sral

SRA L

Low Capacity Digital

Radio System

Introduction

In most countries the largeintroduction of mobile andpersonal telephony and newconcepts in the access networkare greatly increasing the marketof low capacity radios operatingin the RF bands starting from 7up to the millimeter wave bandsof 38 and also 55 GHz. Inparticular GSM and then DCS andRLL (Radio in the Local Loop)technologies (DECT, CDMA, etc.),together with access andsubscriber distribution networkrequire, for the connection amongequipment, very agile and flexibleradio links.

The combination of severalfactors (quick provision and highreliability of the service, veryshort hop lengths and urbanenvironment) has been changingthe requirements that a radiosystem must satisfy in terms offlexibility, performance,management and frequencybands used.

Siemens, in order to meet themarket demand, has developed anew family of low capacity digitalradios, the SRA L, with a systemconcept applicable to frequencybands ranging from 7 to 55 GHzwith a capacity of 2/2x2, 4x2 and8x2 Mbit/s. This large frequencycoverage is necessary to satisfydifferent network configurationsand different propagationconditions.

General

SRA L Indoor Equipment

Thanks to the experience recentlymatured with the latestgenerations of SDH high andmedium capacity radios, one ofthe main targets for SRA L is toreduce dimensions and deliverytime. This objective is achievedbasing the design on the fulldigital concept and on state-of-the-art technologies in RFelectronics and VLSI componentsat baseband level and exploitingas much commonality as possibleamong the different systemconfigurations and RF bands.

The technology employed allowsthe radio system to have theindoor unit completely frequency-independent and to be, on thewhole, capacity-independent,being possible to change the bitrate transmitted by means ofsimple software commands.

The flexibility of the system isfurtherly increased thanks to thepossibility to set, via simplesoftware commands, theoperating radio frequency,transmitter and receiver side, theoutput power, the configurationof the radio system (unprotected,protected, add/drop repeater, ...)and so on.

In order to keep the complexity ofthe RF amplifier low, consideringalso the frequency bandsinvolved, a modulation particularlystrong against non linearity hasbeen chosen: CPM - ContinuousPhase Modulation.

The main characteristics of thesystem in order to satisfy thenew market requirements can besummed up as follows:

Flexibility, obtained by:

• large frequency coverage(RF bands from 7 up to38 GHz with possibility toexpand the family to theRF bands from 7 up to55 GHz) using the sameindoor unit

• maximum frequencytunability within the selectedRF band

• software controlledoperating RF setting

• software controlled systemcapacity without anyhardware change

• software controlled outputpower setting

• flexible system structure(unprotected/protected,terminal/repeater)

Ease of installation, obtainedby indoor and outdoor unitswhich are small in size andlight in weight and the use of asingle coaxial cable for theirinterconnection. Moreover, theoutdoor unit is directlyconnected to the rear of theantenna support by means of astandard RF interface withoutany waveguide and fixed to itby means of four retaininglatches. The antenna itself isfixed to the pole by means ofan appropriate mountingstructure

Very low power consumptionthanks to the use of state-of-the-art technologies in RFelectronics and of VLSIcomponents at baseband levelwhich also results in a bettersystem reliability

No fan use, very important togreatly improve the reliability ofthe system (a version with aprotected fan is available forenlarged temperature rangeapplications)

Built-in advanced managementfacilities, with possibility ofremote management from aNetwork PC or the SiemensNetwork ManagementSystems (NMS)

Improved quality andperformance monitoring (as perITU-T Recc. G.826) withrespect to the previous LCDRgenerations

Management integration insideSiemens SDH NetworkManagement System EM-OS

Mechanical and electricalintegration inside Siemensmobile network BTS’s outdoorshelters

Mechanical and electricalintegration inside SiemensDECTlink (the SiemensRLL equipment based on DECTtechnology) and CDMAlink (theSiemens RLL equipment basedon CDMA technology) RBC’s(Radio Base Station Controller)outdoor shelters

Management integration insideSiemens NetworkManagement System foraccess network including RLLnetwork elements Access/Integrator.

RF Channel Arrangements

The SRA L digital radio system ispresently intended to operate inthe 7, 8, 10,5, 13, 15, 18, 23, 26and 38 GHz frequency bands,with a channel spacing of 3.5, 7

and 14 MHz for 2/2x2, 4x2 and8x2 Mbit/s capacity respectively.Thanks to the high spectrumefficiency of the CPM formatchosen, it is possible to fulfill therelevant ETSI masks eventransmitting a high gross bit rate(nearly 5, 10 and 20 Mbit/s for the2x2, 4x2 and 8x2 Mbit/s capacityrespectively).

In the table below the detailedfrequency bands of the SRA Ldigital radio system are reportedtogether with the relevant ITU-RRecommendations.

Furthermore, the system conceptand the technologies adoptedallows to cover the full range ofRF bands from 7 up to 55 GHzwith very few hardware changesof RF modules.

