Synchronous Radio for Trunk Applications

SRT 1F

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Contents

System overview

System configuration

Main features

Equipment management

System characteristics

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Figure 1: Transport network

Transport Network - Fixed Operators

High capacityRegional Subnetworks

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The radio relay system competitivefeatures, such as the quickdeployment and fast network roll-outwith simple civil works as well as thehigh flexibility, strongly justify amodern telecommunications networkscenario in which radio systems andfiber optic systems will complementand support each other in a veryeffective mixed media approach. Acombined radio fiber transportnetwork requires SDH radio systemdesigned for full compatibility withother SDH Network Elements (fig.1)

The fast-growing demand oftelecommunication services as wellas the increased network topologiesand traffic requirements have beenpushing for a new evolution of point-to-point radio systems for trunkapplications.A cost effective compact RadioSystem allowing a rapid installationwithout any in-field alignment andoffering standard TMN interfaces hasbeen considered as the best choice tosuit these new market requirements.

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Regional/NationalRadio Backbones

Back up to the Fiber

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The base band signals are fed throughan STM-1 optical interface or STM-1electrical interface.In this system, N+1 radio protectionswitching is implemented on theradio side.On the STM-1 base band side, (1+1)multiplex section protection is alsoimplemented for the STM-1 opticalinterface as option.With different combinations of RFtransmit/receive units, RF branchingnetwork unit and modulator /demodulator units, this system cansupport the full range of radiofrequency bands recommended by ITU-R(4G, 5G, L6G, U6G, 7G, L8G, 11G, 13G)and frequency spacing of 28 MHz, 29 MHz, 29.65 MHz and 40 MHz.The system supports both alternatedpattern and co-channel with XPICequalization.

SRT 1F is a digital microwavecommunication system based on theSDH specifications conforming tointernational communications standardssuch as ITU-T, ITU-R and ETSI.The SRT 1F radio forms SDHcommunication network incombination with SDH-based fiberoptical transmission system. For theoperation, maintenance andmonitoring of the whole system, a local craft terminal, elementmanager and network manager areconnected on customer’s requirement.The SRT 1F system processes STM-1(155.52 Mbit/s) base band signals inthe SDH hierarchy, limiting theirbandwidths within a single radiofrequency band stipulated by ITU-Rbased on a multi-level QAMmodulation technology (such as 64 or 128 QAM depending on radiofrequency spacing) (fig.2).

System overview

4

From other main channels

Supervisory, Control & Switching section

Transceiver Unit

Transceiver Unit

MOD Tx

DEM Rx

MOD Tx

DEM Rx

STM-1Electrical/Optical Interface

Optional MSP Protectionfor STM-1Optical

ClockEngineering Order wire

Wayside trafficOperating System Support Interface

User Channel

Local terminal

Main RF Channel

Protection RF Channel

Main

SD

RF B

ran

chin

g se

ctio

n

In

In

Out

Out

OPTINT Y

OPTINT X

Figure 2: Block diagram of the system

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The SRT 1F system consists of an RFBranching section, a Transceiversection and a Supervisory, Controland Switching section (SCS).The Branching section includes anantenna duplexer and RF transmit / receive narrow band filters. The Transceiver Unit integrates the transmitter, receiver, modulation, demodulation , STM-1 base band signal processing, unipolar hitless switch and auxiliary signal processing functions.The SCS base band integrates the synchronous equipment managementfunction (SEMF), remote managementfunction (MCF), radio protectionswitching, order wire, user channel,radio user channel and systemsynchronization functions.Three shelf configurations arepossible:- K-shelf configuration: all the system

sections are integrated in a singlecompact shelf 1155mm high,housing up to 8 transceiver units;an expansion K-shelf can beequipped also, thus allowing up to16 transceivers in one rack.

- Multi-shelf configuration: eachsystem section is implemented by a proper shelf; this configuration isneeded when double terminal E/Win one rack is required or opticalinterface with MSP is required.

