX

a) b) DCULGx2

RX TX RX TX RX

Fig. 27 Standard configuration for a) 2 cells, 4+1 carriers, b) 2 cells, 4+2 carriers



59

Solution 3

Title: Configurations with Partial Diversity


Task


a) b)

c)

RX TX RX TX

Master Cabinet

DCUDUXx0

Cell 0

RX TX RX TX

DCUDUXx1


Cabinet Border

RX TX RX TX

CP:DCU

RX TX RX TX

DCUDUXx2


Cell 0

DCUDUXx0 DCUDUXx1

RX TX RX TX

DCUDUXx0

Cell 0 Cell 1

RX TX RX

DCUDUXx1


Cabinet Border

Cell 2

RX TX RX TX

DCUDUXx3


Cell 0

DCUDUXx0 DCUDUXx1

RX TX RX TX

DCUDUXx2

Cell 1

d)

PD PD

PD PD

Fig. 28 Standard configurations for a) 1 cell, 3 carriers, b) 1 cell, 4+1 carriers, c) 2 cells, 3 carriers, d) 3 cells, 4+3 carriers



61

Solution 4

Title: Configurations without Diversity


Task


a) b)

c)

Cell 0

Master Cabinet

DCUDUXx0

RX TX RX TX

CP:DCU

RX TX RX TX

Cell 1

Master Cabinet

RX TX RX TX

CP:DCU

RX TX RX TX

Extension Cabinet

Cabinet Border


DCUDUXx0 DCUDUXx1 DCUDUXx2

Cell 0 Cell 1 Cell 2 Cell 3 Cell 4 Cell 5

Cell 0

Master Cabinet

RX TX RX TX

CP:DCU

RX TX RX TX

DCUDUXx0

Fig. 29 Standard configurations for a) 1 cell, 1 carrier, b) 2 cells, 2 carriers, c) 6 cells, 4+2 carriers

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