FAQs – VSAT Systems

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Q: Who is Advantech Satellite Networks (SatNet) and what is its position in the VSAT industry?

A: Advantech Satellite Networks, or SatNet for short, is the market leader in DVB-RCS VSAT hub and terminal equipment. DVB-RCS is an open standard, which allows widespread growth through the supply of terminals and hardware from a number of suppliers. SatNet’s satellite broadband access technology and products have evolved from almost 40 years of experience in designing and building advanced communications satellite payloads, as well as over 20 years of R&D in broadband technology development. Advantech Satellite Networks has pioneered the deployment of successive TDMA and MF-TDMA technologies, which are now at the heart of the emerging global DVB-RCS air interface standard for 2-way broadband satellite access.

SatNet has deployed to date over 70 VSAT hub systems worldwide, and thousands of remote terminals (over 15,000), during the last 5 years. SatNet has a world-class systems engineering team that can help optimize product configurations for customer needs. Overall, DVB-RCS manufacturers have deployed over 100 systems worldwide, and tens of thousands of remote terminals, providing a collective experience easily surpassing that of many of the other systems.

As indicated by the figures above, SatNet has established a dominant share of the DVB-RCS hub and terminal market. This has been confirmed in several independent reports published in the last two years.

Q: What is DVB-RCS and why should one consider deploying a VSAT network that is DVB-RCS compliant?

A: DVB-RCS is the only truly open standard for VSAT systems; it forms a two-way extension of the long-lived DVB-S standard and the recent DVB-S2 standard which are used for satellite broadcast. Several vendors, including SatNet, have invested substantially in DVB-RCS developments in order to produce cost-effective solutions that are in themselves very competitive with non-standard offerings. DVB-RCS benefits from an R&D pool that includes all of the world’s major broadcasters, whereas technology advancements with proprietary systems rely on the success of a single private enterprise. In addition, the interoperability offered by DVB-RCS ensures that the customer is not tied to a particular vendor.

Q: What role has SatNet played in the establishment of DVB-RCS?

A: SatNet has been involved in the development of broadband multimedia VSAT systems for over 10 years, and has been on the forefront of satellite communications for much longer. SatNet was chosen to develop the BBI system for SES-Astra; this Satnet-designed system provided the majority of the elements that now constitute the DVB-RCS standard. SatNet has also been actively involved in the standardization process itself and continues to be so in all relevant forums, including DVB and SatLabs.

Q: What is the SatLabs Group and how is vendor interoperability achieved?

A: The SatLabs Group is an organization for all users of the DVB-RCS standard; i.e., network operators, service providers and equipment manufacturers. It is a non-profit organization, established as an EEIG (European Economic Interest Group). SatNet has been an active member of SatLabs since its inception. SatLabs has established and is operating (through a test house) a certification facility for DVB-RCS terminals. Terminals that pass the interoperability test suite are allowed to carry the SatLabs logo and are guaranteed to be able to operate in DVB-RCS systems that operate within the System recommendations defined by SatLabs. This includes all current DVB-RCS system implementations of which we are aware.

SatNet’s terminal product has SatLabs certification, and our system implementation operates in accordance with the SatLabs System Recommendations. Further, SatNet guarantees interoperability of its hub with any vendor’s terminal that has SatLabs certification.

In addition, SatLabs defines interoperability standards that complement DVB-RCS, in particular for higher-layer aspects such as Quality of Service, Performance Enhancing Proxies and Management and Control of terminals. The test facility is being extended to cover these aspects in unison with the completion of these additional standards.

Q: How is the DVB-RCS standard coping with the latest technologies such as DVB-S2 and higher IP layers such as PEP?

A: The DVB-RCS standard encompasses the DVB-S2 standard for forward link transmissions; this has been the case since the publication of DVB-RCS version 1.4 in April, 2005. SatNet offers both hubs and terminals that support DVB-S2; this is in fact the standard product offering. DVB-RCS encompasses all three operating modes of DVB-S2: Constant Coding and Modulation (CCM), Variable Coding and Modulation (VCM) and Adaptive Coding and Modulation (ACM). Support for VCM and ACM is planned for SatNet’s terminal and hub products in 2007.

DVB-RCS has always had a very efficient return link arrangement, including the use of turbo coding and a MAC layer that facilitates very efficient capacity scheduling (MF-TDMA). With the addition of DVB-S2, systems operating according to the DVB-RCS standard use state-of-the art technology throughout and are therefore fully on par with or better than proprietary alternatives.

True multi-vendor interoperability of DVB-RCS equipment is assured by the SatLabs organization. The first version of the interoperability certification programme ensured basic physical and MAC layer interoperability. A second version has been finalized in 2006. In response to demands from customers, this version adds significant new elements of interoperability, which in fact go beyond the standard in many places.

