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CASE WORK: Power Flexing Satellite Links
by Max d'Oreye

Providing IP trunking services to ISPs in a highly competitive market with razor-thin margins requires constant scrutinizing of the operation expenses (OPEX). Satellite service providers, teleports or satellite operators that provide these services are faced with new and complex challenges to maintain their competitiveness, while remaining profitable. Implementing new technical solutions to deal with these challenges is more essential than ever. Technology should address the following business needs:
  • Reduce costs
  • Improve customer satisfaction
  • Achieve very high service reliability
This article explains how the latest DVB-S2 ACM technologies, integrated with a range of smart IP appliances, provide the perfect answer to these business requirements. Newtec’s DVB-S2 FlexACM implementation doubles the data throughput in satellite IP trunking and IP backbone systems, and provides 100 percent link availability. Getting up to speed with these latest technologies allows service providers to double their revenue or reduce their operational costs by half, whichever is their goal. The following case studies explain how companies are using this new technology, and what value it brings to their business:
  • Cobranet – FlexACM & heavy rain fade
    A satellite link throughput gain of 70 percent without acceleration or compression. During heavy rain fade of 20dB, the link remains available, outperforming all competitors.

  • Horizon Satellite Services – FlexACM & suboptimal receive conditions— an increase of 43 percent in IP throughput, without using acceleration or compression.

  • SkyVision – FlexACM & inclined orbit satellites — an average increase of 85 percent in IP throughput, with peaks of improvement up to 137 percent

What is FlexACM?
FlexACM is a unique end-to-end solution for implementing ACM technology, IP shaping, compression and acceleration in a very efficient way for IP trunking and IP backbone satellite links. The implementation of FlexACM can result in a doubling of the data throughput in a given satellite segment while also guaranteeing a 100 percent link availability.

Adaptive Coding and Modulation (ACM), part of the DVB-S2 standard, allows modification of the modulation and coding parameters (modcods) of a satellite signal on the fly, without interrupting the transmission and without losing data.

Newtec’s FlexACM solution is more than DVB-S2 ACM: it is the first commercially available system on the market, which integrates DVB-S2 ACM with advanced IP optimization technologies such as traffic accelerating, compression, and shaping. The FlexACM solution can be used in point-to-point and point-to-multipoint systems, in one way (with terrestrial return channel) as well as in two way configurations (with the return channel also over satellite). It is also possible to implement the FlexACM solution in existing satellite links without changing the rest of the transmission chain, such as the antenna and HPA. The FlexACM solution combines ACM technology with an automatic measurement of the instantaneous link conditions (signal to noise ratio) every few seconds and a system that automatically adjusts the modcods parameters when needed. Under these circumstances, the satellite link always uses the highest possible modulation scheme and the lowest possible level of error correction, while still keeping the signal to noise ratio above the minimum threshold to guarantee an error free transmission at all times.

By using FlexACM, teleport operators do not have to take rain margin into account at all. When the conditions of the link become worse because of rain fade or other reasons, the system will automatically change the parameters to avoid loss of signal reception. In fact, in almost every form of interference or in less optimal transmit or receive conditions, like ground noise, tracking losses, cross poll and inter-satellite interference … FlexACM proves to be beneficial.

The FlexACM system must then decide how the remaining capacity is distributed among the different services and receiving points. This requires a dynamic shaping of the IP services and a QoS management in line with the bandwidth variations caused by the ACM behaviour. In addition to this, the built-in traffic shaper also needs to ensure priority for services with predefined SLA, VoIP, audio and video services. By using FlexACM, technology teleport operators can turn the additional rain margin that was wasted before, into increased data throughput, resulting in extra revenue for the teleport operator. To further optimize the efficiency of the system, FlexACM includes cross layer optimization using advanced features such as traffic acceleration and dynamic compression of the IP traffic, which bring a considerable reduction of the data traffic that needs to be sent over the satellite link.

FlexACM® is part of Newtec’s Elevation product line that allows simple, yet very efficient implementation of ACM (Adaptive Coding and Modulation) in IP trunking and IP backbone systems.

The Value Of FlexACM

Reduce costs
Space segment is one of the biggest operational costs for a teleport operator and is often in scarce supply. The challenge for teleport operators is in the fact that they are buying space segment in MHz, but their customers are typically paying them for Mbit/s throughput. The logical consequence is that the more data throughput they can achieve per MHz bandwidth, the more profitable their business becomes. The Newtec FlexACM solution integrates advanced IP optimization technologies (such as traffic acceleration, compression and shaping) with the complete feature set of DVB-S2 (generic mode, ACM technology) in order to increase the throughput of the satellite channel.

Efficiency gain related to the use of ACM technology can reach up to 130 percent compared to DVB-S systems without ACM. On top of the benefit of DVB-S2 ACM, the integrated result of cross layer optimization (dynamic optimization across the physical and traffic layers) results in a drastic reduction of the required satellite bandwidth for a given data throughput. This means that the cost of the satellite segment per Mbps is reduced from e.g. 2,500 USD/month/Mbps to 1,250 USD/month/Mbps!