Management of SRA L from a PC

Frequency bands (GHz) ITU-R

7.1-7.9 3858.2-8.5 38610.5-10.7 74712,75 - 13,25 49714.4-15.35 63617.7-19.7 59521.2-23.6 63724.5-26.5 74837.0-39.5 749

SRA L is a completely newgeneration of low capacity SHFand millimetre wave radios, thefeatures of which make themideal to meet the requirements inmobile and personal telephonyinfrastructures and in the outerlayer of a telecommunicationnetwork.

The main applications foreseenfor the SRA L digital radio systemare the following:

BTS interconnections in cellularand future microcellular andpicocellular mobile andpersonal communicationnetworks; the amount of smallcells, mainly in urban areas,puts the problem of a very highnumber of short links that onlyvery flexible and easyinstallation radios in millimetricbands, for path clearance,increased frequency reuse andease of installation, canovercome (Fig. 1)

Network elementsinterconnections for the newRadio into the Local Loop (RLL)applications and technologies(DECT, CDMA, etc.), which arealso very promising for newprivate access networkoperators (Fig. 2).

Point-to-point links in accessand subscriber distributionnetworks for the constructionof very short links of a fewkilometers in remote areas orareas with access difficulties(e.g. across a river)

Corporate networksinterconnection; SRA L is verywell suited to the constructionof inter-PABX links and inter-LAN networks when used inconjunction with bridges androuters. These applications canbe implemented in manydifferent contexts overtransmission distances rangingfrom a few hundred metersbetween two buildings toseveral kilometers betweentwo sites

Emergency and temporarylinks to be started in recordtime. This asset is essential toprovide temporary connectionsor to replace failedtransmission equipment

Applications

Fast growing networks, inparticular access networks likethe ones owned by newprivate operators in newlyderegulated markets where thequickest and cheapest way toget up and running is via digitalmicrowave radio

BTS

BTS BTS

BTS

4/8x2 Mbit/s

4/8x2 Mbit/s4/8x2 Mbit/s

4/8x2 Mbit/s 4/8x2 Mbit/s

BTS BTS

BTS

BSC

2 Mbit/s

2x2 Mbit/s

2 Mbit/s4x2 Mbit/s

BTS

BTS

2 Mbit/sBSC

MSC

Switch

PSTN/ISDN

21x2 Mbit/s

STM-1

RBS

RBS

RBS

RBS

RBC

RBC

RBS

RBS

RBS

RBS

RBS

RBS

RBS

RBS

RBC

RBC

RBS

RBS

RBS

RBS

RBS

RBS

RBS

RBS

RBC

RBC

RBS

RBS

RBS

RBS

RBS

RBS

RBS

RBS

RBC

RBC

RBS

RBS

RBS

RBS

RDU RDU

Switch

16 x V5.1 16 x V5.1

4/8 x 2 Mbit/snon redundant

RBS Radio Base Station

RBC Radio Base Station Controller

RDU Radio Distribution Unit

Figure 1 SRA L - Mobile and Personal Communication Networks Application

Figure 2 SRA L - RLL Networks Application (example)

The system design is based onthe use of the most advancedtechnologies and a big effort hasbeen made to transfer complexityfrom analog to digital hardware inorder to take advantage ofcustomised integration (ASICs)and to improve reliability.

The nature of this technologyresults in RF electronics small insize, light in weight, low in powerconsumption and high inreliability. Besides, the high levelof integration and the reducednumber of interconnectionsbetween modules together withthe choice of a Continuous PhaseModulation (CPM) schemeimproves mechanical resistanceto the shocks and vibrations thatare inevitable in outdoorinstallation environments andresults in better stability andimmunity to phase hits andmicrophony.

A full multirate processing in therange 4:1 was the mostchallenging task in implementinga number of functions likemultiplexing, add/dropping, signalframing, signal coding, ForwardError Correction, Tx/Rx signalshaping, modulation anddemodulation processes. Thus, afull multirate capability has beenobtained by a fully programmablebaseband/modemodulationhardware and an extensive use ofDigital Signal Processing (DSP).

A particular Continuous PhaseModulation (CPM) format,obtained by properly shaping thepulses to be modulated to meetthe ETSI masks for emittedspectral power density even withvery high gross bit rates, hasbeen adopted. This, thanks to itshigh immunity to non-linearities,allows carrier frequencymultiplication and high efficiencynon linear saturated poweramplifiers, so allowing reducedmechanical dimensions and lowerpower consumption.

Technology

The choice of a differentialdemodulation associated withViterbi decoding makes the SRA Lsystem particularly resistant tofrequency short term instability,frequency jumps and RF oscillatorphase noise, so improving itsrobustness against mechanicalshocks, vibrations andtemperature changes.

The reduced needed transmitteroutput back-off and the use ofViterbi decoding gives to SRA Lan advantage of system gain inthe order of 3 dB in respect tousual shaped QPSK (4-QAM)solutions with coherentdemodulation.

At RF level a Modulation TransferLoop (MTL) is adopted to directlytranspose to RF the modulatedsignal while the final stage

amplifier is realized with chip-and-wire technology up to 23 GHzand with MMIC technology over26 GHz.

The Tx output power control isoperated, on a 24 dB range,through a linear RF attenuatorwith associated feedback control.