- 1+1 N.E. : compact solution for max1+1/2+0 configuration in 500mmheight.

Rack Configuration/

RF CH AllocationRack configurations for AlternatePattern (AP) and Co-Channel (CC)operations are the following:

• Maximum 7+1 complete system APor CC, single-polarization or double-polarization, is configured in half rack by using a single K-shelf

• Maximum 2x(3+1) complete system CC is configured in half rackby using a single K-shelf, expansible up to 2x(7+1) by addingexpansion K-shelf in the same rack

• Maximum 2x(7+1) complete system CC is configured in one rackby using one K-shelf plus one expansion K-shelf in the same rack

• Maximum 2x(3+1) Double TerminalE/W complete system AP is configured in a single rack by usingMulti-shelf configuration

• 1+1 Not Expansible system AP or CC, single-polarization or double-polarization is configured in a single sub-rack, 500mm high

System configuration

Radio Protection Switching The maximum protection switching(RPS) capacity is 7+1 for alternatedoperation and 2x(7+1) for Co-channeloperation.The RPS of SRT 1F system implementsa switchover between any of workingchannels and protection channel.In this configuration, a unipolarswitch (USW) inside the TransceiverUnit activates the switchover againstpropagation path fading and a bipolarswitch inside the BSW unit activatesthe switchover against Transceiverfailures.The USW has a one-bit error switchingmode to maintain circuit quality forhigh speed fading in very heavypropagation conditions.USW switchover is unidirectional.The bipolar switch is activated in theevent of a Transceiver failure: it is nothitless and it is bi-directional.The RPS ensures redundancy of themain signals (STM-1),Way Side andUser channel (F1) signals.

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1+1 Not Expansible System

TRANSCEIVERSAND

BASEBAND

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6

SRT 1F: Frequency coverage

Frequency band (GHz) U 4 4 5 L6 U6 7 L8 11 13

ITU-R F series No. F.382-6 F.635-4 F.1099-1 F.383-5 F.384-6 F.385-6 F.386-4 F.387-7 F.497-5

Modulation format 128 64 64 128 64 128 128 64 128

(QAM)

Equipment layout

K-shelf configurationhousing 16TRs in one rack

K-shelf configurationhousing 8TRs in half rack

K-shelf

(up to 8 TRs)

Expansion K-shelf

(up to 8 TRs more!)

Half Rack

Free space!

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Transceiver UnitThe Transceiver Unit is an all-in-oneunit that receives the STM-1 baseband (BB) electric signals and, afterprocessing, it outputs the convertedsignals to the antenna port via RFBranching section at the requiredRadio Frequency (fig. 3). All the functions required for thesignal processing are enclosed in thisunit: it implements multi-level QAM(64/128) and the correspondingdemodulation; it processes therequired SOH bytes and pointers; it converts signals into the first IF (70 MHz), then (via synthesizer) toRF through the second IF (844 MHz).The STM-1 electric signals are outputfrom the Transceiver to the outsidevia the BSW unit inside SCS sectionfor N+1 RPS switchover (bipolarswitchover) in the event of a Transceiver failure.

Moreover, to reduce random errors intransmission paths, the MLCM errorcorrection method is used. In addition to the main signals, theTransceiver also processes the input andoutput signals of the 2x2 Mbit/s WaySide traffic (one on SOH and one onRFCOH) and of the user channel usingthe F1 byte. These signals are accessed throughBSW unit in the same way as themain signals. The unipolar switch and Space DiversityDADEing functions are implemented inthe unipolar stage to switchover fromany of working channel to protectionchannel against fading. The orderwirebytes (E1, E2), DCC, Service Channels,MCF data, and RPS switchover data areprocessed in the Supervisory, Control &Switching section. Additional functions of the Unit aredescribed below:

- TVE with DFE: 11-taps TransversalAdaptive Time Domain Equaliserwith, 10-taps Decisional FeedbackEqualiser.

