AL PDH RADIO

Ing. Cesare Zaniboni

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Training itemsPDH AL(/AL+)SCTLCTAL Troubleshooting: alarms and loopsPropagation: one easy example of hop calculation

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PDH AL: hardware and circuitry1

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IDU

Line Interface Module: Up to 16xE1, 3x10/100 BaseT + 4E1, 2xE3Main Controller (Service channels, LCT connection, Alarms IN/OUT)Radio Interface Module 1 and 2 (Cable Interface + Power Supply)

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IDU 2 units

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ODUUnprotected ODU1+1 ODU

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ODU with separated antenna 1+0 pole mountingwaveguide flangeantenna

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ODU with separated antenna 1+1 wall mountingwaveguide flange

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1+1 hot stand-by= Stand-by= ActiveBoth radios, working at the same frequency, are active in Rx but only one is active in Tx:1 antenna Branching losses are inserted in link budget 2 antennas Link is in space diversity (and without branching losses) Best performance for d=150l (d=distance between antennas)ODUODUODUODUIDUIDU1122

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1+1 frequency diversity All radios, working at different frequencies, are active in Rx and Tx1 antenna Branching losses are inserted in link budget 2 antennas Link is in space diversity (and without branching losses)ODUODUODUIDU1122= F2HIGH= F2LOW

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2+0 with Ring ProtectionODU-EODU-WSwitch Hitless(Embedded Media Switch)16xE1 Ports2+0 Fully-Protected IDU A single IDU manages two Radio Links Radio Links can have different capacities E1 streams can be routed: to West side (unprotected connection) to East side (unprotected connection) to both directions (protected connection) East West with no external wiringBranch WBranch E

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Software Keys Following functionalities are enabled through a software key:

Capacity changing

Modulation changing

Way side traffic

OSPF Option

Fade Margin Test Option

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AL : main facilitiesAvailable versionsEquipment structurePRBS generatorATPCEquipment characteristicsInstallation

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AL : available versionNew pdh AL is available in many versionsConfiguration can be set via software :Modulation: 4QAM, 16QAM, 32 QAMCapacity: 2, 4, 8, 16, 32xE1 2xE3 3xLAN+4xE1Configuration: 1+0, 1+1 h.s.by or eterofreq.IDU is frequency, capacity and modulation independentODU depends by frequency only

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User interfaces

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Equipment structure

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Controller

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LIM Tx direction

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LIM Rx directionFEC *(block code)

errors*FEC = Forward Error CorrectorExample: Without BER=10-6 With BER=10-13 (+2.5 dB)

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RIM140 MHz

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ODU

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ATPC (Automatic Tx Power Control)

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AL characteristics (1)Tx power (4QAM/16QAM) in dBm : 4 GHz +29 / +24 7 GHz +27 / +22.5 15 GHz +25 / +20 23 GHz +20 / +15Tx/Rx spacing in MHz: 4 GHz 100 7 GHz168/196/245 15 GHz 490/728 23 GHz 1008Power consumption in W: 1+0< 30 1+1< 55

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AL characteristics (2)Rx HBER thresholds (4QAM/16QAM) in dBm: - in 16x2 4 GHz -85 / -81 7 GHz -84 / -80 15 GHz -83.5 / -79.5 23 GHz -82 / -78 - in 4x2 4 GHz -91 / -87 7 GHz -90 / -85 15 GHz -89.5 / -85.5 23 GHz -88 / -84 Max Rx power - 20 dBm

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IDU InstallationIDU-ODUcable connector : TNC typeE1 way side (in high capacity)Service channelsconnectors : RJ 45 typeAlarms LEDs : IDU ODU REM TESTController FAIL alarm LED75ohm E1 Connectors: micro-coax typeLAN Connectors: RJ 45 type

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ODU installation (1)REF.

