Sit training cr

Presentation On

Satellite Interactive Terminal (DVB-RCS Technology)

By

Infinium (India) Ltd. For

Space Application Centre,Ahmedabad

The DVB- RCS is a star network where each user terminal inter-connects with a hub station via satellite. The communication between the hub station and the user terminal is done through satellite links.

The Edusat network operates at Ku-Band (14/11 GHz) The Edusat network operates at Ku-Band (14/11 GHz) frequency. One of the transponders ( here National frequency. One of the transponders ( here National Beam) of a Geo-stationary satellite (here GSAT-3, Beam) of a Geo-stationary satellite (here GSAT-3, Location 74Location 74E) is used to operate this network.E) is used to operate this network.

Introduction to DVB-RCS System

DVB-RCS VSAT Network

SIT

The Hub is primarily responsible for carrying Internet Protocol (IP) traffic between Satellite Interactive Terminals (SITs). Hub is also responsible for overall network management like Bandwidth configuration, Monitor & Control of all SITs etc.

The IP traffic at Hub is encapsulated in to MPEG-TS in DVB format . After necessary stages for modulation, frequency conversion, amplification etc., the same traffic is uplinked for SITs.

The link from Hub to SIT is called Forward Link (FL) and it uses a standard Digital Video Broadcasting (DVB) format. It allows data rate up to 45 Msps. Presently FL is configured for 10 Msps considering satellite resources available & total traffic expected among all the SITs.

The FL is like big pipe & carries the combined traffic for all SITs.

Forward Link (FL)

The IP traffic at SIT is encapsulated in to either MPEG or ATM cell. After necessary stages for modulation, frequency conversion, amplification etc., the same traffic is uplinked for Hub.

The link from SIT to Hub is called Return Link (RL) and it is responsible to carry the return link traffic using Multi-Frequency Time Division Multiple Access (MF-TDMA) based on ATM or MPEG standard. Single SIT allows data rate up to 2 Mbps. Presently each SIT is configured in Hub for Maximum 624 / 512 Kbps data. The RL BW for SIT is controlled by controlling nos. of time slots.

In MF-TDMA, each carrier is divided in nos. of logical time slots. The Hub assigns un-assigned time slots to particular SIT. The SIT sends the traffic (either ATM/ MPEG cell) to hub using these time slots.

Return Link (RL)

RL- MPEG Frame for Teaching End

Fig: Time slots used by particular SIT in MPEG Frame

At present carrier carrying the MPEG cells is divided in 11 nos. of traffic time slots. Single time slot supports 56.75 kbps data rate. Each Teaching End (TE) is configured permanently (CRA) in Hub with such 11 time slots which will support up to 624 (56.75*11) Kbps RL traffic.

Traffic Time Slots: T1 to T11

Carrier Frequencies: F1 to F8

RL- ATM Frame for Class Room

Fig: Time slots used by particular SIT in ATM Frame At present carrier carrying the ATM cells is divided in 32 nos. of traffic time slots & single time slot supports 16 kbps data rate. Each Class Room (CR) is configured in Hub with request based 24 time slots. I.e. 4 RBDC & 20 VBDC. This will supports up to 384 (16*24) kbps RL traffic.

Traffic Time Slots: T1 to T32

Carrier Frequencies: F1 to F15

RL- Types of Time Slots

Return Link traffic is brought to Hub with use of four types of time slots. The SIT can be configured with one or more types of time slots.

(1) Constant Rate Assignment (CRA) This type of time slots is assigned by Hub when particular SIT logs ON (Switch ON). CRA provides guaranteed RL bandwidth. It is most suitable for real time traffic like Video & Voice Conferencing & other non-real time applications. Each TE is configured with this type of time slots.


(2) Rate Based Dynamic Control (RBDC) This type of time slots is assigned by Hub when particular SIT demands/requests for allotment of time slots. RBDC provides (on demand) RL bandwidth. Hub will allot the no of time slots proportional to data rate at the LAN port of SIT. It is suitable for real time traffic like Voice Conferencing & other non-real time applications like file transfer. Each CR is configured for this type of time slots.


(3) Volume Based Dynamic Control (VBDC) This type of time slots is assigned by Hub when particular SIT demands/requests for allotment of time slots. VBDC provides (on demand) RL bandwidth. Hub will allot the no of time slots proportional to data Volume at the LAN port of SIT. It is suitable for non-real time applications. Each CR is additionally configured for this type of time slots.