- ATPC: saves the powerconsumption and reducesinterference (10dB variable).

- PM: in addition to the conventionalerror Performance Monitoring,monitoring for sending power andreceiving power is added.

- XPIC: 11-taps Transversal Equalizerequipped in Transceiver Unit Co-Channel.

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Main Features

Figure 3: Transceiver unit

TRANSMITTER

RECEIVER

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Supervisory, Control, andSwitching sectionThe SCS section provides supervisoryand control function, includingalarm/event information managementand provisioning data setting.It consists of the following units:MCF/Controller, BSW unit and TimingSource Unit (TSU) (fig.4).

MCF/Controller: it has thesupervisory and control functions forTransceiver Unit; manages andcontrols RPS-USW and RPS BSW;terminates the E1 and E2 order wirebytes (EOW); terminates the DCCline; sets security levels of operators;manages bit error performance,analogue monitoring and eventmonitoring.

BSW: it is the BaseBand physicalinterface for STM-1 signals. It implements a switchover in thebipolar stage for any of Transceiverfailure. The required number of BSWs is same as the number ofworking RF channels. BSW Electricaland BSW Optical (with SFP module S-1.1 or L-1.1) interfaces are available.Also mixed configuration with someBSW Electrical and some BSW Opticalin the same terminal is possible.

TSU: it supplies clock signals forsystem synchronization.

The SCS can have the followingoptional units installed: up to twoEmbedded Channel Units (ECU) forDCC distribution; up to twoHousekeeping (HK) units forsupervisory and control of externalcommunication equipment by usinghousekeeping bits; one redundancyTSU; one Occasional Interface unit(Electrical or Optical) for occasionaltraffic on protection channel; andone BSW Interface for RPS2 in2x(N+1) CC.

In case of Double Terminal E/Wconfiguration in a single rack, the SCSis equipped with two MCF/Controller,two TSU, up to six BSW units, up totwo Occasional Interfaces and up totwo HK units (fig. 5).

OPT MSP sub-rackThis sub-rack is only needed whenMSP protection for STM-1 opticalinterface is required. It can provideSTM-1 optical interface S.1.1 or L.1.1with MSP.

Branching sectionThe Branching section is completelyaccessible from the front part of therack.The high compactness of the systemenables to locate the branching foreight channels together with thebranching for SD receiver in the samesub-rack.It allows mixed polarization (H and V)inside the same rack, and the choiceof frequency and polarization ofstand-by channel (fig. 6).The system is flexible: expansioninside the same shelf can be obtainedup to the maximum capacity withoutremoving the Transceiver Unitsalready located in the rack.The system is scalable: up to 16channels on both polarizations canbe mounted in the same rack byadding the expansion K-shelf for upto 2x(7+1) CC in one rack.

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Figure 4: Supervisory, control and switching section layout

Figure 5: Double Terminal Supervisorycontrol and switching section

Figure 6: Branching logical scheme for alternated operation

MC

F/Con

troller (SV)

ECU

2

ECU

1

BSW7

BSW6

BSW5

BSW4

BSW3

BSW2

BSW1

OC

C IN

TF

HK

2

HK

1

TSU Y

TSU X

TSU X

HK

OC

C.IN

TF

TSU X

HK

OC

C.IN

TF

BSW 1

BSW 2

BSW 3

MC

F/Con

troller (SV)

MC

F/Con

troller (SV)

BSW 1

BSW 2

BSW 3

Antenna PortMain V (H)

TX RX RX SD TX RX RX SD

Antenna PortDiv V (H)

Antenna PortMain H (V)

Antenna PortDiv H (V)

7’

5’

1’

3’

7

5

1

3

7

5

1

3

8’

6’

2’

4’

8

6

2

4

8

6

2

4

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All SDH products in Siemens catalogueuse the same approach toTelecommunication ManagementNetwork (TMN) from the point ofview of hardware and softwarearchitecture in order to have thevarious network elements suitable for integration under a commonmanagement system.SRT 1F management platform basesupon the presence of the MCF /Controller unit with the followingtasks (fig.7):

•receiving and transmitting from/tothe controlled units all theinformation required for systemmanagement;

•transmitting to Local Craft Terminal(LCT) and the Element Manager(EM) the alarms and measurescoming from the units

•receiving controls / settings from LCT / EM.

