Site: Telespazio
Via Tiburtina, 965
00156 Rome
Italy

Date Visited: June 25, 1992

Report Author: R. Jennings

ATTENDEES

NASA/NSF:

C. Bostian
P. Hager
N. Helm
R. Jennings
C. Mahle
L. Riley

HOSTS:

Dr. Paola Palmucci

Business Development

Fulvio

Ananasso Director, Advanced Studies & Experimentations Div.

Antonio Marzoli

Head of Experimentations Department, Satellite Telecommunication Systems

S. Bellaccini

System Studies & Payload

Alberto Pandolfi

System Studies & Payload

Marco Carosi

System Studies & Payload

Gabriele Mocci

Space Technology Department, Space and In Orbit Support System Division

BACKGROUND

Telespazio, in existence since 1963, operates as a private company, but it is totally owned by the Italian Government. Directed by Dr. Raffaele Minicucci, it has about 1,000 employees. Telespazio is the Italian signatory to INTELSAT, EUTELSAT, and Inmarsat and provides operation and maintenance support for satellites belonging to these organizations and their services. Telespazio also operates a control center for ITALSAT and other Italian domestic satellite systems. The company owns and operates earth station facilities at Fucino near Rome, one of the largest earth stations in the world; at Lario, in northern Italy near Lake Como; and at Scanzano, in Sicily. In addition to its system operation responsibilities, Telespazio performs R&D for ESA and the Italian government in the areas of on-board signal regeneration and switching, mobile communication satellite technology, remote-sensing satellite technology, and propagation measurements. The company also performs studies and experiments to support business development in new uses for satellite technology (e.g., mini/microsats for remote-sensing applications). It does no manufacturing.

RESEARCH AND DEVELOPMENT ACTIVITIES

OLYMPUS Satellite

Telespazio is joined with the Istituto Superiore P.T. (ISPT), the lead organization for experiment planning, and Fondazione Ugo Bordoni (FUB) in performing a variety of telecommunication experiments at 14/12 and 30/20 GHz using the OLYMPUS satellite and eleven earth stations located throughout Italy. The earth stations include four "easily-reinstallable," receive- only stations (for 30/20 GHz); five transportable, transmit/receive stations (two for 30/20 GHz and three for 14/12 GHz); and two fixed, transmit/receive stations (for 30/20 GHz). Earth-station antenna diameters are 1.2 m, 2.5 m, and 3.5 m. Telespazio operates all of the earth stations and is responsible for implementation of the experiments which include:

Point-to-Point and Multi-Point Video-conferencing. The point-to- point video-conferencing experiment objective is to establish reference parameter values for the multi-point experiment. The multi-point experiment objective is to determine trade-offs between quality and cost to optimize service and studio facilities. Parameters of interest include human factors, switching procedures and protocols suitable for 30/20 GHz transmission, and video codec technology that requires only two video channels to provide multi-point conferencing. ISPT and FUB are joint lead experimenters.

Thin-Route TDMA/Ku and Thin-Route TDMA for LAN Interconnection.The first experiment, conducted at 14/12 GHz, tests hardware and software for a TDMA controller to provide dynamic allocation of the satellite capacity. The objective is to determine an optimum protocol for the demand assignment feature (FODA-FIFO (first in first out) Ordered Demand Assignment) of the TDMA scheme. The follow-on experiment at 30/20 GHz (for LAN interconnection) will use data rates ranging from 1 to 8 Mbits/sec, 5 MHz bandwidth, and variable coding techniques to examine countermeasures for fading. Centro Nazionale Universitario per il Calcolo Elettronico (Pisa) (CNUCE) is lead organization for the 14/12 GHz experiment; Universita di Firenze is lead organization for the 30/20 GHz experiment.

Frequency Diversity. Frequency diversity (Ka/Ku bands) is examined as an adaptive technique to cope with high propagation losses at 30/20 GHz while maintaining high availability. The principal objective is to develop reliable procedures for switching between the 30/20 and 14/12 GHz bands. The Politecnico di Milano is the lead organization.