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ODU installation (2)

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ODU installation (3)

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Interconnection cableFrequency signals:Tx IF330 MHzRx IF140 MHzTelemetry IDUODU 17.5 MHzTelemetry ODU IDU 5.2 MHz

Max length (1/4 inch cable)4QAM470 m16QAM370 m

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Switch modesAuto Preferential: operator can select which branch must be operative without alarms. Wait Time = time before coming back to the preferential branch when alarms disappear. In this way the controller doesnt switch continuously in case of fleeting alarms. Reset = Wait Time is not respected Full auto: both branches have same priority

Manual forcing Operator can select which branch must be operative despite alarms

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Tx switch criteriaRIM PSU alarmManual forcingCable short/ Cable open alarm Modulator failure ODU unit failure alarm VCO failure alarm IF unit alarmODU PSU alarm Tx power low alarmRx failure on both remote radios Revertive Tx

Highest priority

lowest priority

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Rx switch criteriaRIM PSU alarmManual forcingCable short/open alarmBase band unit failure alarm Demodulator failure ODU unit failure alarm VCO failure alarm IF unit alarmODU PSU alarm High BER alarm (selectable: BER>10-3,-4,-5)Low BER alarm (selectable: BER >10-6,-7,-8) Early warning alarm (selectable: BER >10-9,-10,-11,-12) RF input low (selectable from -40dBm to -99dBm)CRC pulseRevertive RxHighest priority

lowest priority

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SCT : main subjectsAlarm correlationAlarm acknowledgementRoutingOSPF configurationStored Routing TableStation managementCommand loggerEquipment features managementConfiguration backup/restore

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Alarm correlation Every alarm is reported withAlarm beginning Alarm end (gravity info is maintained)

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Alarm acknowledgementAlarm acknowledge is available inalarm history list: every acknowledgement can be managed completelyin station list: new alarm info is highlighted by an asterisk

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Port addressesAll SIAE equipments, regarding SCT software and supervision, are routers: all interfaces need an address and relevant subnet maskAddresses can be set clicking:Set valuesStoreRestart Client (always)

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Routing

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Routing tableType and address of crossed port Type and address of crossed port towards DestinationNetmask and IP address of DestinationDefault destination

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AgentThe Agent is used in the Network Element history to identify the alarmed equipment and in Subnetwork Configuration Wizard to visualize local and remoteNumeric identifier of the equipment (agent is not a real address)Agent:local agent = local Ethernet IP addressremote agent = remote Radio IP address or remote Ethernet IP address

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Stored Routing TableThe Stored Routing Table adds routing lines, after a Restart, to the running Routing Table of the NE.In this way we can change Ports addresses (operation that needs a restart) without loosing a remote NE:In Stored Routing Table add the routing lines relevant to new port addresses you are going to setSet the new port addresses (the equipment restarts)After the restart the equipment has new addresses and the routing table configured already: the NE management is still running

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OSPF Management OSPF window manages configuration parameters of the selected equipment (router) relevant to the OSPF (Open Shortest Path First) dynamic routing protocol: - Properties: general configuration parameters of OSPF protocol - Areas/IFs: configuration parameters of equipment OSPF interfaces and of the areas containing them - Virtual Links: configuration parameters of virtual links - Summ.: configuration parameters of route summarizations - Lsa DB: configuration parameters of LSAs (Link State Advertisements) in the Link State Database - Ext Lsa DB: list of the External LSAs only - Neighbors: list of neighbors - V.Neighbors: configuration parameters of the virtual neighbors - Store: storage of new parameters into the controller flash memory

SKIP OSPF

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LAN IP addressExternal LSA inside databaseIs the unit an ABR?LS Checksum of External LSANew LSA: one more, everytime router produces itLSA received

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OSPF: example IR : Internal RouterABR: Area Border RouterASBR:Autonomous System Border Router

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Areas, Routers and LSAArea is a group of hosts and routers with IP interfaces on same network. An Area is described by one database only.Stub Area: an area with internal routing only. Database and the memory requirement of the routers of the stub area are reduced. Routing from a stub area to outside is based on a default route (a single output point)Internal Router IR: a router with its area database only (intra area)Area Border Router ABR: a router connecting multiple areas (inter area)Autonomous System Border Router ASBR: a router gateway between OSPF and other routing protocols

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BackboneIf multiple areas are involved, Backbone is the Area 0, the area all the others are connected to.