(4) Free Capacity Assignment (FCA) In pool of time slots with Hub, some time slots are free. The free time slots are assigned by Hub to SIT to fulfill the requirement of data transfer. It is like bonus to SIT. It is suitable for non-real time applications.

Hub Overview The system can be divided into two segments: SIT and Hub. The SIT

segment represents what is installed on the customer’s site. The Hub segment represents the equipment used by the service provider.

IDU

ODU

RLSSIDU

ODU

Satellite

FLSS

SNMPManager

Router

ToInternet

EndUser

Router

EndUser

EndUser

EndUser

EndUser

Hub-Sub systemsThe communication between SITs is always through Hub. The datatransmitted from one SIT is first received by Return Link Sub system (RLSS) of Hub. The data received by RLSS is routed toForward Link Sub System (FLSS) for re-transmission. The re-transmitted data is received by another SIT. The complete Hub consists of FLSS & RLSS.

The FLSS consists of IP Router. IP Encapsulator & DVB Multiplexer PCR Inserter (Part of RLSS) L-Band DVB Modulator Ku-Band SSPB & Antenna

Hub-Sub systems

The RLSS consists of Antenna & LNBC Multi Carrier Demodulator (MCD) Board Signaling (SIG) Board Traffic (TRF) Board Operation, Administration and Management (OAM) plus PCR Monitor Board DVB Demodulator (For RCR Monitoring function) IP Router The OAM stores the database of all-valid SITs like MAC address,

IP address, configuration files including permissible Max. bandwidth, type of access etc.

SIT Overview The Satellite Interactive Terminal (SIT) is composed of

the outdoor unit (ODU), which includes the antenna and RF transceiver (Transmitter + Receiver), and the indoor unit (IDU).

SIT receives the educational program from Teaching End (TE). As SIT has transmit facility, the interaction with TE is possible.

TransceiverInter-

FacilityL ink

EthernetIn terface

ODU

AntennaSubsystem

M echanical Subsystem

IDUTo local private

LAN or directly toHost

Ku - FL

Ku - R L

SIT ODU

ODU Provides RF interface with the satellite In Receive chain Ku-Band signal (from satellite)

is down-converted to L-Band signal (i.e. 950-2150 MHz).

In Transmit chain L-Band signal is up-converted to Ku-Band signal.

ODU Mainly composed of: Reflector SSPB (Solid State Power Block Converter) LNB (Low Noise Block) Feed Horn/OMT (Ortho-Mode Translator)

SIT ODU General Safety

Danger area near Antenna

General rule: Don’t stand in front of the Antenna!

SIT Grounding

Grounding The ODU must be grounded in strict

accordance with National and Local electrical codes.

ODU copper ground wire should be connected to the local Lightning Protection System (LPS)

Where the LPS is not available proper grounding requires installation of a ground rod(s). The copper ground wire(s) from the ODU would connect to this ground system.

Functions of ODU

ODU includes: 1.2M Ku Band Antenna with 2-port

Offset feed 2W Solid State Power Block Converter

(SSPB) Low Noise Block Converter (LNBC) Inter Facility Link (IFL)

ODUs

SSPB

LNBC

Feed (Part of Antenna)

Reflector(Part ofAntenna)

Base Frame& Cement Blocks (here not shown)

1.2M Antenna 1.2M Antenna consists of 1.2M single Piece solid

parabolic reflector, 2-port Linear offset feed, non-penetrating mount structure etc. It receives & transmits Ku-band signal from satellite.

At present Antenna looks GSAT-3 located at 74 deg East. The Line Of Site (LOS) must be clear for antenna through out its life of operation. The antenna, after installation, must be tightened & marked for its position.

As Antenna is Non-penetrating type, It uses base frame for installation on flat/hard surface. The 6-8 Ballasts (Cement Blocks) supplied along with SIT are to be kept on tray for tight holding of Antenna for required LOS. The supplied cement blocks are sufficient to survive the antenna against wind speed of 100-125 Km/hour.