A dual UHF synthesizer is usedfor frequency control and setting,so that the system is as much aspossible independent from theTx/Rx frequency spacing.

The technology used and theoutdoor unit architecture chosenallow to include all theRF- dependent parts of thesystem in one single block in themicrowave section so reducingdeveloping time for new RFbands and delivery time of theequipment.

SRA L Outdoor Unit

The key features of the systemare:

Performance improvementthrough advanced technologysolutions

Forward Error Correction (FEC)

The equipment includes a ReedSolomon error’s corrector (FEC)with a correction capability of upto 5 errored bytes per frame.This improves the system gainof SRA L

RF independent Indoor Unit

Any indoor unit can be used withany outdoor unit since they areseparately produced and tested infactory.

Large RF bands coverage

The SRA L equipment ispresently intended to operate inthe 7, 8, 10.5, 13, 15, 18, 23, 26and 38 GHz RF bands, but acomplete frequency coveragefrom 7 to 55 GHz can be veryeasily obtained by changing onlyfew RF modules into the ODU.

Wide frequency coverage ofRF units and synthesizer(minimum a whole sub-band)

System configuration-independent mechanicalarrangement

All system configurationsavailable make use of the sameblocks (hardware) and theconfiguration change isperformed via software.

The following configurations areavailable using the same 2 19"rack units high indoor shelf onlywith software commands andusing a number of radio transportmodule cards (the BB-modemcards) and ODU’s equivalent tothe needed transceivers:

• (1+0)

• 2x(1+0)

• through repeater

• add/drop repeater

• (1+1) hot stand-by on 1 or2 antennas (space diversityoption)

• (1+1) frequency diversity on2 antennas (space diversity)

Software controlled capacityupgrading (from 2 up to8x2 Mbit/s)

The indoor unit of the equipmentadopts a baseband structurepermitting the software setting,from the Local or Network PC orfrom the management system, ofthe transport capacity while thesame outdoor unit is adopted forall the capacities foreseen.

The effective maximum capacityavailable by using a particularindoor unit is then fixed viasoftware and is managed bymeans of licence fees. Four typesof licences are foreseen:

• 2 Mbit/s fixed capacity

• up to 2x2 Mbit/s programmablecapacity

• up to 4x2 Mbit/s programmablecapacity

• up to 8x2 Mbit/s programmablecapacity

Outstanding features

Figure 3 SRA L - (1+1) Configuration on 2 Antennas

Maximum software controlledin-field frequency tunability

The in-field tunability of SRA L isonly limited by the RF filtersbandwidth limitation necessary toobtain the requested Tx/Rxisolation

Software controlled outputpower setting (24 dB range)

This feature is useful to decreasetransmitted power when theradio is used for very short hoplengths so reducing interferencestowards other links and improvingthe nodal efficiency and theflexibility of the system. Besides,better frequency re-use can beobtained.

Mechanical compactness

The SRA L radio system indoorunit is arranged in a 2 19" rackunits high shelf, where indoorelectronics for two (1+0)unprotected systems, also in add/drop repeater configuration, orone (1+1) hot stand-by orfrequency diversity protectedsystem can be housed.Besides, mechanically compactand light outdoor unit providesease of handling for equipmentset-up and commissioning. Twoof these identical ODU’s are usedfor the (1+1) protected or 2x(1+0)configuration.

The antenna diameters foreseenfor integrated installation with theODU are 30, 60 and/or 120 cmdepending on the RF band.

Figure 4 SRA L - (1+1) Configuration on 1 Antenna

Easy and quick installation

Besides the reduced mechanicaldimensions and weights of IDUand ODU, the installation of theSRA L radio system is made veryeasy and quick thanks to theadoption of a front access onlyIDU (front/rear access can beoffered on request), the adoptionof a single coaxial cable for theconnection between IDU andODU and of a very easy and quickmounting of the outdoor case onthe antenna support by means offour retaining latches avoiding theuse of any waveguide.

The protected configuration isobtained using either a dualantenna mechanical structurewith each ODU connected to thecorrespondent antenna in thesame way as per the singleconfiguration (see Fig. 3) orconnecting the two ODU’s to asingle antenna by means of a RFcoupler (hot stand-by) (see Fig. 4).In both cases the ODU’s are

connected to the antenna supportitself without using anywaveguide.

Low power consumption

The use of state-of-the-art RFtechnologies in the microwavepart and of VLSI circuits atbaseband level has provedremarkably important in reducingpower consumption, in increasingthe system reliability and inavoiding the use of any fan in theIDU.

No fan use in the IDU (fornormal temperature range)

Built-in advanced managementfacilities.

A suitable network elementconcept and an optimizedembedded software architecturehave been selected to allow botha stand alone radio management(Local and Network Remote PC)and a radio management fully

integrated with the SiemensNetwork Management Systems(NMS). From these all thesoftware selectable parametersof the SRA L system (likecapacity, RF channel, systemconfiguration, output power, etc.)can be set and checked while acomplete fault management andperformance monitoring, as perG.826 standard, can beperformed locally (Local PC) orremotely (Network PC or NMS).

