A Simulation-Based Study of
Scheduling Algorithms for DVBRCS Based Satellite
Communication Systems
Students:
Inbal Cohen
Jonatan Roisman
Supervisors:
Dr. Yehuda Ben-Shimol
Mr. Itzik Kitroser
Ben-Gurion University of The Negev, Department of Communication
System Engineering
The Project’s Goals
MF-TDMA networks
 Allocation of the resources
 The project’s goal
Implement a simulated DVB-RCS based system that
supports QoS to the applications and efficiently utilizes the
channel bandwidth
DVB-RCS = Digital Video Broadcasting - Return Channel Satellite
Solution Outlines
Step 1: Study the evolving DVB-RCS standard
Step 2: Study the network simulator
Step 3: Develop a detailed block diagram
Step 4: Modular software implementation
Step 5: Simulation based-study
The DVB-RCS Standard
 Part of the DVB standards for satellite communication
 Purpose of the standard
 Maintained by the DVB Project
 Officially defined in ETSI EN 301 790
Satellite Networks
Satellite Forward Link
Satellite Return Link
Network Control
Center: provides
Control and Monitoring
Functions (CMF)
Feeder: transmits
the forward link
signal
VSat
VSat
Internet/
Intranet
VSat
VSat
NCC: Network Control
Center Includes: Feeder
and Traffic Gateway
VSat: Very Small
Aperture Terminal
PSTN
Traffic Gateway: receives the Vsat’s return
signals
Simulator Modules
Satellite Forward Link
Satellite Return Link
Channel
VSat
VSat
VSat
VSat
VSat
Hub
Internet/
Intranet
PSTN
Hub Module
Prefix Method/
Contention Method
Data & Request
Data Request
Data Request
Data
SI Tables
Scheduling
Scheduling
Map Algorithm
Principles
Data
Scheduling Principles
High
Priority
Medium
Priority
Policer
Frequency
Domain
Superfarme
Time Domain
Low
Priority
Input
Scheduling Algorithm
2D Mapping
Queues
Under Qos Constrains
According to DVB-RCS
Standard
SI Tables
1 Superframe
2 Frame
3 Timeslot
SI Tables
1. Superframe Composition Table (SCT)
Timeslot
8
7
6
2. Frame Composition5Table (FCT)
Frequency
Domain
3. Time-Slot Composition
3 Table (TCT)
4
2
4. Satellite Position Frame
Table
0 (SPT) 1
5. Correction Message Table (CMT)
6. Terminal Burst Time Plan (TBTP)
Time Domain
VSat Module
Classify:
Queue number?
Voice
Data
Prefix Method?
Contention Method?
Sequence
number is 0?
Update Data
Data Request
C_R
Request
Time Out?
Threshold?
SI Tables
Data
Channel Module
Packet
Packet
OMNeT ++
 Objective Modular Network Test-bed in C++
 OMNeT++ attributes
 Primary application area
 Generic and flexible architecture
What have we learned so far ?
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Read Standard (DVB-RCS)
Team Work
Design Review for Satellite Network
Working with The Industry (Gilat Satellite Networks)
How to Simulate a Communication Network
OMNeT++ (Simulation Tool)
Practicing C++
How to combine Study, Project and Mundial… . ()