Solid State Power Block (SSPB)

A 2W, feed mount SSPB sits on TX port of feed. The SSPB converts L-Band frequency to Ku Band frequency & amplifies the Ku Band signal up to 2W. It uses the required DC power from IDU through IFL. The IDU also sends 10MHz to SSPB.

After installation of SSPB on antenna feed, it must be sealed properly to avoid entering of rain water inside the SSPB.

Low Noise Block Converter (LNBC)

A feed mount LNBC sits on RX port of feed. LNBC converts incoming Ku Band signal to L-Band frequency & amplifies the L-Band signal. The IDU provides the required DC power for LNBC over IFL cable.

As it is ODU, after installation on antenna feed, It must be sealed properly to avoid entering of rain water inside the LNBC.

Inter Facility Link (IFL)

The IFL cables (#2) interface the ODUs with IDU. They carry the L-Band signal & DC voltages for ODUs (from IDU).

IDU 4100- Front View

LEDs • Power: On /Off• Ready: Ethernet communication ready• Ethernet Rx activity• Ethernet Tx activity• Satellite Rx Link acquired• Satellite Tx Link acquired

IDU 4100

IDU 4100 is the main indoor unit responsible for exchanging data from one SIT to other SIT.

It provides the Ethernet interface for customer’s equipment (here PC).

IDU operates on 1-ph 230V AC supply.

IDU 4100

The sequence of LED glow for functional SIT will be:

1. POWER LED will glow first when IDU is powered.

2. READY LED will glow after 30-40 seconds.3. SATELLITE RX LED will glow after Forward

Link (i.e. Carrier from Hub) is acquired.4. SATELLITE TX LED will glow after Return Link

(i.e. Carrier from SIT to Hub) is acquired.5. ETHERNET TX & RX LEDs will glow whenever

there is traffic from PC connected with IDU.

IDU 4100

The IDU must be installed near to computer or LAN. The length of Ethernet cable (between IDU & computer) is 100 Mtr. (Max.).

The controlled environment (i.e. Air Conditioner) is more preferable.

One mounting plate is used to hold IDU, its AC adaptor & IFL cables. This plate also serves as heat sink.

IDU supports Data Rate: Up to 2 Mbps via Return

Path Up to 45 Mbps via Forward Path

Interface with IDU

Interface IDU supplies to SSPB (Tx)

24V DC Transmit signal 950-1450MHz 10 MHz reference

IDU receives 950-2150 MHz Rx signal from LNBC (Rx) &

supplies 18 VDC to LNBC (Rx) LAN Port interfaces customer’s equipment.

Local Area Network (LAN)

One or more IP address based devices (called hosts) like PC, Server etc. all to gather make one LAN at customer’s site.

The SIT is the part of local LAN & functions to provide connectivity of Local LAN with other LAN located at geographically different place.

The IDU acts as a Gateway when traffic is towards other LAN.

IP Address & Subnet Mask IP address is a 4 bytes (32 bits) logical

address to be assigned to each PC (also other Ethernet protocol device).

IP address is one type of identification no. required during communication in Internet Protocol (IP) environment.

The IP Address is unique for each device. Subnet Mask is used to separate out the

hosts on LAN (Sub network) from whole network.

IP Address Scheme for IDU & Host IDU: IP Address: 172.19.Y.1

Subnet Mask: 255.255.255.0 Where Y: SIT Sequential No. & conveyed to SIT

user after installation of SIT.

Host: IP Address: 172.19.Y.2 to 254Subnet Mask: 255.255.255.0 (i.e. same as of IDU)Gateway: 172.19.Y.1 (i.e. same as of IDU)

The traffic within LAN may be 10 Mbps or more depending on type of LAN i.e. 10/100 BaseT. But the traffic over satellite link must be less than bandwidth (pipe) assigned to particular SIT.

Teaching End (Sub Hub) & Class Room (CR)

Teaching End (TE)- Sub Hub

All the SITs in network are physically same. Any SIT of particular user agency can be configured as a Sub Hub.

The main differences in parameters configured in Hub are: For Sub Hub

· Multicast facility is enabled.· Constant (CRA) 624 kbps (Sub Hub to Hub) RL BW is

allotted for Multicast & other traffic.

For Class Room (CR)· Multicast facility is disabled & BW is of different type &

less (I.e. 384 Kbps with combination of RBDC & VBDC).