Improved quality andperformance monitoring (as perITU-T G.826)

Local and remote basebandloopbacks (at 2 Mbit/s level)

Mechanical integration intoSiemens BTS outdoor shelters

Two different outdoorconfigurations are foreseen forthe BTS’s of the new Siemensgeneration of mobile networkequipment, the SBS (SiemensBase Station). One of these,called BS 61, is able to house sixGSM or DCS transceivers and theother, called BS 21, twotransceivers.

Inside the BS 61 outdoor shelterroom for six 19" rack units IDUequipment has been left empty,while room for two 19" rack unitsIDU equipment is present insidethe BS 21 outdoor shelter.

So three standard IDU’s(corresponding to a maximum ofsix transceivers) can beintegrated into the BS 61 outdoorshelter and one IDU (twotransceivers) in the BS 21 one. Inthis way the overall system costcan be significantly reduced

Mechanical integration intoSiemens Dectlink Radio BaseStation Controller (RBC)outdoor shelter

This allows Siemens to be in theposition to offer a compact, easyto install and affordable solutionfor Radio in the Local Loopapplications.

Management integration insideSiemens SDH NetworkManagement System EM-OS

Management integration insideSiemens NetworkManagement System foraccess network including RLLnetwork elements Access/Integrator

Software downloading.

SRA L Outdoor equipment for add/drop repeater configuration

The engineering of the SRA Ldigital radio system ischaracterized by the highoperating frequency. For thisreason, in order to minimize thefeeder loss and the installationtime, an indoor/outdoor splitconfiguration has been chosen.The indoor part, consisting of thebaseband and IF units, isconnected by means of one (two)single IF coaxial cable to one(two) very compact outdoortransceiver integrated with theantenna (see Fig 5).

Taking into account the networkapplications foreseen for theequipment and the RF bandsadopted, the following systemconfigurations are made available,using the same indoor shelf andthe same indoor blocks (thenumber of radio transportmodules fit in the shelf is equal tothe number of transceivers):

System Building Blocks

IndoorUnit

OutdoorUnit

OutdoorUnit

PLO

PLO

Rx 70 MHz, FSK 5.5 MHz

coax cable (max length 400m)

Tx 320 MHz, FSK 6.5 MHz, VDC

F(local PC)

Qx/Q3(optional)

64 kbit/sbus structured RS 485

2/2x2/4x2/8x2 Mbit/s

64 kbit/s V.11

EOW (optional)

- radio transport module (up to 2) (BB / Modem unit)- controller- tributary interface- EOW (optional)- Q-Adapter- BB hitless switch

- transmitter- receiver- ODU slave controller- IF diplexer- RF diplexer- dual synthesizer- Tx VCO- Rx VCO- RF switch- power supply unit

Figure 5 SRA L - System Architecture

All the above mentionedconfigurations use the samemechanical structure with regardsto the indoor equipment and thechange of configuration isperformed via software (one radiotransport module is added to passfrom (1+0) to (1+1) or 2x(1+0) orrepeater configuration).

With regards to the outdoor unit asingle compact mechanicalstructure is foreseen for thesingle terminal configuration andtwo of these identical mechanicalstructures for the otherconfigurations.

In case of unprotectedconfigurations the ODU is directlyconnected to the rear of theantenna support by means of astandard RF connector and fixedto it by means of four retaininglatches without using anywaveguide. The remote mounting

of the ODU separated from theantenna, useful for examplewhen an antenna bigger than thestandard one is used for very longhops, can be obtained thanks tothe use of a kit for the mountingof the ODU to the pole and of astandard waveguide.

For the protected configurationstwo solutions are available, thefirst using the same standardODU/antenna mechanicalarrangement used in theunprotected configuration withthe two ODUs directly connectedto the rear of two differentantennas (normally used with30 cm diameter antennas) (seeFig. 3), and the second one usinga kit composed of a RF couplerand the supporting hardware forthe connection of the 2 ODUs toa single antenna (normally usedwith 60 and 120 cm diameterantennas) (see Fig. 4). In bothcases the ODUs are connected tothe antenna support itself (and nowaveguide is needed). The firstmounting structure allows tohave no additional RF losses withrespect to the unprotectedconfiguration and the same easeof installation, while the second

• single terminal (1+0)• dual terminal 2x(1+0)• through repeater (unprotected)• add/drop repeater (unprotected)• hot stand-by protected terminal (1+1) (on 1 or 2 antennas)• frequency diversity protected terminal (1+1) (on 2 antennas)

one is advisable when a lowerenvironmental impact is needed.When an antenna different fromthe SRA L standard one, forexample a bigger one for verylong hops, is used, a kit for themounting of the two ODUs andthe RF coupler to the pole and astandard waveguide are used.

In Fig. 5 the location of thesubunits composing the SRA Ldigital radio system is showntogether with the availableexternal interfaces and thecommunication service channelbetween indoor and outdoor parts(FSK signals) necessary for alarm,status and configuration datatransmission.

Indoor Unit

In Fig. 6 a block diagram of theindoor part of the equipment isreported.