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Virtual Link (VL)In areas not phisically connected to backbone, a virtual link is used to provide a logical path.The virtual link is estabilished between two ABRs that have a common area, with one ABR connected to backbone.

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NeighboursRouters sharing a common segment are Neighbours if:their interfaces belong to same area and same subnetthey exchange the same password on that segmentthey have same Hallo and Dead Intervalthey have same stub area flag in Hello packets

These rules affect neighbour election process.LSA : Link State Advertisements describe router database and must be send to all neighboursDR : Designated Router as information exchange central point to minimize information traffic on a segmentBDR: Backup Designated Router, in case DR goes down

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AdjacencyEach router on the segment establishes an adjacency with DR and BDR that relay information to everybody.DR and BDR election is done via Hello protocol: the router with highest OSPF priority is DR, after BDR. In case of parity, RID (router ID) is checked.A zero priority router is called DROTHERRTA and RTB have same priority but RIDB>RIDA RTB=DRRTC > RTB RTC=DR

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Shortest PathIn a router database all reachable segments and relevant cost are listed: segment next-hop cost + router next-hop costAny router interface has a cost inversely proportional to its throughput: Cost = 100.000.000/bitrate [bps] Any router prepares a shortest path tree putting itself as root and calculating smallest cost for each destination. After this passage the router builds the routing table accordingly.Any change in area composition (new router insertion) is communicated to other routers causing dynamic re-adjustments of routing tables.

(OSPF allows also a TOS sensitive interface cost: depending on packet Type Of Service, the router interface has different cost)

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Router A Router B Router C Router D38kbit/s155Mbit/s155Mbit/s155Mbit/s C=2600C=0,65C=0,65C=0,65

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OSPF Link-State algorithmAny router generates a LSA : the collection of all link-states on that routerRouters share link-states via flooding: a link-state update is received, stored and sent to otherAs router database is completed, Shortest Path Tree to all destinations is calculated (Dijkstra algorithm). Destinations, associated cost and the next hop to reach them forms IP Routing TableChanges are communicated via link-state packets and Shortest Path Tree is recalculated. If network configuration does not change, OSPF traffic is quiet.

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HELP:inactiveactiveto be applied

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Stations and equipmentsNEs connected to SCT can be assigned in various stations using Subnetwork Configuration Wizard

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Link managementPrepare new networkSend new configuration to local equipmentLog as System on both equipmentsRetrieve the configuration of local equipment

Send new configuration to both equipments

RetrieveSend/Reset

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Command loggerCmd Logger reads the list of operations, executed by the user, stored on the controller of the equipment.The log, uploaded from equipment, is stored on the PC for further consultations. Following filters are available:Operations dateUser addressUser typeOperation name

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EQUIPMENT FEATURE MANAGEMENT

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Configuration upload/downloadUpload (from equipment)From Tool menu, open the proper TemplateSelect Upload operation and the equipment you want to upload information fromSave them in a file (*.cfg)Download (to equipment)From Tool menu, open the proper file (*.cfg)Select Download operation and the equipment you want to download information to

Uploaded parameters and *.cfg file are editable usingEquipment Configuration Wizard.

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Configuration TemplateConfiguration template: it is relevant to equipment radio parameters as frequency, attenuation, capacity, thresholds,Address configuration template: it is relevant to management parameters as port IP addresses, routing tables, remote elements tables, OSPF.

Both configurations are necessary during first installation or when Controller module is substituted with a spare one: you can use a file to download or set every parameter manually.

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Full backup The whole amount of parameters (equipment parameters, address parameters and remote element table) can be uploaded from equipment, saved in a file (*.bku), downloaded to equipment. These parameters cannot be editated.

