OTA Facilities
OTA Facilities: Over-The-Air Antennas, Modems and Experimentation Facilities
Description
The SIGCOM group has installed several facilities for Over-The-Air (OTA) experimentation in coordination with its Communications Lab and Radar Lab. These facilities include:
- Ku- / Ka-Band parabolic dish antennas for GEO satellite BCAST and VSAT communication
- COTS DVB-S2(X) modems from different vendors and
- Spectral / signal analysis professional equipment up to 13 GHz.
These facilities will be completed with the installation of two 5G Non-Standalone (NSA) gNBs.
Rooftop Antennas
Several parabolic dish antennas for GEO satellite communication have been installed at the SnT building rooftop with direct cable connection with the Communication Lab facilities.
The largest parabolic dish has a size of 125 cm of diameter model Gibertini OP 125 LP. The configuration LP offers the possibility of elevation angle 0° - 90° and provides a strong stability thanks to the special feed arm profile. This dish is built in aluminium and steel alloy painted with U.V. inhibited polyester-based finishes. The mounted LNB has dual-twin output with full and independent configuration capabilities.
Figure 1: Gibertini OP 125 LP parabolic dish antenna.
The main specification of this antenna are the following:
| Frequency range (GHz) |
10.00-13.00 |
Outside dimension(cm) |
124.5x133.5 |
| Reflecting dimension (cm) |
121.0x130.0 |
Illumination efficiency (%) |
70 |
| Gain @ 10.70 GHz (dB) |
41.10 |
Cross polarization(¹);(²) on axis (dBc) |
-28 |
| Gain(¹) @ 11.70 GHz (dB) |
41.90 |
First side lobe level(¹);(²) (dBc) |
-24 |
| Gain(¹) @ 12.75 GHz (dB) |
42.60 |
Noise temp.(¹) @ 12GHz, 30° elevation (K) |
34 |
| -3 dB Beam width(¹) @ 11.7GHz |
1.32° |
Elevation angle |
0° - 90° |
Currently, this dish is pointing towards SES-14 satellite in order to conduct the OTA experimentation with multi-beam precoding interference mitigation techniques planned in the ESA LiveSatPreDem project. The antenna is receiving signals at Ku-band, which are conducted via coaxial cables to the Communications Lab DVB-S2X Precoding Testbed.
Another set of 4 parabolic dishes working at Ku-band is also available. These are pointed to common broadcasting satellites (such as Astra 19.2E and Hotbird 13.0E) for modem testing purposes. These dishes have a diameter from 75 to 90 cm.
Figure 2: Set of 4 parabolic dishes at Ku-band.
Eventually, a Ka-band 80 cm dish for a VSAT modem has also been installed at the SnT rooftop. This antenna is used by the Radar Lab in the context of the FNR RAFAEL project.
Figure 3: Installation of the Ka-band 80 cm parabolic dish antenna for VSAT modem.
The Ka-band parabolic dish is pointed to Astra 3B 23.5 E orbital position with access to the SES Broadband service.
Figure 4: Ka-band LNB / amplifier.
DVB-S2(X) Modems
Two different COTS DVB-S2(X) modem models are available at SIGCOM facilities to conduct OTA testing and validation.
Figure 5: Dreambox One UHD Dual-Tuner.
Dreambox is a series of Linux-powered DVB satellite, terrestrial and cable digital television receivers (set-top boxes), produced by German multimedia vendor Dream Multimedia. The Dreambox ONE is equipped with a multistream-capable Twin-DVB-S2X tuner, which allows tuning independently each one of its inputs. Moreover, thanks to the Ethernet connectivity, the DVB-S2X receivers can be configured remotely.
Figure 6: Dreambox and 1.2 m antenna setup.
The purpose of the Dreambox in the Communications Lab is twofold. On one hand, it allows testing the reception of DVB-S2(X) signals from a GEO satellite. On the other hand, it allows controlling the polarization and band set at the LNB for experimentation purposes with the Software Defined Radio Testbeds.
Figure 7: SKYEDGE II-C GEMINI modem.
The Gilat SKYEDGE II-C GEMINI modem can connect to the SES Broadband service, which makes broadband Internet access available to homes in rural locations or otherwise beyond the reach of existing terrestrial broadband services. Outside the major European urban centers, there are millions of households currently without broadband access through landlines and by 2010, up to 6 million, or 3.5%, of the 170 million homes in Western Europe will still be without terrestrial broadband access. As well as Internet access, SES Broadband is used for dual play (broadband internet and telephony) and triple play (broadband Internet, telephony and TV) services.
SES Broadband uses a satellite link to carry IP data in both directions between the central hub and remote terminals. At the hub, routers connect to the Internet backbone and IP data is embedded in a DVB-S2 format carrier to be uplinked to the satellite from SES teleport and, from there, downlinked to the remote terminal where the signal is received with a domestic-type dish for the satellite internet modem, which extracts the IP data for the end user's PC. The return path is handled similarly, but with a low power 500 mW transmitter on each terminal dish providing the uplink to the satellite, with multiple-frequency time division multiple access techniques employed to handle many remote terminals simultaneously. SES Broadband combines two standards for the return path: Satmode for modulation and coding, and DVB-RCS for the access scheme.
SES Broadband uses the Astra 3B communications satellite at the 23.5° east orbital position to handle uplinks and downlinks in both directions. A number of transponders are used for the hub-to-terminal downlink in the downlink segment of the Ka-band (~20 GHz). The terminal-to-hub uplink to the satellite uses the uplink segment of the Ka-band (~ 30 GHz).
Spectrum / Signal Analyzers
Figure 8: R&S®FSVA3013 signal and spectrum analyser.
The R&S®FSVA3013 signal and spectrum analyser is professional laboratory equipment to analyse RF signals up to 13 GHz. It has a maximum analysis bandwidth of 400 MHz, an outstanding phase noise of –120 dBc (1 Hz) at 10 kHz offset and a high dynamic range. The R&S®FSVA3000 series can keep up with demanding measurement applications such as 5G NR measurements and may be equipped with DVB-S2(X) signal analysis software tools.
Relevant Links:
- DVB-S2 Standard (EN302307)
- Ku-band Spectrum Usage (EN301428)
- Ka-band Spectrum Usage (EN301459)
- R&S®FSVA3013 Signal and Spectrum Analyzer
Relevant Projects:
Contact:
| URL: https://wwwfr.uni.lu/snt/research/sigcom/ota_facilities | Date: lundi 20 mars 2023 23:19:08 |