Each block represented in thisdiagram corresponds to a singlecard housed in a 2 19" units highshelf assembly, also compatiblewith a 600x300 mm ETSIstandard rack (see Fig. 7).

The multirate capability isobtained by a fully programmablebaseband/modem hardwareimplemented into the radio

Figure 6 SRA L - Indoor Unit Block Diagram

Radio Transport ModuleAvailable Configurations (same IDU)- (1+0)- 2x(1+0)- (1+1) hot stand-by- (1+1) frequency diversity- space diversity option (HSB and F.D.)- unprotected through repeater- unprotected add/drop repeater

Radio Transport Module

Q-Adapter(opt.)

EOW(opt.)

Controller

TributaryInterface

(75 or 120 ohm)

Alarm

Unit

Figure 7 SRA L - Indoor Unit Equipment Layout

transport module card. One ortwo of these cards can be fit intothe indoor assembly so that theIDU, common to all RF bands,has been implemented with aflexible and modular structure,able to be set in different systemconfigurations:

(1+0) or 2x(1+0) configuration,to be adopted for unprotectedpoint-to-point links or starnetworks

add/drop or through repeaterfor ring (multidrop) networks

(1+1) configuration withfrequency diversity or hotstand-by protection

The radio transport module cardperforms all the basebandprocessing, modemodulationfunctions, IF conversions, thecable multiplexing and protectionand the management of

telemetry channel. Furthermorethis card houses an hitless switchworking on the aggregate signalto offer protection againstmultipath fadings (considerable inthe RF bands from 7 up to 18GHz) in the frequency and spacediversity configuration with anerror-free switching.

Furthermore, the hardwareprotection of the radio transportmodule card itself againstbreakdown is performed bymeans of a switch operating at2 Mbit/s level.

The tributary interface card (onefor each IDU) is used forimpedance adaptation of the2 Mbit/s interfaces and theirprotection against lightningpulses.

The controller card is in charge ofinternal supervision and protocolhandling towards local and

Tx

Rx

Transport Module

Modem Baseband

TributaryInterface

up to 8x2 Mbit/s

Tx

RxModemBaseband

IDU

ODU ODU

EOW

(opt.)

Q-Adapter

(opt.)Controller

Alarm

Unit

local PC

Q interface 64 kbit/s RS 485

Transport Module

Outdoor Unit

Several requirements have beentaken into account during thedesign of the external transceiver:high compactness and simplicity,frequency agility over at least halfa sub-band (~ 500 MHz) andelectronic tunability, low powerconsumption.

In Fig. 8 a simplified blockdiagram of the ODU with themain IF/RF system functions isshown.

The complete frequencycoverage from 7 to 38 GHz isobtained by changing only fewmodules into the ODU, being thedifferent RF bands obtainedthrough RF frequencymultiplication.

Within the particular frequencyband a typical half-band tunabilityis obtained through independentTx/Rx synthesized VCOsassociated with a modulationtransfer loop to directly transposeto RF the modulated signal which

is digitally processed within theIDU. The RF filters are of themaximum bandwidth allowed forthe chosen RF band and Tx/Rxspacing to maximize in-fieldtunability.

Signalling interfaces to/from IDU,including the complete setting ofRF parameters (Tx/Rx frequency,Tx power, multiplication factor, IFselectivity), is managed, throughan ODU on-board microprocessor,by the IDU controller card.

A complete system setting interms of configuration andfrequency capacity, in addition tothe above mentioned RFparameters, is also operated bythe controller card in a local (LocalPC) or remote (Network PC orNMS) mode.

remote management interfaces,while the alarm card is used tohave a parallel alarm interface.

The equipment can also includethe following two units asoptions:

The Q-Adapter card, to beinstalled in the gatewaynetwork element restituting aQx/Q3 (or a QD2) interfacetowards the networkmanagement system.

The EOW card that allowsbuilding up a service channelnetwork adopting DTMFsignalling (selective calling).The same EOW card can beused during the installationphase for telephoneconnections between the IDUand the ODU (where a portablelocal operator must be used) ofboth ends of a link and duringthe normal operation forconnections among all theradios of the network (selectivecalling facility by means ofDTMF signalling).

Diplexer FSKMODEM

µP

Alarms&

CommandsEOW

TxAGC

MTL xN

To/FromµP

LNARxAGC

&IF Filtering

LO

70 MHz

DUALUHF

SYNTH

RXVCO

xN

To/FromµP

From/ToIDU

320 MHz

Figure 8 SRA L - Outdoor Unit Block Diagram

Referring to the majorapplications intended for this newLCDR family, a suitable NetworkElement (NE) concept and anoptimized embedded softwarearchitecture have been selectedto allow both a stand alone radiomanagement (Local and NetworkPC) and a radio managementfully integrated within the existingTelecommunication ManagementNetworks (TMN) and NetworkManagement Systems (NMS) bySiemens (in particular EM-OS fortransport networks and Access/Integrator for access networks).

This NE architecture, sketched inFig. 9, is based on a singlecontroller exchanging messageswith all the other system units(S-interface to/from the outdoorunit and all the indoor cards) witha Master/Slave structure.