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LCTfor AL3

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Radio link parametersMain parameters of the link are:ConfigurationCapacityModulationLink IDFrequency For local terminal Setting has to be copied in remote terminalFrequencyCapacityModulationLink IDFor both local and remote terminal

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GeneralConfigurationBitrateModulationLink ID (local only)

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1) General preset:thresholdsHBer,LBer, EWL thresholdsRx Power Low thresholds

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2) General preset:Rx switches1+11+0In case of Hber, Lber, EWL, first CRC correction In case of no Rx

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3) General preset:Tx switchIf both remote radios dont receive, on local side Tx switch is performed

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Ethernet switch*MAC Address Table sizeEmptying algorithm of queues: 8421 WFQor strictly priorityLife of info in MAC Addr. tablePacket sizeQueue assignement depending 802.1p: depending on input priority, the packet is sent to the selected queue of a port (level 2)Queue assignement (level 3) depending on PTOS or DSCPVLAN management Setting of waiting time before Link Loss Forwarding (010 sec.)*only on Ethernet LIM !(512/1024/2048)(1522/1536)

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Queue selectionDepending on priority TOS the queue is selected.View filterPTOS values(64 = 26)DifferentialServiceCodePoint values 14 = 1 + 4x3 + 1 AF=Assured Forwording (4 classes and 3 values) PrecedenceRoutinePriorityImmediateFlashFlash overrideCritic/ECPInternet CtrlNetwork Ctrl DelayNormalLowThroughputNormalHighReliabilityNormalHigh

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VLAN map (level 2)Port 1Port 2Port 3RadioPortVLAN 760 doesnt transit through port 2760VLAN 760 exits through port 2 untaggedVLAN 760 exits through port 2 with tag 760VLAN 760 exits through port 2, with the same tag it has at input (unmodified) VLAN tag given to untagged packet

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VLAN managementExample of VLAN list: VLAN tag of input packet is not included, see Virtual LAN card in LAN-x [x = 1, 2, 3]Not assigned

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LAN settings: InterfaceCable: straight or crossedPort statusLAN SpeedFlow controlLLF statusLAN status

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LAN settings: Virtual LANUntagged frame in output:Unmodified, Tagged, UntaggedOutput ports of packets in input at LAN1Tag added to untagged frame if output is taggedDisable 802.1q: no Tag filter, LAN per port rulesFallback: if input is tagged, Virtual LAN map rules will be followed; if input tag is not present in the map or input is untagged, Lan per port rules will be followedSecure: if input is tagged, Virtual LAN map rules will be followed; if input tag is not present in the map or input is untagged, packets will be dropped 1

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LAN settings: PriorityHow to manage input priority:Disable (No check): forcing of default values- 802.1p (level 2)- IpToS (level 3)- First 802.1p then IpToS First IpToS then 802.1pdefault Queue and default Priority added to output if input is without priority

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Local LAN1 Remote LAN14 settings:LAN1Internal LOCALInternal LAN 1 LOCALInternal LAN1 REMOTELAN1 Internal REMOTEANYENABLED

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Local LAN1 Remote LAN1Local LAN2 Remote LAN2SEGREGATED!LAN1, LAN2, Internal : Enabledall the LAN per Port : DisabledDefault VLAN tag (Vid): LAN14001, LAN24002, Int.anyIngress Filtering Check: FallBackUntagged frame Egress mode: UntaggedVirtual lan map

On local and remote equipment

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Local VLAN1 Remote VLAN1Local VLAN2 Remote VLAN2SEGREGATED!LAN1, LAN2, Internal : Enabledall the LAN per Port : DisabledDefault VLAN tag (Vid): LAN1any, LAN2any, Int.anyIngress Filtering Check: SecureUntagged frame Egress mode: TaggedVirtual lan map

On local and remote equipment

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PRBS (Pseudo Random Bit Sequence)Alarm on Checked signal lineMeasure results and duration Tributary selection if checked is Signal 2MBitP.R.B.S replaces the traffic on selected channelP.R.B.S. test is pointed out as Manual Operation (subject to timeout)