Small-Scale Site Diversity. Site diversity (another technique for coping with high propagation losses at 30/20 GHz) is examined. Testing will determine the site separation that provides performance improvement (it is expected to be greater than the horizontal extent of the rain cell). The principal objectives are to determine switching criteria and operational procedures. ISPT and FUB are joint lead experimenters.

Service Diversity. Trade-offs among quality, availability, and service costs are being examined. The objective is to obtain information to promote growth of satellite networks. The concept is based on networks of inexpensive earth stations that can communicate only via a central hub station and the expectation that some users can and will accept reduced quality and/or availability of service if the cost is low enough. (This is the rationale behind VSAT and USAT networks and services in other countries.) ISPT is the lead organization.

Atomic Clock Synchronization and Ranging Measurements. This entails the use of a 2 Mbits/sec BPSK signal, modulated by a pseudo-random sequence, to examine the precision achieved in synchronizing atomic clocks provided by signals transmitted through a 30/20 GHz satellite link. The experiment is in response to a recommendation from CCIR SG 7 concerning development of special equipment and new methods for synchronization of atomic clocks using GEO satellites. Range and range-rate information also are available. Additional experiments at 14/12 GHz are deemed necessary but not planned. ISPT is the lead organization.

Tele-Education. This entails the use of small earth stations (at students' locations) communicating with a central hub station (at the teaching center) to provide "unbalanced" links at 30/20 GHz. Data rates will be 384 to 512 kbits/sec in the teaching-center-to-student link, 64 kbits/sec in the opposite direction. The objective is to evaluate user acceptance and teaching efficiencies. Centro Studie Applicazioni in Technologie Avanzate (Bari) (CSATA) is the lead organization.

Digital TV Broadcasting and Performance Evaluation. The quality of digital TV via satellite is investigated for possible use of the 23 GHz band in CCIR Region 1. The experiment is organized in two phases. The first, following CCIR Rec. 601, uses a 34 Mbits/sec video coder, based on the DCT (discrete cosine transform) algorithm, to generate signals transmitted through the satellite. The complete installation for generating digital video signals is being developed by RAI Centro Ricerche (Torino). In the second phase, a 70 Mbits/sec pseudo-random binary sequence signal will be utilized for BER measurements. The objective is to contribute to international studies on possible HDTV transmission by satellite in the 23 GHz band. RAI Centro Ricerche is the lead organization.

Mobile Radio Coding. Voice coding techniques at 16 kbits/sec for mobile radio communications at 64 kbits/sec will be investigated. The principal concern is decoding impairments due to delay in the satellite link, noting that the digital mobile radio service already foresees an 80 ms delay. The Centro Studi e Laboratori Telecomunicazioni (Torino) (CSELT) is the lead organization.

Propagation experiments also were planned and are being conducted using both OLYMPUS and ITALSAT. Beacon signals from OLYMPUS at 12, 20, and 30 GHz and from ITALSAT at 20, 40, and 50 GHz are recorded at 25 locations in Italy and an additional 25 locations throughout Europe. The OLYMPUS-ITALSAT Data Collection Center, developed and operated by Dataspazio, polls receiving locations for transfer of received data for aggregation and analysis. Measured parameters include attenuation, depolarization, phase and amplitude dispersion, scintillation, other "dynamic characteristics," and ancillary meteorological information.

These experiments with OLYMPUS (and ITALSAT) were described by Mr. Antonio Marzoli.

