ALC PDH RADIO Technical Training Instructor Mr. Monthien Satantoranin Senior Manager Technical Support ALC
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Training Topics 1. 2. 3. 4. 5. 6.
ALC
ALC Equipment Structure Installation , Configuration and Operating SCT Network Management Faults and Alarm Understanding Troubleshooting and Looback Test Path/Link Calculation
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ALC Equipment Structure 1. 2. 3. 4. 5.
ALC
ALC IDU ( Indoor Unit) ALC ODU ( Outdoor Unit) LIM ( Line Interface Module) RIM ( Radio Interface Module) Interconnection IDU to ODU cable
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IDU ( Indoor Unit)
Mains Features Max capacity : 16 E1 + 3 Ethernet Port IDU size: 1U high only and single board Service channel: optional V11 codirectional. Loops: RF loop, IF loop and Baseband loops ATPC range : depending on frequency (20dB or 40 dB) Internal PRBS IDU-ODU cable: 370 meter of ¼” or RG8
ALC
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IDU (Indoor Unit) SCT LAN port 120ohm E1 Sub-D type connectors
LCT USB connector
PSU connector Trib. 1-2-3-4
Q3
LCT
PSU alarm LEDs
Trib. 9-10-11-12
48V2
48V1
USER IN/OUT
PS1
TX RX 1 2 Trib. 13-14-15-16
-
PS2
Manual operation / Loop active Fuse: 3.15A (M)
Tx Rx R
TEST
1
AL
2
+
2 Trib. 5-6-7-8
+
TEST R AL
1
2
-
IDU-ODU cable SMA connectors
Reset Alarms ALC
Active branch (Tx / Rx)
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Reference Tooth
Volt/dBm in Rx Weight = 4.5 Kg
ODU (Outdoor Unit) ALC
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ODU Mounting
Max.1 dB Loss ALC
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ALC
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ODU with Integrated antenna
1+1 ODU
1+0 ODU
Unprotected ODU ALC
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Interconnection cable Frequency signals: Tx IF Rx IF Telemetry IDUODU Telemetry ODUIDU Power 48 VDC
330 MHz 140 MHz 17.5 MHz 5.2 MHz
Max length (1/4 inch or RG 8 cable) 4/16QAM
ALC
370 m 10
Equipment Composition ALC is made up by different sub-modules housed in two mechanical structures: 1) IDU
LIM Controller RIM (one per branch)
2) ODU
Radiotransceiver (RT, one per branch)
ALC
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Module functionalities Line
interfaces
Line
Mux-Demux circuits, Service Mux-demux circuits
Bit
insertion-extraction,
Modulator Switch BER
LIM
- Demodulator (digital side)
management
counters
Power
supply
Cable
interface
Modulator
RIM
(analog side) 330 MHz
Demodulator
(analog side) 140 MHz Radio
Power supply
Cable
interface
IF
ALC
Service interfaces
Management software ports
Equipment controller
EOC
Alarm LEDs
User in / Alarm out facilities
CONTROLLER
RT
unit
RF
unit: Transmitter, Receiver
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Equipment structure ALC
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Controller
ALC
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)
ALC
LIM
Tx direction
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LIM
Rx direction *FEC = Forward Error Corrector Example: FEC *
Without BER=10-6 With BER=10-13
(+2.5 dB)
(block code)
errors
ALC
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RIM
ALC
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ODU
ALC
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ALC characteristics (1) Tx
power (4QAM/16QAM): 7 GHz +27 dBm / +22 dBm 15 GHz +25 dBm / +20 dBm 23 GHz +20 dBm / +15 dBm
Tx/Rx
spacing: 7 GHz 154/161/168/196/245 MHz 15 GHz 420/728 MHz 23 GHz 1008/1232 MHz
Power
1+0 1+1 ALC
consumption < 30 W < 55 W
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ALC characteristics (2) Rx
HBER (10E-3) thresholds (4QAM/16QAM): - in 16x2 7 GHz -84 dBm / -80 dBm 15 GHz -83.5 dBm / -79.5 dBm 23 GHz -83 dBm / -79 dBm - in 4x2 7 GHz -90 dBm / -86 dBm 15 GHz -89.5 dBm / -85.5 dBm 23 GHz -89 dBm / -85 dBm
Max ALC
Rx power
- 20 dBm 20
Installation ,Configuration and Operating 1. 2. 3. 4. 5. 6.