Checked signal selectionMeasure statusPattern typeSync Los events during test

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Fade margin

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1) Fade margin : Remote linkRemote terminal must be declared as Remote linkIn equipment 2 we want to perform Fade margin measurement

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2) Fade margin : summaryInput data : Expected F.M. (calculated by the customer directly, basing on nominal output power and nominal LBER threshold) External Atten. : all the losses between radio and antenna (excluding Branching)Curr. Step : four step (TxL1RxL1 , TxL2RxL2 , TxL2RxL1 , TxL1RxL2) Real F.M. : value based on expected F.M. adjusted with real output power, real LBER threshold (and External Atten.) measured at Final Test Departiment in SIAE and stored in ODUReal F.M.v. : value calculated decreasing Local Output power (1 dB step) until Remote LBER alarm activation. This value should be compared with declared one (Input data)

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AL PLUS: the IDUMain differences Out of standard capacities Adaptive modulationSTM-1 input

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AL PLUS: LCT

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Configurator

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Modulation/CapacityCapacities for selected modulation

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Configuration parametersLink ID 0 not usedLink ID 0 enable LinkIDLOC LinkIDREM (always) After Controller unit replacement a configuration mismatch can be solved in two ways:push Apply Configuration button: controller standard setup is applied on the equipmentdownload the old configuration file and push Apply Configuration button: old setup is downloaded on the controller and after on the equipment

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Adaptive modulation During bad propagation periods the system changes modulation to increase system gain keeping constant the transmitted bandwith and reducing transmitted capacityModulation has been varied and capacity has been reducedBelow this PRx threshold, remote PTx increases (as ATPC feedback). This PRx threshold is the number of dBs from PRx(@LBER) +2. Default is 2.Use of available new system gain dB of available new system gain added to previous PTxAdaptive mod. EnablingATPC hysteresis in dB for 4QAM modeSeconds of stable PRx between ATPC thresholds

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Adaptive modulation:32/16QAM to 4QAM mod. change request if, at both ends:PTx = PTx | MAXRemote needs more powerPRx is lower than ATPC Low thresholds

4QAM to 16/32QAM mod. change request if, at both ends:PTx = PTx | MAX@16/32QAMPRx is between ATPC thresholdsBER is better than 10-9

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TributariesLine loopInternal (radio) loopLine enabled53E1= 32+21

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What IDU PLUS offers:

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Normal operating conditionRx level on both ODU match values given by hop calculation.Rx level accuracy: -40 dBm -75 dBm range 3dB-30 dBm -40 dBm range 4dB

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Faulty condition: alarm notificationA faulty condition is pointed out byIDU front panel LEDs: - FAIL: controller self test failed- IDU: alarms from LIM and/or RIM- ODU: alarms from radio transceiver - REM: any alarm from other end- TEST: manual operation activeSCT window:- Log history area (with alarm correlation)- Equipment view current alarms (with alarms grouping)

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Alarms grouping : Current Alarms

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AL ALARMSThere are two directions of alarms: Tx and RxTx This line starts in LIM and arrives to output flange: when a situation of more alarms is occurring, the most significative alarm of them is at the beginning of Tx chain, all the others after are due to this Rx This line starts in output flange and arrives to LIM: when a situation of more alarms is occurring, the most significative alarm of them is at the beginning of Rx chain, all the others after should be caused by this

Most Significant alarmRxTx4

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Synthesis, Local/Remote groupAlarms are divided in groups: the name of the group is the name of the module where alarms come from, or the name of a specific characteristic of these alarmsA Synthesis alarm, with the name of relevant group, is the OR of alarms of that group (AL only).If an alarm occurs, also relevant LOCAL synthesis occurs (while REMOTE synthesis occurs in remote equipment)

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Alarms grouping : COMMON Alarms not related to a specific part of the equipment but relevant to the link.Example:EOC radio alarm (relevant SCT management)Link telemetry fail (relevant traffic, ATPC info, man op)

