FODA/IBEA: A system for synchronous and asynchronous data satellite transmission able to counter the signal attenuation due to bad atmospheric conditions

Related technological areas

satellite, time division multiple access, Ka frequency band, real-time data, non real-time data, TDMA bandwidth allocation, attenuation, coding redundancy, bit rate redundancy.

Italian patent

Nedo Celandroni, Erina Ferro, Francesco Potort́
Sistema per la trasmissione via satellite di dati sincroni e asincroni in grado di contrastare l'attenuazione del segnale dovuta ad agenti atmosferici
Application date:
1996, March 28
Consiglio Nazionale delle Ricerche, Italy

Description of the invention

The FODA/IBEA system is suitable for the simultaneous transmission of both real-time and non real-time data via satellite, such as during a video-conference. The system is able to counter the signal attenuation due to bad atmospheric conditions, which is a serious problem in the Ka frequency band (20/30 GHz) where the rain attenuation can exceed 15 dB. This invention consists of a sophisticated satellite channel access scheme in TDMA (time division multiple access). The satellite capacity is assigned on demand, while maintaining the quality of the data transmissions even during signal fading. The aim of the FODA/IBEA system is to maintain the desired quality of service of the transmitted data, even when a heavy attenuation of the transmission signal occurs, by using three different fade countermeasure techniques:

  1. up-link power control (optional feature of the ground station);
  2. dynamic data redundancy obtained by increasing the data coding rate;
  3. dynamic data redundancy obtained by decreasing the data bit rate (heavy fades only).

Points b) and c) are implemented via software in the prototype FODA/IBEA system.


Ten prototypal units of the FODA/IBEA system have been built. Four of them are hosted in the CNUCE laboratory (IT), two at the ESA-ESTEC (NL), two are at the Swisse PTT (CH), and two at the Deutsche PTT (DE). All these units were used during the Olympus satellite experimentation, and subsequently on the Italsat satellite. The prototypes use an innovative modem developed by the GEC Marconi Research Center (UK) following the specifications provided by CNUCE.

Innovative features

The modem and the TDMA controller, where the FODA/IBEA software runs, exhibit a unique feature: they are able to dynamically switch the data bit and coding rates on a packet-by-packet basis. This ability enables each station to tune the redundancy of the transmissions so to avoid wastage of the expensive satellite bandwidth.

Also unique to the system is the method for measuring the instantaneous attenuation of the signal. This method is cheap, fast and accurate, and has been extensively studied and reasonably tested. Accuracy and speed are essential for the effectiveness of the fade countermeasure feature.

Market outlook

The invention has a natural application as a tool for videoconference via satellite, not only point-to-point, but also among a number of stations spread anywhere in the satellite coverage area. Other areas of interest include telemedicine and teleducation.

Another interesting application of this system is to quickly set up a geographically distributed network in emergency conditions, such as natural disasters, and to interconnect isolated locations not reached by terrestrial or cellular networks.

Connection to the Internet is transparent to the system, which is also naturally suited for setting up intranet private networks. A satellite-based intranet can work as a backup for existing terrestrial networks, either as an emergency recovery in case of terrestrial network breakdown, or for occasionally providing additional bandwidth.

Possible users of the system and interesting applications include:

Actions needed

The required know-how includes expertise in developing advanced satellite modems, in writing telecommunication software, and in international marketing operations with the possible target users, such as those above identified.

Competitive advantages


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