ALC
IDU, ODU Installation SCT :Network Management Software LCT :Local Craft Terminal Parameter and Configuration Alarm Monitoring Backup ,Upload and Download firmware
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Installation IDU
Installation Power Supply and Grounding E1 Cable and Wiring Antenna and ODU Mounting
ALC
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Installation IDU
Installation (1) USB/LCT E1 Power Supply IDU to ODU Cable
ALC
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Installation IDU
Installation (2)
IDU to ODU Cable
ALC
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Power
Installation
Supply and Grounding Power Supply -48 to -57.6 Vdc Nominal Consumption 44 watts (1+0) 24 watts ( IDU only)
ALC
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Installation Power
Supply and Grounding
1= IDU grounding point
5=IDU matching tail grounding
2=ODU grounding point
6=Battery grounding point
3= IDU-ODU interconnect cable 7=Grounding cord connect to Earth ground rod 4=Cable grounding/Station ground ALC
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Installation ODU Grounding
ALC
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Installation E1
ALC
Cable and Wiring
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Installation Antenna
ALC
and ODU Mounting
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Installation Antenna
ALC
and ODU Mounting
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Installation Antenna
ALC
and ODU Mounting
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Installation Antenna
and ODU Mounting
ODU final housing position for
ODU final housing position for
Vertical Polarization
Horizontal Polarization
ALC
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Antenna and ODU mounting 1
4
ALC
3
2
5
6
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SCT/LCT : Main Features SCT/LCT
connection SCT Main Window Menus Routing Stored Routing Table Station management Commang Logger Equipment features management Configuration backup/restore Alarm monitoring LCT Main Window Manus Radio Parameter Configurations ALC
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SUBNETWORK and LOCAL CRAFT TERMINAL SCT/LCT
PERSONAL COMPUTER WITH GRAPHICAL DISPLAY WINDOWS 98, NT, 2000, XP SW PLATFORM TCP/IP COMMUNICATION PROTOCOL USING: RS232 Serial port (COM1/2 + PPP) USB +PPP Ethernet LAN
ALC
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“ALC” RADIO IP PROTOCOL STACK APPLICATION SOFTWARE SNMP TCP / UDP IP / OSPF LLC 802.2 MAC 802.3 802.3 (ETH LAN)
ALC
PPP LCT USB
EOC (Radio) 64Kb/s
ASYN-RS232 57.6Kb/s
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SCT : Connections
C
ALC
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Connection to the equipment
ALC
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Login
User: SYSTEM Password: ALC
(read & write) ; RLOM
(read only)
siaemicr 39
Stations
Equipments inside the station
lo y r o Hist
ALC
g
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Read again the status of the equipment
User management and time alignment
Configuration upload/download and station management
Configuration of the equipment Log as SYSTEM an equipment in monitor
History log management
Configuration of the connection
list of commands
ALC
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SCT Menu-Equipment
ALC
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SCT Menu-Option
ALC
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SCT Menu-Network
ALC
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SCT Menu-Tool
ALC
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Equipment menu
Equipment configuration Agent, name, time Alarms, group by group Alarms’ configuration Test, loops, manual operations Alarms reading (refresh) Firmware update Performance monitoring Units Automatic troubleshooting Routing and addressing
ALC
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ALC
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Properties Equipment name Agent, used in alarm history and in subnetwork wizard Equipment time alignment and network time alignment Software restart (doesn’t cut the traffic)
ALC
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View Current Alarms
ALC
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Alarm configuration
ALC
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Manual operations list
ALC
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Firmware Update Firmware Switch Download of the firmware
Upload of the actual firmware
ALC
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Download of the new firmware Position of the file firmware.dwl
Overwriting of old firmware (total dowload – slow) Download of different sections only (fast) or towards peripheral (radio) Bench switch after the download ALC
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Performance Monitoring
Start/Stop of selected item
Quality results Output power Input power
ALC
Show of the results of the selected item
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UNITS
Part number
Part number
Status
Kind of trouble ALC
Trouble severity 55
Diagnosis Reading the actual alarms the Diagnosis prepares an explanation of every trouble and the procedures to follow to solve the problem
ALC
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Port addresses All SIAE equipments, regarding SCT software and supervision, are routers: all interfaces need an address and relevant subnet mask
Addresses can be set clicking: 1.
