The following story reached us from Bercenay-en-Othe in France where Stelios Tamouridis, Application Engineer at Newtec, has recently demonstrated a set of different technologies to improve bandwidth efficiency for Orange.
Mid July is the harvest period for the wheat fields in the region of Champagne in France. The road from Troyes to Bercenay-en-Othe is almost congested by the tractors which are caring the crops. Suddenly, behind the sunflower fields and the vineries the Orange teleport peeps out. It’s almost impossible not to notice it, as the 32 meter antennas make an impressive contrast with the rustic surroundings: a perfect context to demonstrate some of our Newtec bandwidth-efficient technologies.
Orange is operating various IP trunking and Telco point-to-point links which set an ideal “ground” to apply bandwidth cancellation and increase the amount of bits per Hertz. On top of this, the recently launched DVB-S2X standard provides a new set of technologies which are available in the MDM6000 satellite modems, ready to boost bandwidth efficiency even further. But let’s have a closer look at these technologies:
- Bandwidth Cancellation: With legacy satellite communication systems, separate satellite bandwidth must be assigned for each direction of a full duplex satellite link between two communication sites. Using bandwidth cancellation technology the forward and return transmissions are combined in the same satellite bandwidth resulting in a considerable increase of capacity.
- DVB-S2X standard: The successor to the DVB-S2 standard combines a set of innovative technologies that improve efficiency over satellite links. To name just a few: reduced roll-off factors (15%, 10% and 5%) and advanced filtering, constellations optimized for non-saturated transponders, increased modcod granularity (from 28 in DVB-S2 up to 112 in DVB-S2X) which combined with Newtec’s FlexACM® (Adaptive Code and Modulation) allows for optimal utilization of the available link margin.
The Test Plan
For the aim of the test two antennas were provided by Orange: an 18m antenna to uplink the “hub” carrier and a 4.5m antenna to uplink the “remote” carrier. The available space segment was 14 MHz on Intelsat’s IS-702.
Initially two symmetrical carriers of 7MHz with 5% roll-off were uplinked from both sites at Bandwidth Equivalent Power (BEP), occupying two different frequency slots. The 4.5m antenna was operating error free receiving a 16 APSK 13/18 while the 18m antenna receiving a 64 APSK 4/5, both with a link margin of 0.5 dB. The total throughput measured for this typical scenario was 49.51 Mbps.
Following the previous typical scenario, this time two symmetrical carriers of 14 MHz with 5% roll-off were uplinked from both sites on the same frequency slot. Attention was made not to violate the BEP by respecting the reference power level. The 4.5m antenna was operating error free received a 16 APSK ½-L while the 18m antenna receiving a 16 APSK 3/4, both with a link margin higher than 0.5 dB. The total throughput measured for the bandwidth cancellation scenario was 64.46 Mbps.
On top of bandwidth cancellation, FlexACM was also enabled to take better advantage of the MODCOD granularity that the DVB-S2X standard offers. The 18m antenna for example, could now receive error free up to 32 APSK 2/3-L operating with a link margin of 0.2 dB. This translates to a higher efficiency which goes from 2.89 bits/baud for 16 APSK ¾ to 3.21 bits/baud for 32 APSK 2/3-L.
Bandwidth cancellation in combination with the DVB-S2X standard helped to increase the satellite throughput by 30.2%. This extra capacity can either be used to decrease the OPEX or deploy new services keeping the same bandwidth resources.
With FlexACM further deployed in addition to the above technologies an extra capacity of 11% was gained by taking advantage of the available link margin: A synergy of different technologies which gives added value to every single hertz.
Application Engineer at Newtec