In other words, IP trunking networks based on Newtec’s FlexACM technology can increase the revenue for the teleport operator by a factor of 2!

Improve Customer Satisfaction
The FlexACM solution contributes to improving customer satisfaction at many levels. FlexACM offers advantages for the ISP as well as for the end-user. Because the FlexACM system recognizes data packets at application level, the FlexACM system can dynamically assign bandwidth and priority to each individual service or application. For example, VoIP applications typically get one of the highest priorities while FTP download gets a lower priority, and services are differentiated according to the Service Level Agreements (SLA) subscribed by the customers.

This process of dynamically assigning bandwidth and providing prioritization is called shaping of the IP traffic and is embedded as a standard capability in the FlexACM solution. Shaping allows the ISP to avoid congestion even at peak times and provides customers with a ‘superior user experience’.

The ISP can also define different sets of profiles for groups of customers, determining features such as Maximum Information Rate (MIR), Committed Information Rate (CIR) and overbooking ratios. With all these features, the ISP can avoid having a small part of its customers consume almost all the available bandwidth and affect the satisfaction of the other users.

Achieve very high service reliability
A unique feature of FlexACM is its ability to react very fast to heavy rain storms, increasing dynamically the level of error correction so the satellite link is never interrupted. This results in a reduction of the available throughput, but the shaping function makes sure the SLA are respected and that critical services are not affected. When the storm is over and the link conditions improve again, every customer immediately recovers its original transmission speed. Even in the worst weather conditions, FlexACM guaranteed “Always on” connectivity. Higher SLA’s can offer and result in higher revenues for the teleport owner.

Case studies
Cobranet – FlexACM & heavy rain fade
Nigeria-based CobraNet is a leading provider of broadband Internet services. CobraNet wanted to improve the bandwidth efficiency of its satellite link between the Intelsat Teleport in Fuchsstadt, Germany, and its own in Lagos, Nigeria, as well as carrying out upgrades from DVB-S to DVB-S2 modems. Newtec’s technology was incorporated into both ends of the link introducing 16APSK and 32APSK capabilities and Newtec’s FlexACM technology. Before the upgrade, the link was implemented with 8PSK signals and the throughput was limited to 38 and 14 Mbit/sec respectively. Following the upgrade, the satellite link gained on average 70 percent in throughput: a forwards efficiency of 65Mbps with 32APSK and a return efficiency of 32 Mbps with 32APSK.

Additionally, the satellite transmission is now also much more robust, able to sustain very heavy rain fades: during rain fades as deep as 20 dB, the modulation parameters are changed gradually to QPSK 2/3 and the data throughput drops momentarily to 20Mbit/s in the forward, but the system does not loose synchronization. This is the only satellite system in the region to maintain its service in presence of such heavy rain.

SkyVision – FlexACM & inclined orbit satellites
SkyVision is a leading global provider of Internet services over satellite. The company operates a point-to-point link between its Teleport in Kenya and its main teleport in Austria using satellites in an inclined orbit. In order to follow the position of satellites in inclined orbits SkyVision needs to use tracking on outbound and inbound antennas.

However, due to interference from different satellites during the movement of the satellite, the receiving site conditions can drop by as much as 6dB, which means that a low modulation scheme and increased error correction (QPSK 2/3) has to be used, resulting in data throughput of only 40Mbps in a full transponder. However, most of the time, the receive conditions are much better and a link margin is present that is not being used, effectively wasting available throughput.

Newtec’s Elevation modems with on-board FlexACM client/controller provide the ideal solution in this situation. With FlexACM, SkyVision can use a higher modulation scheme and less error correction (up to 16APSK 4/5) whenever the situation allows, which results in an average data throughput of 74Mps, an increase of 85 percent for most of the time, and 95 Mbps or 137 percent increase during the best link conditions. The activation of FlexACM on this link also guarantees 100% link availability.

Horizon Satellite Services – FlexACM amd limited
receive conditions

Horizon Satellite Services, headquartered in UAE, is a leading provider of end-to-end communications solutions for corporate networks and facilitates access to tier one internet backbones for the regions largest companies and internet providers. Horizon has a link with an uplink in Europe, connecting to several sites including Lebanon and Iraq. The throughput of these different links varied between 7Mbps and 74 Mbps. For a certain link, conditions on the receive side were not optimal, as the receive site was on the edge of the satellite footprint. Further, the link experienced a daily variation of 2dB peak-to-peak in C/N, for unknown reasons. Horizon upgraded its existing Newtec Elevation equipment to enable Newtec’s FlexACM solution. With this solution, the link remained up at all times, even during degraded link conditions. In addition to this, Horizon was able to utilise a higher modulation order on its links, increasing from 8PSK 3/4 to 16APSK 4/5. This meant a gain of 65 Mbps to 93 Mbps (an increase of 43%, without acceleration or compression used). Horizon is now assured that the link performs to the maximum capacity achievable in the given situation.