Set values
2.
Store
3.
Restart
Client (always) ALC
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Routing
ALC
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Routing ALC Port and Address
ALC
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Routing ALC Port and Address in daisy chain
ALC
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Routing table Type and address of crossed port towards Destination
Netmask and IP address of Destination Type and address of crossed port Default destination ALC
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Stored Routing Table The “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: 1. In “Stored Routing Table” add the routing lines relevant to new port addresses you are going to set 2. Set the new port addresses (…the equipment restarts) 3. After the restart the equipment has new addresses and the routing table configured already: the NE management is still running
ALC
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Station management NEs connected to SCT can be assigned in various stations using the tool : “Subnetwork Configuration Wizard”
ALC
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Alarm correlation Every alarm is reported with Alarm beginning Alarm end (gravity info is maintained)
ALC
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Alarm acknowledgement Alarm acknowledge is available in alarm history list: every acknowledgement can be managed completely in station list: new alarm info is highlighted by an asterisk
ALC
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Command logger Cmd Logger reads the list of operations, executed by the users, 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 date User address User type Operation name
ALC
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Configuration upload/download Upload (from equipment) From
Tool menu, open the proper Template Select Upload operation and the equipment you want to upload information from Save 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 using Equipment Configuration Wizard. ALC
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Configuration Template Configuration
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. ALC
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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.
ALC
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LCT for ALC
ALC
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Configuration
General Bitrate
Modulation
Link ID (local only)
ALC
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Rx Power Low thresholds
HBer,LBer, EWL thresholds
ALC
1) General preset: thresholds 72
2) General preset: Rx switches
1+0 1+1
In case of no Rx
In case of Hber, Lber, EWL, first CRC correction ALC
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Radio link parameters Main parameters of the link are: Configuration Capacity
For local Modulation terminal
Setting has to be copied in remote terminal
Link ID Frequency Frequency
For both Only “Configuration” Capacity local and has to be set locally (on Modulation remote local and after on terminal remote) Link ID ALC
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PRBS (Pseudo Random Bit Sequence) Measure results and duration
Alarm on “Checked signal” line
Sync Los events during test Measure status Pattern type
Checked signal selection
Tributary selection if checked is Signal 2MBit
P.R.B.S replaces the traffic on selected channel P.R.B.S. test is pointed out as Manual Operation (subject to timeout) ALC
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ATPC (Automatic Tx Power Control)
ALC
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ATPC Characteristics Maximum ATPC range:
This range is limited by the amount of fixed attenuation with respect to the nominal TX power
Power Control Criteria:
Remote terminal Received Signal Level (RSL) and BER
ATPC speed:
30 dB/s
Purpouse:
To counteract the effect of flat fading, minimizing nodal interferences
ALC
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Maintenance 1. 2. 3. 4. 5.
ALC
Reriodical Check Alarm Meaning Root Cause of Failure Troubleshooting Loop Facilities
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Periodical Check Periodical Checks are used to check for radio equipment operation without the presence of any alarm conditions
Check of the TX Power
Check of the Receive Signal Strength ( Reading Value must be match with link hop Cal.)