The information stored and processed by MCF/Controller unit (configuration,events, performance monitoring) aremade externally available in differentways in order to allow the radio to beconsidered as a Network Element of the Network.

A powerful local control is managedby a Windows PC as craft-terminal viaRS-232-C interface. The LCT handlesunits status and configuration,provides alarms and performancemonitoring and reports analoguesmeasures. In addition Security andInventory facilities are available.

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Equipment Management

BSWinterface

To/fromexp.shelf

MCF/Controllerunit

BSWunits

Transceiverunits

SCSsection

LCT

Interfacetowards EM

OPT/MSPshelf

Figure 7: Management architecture

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NetViewer NME SuiteThe Microwave Management SystemNetViewer is a versatile TMN productfor the management of PDH, SDHand WiMAX systems, able tosupervise other vendors’ devices aswell through a standard SNMPinterface. An overall view of thecomplete network structure and itsability to enter down to the NetworkElement details give a clear pictureof the whole network, itsconfiguration and events. Fault,Configuration and Performancemanagement are carried out atNetwork Element level; at Networklevel Fault and Security configurationare available.Netviewer is the basic part ofSiemens offer for NetworkManagement oriented to microwavenetworks that is represented by theNetViewer NME Suite. The suite is composed of a numberof modules:

Figure 8: Example of Radio Network

NetViewerClients 1÷20

NetViewerServer

ADM

ADM

SRT 1FSRT 1F

SRT 1FSRT 1F

SRT 1F

SRT 1F

SRT 1FSRT 1F

ADMADM

• NetViewer, core of the system, asElement Manager;

• SNMP Agent, a real-timenorthbound interface;

• TCOA (TMF CORBA Agent), a real-time northbound interface;

• Path Manager module, as NetworkManager;

• HP-Compaq TeMIP add-on, thatallows the integration of NetViewerin HP OpenView TeMIP (product ofHP-Compaq).

Moreover, NetViewer can be easilyintegrated both in Siemens SDH TMNplatform (TNMS) with TNMS CoreRadio add-on, and in Mobile TMNplatform (Radio Commander) in orderto offer to the operator a uniqueinterface for management purposes.

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System characteristics

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RF band 4/5/U6/11 GHz (40 MHz)U4 GHz (29 MHz)L6/L8 GHz (29.65 MHz)L7/U7/13 GHz (28 MHz)

Modulation 128QAM single carrier64QAM single carrier

Capacity Alternated STM-1 per RF (V or H-pol.)

Co-channel 2 x STM-1 per RF (V and H-pol.)

Signal STM-1 155.52 Mbit/s electricalInterface 155.52 Mbit/s opt. (S-1.1)

155.52 Mbit/s opt. (L-1.1)

Transmitter Output power +29 dBm (4-8 GHz) *(measured at Tx output) +29 dBm (11 GHz)

+27 dBm (13 GHz)

Local oscillator ±10 ppm guaranteed (4-8 GHz)stability ±5 ppm guaranteed (11-13 GHz)

IF TX side 70/844 MHzRX side 70/844 MHz

Roll-off factor 35 % (64QAM)25 % (128QAM, 28/29/29.65 MHz)

Receiver Local oscillator ± 10 ppm (4-8 GHz)stability ± 5 ppm (11-13 GHz)

Threshold BER at 10(-3) 64QAM MLCM Measured at 4GHz -76.5 Receiver input 5GHz -76.5 (dBm) U6 -76.5

11GHz -75.5128QAM MLCMU4 -74L6,L7,U7 -748GHz -7413GHz -71.5

FEC Coding method MLCM (Multi-Level CodedModulation)