The information stored andprocessed by the controller aremade available externally to thenetwork operator through thefollowing interfaces:

a) RS232 interface toward a localPC

b) Bus structured RS485 interfaceused for connection (“daisychain”) of different SRA Lsystems located in the samesite, that is typical for star, ringor multidrop connections. Anembedded 64 kbit/s channel inthe radio frame overhead (theNMS channel) provides the linktowards the Gateway NetworkElement (GNE) of TMN

c) Qx/Q3 (for EM-OS) or QD2 (forAccess/Integrator) interface, bymeans of an optional cardcalled Q-Adapter, necessary inthe Gateway Network Elementfor the connection with theradio element manager locatedeither on the EM-OS (Qx/Q3interface) or on the Access/Integrator (QD2 interface)NMS.

In the last case the Q-Adaptercard acts as a protocol converterfrom the Qx/Q3 or QD2 interfacetowards the internal SRA Lprotocol carried on the embedded64 kbit/s NMS channel andavailable on the RS485 interface.The routing of the managementinformation inside the SRA Lnetwork is obtained by means ofa TCP-IP protocol directlyintegrated within the radiocontroller.

Management

Figure 9 SRA L - Internal Management Architecture

Controller

Routing

Q-AdapterS-Int

Alarm/FANS-Int

Trib-IntS-Int

IDU

EOWS-Int

EEPROM

(black-plane)

S-Int

S-ODU 1/2

NMS channel

S-IDU

ODU-Int ASIC

RadioTransport

Module

FSK Modem

RS 232C

RS 485

Qx / Q3RF Cable

FSK Modem µP

ODU

When it is not possible to directlyconnect either the NMS channel(RS485) interface to anotherSRA L system because these arenot co-located, but connected bymeans of a transmission medialike optical fibre or the Q-Interfaceto the TMN Q-Interface for thesame reason, a 64 kbit/s signaladd-drop facility is available to usea slot of a 2 Mbit/s traffic signal.In this case, the networkmanagement system channel orthe Q protocol can be inserted inan empty time slot of thepayload.

A Local PC can be connected tothe SRA L system via a RS232-Cserial interface and used to setand control the local radio chosingthe configuration of the systemand showing local, remote andlink alarms and status. The samesoftware package and the samePC can be used for themanagement of a completeSRA L network (Network PC)using the RS485 bus interface for

the connection among differentsystems in the same site, theembedded 64 kbit/s NMS channelfor the connection of remotesites and optionally the add/dropfacility of the NMS channel insidethe 2 Mbit/s payload for theconnection between twosystems connected by means ofa different media. Using the PC acontinuous supervision of thewhole SRA L network withautomatic alarm reporting andcomplete network blockrepresentation is available.

Fig. 10 shows an example of aradio network management froma network PC with the details ofthe managementinterconnections.

The same SRA L network canalso be connected to the TMN ofan SDH network through aQx/Q3 interface made availablein the Gateway NetworkElement by means of theQ-Adapter card (Fig. 11).

The integration of the SRA Lelement manager inside theElement Manager OperatingSystem EM-OS used for thenetwork element management ofthe Siemens SDH networkelements gives the bigadvantage, thanks to the use ofthe Q-Adapter facility, of havingan integrated solution for themanagement of a whole SDHnetwork and the PDH links from itobtained by using the SRA Lequipment (Fig. 11). Thisadvantage is also increased takingin mind that EM-OS can alsoperform the network control layerfacilities in case of networks notusing cross-connects.

These two possibilities of remotenetwork management of a SRA Lnetwork become even moreinteresting in the case of mobilenetworks. In fact in this case theSRA L equipment is used in thelast layer of the network (forBTSs interconnection) while forthe connection of BSCs to MSCs

Figure 10 SRA L - Management by a Network PC

SRA LSRA L

SRA L

SRA L SRA L

SRA L

RS485

NMS channel

SRA L

RS485

NMS channel

SRA L

LT LT

2 Mbit/s G.703 2 Mbit/s G.703

64 kbit/sadd/drop

MCF

EM-OS

Ethernet Qx/Q3

GNE

NE

NE

NE

MCF

NE

SDH Network

GNEQ-ASRA L

Qx / Q3

SRA LNE

SRA LNE

SRA LNE

SRA LNE

SRA LNE

GNEQ-AS R A L

SRA LNE

SRA LNE

SRA LNE

RS485

L T

G.703

SRA LNE

SRA LNE

L T

G.703

64 kbit/sadd/drop

SRA LNE

SRA LNE

and among MSCs or from MSCsto PSTN/ISDN higher capacitiesare used then making SDHnetwork a must (Fig. 12).

When at the starting of themobile network, the radioinfrastructure is used only for theBTSs interconnection (SRA L)confiding on leased lines for theother network layers the NetworkPC is the best, quickest andcheapest way to start the service.The EM-OS is introduced onlywhen the increasing number ofthe customers suggests theoperator to build up also the otherpart of the transmission network.In this way the big advantages ofSDH in terms of protection (ringarchitectures), performancemonitoring, traffic provisioningand TMN can be introducedsaving the previous investmentsand resulting in a cheaper andbetter in performancing network.