If both alarms are ON, the link is interrupted. Investigation must be made on a possible condition of bad propagation, or equipment failure

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Link telemetry failNo link between Local and Remote station. Traffic is cut.Link telemetry is inserted in main radio frame in Bit Insertion circuit inside LIM, and contains commands for the remote station: switch off the radios on remote side in case of local RF loop, Link ID, ATPC info.Telemetry link is a connection between local and remote IDUs.TEST - if this alarm occurs, a double IDU loop (both branches) can be done: if this alarm disappears, local IDU is OK and the problem is after (propagation, local radios, remote equipment).

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Communication Radio EOC Data link No link between Local and Remote station or wrong port address configuration.EOC is the channel involved in management communication. If EOC radio link is active: - Traffic is OK - Management is cut (no remote)

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PRBS FailWhen PRBS is working and no signal is received on checked signal, in PRBS window the field Sync Los Alarm is active together with PRBS Fail in Current alarms windowEvery ON-OFF transitionincreases the fieldPRBS Fail Alarm Counter

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Communication 2Mb EOC Data linkNo EOC channel is present on selected tributary in selected timeslot : wrong port address configuration or no tributary input (LOS).EOC is the channel involved in management communication.If EOC 2Mb link is active:- Management is cut (no remote)- If relative LOS is active, traffic on that tributary is out

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Revertive When a branch is declared preferential, the switch on opposite branch gives Revertive alarm.The return to preferential branch, when available again, happens after Wait Time period.

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2Mb/s G.704 (Trib.x) Radio Fail/AIS and/or Line Fail/AISWhen management messages come via tributary timeslot, further checks are performed on both directions of used tributary

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Tx FailWhen on remote side both radios dont receive, on local side a Tx switch command is performed and Tx fail alarm is enabled.When this alarm is on,check local ODU in stand byThis functionality is enabledin LCT General PresetThe alarm remains activeuntil Reset is given

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Link IDAlarm is on if Link ID check is enabled (Link ID 0) and remote Link ID is different from the local one. Traffic is cut but signal is received and measured. Output = AIS This alarm causes:

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Alarms grouping : LIMThese alarms come fromExternal fault: tributary LOSLIM failure: -Multiplexer/demultiplexer failure -Modulator/demodulator failure Warning: modulator/demodulator circuitry is spread into LIM and RIM modules.RIM or ODU alarms propagation (seen in LIM as Baseband RX alarm)

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Tributary-1 Signal lossLoss Of Signal alarm is active when a situation opposite to that foreseen by configuration is performed on tributary interface:No input ororcable disconnectedTributary connectedTRIB. STATUSTx

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Multiplexer failThe alarm is given during multiplexing of input tributaries by Overflow stuffing memoriesOverflow is due to bad clock of one tributary (too fast: >+50ppm) or hardware failureIn case of Multiplexer Fail the signal forwarded to the radio is N x AIS (from all the N tributaries)Tx

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Branch-x Modulator FailThis alarm is active when at cable interface Tx IF modulated signal (330 MHz) is missing or is under a certain value; this is due to: Modulator faulty Cable IDU-ODU open (that produces high VSWR value)Traffic is cutTx

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Branch-x ODU-IDU Communication failThis alarm occurs when on carrier used to receive information from ODU, or remote commands from other side, are detected: CRC errors Loss of frame

This carrier is separated from carrier used for opposite direction (IDUODU) and from TX or RX carriers

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Branch-x Demodulator FailTraffic is cutThis alarm is active when average deviation of symbol recognition is higher of a certain level.Every problem in constellation gives Demodulator alarm: Problem of digital conversion of received signal from RIM I or Q signal missing High level of interference (bad quality but good Rx level) No Rx IF modulated signal (140 MHz) from ODU (no Rx, ODU faulty, IDU/ODU cable open)Demodulator alarm causes: Rx quality alarms (HBER, LBER, EWL) Rx signal alarms (BaseBand Rx)RxBranch Rx quality alarm (software settable)