ALC
Check of BER and HOP performance
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Normal operating condition
Rx level on both ODU match values given by hop calculation. Rx level accuracy: -40
dBm -75 dBm range -30 dBm -40 dBm range ALC
± 3dB ± 4dB 80
Faulty condition: alarm notification A faulty condition is pointed out by IDU front panel LEDs: - AL: alarms, internal or external - TEST: manual operation active SCT
window:
- Log history area (with alarm correlation) - Equipment view current alarms (with alarms grouping)
ALC
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ALARMS There are two directions of alarms: Tx and Rx Tx
– 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
ODU
Rx Most Significant alarm
RIM LIM ALC
Tx
ODU RIM LIM 82
COMMON group 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
ALC
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ALC
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Link telemetry fail No 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).
ALC
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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)
ALC
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PRBS Fail When 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 window Every ON-OFF transition increases the field PRBS Fail Alarm Counter
ALC
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Communication 2Mb EOC Data link No 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 cut
ALC
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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.
ALC
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2Mb/s G.704 (Trib.x) Radio Fail/AIS and/or Line Fail/AIS When management messages come via tributary timeslot, further checks are performed on both directions of this tributary
ALC
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Tx Fail When on remote side both radios don’t 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 by This functionality is enabled in LCT – General Preset The alarm remains active until Reset is given
ALC
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Link ID Alarm 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:
ALC
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LIM group These alarms come from External fault: tributary LOS LIM 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) ALC
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ALC
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Tributary-1 Signal loss
Tx
Loss Of Signal alarm is active when a situation opposite to that foreseen by configuration is performed on tributary interface: No input or or cable disconnected TRIB. STATUS
Tributary connected
ALC
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Multiplexer fail
Tx
The alarm is given during multiplexing of input tributaries by
Overflow stuffing memories
Overflow is due to bad clock of one tributary (too fast: >+50ppm) or hardware failure In case of Multiplexer Fail the signal forwarded to the radio is N x AIS (from all the N tributaries)
ALC
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Branch-x Modulator Fail
Tx
This 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 cut
ALC
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Branch-x ODU-IDU Communication fail This 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
ALC
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Branch-x Demodulator Fail
Rx
This 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) Branch Rx quality alarm
Demodulator alarm causes:
(software settable)
Rx quality alarms (HBER, LBER, EWL) Rx signal alarms (BaseBand Rx)
Traffic is cut ALC
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Branch-x BaseBand Rx
Rx
This alarm is active when
Bit Extraction does not work (in LIM)
Demodulator does not work (in LIM)
Demodulator does not receive from RIM or ODU
BaseBand Rx causes: Demultiplexer Fail
Traffic is cut
ALC
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Demultiplexer Fail
Rx
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)
ALC
101
RIM group These alarms come from External fault: demodulator fail alarm and ODU alarm are generated when ODU becomes faulty RIM 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.
ALC
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ALC
103
Branch-1 Power Supply This alarm is active when the PSU (Power Supply Unit) of one RIM is switched off or is in failure condition
Analysis order is:
PSU
IDU
All alarmed from now on
RT
If the PSU is off, all the alarms of that RIM are activated: this alarm causes all Rx Branch-1 alarms except those relevant Radio1 (is OFF)
ALC
104
Branch-1 Cable open/short This 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 interface If both alarms are active, 48 V source has no enough current
Caused by high VSWR value of damaged cable
Cable open situation ALC
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RT group These alarms come from External fault: Rx power low alarm is generated because of bad propagation or by remote terminal faulty ODU failure: PSU fail alarm or RF VCO alarm or RF IF alarm is activated
ALC
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ALC
107
Branch-x IDU-ODU Communication fail This 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
ALC
108
Branch-1 RT Radio Power Supply This alarm is active when the Power Supply section of the radio doesn’t 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.
ALC
109
Branch 1 RT VCO fail
Tx & Rx
This 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.
