SatGuard – VSAT Interference Monitoring

SatGuard is a novel solution for identifying VSAT terminals causing cross-polar or adjacent satellite interference. The unique technology (patent pending) detects the individual bursts from terminals causing interference, and determines the unique terminal identifier (MAC address or unique system id). With this information, the VSAT network operator can take necessary actions to correct the problem.


For more information go to… Verisat-Logo


GSM Re-Transmission Tool from… Eutelsat-Logo

The Problem with GSM retransmission…  Eutelsat - GSM interference (PDF)

GSM Services on Satellite:

  • Equipment failure in transmit systems with L-Band IF
  • One particular part of the IF system performs as antenna and picks up GSM signals
  • The IF Band is upconverted in Ku-Band and transmitted via satellite
  • It produces interference with other legitimate payload

Signals from the GSM BTS:

  • GSM beacons contain location information that is in general better than geolocalisation results
  • The interfering station can be found in a short distance from the base station
  • Most stations are identified by Google Earth review
  • Regulator bodies can be immediately informed if unmanned station operations are observed

System Overview…

GSM-System-OverviewConditions for successful demodulation:

  • The received signal in L-band GSM must contain an interfering signal
  • The signal to noise ratio (SNR) at the reception must be more than 9 dB
  • The GSM signal reception must be interfering with one of the four GSM bands (850, 900, 1800, 1900 MHz)

Most affected Frequency Bands:

  • 13750 – 13760 MHz -> LOF 12800 MHz
  • 13950 – 14010 MHz -> LOF 13050 MHz
  • 14490 – 14500 MHz -> LOF 15450 MHz (inverted)

Result: The EXCEL file contains the following information…

  • GSM beacon:
  • ARFCN – Absolute Radio Frequency Channel Number
  • Signal power in dB
  • BSIC – Base Station Identity Code
  • MCC – Mobile Country Code
  • MNC – Mobile Network Code
  • LAC – Location Area Code
  • Cell ID – Cell Identity

Note: When the scanned channel is a traffic channel, the information returned is ARFCN and signal power only.

Eutelsat has also setup a dedicated email for any CID or GSM related enquiries concerning its satellites or tools.

Setting up a VSAT Terminal then take a look at SatMotion Pocket…