ITALSAT

The ITALSAT (Experiments) Program is supported by Telespazio both operationally and as a participant, primarily in the propagation experiment. ITALSAT is a multibeam (six beams using two antennas) digital system that operates in the 30/20 GHz (uplink/downlink) frequency bands, providing on-board switching of signals using a baseband matrix switch. ITALSAT is a pre- operational system (launched in January 1991) which provides opportunities for experiments with three objectives, noted below. ITALSAT F2, launch expected in 1994, will be the next satellite in this program. It will provide multibeam capabilities at 30/20 GHz as well as ISDN capability. Program objectives are:

  1. Investigate innovative on-board signal regeneration and switching technologies.
  2. Evaluate performance of a digital satellite network integrated into the terrestrial network.
  3. Collect additional data with which to better understand the propagation impairments that must be overcome in using 30/20 GHz (and higher) frequency bands for satellite telecommunication.

Mr. S. Bellaccini described the ITALSAT program and Telespazio's participation.

In on-board switching technology, Telespazio is the prime contractor to ESA on Phase B activities for an advanced satellite system known as OBP. The Phase B activities encompass two main efforts: to define the system and develop system specifications, and to develop a laboratory model of the OBP that will include an engineering model of the on-board baseband switch matrix.

The major technical innovations of the OBP package are as follows:

  1. New generation VSAT networks that will provide higher data rates and full interconnectivity on demand.
  2. ISDN services.
  3. Multiple-stage baseband matrix, employing time-switching stages (T-stages).
  4. Multiple-frequency TDMA for uplink access with a "very tight" synchronization scheme (to realize symbol synchronous operation) to achieve very efficient exploitation of the uplink capacity.

Experimental and pre-operational phases currently are planned using a "reduced OBP payload" on the proposed ITALSAT F3, which could be launched as early as 1996. Characteristics of the OBP system were described by Mr. Alberto Pandolfi.

Mobile Satellite Applications

Telespazio's involvement in technology development and experiments for mobile applications includes the following:

  1. A prototype satellite network, operating in the 14/12 GHz frequency band, that employs SS-CDMA (Spread Spectrum-Code Division Multiple Access) to provide basic communication services, e.g., bidirectional voice, facsimile, and video broadcasting to remote areas. This work is sponsored by ESA.
  2. A Mobile Satellite Business Network (MSBN) to provide facsimile and messaging at 2400 bits/sec. The pilot phase will begin in late 1993 using MARECS and Inmarsat II. This work is sponsored by ESA.
  3. An assessment of a public mobile satellite system that is compatible with the GSM cellular network. This work is sponsored by ESA.
  4. A messaging system known as PRODAT II. This system will provide access to mobile users through the public terrestrial network in accordance with CCITT Recommendation X.400. This system operates at 300 bits/sec, using CDMA in the forward direction and TDMA for replies. This work is sponsored by ESA.

The mobile applications technology was described by Mr. Marco Carosi.

Mini/Micro Satellites

Telespazio is developing mini/micro satellite technology for retrieval (at VHF/UHF frequencies) of data from remote sensors. Company representatives state that their microsats will provide Europe's first commercial data communications services using store and forward techniques. In this project, called TEMISAT (Telespazio Micro Satellite), Telespazio plans to manufacture and launch two satellites and provide commercial services. Launch for the first satellite was scheduled for July 1993. Plans call for launch of a second satellite in mid 1995. The TEMISAT program envisions 1000 user terminals and 50 collection centers. Key personnel for the project are Mr. Giuseppe Rondinelli and Mrs. Brunella Pavesi.

Regulatory Issues

In a brief discussion concerning telecommunication regulation in Italy and throughout Europe, it was noted that some deregulation is coming, but significant changes are not expected before 1994/5.

SUMMARY

Telespazio's technology strengths include the development of on- board signal regeneration and baseband switching and the development of mobile applications (considered so by Telespazio - - Mr. Fulvio Ananasso -- and recognized as such by the panel members). Telespazio also has made and continues to make significant contributions to the design, testing, and operation of the ITALSAT satellite series. Telespazio's participation in OLYMPUS experiments and its collection and reduction of measured propagation data, using OLYMPUS and ITALSAT, are both substantial and significant.


Published: July 1993; WTEC Hyper-Librarian