In case of use of the SRA Lequipment in conjunction withSiemens access networkelements another version of theQ-Adapter card providing a QD2interface for connection to theSiemens access networkmanagement system, theAccess/Integrator, is used.

In this case the access to theTMN can be obtained with thearchitecture of Fig. 13, where thecase of use of the SRA L radiowith the Siemens DECTlinkequipment for Radio in the LocalLoop is shown.

For what concerns the featuresavailable via software ,the highdegree of digitalisation employedallows setting up most of theconfigurable parameters throughsoftware commands. The mainembedded softwarefunctionalities can besummarised as follows:

Figure 11 SRA L - Management of SRA L Equipment in Conjunction with SDH

BTS

SRA-L

EM-OS

Ethernet Qx/Q3

nx2 Mbit/s

NE

NE

NE

SDH

ADM

ADM

ADM

ADM

SDH

MSC

PSTN-ISDN

nx2 Mbit/s

BTS

SRA-L

BTS

SRA-LBTS

SRA-L

BTS

SRA-L

BTS

SRA-LBTS

SRA-L

BTS

SRA-L

21x2 Mbit/s21x2 Mbit/s

2 Mbit/s4/8x2 Mbit/s

63x2 Mbit/s

MSC

STM - 1 Ring

2 Mbit/s

21x2 Mbit/s

BTS

SRA-L

2 Mbit/s

4x2 Mbit/s

BTS

SRA-L2x2 Mbit/s

BTS

SRA-L

BTS

SRA-L 2 Mbit/s

BSC

SRA-L

Q-Ad

BSC

SRA-L

Q-Ad

BSC

SRA-L

Q-Ad

Figure 12 SRA L Management of the Transmission Equipment associated to a Mobile Network

Figure 13 SRA L - Management of an Access Network (RLL Application)

Configuration management

It is possible to change thetransported capacity, to set theequipment configuration and todefine several operatingparameters:

• system configuration (single,hot stand-by, add/droprepeater, ..)

• system capacity

• operating channel (Tx and RxRF)

• RF channel plan

• RF output power

• equipment options (with/without Q-Adapter, with/without EOW, ...)

• BB and RF switches(protected configuration)

• link ID

• system address (NMS andEOW)

• 64 kbit/s drop/insertactivation/deactivation and64 kbit/s time slot selection

• output alarms assignment

Fault management, includingalarm monitoring andequipment status, loopbacksactivation and other facilities

Performance monitoring

• G.826 parameterscalculation and display

• BER

• IDU and ODU internaltemperature

Measurements

• received signal level

• transmitted power

Security management

• access control viapasswords

• different user classes

Inventory data

• factory

• user

Software downloading

• local

• remote.

RBCSRA-L

RBCSRA-L

RBCSRA-L

RBCSRA-L

SRA-LQ-Ad

RDU

QD2

SRA-LQ-Ad

RDU

QD2

Conc. Conc.

QD2

QD2

4x2 Mbit/s

4x2 Mbit/s

4x2 Mbit/s

4x2 Mbit/s

4x2 Mbit/s

4x2 Mbit/s

Conc.

Access / Integrator

QD2

RBS Radio Base StationRBC Radio Base Station ControllerRDU Radio Distribution Unit

Technical data

GeneralConfigurations (1+0)

2x(1+0)(1+1) hot stand-by (1 or 2 antennas)(1+1) frequency diversity (2 antennas)through repeateradd/drop repeater

Traffic capacity (2)/2x2/4x2/8x2 Mbit/sFrequency bands 7/8/13/15/18/23/26/38 GHz

Frequency range

• 7 GHz 7.1-7.9 GHz• 8 GHz 8.2-8.5 GHz• 10,5 10.5-10.7 GHz• 13 GHz 12,75-13,25 GHz• 15 GHz 14.4-15.35 GHz• 18 GHz 17.7-19.7 GHz• 23 GHz 21.2-23.6 GHz• 26 GHz 24.5-26.5 GHz• 38 GHz 37.0-39.5 GHz

Tx/Rx channel spacing

• 7 GHz 154/161/245 MHz• 8 GHz 126MHz• 10,5 GHz 91 MHz• 13 GHz 266 MHz• 15 GHz 336/420/490/644/714/728 MHz• 18 GHz 340/1010 MHz• 23 GHz 1008/1232 MHz• 26 GHz 1008 MHz• 38 GHz 1260 MHz(other shifters available on request)

Co-polar RF channel spacing

• 2/2x2 Mbit/s 3.5 MHz• 4x2 Mbit/s 7 MHz• 8x2 Mbit/s 14 MHz

In-field tunability range depending on frequency bandand Tx/Rx channel spacing

Synthesizer step size 250 kHzRF stability ±3 ppm

Transceiver

Output power

• 7/8 GHz 24 dBm• 10,5 GHz 20 dBm• 13 GHz 20 dBm• 15 GHz 20 dBm• 18 GHz 18 dBm• 23/26 GHz 18 dBm• 38 GHz 17 dBm