Version 2 has added:

  • Interoperable Management and Control of terminals, allowing a single Network Management System to configure, control and troubleshoot terminals from multiple vendors in a unified manner. This feature also allows interoperable download of new software versions to terminals.
  • Interoperable Quality-of-Service provisioning; this allows QoS provisioning in a multi-vendor environment, for example to support Voice-over-IP or other real-time services.
  • Interoperable Performance Enhancement Proxies, which allows a single server at the gateway to provide Performance Enhancement functions to terminals from different vendors, even if those terminals provide different PEP clients.
  • Support for DVB-S2 CCM, VCM and ACM.The test laboratory for Version 2 is expected to be ready in the second quarter of 2007. Certified terminals can be expected soon after that.Both DVB-RCS and SatLabs strive to provide the best possible performance for the lowest possible cost in terms of both equipment and bandwidth. Backwards-compatible enhancements are therefore being added as the market demands them. DVB-RCS is currently being enhanced with new functionality that is demanded by the marketplace. This includes new modulation schemes that improve the bandwidth utilization as well as access and modulation methods that reduce the equipment costs for small networks. The most significant modification currently considered is however the addition of support for mobility, so that DVB-RCS systems can be used from ships, aircraft and vehicles such as trains and buses.SatLabs is currently considering the addition of a hub validation programme; this is intended to ensure that the operating parameters of a system sold as DVB-RCS does indeed operate within the space of parameters that certified terminals must support.

Q: What are the benefits that SatNet’s DVB-RCS VSAT products and network solutions have to offer?

A: Benefits include:

  • Open Standard Solution: our customers benefit from having multiple DVB-RCS vendors for both hub and terminal equipment, capable of interoperating with equipment that we offer.
  • Bandwidth Efficiency: our solution offers unrivalled bandwidth efficiency, with very low channel spacing and the most advanced MF-TDMA DAMA system.
  • High Speeds: our equipment supports very high data rates (up to 80Mbps on the hub outbound and 4Mbps per terminal on the hub inbound), but it also supports very low data rates (down to 64kbps on the hub inbound) for bandwidth sensitive applications.
  • Secure Communications: we can accelerate TCP/IP traffic together with the protection of encryption.
  • QoS/VoIP: our solutions allow to manage QoS (Quality of Service) at both the remote level and the system level; high priority traffic such as VoIP is prioritized over less real time traffic such as data transfers.
  • Private Networks: our networking approach preserves the system resources and security aspects between private networks while sharing bandwidth efficiently whenever applicable.
  • Low Capital and Operating Costs: the low entry cost, the scalability and the high bandwidth efficiency of our equipment allows to minimize capital investment expenditures (CAPEX) and operating expenditures (OPEX).
  • And more…

Q: What are the drawbacks of proprietary, non-DVB-RCS VSAT systems?

A: Aside from any technical and performance issues, the user of a proprietary system is inextricably tied to one specific vendor, with little recourse when this vendor fails to meet the technical and commercial objectives of the system operator.

Q: What is the real story about VSAT bandwidth efficiency?

A: Real bandwidth efficiency in a demand-assigned (DAMA) satellite system is a complex matter; it depends not only on the physical-layer properties of the transmission scheme such as modulation and coding schemes and carrier spacing. Additional factors that must be taken into account include efficiency of use of the allocated capacity, efficiency of capacity scheduling (i.e., can the system actually allocate the available resources when demand exists) and responsiveness to changes in demand.

DVB-RCS has been designed from the start for optimal performance on a geostationary satellite channel in the presence of rapidly varying demands. The regularly-structured MF-TDMA air interface allows very efficient scheduling with only moderate computational effort. This in turn allows the use of relatively short capacity allocation cycles; this ensures responsiveness to changes in demand.

Promoters of proprietary systems often emphasize one or two of these parameters but are silent about the others. The true answer can only be found by considering all of them. In this context it should be noted that some proprietary VSAT systems have adopted techniques developed and optimized for terrestrial networks such as cable systems, with no or little modification.

Q: What is the minimal configuration supported by SatNet’s hub products and how easily do they scale up?

A: SatNet’s portfolio of hub products will support the service provider’s requirements at all stages of his network deployment. Starting from an SCPC-based network, our Pay-as-You-Grow™ approach enables the network operator and service provider to migrate to DVB-RCS while re-using the same user terminal equipment and forward link equipment. This allows to easily grow the system from a few SCPC terminals to tens or even hundreds of DVB-RCS terminals. From that point on, the DVB-RCS hub can be grown to support thousands of terminals, and more. Hot hitless redundancy can also be implemented for the more operationally critical systems. No hardware is put to the side; the existing hub equipment is re-used and new hardware, including demodulator and processor cards, is added to grow the system economically. The per-terminal-CAPEX cost of the hub spirals down. Further, SatNet’s most basic DVB-RCS hub is capable of supporting many more terminals than an equivalently priced hub from any of our competitors.

Q: Who are SatNet’s customers and how does DVB-RCS suit their applications?

A: SatNet’s products are used to provide solutions to a large variety of applications. Virtually any IP application can reside behind a remote terminal. Aside from basic internet and file transfers, such applications include VoIP, videoconferencing, distance learning, rural telephony, internet cafes, ATM banking, point of sale, Wi-Fi/Wi-Max networks, GSM backhaul, satellite news gathering, tele-medecine, emergency management, government & defense, maritime platforms, and more. The DVB-RCS standard implements a shared network architecture; this allows to make the best possible use of the satellite bandwidth and make high bit rates available to end user applications only when this is needed.

Q: Is SatNet providing solutions for professional and consumer markets?

A: SatNet aims at providing low cost and effective satellite connectivity solutions to all types of users

  • SatNet is providing VSAT solutions and equipment for the professionally oriented user; this includes governmental, enterprise and SOHO users who wish to deploy terminals at various locations.
  • Further, because our remote terminal equipment supports a standard ethernet/IP interface, consumer-oriented and/or rural-based end users can access the system via a wi-fi or a basic wired-LAN network topology.