ALC
110
Branch 1 RT If fail This alarm occurs when is not present IF signal inside ODU. There are two different IF signals but one alarm only. No IF Tx : the alarm is on and causes Tx Power Low No IF Rx: the alarm is on with all Rx alarms Rt If fail can be caused by Modulator fail (no IF Tx) When VCO is faulty, RF unit gives a IFRX signal made up of noise: this is enough to mantain IF fail alarm off (but Demodulator cannot work Rx alarms). ALC
111
Branch 1 RT Tx Power Low
Tx
This alarm occurs when Tx power is 3 dB under standard output of ODU-RF unit. ATPC and manual attenuation do not affect this alarm that is due by internal failure of RF unit. 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 faulty
ALC
112
Branch 1 RT Rx Power Low
Rx
This alarm occurs when Rx power is under a defined threshold (about 10 dB under standard Rx level) Threshold 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 switch
ALC
113
UNIT group This group generates alarms when one of the units, the equipment consists of, is faulty or does not respond to controller polling: Unit fail Unit is not responding Unit is missing Unit hardware mismatch Unit software mismatch ALC
114
ALC
115
OTHER ALARMS
ALC
116
Performance alarms Every performance measure can drive the relevant alarm if threshold is exceeded. Threshold in sec. relevant 15 minutes alarm Threshold in sec. relevant 24 hours alarm Threshold in dB of Rx alarm alarm counter reset
If 0, alarm is disabled ALC
15 minutes alarms severity 117
Performance monitoring 15 min. alarms 24 hours alarms
PRX < -70
dBm
P
>
5 -5
dB
m
RX
R = 15 minutes
ALC
118
Recorder : Prx
date
ALC
LCT
time
dBm
119
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 (the download needs bitrate). 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.
ALC
120
Current Alarms
ALC
121
Switch modes Auto
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 doesn’t 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
ALC
122
Tx switch criteria 1. 2. 3.
4. 5. ALC
RIM PSU alarm Highest priority Manual forcing Cable short/ Cable open alarm Modulator failure ODU unit failure alarm VCO failure alarm IF unit alarm ODU PSU alarm Tx power low alarm Rx failure on both remote radios lowest priority Revertive Tx 123
Rx switch criteria 1. 2. 3.
4. 5. 6. 7. 8.
RIM PSU alarm Highest priority Manual forcing Cable short/open alarm Base band unit failure alarm Demodulator failure ODU unit failure alarm VCO failure alarm IF unit alarm ODU 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 pulse Revertive Rx lowest priority ALC
124
EQUIPMENT FEATURE MANAGEMENT ALC
125
LOOP FACILITIES Local Tributary Loop : used to test the cable interfacing
for the equipment upstream Remote Tributary Loop : used to test two direction link
performance making use of an unused 2 Mbit/s signal
Baseband Loop : it permit to test the LIM circuits
IDU Loop : it permit to test the complete IDU (optional)
RF Loop : it permit to test the complete radio terminal
ALC
126
BASEBAND LOOP
RF LOOP
IDU LOOP
MOD-DEMOD
RF
RIM 1
Branch
Line side
BASEBAND 1 LOOP
ODU 1
AL : available loops
data direction: - towards the equipment that has enabled the loop (baseband, IDU, RF - selectable for E1 loop - only local loops MO DEMO RF RIM1 IDULOP ODU1 RFLOP
MUX -DEMUX
BA
E1LO
D-
OP
SEBAND OPL LA dat
:av
ilabe
directon: onlyca-setbwrdh
lops
lopsfrE1equimnt
thasenb
ledthop(
basend,ID
U,RF)
LIM
MUX-DEMUX
E1 LOOP
LIM
Radio side ALC
LOOPS 127
Line side
ALC loop: external PRBS
Radio side
E1 loop line side : loop works with line enabled or not E1 loop radio side : loop works with line enabled on local side and on remote side Base Band, IDU, RF loop : loop works if line used is enabled local side and on remote side ALC
128
loops: internal PRBS
Alarm OFF: signal is back!