Output power setting range

• 7/8/10.5/13/15/18/23 24 dB• 26/38 GHz 20 dB

BER = 10-6 threshold 2x2 Mbit/s 4x2 Mbit/s 8x2 Mbit/s• 7/8/10,5/13 GHz -90.5 dBm -87.5 dBm -84.5 dBm• 15 GHz -90 dBm -87 dBm -84 dBm• 18 GHz -89.5 dBm -86.5 dBm -83.5 dBm• 23 GHz -89 dBm -86 dBm -83 dBm• 26 GHz -88.5 dBm -85.5 dBm -82.5 dBm• 38 GHz -85.5 dBm -82.5 dBm -79.5 dBm

BER = 10-3 threshold 2x2 Mbit/s 4x2 Mbit/s 8x2 Mbit/s

• 7/8/10,5/13 GHz -92.5 dBm -89.5 dBm -86.5 dBm• 15 GHz -92 dBm -89 dBm -86 dBm• 18 GHz -91.5 dBm -88.5 dBm -85.5 dBm• 23 GHz -91 dBm -88 dBm -85 dBm• 26 GHz -90.5 dBm -87.5 dBm -84.5 dBm• 38 GHz -87.5 dBm -84.5 dBm -81.5 dBm

System gain (BER=10-6) 2x2 Mbit/s 4x2 Mbit/s 8x2 Mbit/s

• 7/8 GHz 114.5 dB 111.5 dB 108.5 dB• 10,5/13 GHz 110.5 dB 107.5 dB 104.5 dB• 15 GHz 110 dB 107 dB 104 dB• 18 GHz 107.5 dB 104.5 dB 101.5 dB• 23 GHz 107 dB 104 dB 101 dB• 26 GHz 106.5 dB 103,5 dB 100.5 dB• 38 GHz 102.5 dB 99.5 dB 96.5 dB

System gain (BER=10-3) 2x2 Mbit/s 4x2 Mbit/s 8x2 Mbit/s

• 7/8 GHz 116.5 dB 113.5 dB 110.5 dB• 10,5/13 GHz 112.5 dB 109.5 dB 106.5 dB• 15 GHz 112 dB 109 dB 106 dB• 18 GHz 109.5 dB 106.5 dB 103.5 dB• 23 GHz 109 dB 106 dB 103 dB• 26 GHz 108.5 dB 105.5 dB 102.5 dB• 38 GHz 104.5 dB 101.5 dB 98.5 dB

Maximum Rx input level

• for BER=10-10 -20 dBm• damage-free operation -10 dBm

Background BER ≥10-11

Noise figure (typical)

• 7/8 GHz 5 dB• 13 GHz 5 dB• 15 GHz 5 dB• 18 GHz 6 dB• 23 GHz 7 dB• 26 GHz 6.5 dB• 38 GHz 9.5 dB

Spectral power density in accordance with the relevant recommendations

Spurious emissions in accordance with the relevant recommendations

Modemodulator

Modulation Continuous Phase Modulation

Demodulation differential with Viterbi Decoding

Tx intermediate frequency 320 MHz

First Rx intermediate frequency 1310 MHz

Final Rx intermediate frequency 70 MHz

Baseband Interfaces

2 Mbit/s ITU-T G.703Impedance 75 Ω unbalanced or

120 Ω balanced

Auxiliary Capacity

User service channel 1x64 kbit/sV.11 contradirectional or codirectional

Engineering Orderwire 1x64 kbit/s (DTMF)(optional card)

Network Management Systems channel 1x64 kbit/s(internal)

Power Supply

Nominal voltage -48/-60 VDC

Tolerance ± 20%

Power Consumption (from battery)

1+0 (IDU+ODU) 40 W

Environmental Operating Conditions

The equipment meets the environmental conditions standardized in ETSI prETS 300 019.

Indoor unit

• normal temperature range 10 to +50°C• extended temperature range -10 to +60°C

Outdoor unit

• normal temperature range -33 to +60°C• extended temperature range -50 to +60°C

Mechanical Dimensions

Indoor Unit 2 U (19")Outdoor Unit 238x238x120 mm (hxwxd)

Software Features

System type setting (1+0)/2x(1+0)add/drop repeater(1+1) hot stand-by(1+1) frequency diversity

System parameter setting operating channel (Tx and Rx)RF channel planRF output powercapacity (2x2, 4x2, 8x2 Mbit/s)system address (EOW and NMS)link ID

Fault management alarm monitoringequipment statusloopbacks activation

Performance monitoring BERG.826

Measurements received fieldtransmitted powerIDU and ODU internal temperature

Security password protectionuser classes definition

Inventory data user datafactory data

Software downloading localremote

Italtel spa

A Stet and Siemens CompanyInternational sales offices

20093 Cologno Monzese (MI) - ItalyViale Europa, 46Fax (++39.2) 2536135

Figures and data contained in this document are forreference only and must be specifically confirmed inwriting, before they become applicable to any particularorder or contract. The company reserves the right tomake alteration or amendments to the detailedspecification at its discretion.

Rel

ease

d by

Ital

tel C

omm

unic

atio

ns D

epar

tmen

t - C

7.1.

1752

/200

0