Additionally Sub Hub will have more facilities like servers, studio etc.

Assigning IP Address to Computer Follow the steps given bellow: Double Click on “My computer” icon on the screen of the

Laptop. Double Click on “Control Panel” icon. Double Click on “Network and Dial-Up Connections” folder. Double Click on “Local Area Connection”. Click on “Properties” button. Select “Internet Protocol (TCP/IP)” from connections window. Click on “Properties” button. Select “Use the following IP Address” button. Make the following changes in IP addresses as described

below. IP Address: 172.17.y.2 to 254 Subnet Mask: 255.255.255.0 Default Gateway: 172.17.y.1 ( IP address of SIT)

Where y is same as of IDU Click “Ok” button on window to come out.

SIT Functionality ChecksThe following steps confirm the full functionality of SIT. (1) first assure that POWER, READY, Satellite TX & RX LED glow on

IDU.(2) Ping IP address of PC itself first. The reply is expected within 10 ms. (3) Ping the IP address of IDU. The reply is expected within 10 ms. Also Ethernet TX & RX LEDs will glow.(4) Ping the IP address of Hub Router (ping 192.168.2.1 –t –w 2000). The reply is expected within 600 ms (single hope satellite delay). Note: -t is used for repeated ping.

-w 2000 is used for 2000 ms waiting period for reply.(5) If the reply from Hub is within 600 ms & without any packet loss, the connectivity of Local station/SIT with Hub can be considered perfectly OK.

SIT Functionality Checks

(6) Ping the IP address of Remote IDU (ping 172.X.Y.1 –t –w 2000). The reply is expected within 1200 ms (double hope satellite delay). (7) If the reply from remote SIT is within 1200 ms & without any packet loss, the connectivity of local SIT with Remote SIT can be considered perfectly OK.

SIT Fault Diagnosis

The SIT user has to follow steps in sequence dependingOn particular fault. POWER LED does not glow.

Check the mains supply for 230V AC. Remove the adaptor pin from IDU & check the DC supply

at the pin for 24V DC. IDU has been faulty & requires replacement.

SIT Fault Diagnosis POWER LED glows, but READY LED

does not glow. IDU fails to reboot, switch ON/OFF

two/three times. IDU has been faulty & requires

replacement.

SIT Fault Diagnosis Satellite RX LED does not glow. (It means the problem is in Receive path).

Switch OFF & switch ON once. Wait for few minutes.

Outdoor antenna is moved from its earlier position. Check the antenna for required marking on antenna. Antenna is required to be re-align by trained person.

Problem in IDU, IFL (RX) cable or LNBC. They are required to be attended trained person.

Problem in Hub. Wait till Hub becomes functional.

SIT Fault Diagnosis RX LED glows, but TX LED does not

glow. (It means problem is transmit path).

It will glow when traffic is received by IDU from local Host.

Problem in IDU, IFL (TX) cable or SSPB. They are required to be attended by trained person.


SIT Fault Diagnosis No reply from Local IDU while pinging.

Assure that POWER & READY LEDs glow on IDU & Ethernet cable is connected at both ends.

Assure that there is no proxy between Host & IDU. Check the IP address & Subnet Mask of PC. Ping the IP address of PC itself first. The reply is

expected within 10 ms. Replace the cable & ping IDU again. Replace the PC once, assign the required IP settings

& ping the IDU again. IDU is required to be attended by trained person.

SIT Fault Diagnosis Reply from Local IDU, but No

reply from Hub while pinging. Assure that Satellite RX LED glow. Check the Subnet Mask & Gateway in

PC. Add –w 2000 after ping command to

allow PC to wait for 2000 ms for reply. Problem in IDU, IFL (TX) cable or SSPB.

They are required to be attended by trained person.


SIT Fault Diagnosis Reply from Hub, but no reply from

Remote SIT while pinging. Remote SIT is OFF/ Non-functional etc. Instruct Remote SIT to ping Hub first. Problem is of Remote SIT, not of Local

SIT. Remote SIT is not in same group of

users.

SIT Fault Diagnosis Poor Performance of SIT

Check the performance of Local & Remote SIT as per steps given in “SIT Routine Functionality Checks”.

Check that there is no obstruction in antenna Line of Sight (LOS).

Check the outdoor for sealing, damage etc.