Total bit addition 10 % for 64QAM8.9 % for 128QAM

Adaptive (1) Frequency domainEQL Slope equalizer (SLP)

(2) Time domain11-tap full digital TVE with10-tap DFE EQL in BB

XPIC Type 11-tap full digital TVE EQLOnly for CC for co-channel operation

Radio Protection Capacity (1) Max 7+1 AP or CCSwitch (2) Max 2x(3+1) co-channel

in one K-shelf (half rack)(3) Max 2x(7+1) co-channel inone rackTwo protection CHs are activatedFor V-pol and H-pol systemsIndependently in 2x(N+1) CC

Method Errorless switchingwith early warning detection

SW Initiation (1) Frame loss(2) BER 10(-3) to 10(-7)presettableBER is detected before FEC(3) Signal loss

OCC AvailableOne OCC for N+1 systemTwo OCC for 2x(N+1) system

Mechanical Rack dimensions 2200 mm (H)600 mm (W)300 mm (D)

K-shelf 1155 mm (H)

Expansion K-shelf 930 mm (H)

1+1N.E. 500 mm (H)

DSC/AUX EOW 1 CH(E1) for omnibus1 CH(E2) for expressExternal telephone set

Wayside (WS) 2 CH/STM-11CH on SOH1CH on RFCOH

Service channel 1 CH 64 kb/s/STM-1Co-directional/contra-directionalusing F1 byte- Max 2 CH per systemVF and/or 64 kb/s availableFor 64 kb/s, co-directional or contradirectional (async)Service channels are doubled in 2x(N+1) configuration

Power Typical 100 W/STM-1consumption for 4-8 GHz

Typical 110 W/STM-1for 11-13 GHz(BB+modem+RF TX/RX with SDRX)25% reduction by setting ATPC low

* +32 dBm high-power version available as option

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Siemens Mobile Communications S.p.A.Sales OfficeViale P. e A. Pirelli, 1020126 Milano - ItalyPhone + 39 02 243 1

C6.1 1762/1000 • Siemens Mobile Communications SpaPrinted in Italy

This publication is issued to provide information only and is not to formpart of any order or contract. The products and services described hereinare subject to availability and to change without notice.

www.siemens-mobile.com

Acronyms and AbbreviationsAGC Automatic Gain Control

AMP Amplifier

ATPC Automatic Transmitter Power

Control

BBC Base Band Control

BER Bit Error Ratio

BSW Bipolar Switch

DADE Differential Absolute Delay

Equalizer

DCC Digital Communication Channel

DEM Demodulator

DFE Decisional Feedback Equalizer

DSC Digital Service Channel

ECU Embedded Channel Unit/

Embedded Communication Unit

EM Element Manager

EOW Engineering Order Wire

ETSI European Telecommunication

Standard Institute

FEC Forward Error Correction

HK Housekeeping

IF Intermediate Frequency

INTF Interface

ITU International

Telecommunication Union

LCT Local Craft Terminal

MCF Message Communication

Function

MLCM Multi Level Code Modulation

MOD Modulator

MSP Multiplex Section Protection

OCC Occasional

OPT Optical

PDH Plesiochronous Digital Hierarchy

PM Performance Monitor

QAM Quadrature Amplitude

Modulation

RDP Receiver Digital Processing

RF Radio Frequency

RFCOH Radio Frame Complementary

Over Head

RPS Radio Protection Switching

RSL Receive Signal Level

SCS Supervision, Control and

Switching unit

SD Space Diversity

SDH Synchronous Digital Hierarchy

SEMF Synchronous Equipment

Management Function

STM-1 Synchronous Transfer Module

level 1

TDP Transmission Digital Processing

TMN Telecommunication

Management Network

TSU Timing Source Unit

TVE Transversal Equalizer

USW Unipolar Switch

VF Voice Frequency

WS Wayside Signal

XPIC Cross Polarization Interference

Canceller

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