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Branch-x BaseBand RxThis alarm is active when Bit Extraction does not work (in LIM) Demodulator does not work (in LIM) Demodulator does not receive from RIM or ODUBaseBand Rx causes: Demultiplexer FailTraffic is cutRx

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Demultiplexer Fail The alarm is given during demultiplexing by: Frame Alignment Word not recognised (LOF - loss of frame) Overflow destuffing memories Overflow memories of hitless Rx switch BaseBand Rx alarm

In case of Demultiplexer Fail, output is AIS (from all the tributaries)Rx

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Alarms grouping : RIMThese alarms come fromExternal fault: demodulator fail alarm and ODU alarm are generated when ODU becomes faultyRIM failure: PSU alarm with cable open/short alarm or modulator/demodulator alarms are active Warning: modulator/demodulator circuitry is spread into LIM and RIM modules.

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Branch-1 Power SupplyThis alarm is active when the PSU (Power Supply Unit) of one RIM is switched off or is in failure conditionIf the PSU is off, all the alarms of that RIM are activated:this alarm causes allRx Branch-1 alarms except those relevantRadio1 (is OFF)Analysis order is:

PSUAll alarmedfrom now onRTIDU

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Branch-1 Cable open/shortThis alarm is active when the following situations occur: Cable open alarm no current through cable interface: ODU is not supplied so situation looks like PSU alarm (Rx alarms) with cable alarm instead PSU alarm Cable short alarm overcurrent/low voltage through cable interfaceCaused by high VSWRvalue of damaged cableCable opensituationIf both alarms are active, 48 V source has no enough current

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Alarms grouping : RTThese alarms come fromExternal fault: Rx power low alarm is generated because of bad propagation or by remote terminal faultyODU failure: PSU fail alarm or RF VCO alarm or RF IF alarm is activated

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Branch-x IDU-ODU Communication failThis alarm occurs in ODU when on carrier used to receive command from IDU, are detected: CRC errors Loss of frame

This carrier is separated from carrier used for opposite direction (ODUIDU) and from TX or RX carriers

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Branch-1 RT Radio Power SupplyThis alarm is active when the Power Supply section of the radio doesnt work properly or is in failure condition (voltage in input out of range).Depending voltage value, radio can work.When the under/over voltage is too high, radio is off and other alarms (cable open) cover this.

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Branch 1 RT VCO failThis alarm occurs when VCO in RF unit is not able to lock any frequencies. Every problem in VCO causes alarms in both directions: RF unit is not able to convert IF Tx in RF Tx (Tx Power Low alarm) and RF Rx in IF Rx .In this situation the alarm is active together with Tx Power Low and all Rx alarms because RF channel is not locked.

Tx & Rx

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Branch 1 RT If failThis alarm occurs when is not present IF signal inside ODU. There are two different IF signals but one alarm only.IF Tx: the alarm is on with Tx Power LowIF Rx: the alarm is on with all Rx alarms

When VCO is faulty, RF unit gives a IFRX signal made up of noise: this is enough to mantain IF fail alarm off.

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Branch 1 RT Tx Power LowThis alarm occurs when Tx power is 3 dB under standard output of ODU-RF unit. ATPC or manual attenuation do not affect this alarm that is given by internal failure of the radio.This alarm can be activated by a manual operation also: Tx Transmitter off in Radio Branch - Settings If both Rx Power Low and Tx Power Low are active, RF unit inside ODU is faultyTx

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Branch 1 RT Rx Power LowThis alarm occurs when Rx power is under a defined thresholdThreshold value can be set for both branches in range - 40 dBm- 99 dBm in LCT - General preset The alarm Rx Power Low is a branch alarm and it is used to drive Rx switchRx

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Alarms grouping : UNITThis group generates alarms when one of the units, the equipment consists of, is faulty or does not respond to controller polling:Unit failUnit is not respondingUnit is missingUnit hardware mismatchUnit software mismatch

