Mobile Satellite Communications - LEO, MEO and GEO Systems Architecture and Applications

With nearly 30 years of experience, mobile satellite service (MSS) has become a facet of the international telecommunications scene. The applications range from the first uses in maritime and aeronautical, to the development of a strong following on land.

This updated course builds on the early foundation and extends beyond the systems introduced prior to 2000. One must understand how we got here and what works before delving into what the new generation of MSS systems must look like. We review all of the applications, technology and operational issues in MSS, considering geostationary earth orbit (GEO) and non-GEO concepts and systems alike. The orbit strategy is only part of the equation – the course examines the elements of the overall architecture so that attendees will understand just what constitutes a working MSS network. This considers the all important air interface, the systems for processing and completing telephone and data calls across a wide region or the globe, and the regulatory issues that hamper the creation of a viable business.

In four days, we go in depth into the major aspects of a state-of-the-are MSS network – no important area is left uncovered. Currently, there are two working non-GEO systems, neither of which avoided bankruptcy. From this basic foundation, the course will identify how a new system can conceive and direct itself toward a success strategy; consideration of how any of the existing systems might expand their application base is also given. At all times, attendees are encouraged to ask questions and offer their own views and ideas throughout the course.

Instructor and Coordinator – Bruce Elbert, President, Application Technology Strategy, Inc., MSEE, MBA.

Bruce Elbert has over 30 years of experience in developing and managing satellite communications systems used for mobile and fixed applications. He was architect of the first GEO mobile satellite to service handheld users. As an early participant in MSS studies at COMSAT and Hughes, he contributed to the definition of the space segment and associated user terminals. He held senior technical management and business development positions at Hughes Electronics, including that of Senior VP of Operations in the Space and Communications division. Mr. Elbert authored seven books on satellites and telecommunications and has taught courses in these fields at UCLA and University of Wisconsin.

DAY 1 THE OVERAL SPACE SYSTEM

1. Mobile Satellite Orbits and Radio Links

Mobile satellite service (MSS) definitions

Space segment - the orbiting satellites

Gateway earth stations and network control

User terminals and mobile handsets

MSS constraints and recent developments

Geosynchronous orbits

Orbital parameters - with and without north/south stationkeeping

Coverage footprints, access area and overall performance

Non-geosynchronous orbits and satellite constellations

Altitude versus propagation delay, number of satellites, and orbit period

Other parameters - planes, inclination, eccentricity

Consideration of orbit period and elevation angle dwell

Link budget and mobile link fading review

Service availability, voice and data quality

Space hazards and other orbit related considerations

2. Satellite Platforms and Payload Technologies (Analog and Digital)

Satellite size and cost according to orbit

Satellite requirements (power and mass)

Cost (initial and life-cycle)

Communications payload

Analog and digital configurations

Repeater technologies (digital processing)

Spacecraft antenna systems

Fixed and deployable

Multibeam antennas - beam forming techniques

Space segment implementation and operation

Launching strategies (GEO and non-GEO)

Ground monitoring and control

De-orbiting considerations

DAY 2 THE MOBILE SATELLITE NETWORK

3. Air Interface Principles

The mobile satellite terminal air interface

How it is the same as terrestrial cellular

How it could be different from terrestrial cellular

The facilitating technologies - hardware and software

How the satellite orbit affects handset design

GEO satellites - long but constant propagation delay

Non-GEO satellites - less delay but greater dynamic range

4. Air Interface Details

Fundamental air interface options in a digital world

Time division multiple access (TDMA)

Code division multiple access (CDMA)

Explanation of exact timing and frequency details

TDMA

CDMA

How satellites enter into the air interface

For the satellite acting as a simple repeater

Alternatively, as part of end-to-end network processing

How fixed earth stations enter into the MSS system and air interface

Call handling and connection to the terrestrial network

Network control and demand assignment

5. The Network Demanded by an MSS System

Alternatives for the overall satellite network plan

A completely stand-alone mobile satellite service, offering global PCS independent of the terrestrial infrastructure

Alternatively, a satellite operation added onto existing (fully connected) regional ground fixed and mobile networks (GSM)

Requirements for ground entities to support the network alternatives

Signaling activity to set up a call in each case

Managing data connections

DAY 3 CALLING SERVICES

6. MSS Service Area Coverage

Coverage ability of MSS versus terrestrial cellular and PCS/PCN

Overcoming weak in-city MSS penetration using transfer to ground-based networks

Requirements for dual mode handsets to allow transfer to ground-based networks

Potentials for in-building coverage - user cooperation issues

7. Setting Up a Connection

Requirements for the numbering system and hierarchy

Relating MSS numbering to the GSM numbering plan

How is number roaming facilitated in MSS?

What cost and complexity do roaming agreements involve?

Relationship of the network arrangement to the numbering system in use

8. Voice Coding Attributes

Delivering good speech quality using narrowband MSS service

Measures of speech quality - MOS scores and other approaches

Fall-back modes to adjust speech quality to service levels - how acceptable to users?