Check IFL cable for any type of damage including loose connector assembly.

Do

It is recommended that each site must have one low

cost Digital Multi Meter (DMM) to measure the Mains supply

(i.e. 230V AC), DC supply (i.e. 24V DC) & other preliminary

checks (i.e. continuity of IFL cables) for SIT.

Always switch OFF the SIT whenever it is not required for

Prolonged time.

Always maintain the effectiveness of Earth pit by watering

it at regular interval.

Important Instructions

Always assure that the equipments to be interfaced with

IDU are properly grounded.

While demonstrating the ODU to visitor, students, always

stand in the back side of antenna.

Always go through steps shown in chapter “SIT Routine

Functionality Checks” whenever SIT functionality is doubtful.

Always inspect the ODU & IFL cable for any damage or

misalignment whenever IDU does not lock to FL from Hub.

Always keep the backup of application SW.

Always handle IDU, IFL cables carefully. Assure that IFL

are tension free.


Always confirm SIT functionality with use of standalone PC

& small cable whenever SIT functionality is doubtful.

Always prefer regulated supply & air-conditioned

environment for operation of SIT.


Don’t

Don’t stand in front of antenna when IDU is in powered condition.

Don’t disturb the cement blocks kept on antenna base frame. If disturbed Antenna may loose its original pointing.

Don’t try to shift antenna. If disturbed from original position, antenna may loose LOS.

Don’t connect & disconnect IFL cables when IDU is in powered condition. The IFL carries the DC voltage.

Don’t connect other equipment with dedicated Earth pit provided for SIT.

Don’t put any thing on IDU.


Don’t try to extend cable by connecting other type of cable.

The IDU meets the specifications only with supplied cable.

Don’t operate SIT with unreliable power source like Genset,

Locally made Inverter etc.

Don’t try to troubleshoot SIT by your own.

Don’t change Subnet Mask of PC other than 255.255.255.0

Don’t use any proxy between PC & IDU. The IDU doesn’t

function with any proxy.

Don’t use Ethernet cable more than 100 Mtr. The exact length

depends on quality of Ethernet cable.


Application Software The actual SW for registering/submitting

question from CR during interaction in the form of text file/voice mail will be supplied later. The same SW is required to be loaded in PC of class room. The appropriate (supporting) SW is required to be loaded in PC of TE also.

It will be Manu based user friendly. The training/operating instructions etc. will be provided by SW manufacturer.

However following SW applications will be used for TE & CR both.

Running application on PCVLC Media Player This application SW is used for streaming & multicasting Video & Audio

at TE (Teaching End) & for receiving multicast stream at CR Class Room).

Any SIT (including ROT) installed in edusat network may receive any stream with correct multicast IP & port.

To receive the stream on PC, particular PC must have this application SW loaded in it. Follow the following path for receive of multicast stream.

Open VLC Media Player / File / Open Network Stream /

Select UDP/RTP Multicast / Address: 234.123.123.x & Port: 1234

Where X : 1 for Video stream from Hub

2 for Video Stream from IGNOU

3 for Video Steam for CIET

4 for Video Stream for CEC etc.

Running application on PCNet Meeting The Net meeting is part of office 2000 & can be

loaded in PC with CD for Office 2000. The net meeting provides the facility for chat, file

transfer, sharing of PC. If PC at both ends has web camera, Mic & speaker, then full-fledged video conference can be conducted with net meeting.

The operator has to place call on net meeting with IP address of remote PC while calling the remote person.

The Net meeting must be ON on the Remote PC while calling.

SIT Performance During Rain

The Edusat Network is operating at Ku band frequency. 3 to 5 dB attenuation due to rain is common at Ku band frequency.

At present both links (FL & RL) are operating with extra link margins. The both links will sustain during heavy rain. However SIT performance (i.e. quality of Video & Audio) may get slightly affected in the zone where satellite coverage is poor.

Help desk is provided in SIT Training Manual.

If SIT has minor fault & two way communication with SIT exists, the particular SIT can be monitored from Hub & proper actions can be taken from Hub itself.

However if SIT has major problem like failure of SIT sub-system, the site requires visit of maintenance engineer. In this case, SIT user has to send Service Call Form with complete information to maintenance office prior to site visit by service engineer.

Help Desk & on-line support

Documents

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