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OTHERALARMS

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Performance alarmsEvery performance measure can drive the relevant alarm if threshold is exceeded.Threshold in sec. relevant 15 minutes alarmThreshold in sec. relevant 24 hours alarmThreshold in dB of Rx alarmalarm counter reset15 minutes alarms severityIf 0, alarm is disabled

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Performance monitoring15 min.alarms24 hoursalarmsPRX > -55 dBmPRX < -70 dBmR = 15 minutes

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Recorder : Prxdate timedBmLCT

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Measures Performances is a group of measures, 15 minutes by 15 minutes, day by day, recorded by the equipment itself and downloaded on the PC. These measures remain active also with SCT (and PC) disconnected. Recorder Prx is the recording of Rx power on a log file inside the PC: every time a new value is measured a new record is written inside the log file with info of when (day, hour, minutes and seconds) and how much (dBm measured). This recording remains active until SCT is connected to the equipment.

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LOOPSLine sideRadio sideBranch 1BASEBAND LOOP

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AL loop:external PRBSE1 loop line side : loop works with line enabled or notE1 loop radio side : loop works with line enabled on local side and on remote sideBase Band, IDU, RF loop : loop works if line used is enabled local side and on remote sideLine sideRadio side

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AL loop:internal PRBSE1 loop line side : is before PRBS checking pointE1 loop radio side :loop works with line enabled on remote side, indifferent* on local side.Base Band, IDU, RF loop : loop works any status of local* and remote line__________________________ * PRBS enables automatically the local side of used lineAlarm OFF: signal is back!

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Loop timeout

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PropagationFree space loss (L in Km, f in GHz)Received powerLPTPRh5

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AntennaAntenna gainDD = antenna diameter = wave lenght = c/f = Aeff / Ageo= antenna efficiency 0,6c = speed of light =

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1) Refractionk < 4/3 (sub-standard)k = 4/3 (standard)k > 4/3 (super-standard)Snell law: 12n1n2n1n2n3n4

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2) hgeo earth is not flathgeoR0 = 6378 kmLwith k4/3 considering the refraction of troposphere (previous page) considering geometrical visibility on a planet with no air

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3) First Fresnel zoneRML A nth fresnel zone gives in phase contributes to radio waves propagation. In order to avoid attenuation is important that first fresnel zone is without obstacle: to tower height calculation, must be add the ray of biggest fresnel zone, the first zone

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Height of the towersWe have to consider: earths curvature k effect (refraction) first Fresnel zone freeFrom the first we obtain hgeo , with refraction hgeo becomesand from the last we have to add also RM

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exampleL = 20 kmf = 23 GHzk = 4/3R0 = 6378 km+htower= 47m + 8,1m = 55.1m

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Fade marginfrom previous page: 4QAM/16x2L = 20 km PT= +20 dBm f = 23 GHz HBER - 82 dBm

x = gain of antennas FM= PR-HBER PR= -82dBm+40dB = -42dBmFM= 40dB (purpouse)GT+GR= 2G = PR-PT+Afs= -42dBm-20dBm+146dB=84dBGT=GR=42dB D=60cm G=40dB D=80cm G= 42,6dB

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Rain attenuation (f > 8GHz ) 25 mm/h 100 mm/h10 GHz 0.5 dB/km 2.5 dB/km15 GHz 1.5 dB/km 7 dB/km20 GHz 2.1 dB/km 10 dB/km30 GHz 4 dB/km 15 dB/km40 GHz 6 dB/km 20 dB/km

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Rain depolarizationWind Drag (air resistence)Drop weightEHvertical polar. e.m. waveEHhorizontal polar. e.m. waveIGHzhv

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MultipathDirect rayIndirect ray Indirect ray, depending on its phase, can increase or decrease the power of the main stream Two rays modelDirect ray: amplitude = Indirect ray: amplitude = b , phase delay = , time delay = AB In B position, received signal has a notch every 1/ Hz with deepness depending on b

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