E1 loop line side: it is before PRBS checking point E1 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 __________________________________________________________ ALC * PRBS enables automatically the local side of used line
129
Propagation Link E.I.R.P = Pt + Gt+ Cable loss Free space loss (L in Km, f in GHz) Received power
PT
A fs = 92.44dB + 20 Log ( L ⋅ f )
PR ( dBm ) = PT ( dBm ) − A fs ( dB ) + GT ( dB ) + GR ( dB )
L
PR
h
ALC
130
Antenna D = antenna diameter λ = wave lenght = c/f
D
η=
Aeff / Ageo= antenna efficiency ≈ 0,6
8 −1 3 ⋅ 10 ms c = speed of light =
D 2 ⋅π 2 Antenna gain G = 10 Log ⋅η 2 λ
ALC
131
1) Refraction Snell law:
α2
n2
n1senα1 = n2 senα 2
α1
n4
n3
n1
n2
n1
k < 4/3 (sub-standard)
k > 4/3 (super-standard)
ALC
k = 4/3 (standard)
132
2) hgeo …earth is not flat 2
hgeo
L = R0
considering geometrical visibility on a planet with no air 2
L ′ = hgeo k ⋅ R0
with k<4/3 , k=4/3 , k>4/3 considering the troposphere refraction (previous page)
hgeo L ALC
R0 = 6378 km
133
3) First Fresnel zone 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
λ⋅L RM = 2 L RM ALC
134
Height of the towers We have to consider:
earth’s curvature
k effect (refraction)
first Fresnel zone free
′ } From the first we obtain hgeo , with refraction hgeo becomes hgeo and from the last we have to add also RM
L λ⋅L ′ + RM = = hgeo + k ⋅ R0 2 2
htower ALC
135
example L = 20 km f = 23 GHz k = 4/3
2
L ′ = hgeo = 0.047 km = 47 m 1.333 ⋅ R0
R0= 6378 km
+
λ⋅L RM = = 8.1m 2 htower= 47m + 8.1m = 55.1m ALC
136
Fade Margin
…from previous page: 4QAM/16x2 L = 20 km
PT= +20 dBm
f = 23 GHz
HBER - 82 dBm
A fs (dB) = 92.44 + 20 Log ( L ⋅ f ) = 92.44 + 53.26 = 145.7dB x = gain of antennas
FM = 40dB (purpouse)
FM= PR-HBER PR= -82dBm + 40dB = -42dBm
PR ( dBm ) = PT ( dBm ) − A fs ( dB ) + GT ( dB ) + GR ( dB ) GT+GR= 2G = PR-PT+Afs= -42dBm-20dBm+146dB=84dB GT=GR=42dB
ALC
D=60cm G=40dB
D=80cm G= 42,6dB
137
Rain attenuation (f > 8GHz ) freq
\
rain
25 mm/h
100 mm/h
10 GHz
0.5 dB/km
2.5 dB/km
15 GHz
1.5 dB/km
7 dB/km
20 GHz
2.1 dB/km
10 dB/km
30 GHz
4 dB/km
15 dB/km
40 GHz
6 dB/km
20 dB/km
ALC
138
E
Rain depolarization
H vertical polar. e.m. wave
Drop weight H E horizontal polar. e.m. wave
Wind I
h
v GHz
Drag (air resistence) ALC
139
Multipath
Direct ray
A
B
Indirect ray
Indirect ray, depending on its phase, can increase or decrease the power of the main stream Two rays model
[
H (ω ) = α ⋅ 1 − b ⋅ e
− j (ωτ −δ )
]
Direct ray: amplitude = α Indirect ray: amplitude = αb , phase delay = δ , time delay = τ In B position, received signal has a notch every 1/τ Hz with deepness depending on b ALC
140
THANK YOU
ALC
141
