Overview

Throughout this course, attendees gain an in-depth understanding of the technical aspects of Satellite Earth Station design, deployment and link budget analysis, using calculator exercises and detailed analysis using spreadsheets. Each module of this course builds upon the previous modules, culminating in a complete performance analysis of a Geosynchronous Satellite network, based on equipment specifications, system configuration and satellite parameters.

Duration

4 days

Audience

  • Technicians and Engineers wanting a solid introduction to the field of satellite communications.
  • Engineers, Communications managers, and Technicians working with in Earth stations or with VSAT equipment.

Prerequisites

Objectives

Develop a system design based on communications requirements and limitations.
Select system components, based on their specifications, to satisfy system requirements.
Perform detailed EIRP and G/T analysis.
Establish proper signal levels for optimum performance.
Select the proper access technique based on system requirements and network topology.
Perform availability analysis based on required fade margin, equipment reliability and sparing strategy.
Perform detailed end-to-end link budget analysis based on system limitations and equipment parameters.

Content Headings

Digital Communications for Geosynchronous Satellites
Digital versus Analogue signals
Network components and topologies
Switching terminology
Digital/Analogue comparison

Line Codes: Bit Rate, Baud Rate and Bandwidth
Nyquist theory, Shannon’s law
Bandwidth and bit rate at baseband
Line code variations

Voice Encoding Techniques: Bandwidth vs. Latency
Waveform encoding
Pulse Code Modulation (PCM)
Adaptive Differential PCM
Source coding
Linear Predictive Coding
Code-book Excited Linear Prediction (CELP)
Voice coding issues over satellite links

Digital Communications Protocols
Overview of protocol layers
Physical layer aggregation and switching protocols
Standards-based TDM: T-carriers and E-carriers
Proprietary TDM: aggregate rate multiplexing
Digital Cross-Connect Switching (DCS)
Digital Circuit Multiplication Equipment (DCME)
Data Link layer protocols and equipment
Frame Relay FRADs and switches
ATM and negative latency
Network layer devices and functions

Network timing and synchronisation
Timing terminology and concepts
Stratum levels and timing architectures

Satellite Communications Overview
History of satellite communications
Geosynchronous satellites
Overview of Earth station sub-systems

Geosynchronous Satellites: Strengths and Weaknesses
Common satellite deployments
Problems caused by long path delays
– The need for echo cancellation
– Perceptible delay in conversation
– Talk collisions over double-hops
– Reduction in throughput when using protocols that require acknowledgement and re-transmission
Problems caused by relative satellite motion
– Doppler shift of high-speed data streams
– Tracking requirements due to satellite inclination

Overview of Satellite Access Techniques
FDMA for digital and analogue access
TDMA and F/TDMA for digital access

Earth Station Equipment: Parameters and Impairments
Review of decibels and dB units
Logarithms and their functions
When NOT to use decibels

The Electromagnetic Spectrum
Frequency vs. Wavelength
Band designations
Radar bands common to satellite communications

Radio Building Blocks
Basics of radio amplifiers
Filter types and functions
Type of oscillators
Mixers and multipliers

Earth Station Uplink Equipment
Upconverter types and characteristics
Typical Upconverter specifications
Amplifier types and characteristics
Amplifier impairments due to non-linearity
– Intermodulation distortion
– Spectral Regrowth
Typical amplifier specifications
Post-amplifier combining techniques
– Wide-band signal combining
– Frequency-specific signal combining
Transmission line characteristics

Antennas and Tracking Systems
Antenna types
Antenna patterns and Gain calculations
Antenna polarisation techniques
– Linear polarisation
– Circular polarisation
– Comparison of Linear and Circular polarisation
Example antenna specifications
Antenna tracking systems
– Step-tracking systems
– Mono-pulse tracking systems

Earth Station Downlink Equipment
The Low Noise Amplifier
– LNA Types
– LNAs vs LNBs
– LNA/LNB characteristics
– Typical LNA/LNB Specifications
Downconverter characteristics

Modems and Error Correction
Modulation: Digital and Analog
Basics of digital modulation
– Modulation scheme constellations
– Noise, Errors and Free Distance
– C/N and Eb/N0 calculations
Error Correction techniques
– Block Coding
– Convolutional Coding
– Concatenated Coding
– Turbo Block Coding (TBC)
– LDPC
– Polar codes
Modem variations
– Coherent vs Differential demodulation
– Trellis Coded Modulation (TCM)
– Offset QPSK for PAPR improvement
Timing considerations for satellite links
– Loop timing systems
– Master/Slave timing systems
– Doppler buffers for high data rates
Band-limited vs Power-limited operation based on Modulation/FEC
Important modem characteristics and specifications

Thermal Noise and C/N
Quantifying noise
Determining the C/N
Adding the Uplink C/N and the Downlink C/N

Power and M&C Systems
System components and alarm types
Critical and technical power systems

Earth Station Design
Comparison of access techniques
Dedicated carrier access
Demand Assigned Multiple Access
– FDMA
– TDMA
– F/TDMA
Access technique selection criteria
Cost Analysis: FDMA vs. TDMA
Hub-spoke vs. Mesh Networks

Uplink Design Considerations
Antenna gain and efficiency
Earth station EIRP
Earth station gains and losses
Setting uplink levels

Downlink Design Considerations
Downlink levels
Internal and external noise contributions
Noise figure and noise temperature
Performing a cascade analysis
G/T contributing factors
Performing a detailed G/T analysis

Determining System Availability
Equipment configuration
Sparing strategy
Equipment reliability
Link availability and rain fade

Link Analysis Techniques
Overview of Link Analysis
Limiting factors in link analysis
Satellite considerations
Earth terminal parameters
Operational parameters

Sources of Interference
Adjacent satellite interference
Terrestrial radio interference
Interference due to Intermodulation Products

Spreading Loss and Path Loss
Determining distance to satellite
Determining power flux density at the satellite
Free Space Loss calculation
Other loss contributions
– Pointing loss
– Polarisation Offset loss
– Absorption Loss

Satellite Transponder Parameters
Saturation flux density
G/T
Saturation EIRP
Transponder frequency translation
Transponder padding
Transponder bandwidth
Transponder footprint
Satellite Inclination

Performing Link Budgets for Bent-pipe Satellites
Determining Total C/N on a link
Determining EIRP for bandwidth-limited operation
Performing detailed Uplink/Downlink power budgets
Putting it all together: Link Budget exercises

Ka-band and Processing Satellites
Processing satellites: Pros and Cons
Link Budgets for processing satellite
Ka-band and the future of Geosynchronous Satellites