A Complete Guide to VSAT Technology

A Complete Guide to VSAT Technology

29 Nov 2021

A globalised economy depends on broadband connectivity day and night, 7 days per week, 365 days a year. As satellite technology continues to evolve and advance, so do IEC Telecom’s solutions for reliable broadband access at reasonable costs, no matter where your business takes you.

Throughout the pandemic, network-based services like video conferencing and cybersecurity have taken on even more importance. VSAT satellites offer easy installation and set-up, so these and other crucial network-based technologies are always accessible.

To connect teams throughout the world, IEC Telecom offers VSAT systems and tailored solutions designed specifically for enterprise users on land and at sea.

IEC Telecom also provides unparalleled VSAT support services to enhance connectivity and user experience, thereby ensuring operational continuity and the wellbeing of crewmembers, and delivering remote assistance no matter the location.

Before choosing a satellite product and network solution, it is important to understand the basic elements of VSAT satellites along with the benefits and limits of VSAT technology.

Read on to find out more about what VSATs are, how they work, and why IEC Telecom’s unique offerings can enhance your VSAT experience and add value to your organisation.

What is a VSAT?

VSAT is the acronym for ‘very small aperture terminal’, which is a type of two-way satellite that enables communication and data transfer.

VSATs are often used in areas with underserved or unserved terrestrial communications infrastructure. VSATs are also used onboard marine vessels, aeroplanes and vehicles to facilitate broadband access on-the-move with ground network access.

What is a VSAT Network?

The streamlined architecture of a VSAT network has only a few key components. These include the satellite (the medium where the communications happen), a gateway or hub station (the crux of the VSAT network), and remote stations.

The gateway station is where the interface with a wide area network (WAN) occurs. This can either be the internet in the case of satellite internet service or a corporate intranet such as in the case of an enterprise VSAT network.

The remote stations can be located on moving transport like ships, aeroplanes, and trucks or at fixed locations on the ground such as homes and offices.

VSAT networks utilise star topology, also called point-to-multipoint architecture. This allows the gateway station to communicate with the multiple remote stations via satellite.

Why Choose VSAT?

There are a number of reasons why VSAT is a popular choice for enabling broadband connectivity throughout the globe.

They offer ubiquity of coverage because the footprint of satellite transmission is widespread. Wherever the terminal is located, there will be network coverage within the footprint.

This allows VSATs to enable connectivity in remote locations as well as mid-air and at sea; any place that cannot be reached by terrestrial communications can still receive stable broadband service with VSAT.

The nature of VSAT architecture also makes it reliable and consistent with a uniform service level agreement (SLA) and quality of service across the satellite’s reach.

It is also easy to scale because of the relatively few components (the gateway, satellite and remote terminal) and the simplicity of the network design. More remote terminals can be added to the network without negatively impacting the SLA or quality of service.

No matter how large the network, it can be managed from a central location. This makes it easier to diagnose and correct any VSAT performance or maintenance problems.

More importantly, VSATs provide alternative or supplemental broadband connectivity independent of terrestrial communications services. Enterprises can enable high-availability networking in areas where there might be none available, whether in a remote oil field or on a ship in transit.

Where Are VSATs Used?

VSAT is a good choice for businesses that need more remote connectivity. They are popular in sectors ranging from oil and gas exploration to cargo shipping to retail outlets, which use VSATs to complete credit card transactions.

Businesses might choose a VSAT satellite solution to fill in coverage left by broadband gaps in the terrestrial service area. Or they might choose VSATs to enable high-availability networking that can complement existing DSL and other wireless services.

At a remote ground location, a business may install both a terrestrial communications path as well as a VSAT for a satellite communications path. If the terrestrial communications path goes down for any reason, the satellite communications path can carry all the traffic seamlessly without impacting operations, acting as a back-up for the enterprise.

The satellite path can also augment the terrestrial path, creating a load-sharing solution that offers additional capacity alongside ground communications.

VSAT for Mobile Use

There are two ways that VSATs are used for mobile applications: on the pause and on the move.

When a VSAT is transported to a location, set up there and used for communication, it’s being used ‘on the pause’. When a VSAT is attached to a vehicle, aeroplane or marine vessel, it’s being used ‘on the move’.

A VSAT on-the-move has a more complex job, as it must continually track the satellite and make path adjustments while in constant motion.

For marine use, the antenna of the VSAT remote terminal must be fixed at the horizon line and at true north in order to transmit and receive communications.

VSATs Generate Bandwidth Efficiencies

By nature, satellites have a limited amount of bandwidth. This means that for a VSAT to be cost effective, it must generate bandwidth efficiencies.

The bandwidth efficiencies are created at two layers: the lower layer, which is at the physical or data link level, and at the higher layer, which is the transport and network level.

At the physical or data link level, DVB-S2 with adaptive coding and modulation on the forward channel (the channel that travels to the remote terminal) generates physical level efficiencies.

The same thing happens on the return channel where FD-TDMA access techniques combine many signals from remote terminals together into one frequency.

At a higher layer or application, transport and network level, VSATs generate efficiencies through acceleration and optimisation.

This is done with HTTP object prefetch, which pushes objects over the satellite to reduce capacity on the return channel. This allows the VSAT to ignore browser requests and transmissions across the satellite.

TCP spoofing is another method of acceleration and optimisation wherein the TCP protocol is not run all the way across the satellite. This helps save bandwidth.

Point-to-Point Versus Point-to-Multipoint

There are two kinds of VSAT access technologies: single channel per carrier (SCPC) and DVB-S2 (TDM)/FD-TDMA (Star Access technology). These two types of VSAT access technology are suited to different needs.

SCPC operates in a point-to-point mode that’s well suited for high-capacity links where the traffic is relatively high-volume and does not vary, such as an E1 or 10-megabit link from one location to another location. In maritime use, this type of access technology is used for offshore oil drilling platforms and large fleets.

DVB-S2 (TDM)/FD-TDMA, or point-to-multipoint forms the largest portion of the VSAT market because the technology allows for very efficient traffic multiplexing between many remote stations and the gateway station. This is the most effective method to connect remote terminals to the internet or connect enterprise branch locations to headquarters.

For small to mid-sized fleets, point-to-multipoint is the most commonly used access technology.


Satellites are subject to specific considerations that affect their ability to transmit signals, namely latency and rain fade.

VSATs orbit 35,000 kilometres above the earth. Because of this physical distance, there is a delay of about 250 milliseconds as communications travel from the earth to the satellite and come back. Protocol processing adds another 300 to 500 milliseconds.

These add up to create latency, also called ‘ping time’, which is the time lag between a signal’s broadcast and when it is received at the destination.

There are ways to mitigate latency, such as TCP processing or spoofing.

Spoofing means that instead of running TCP acknowledgements all the way across the satellite, the TCP protocol is terminated at the remote terminal and the gateway station. This offers a better user experience for web browsing and transferring data.

Rain fade is caused by rain or moisture in the atmosphere, which can lead to the loss of strength or degrade the quality of the satellite signal at higher Ku and Ka-band frequencies.

To mitigate rain fade on the forward channel, adaptive coding and modulation can increase the power of the signal. On the return channel, adaptive coding and changing the return channel symbol rate increases the signal quality.

It is also possible to increase the uplink power available at the remote location to avoid rain fade.

IEC Telecom’s VSAT satellite add-on services are important enhancements to your custom solution that provide network continuity when the VSAT link is down or weakened due to rain fade. This way, business-critical applications can continue to perform their intended functions until the issue is resolved.

Issues To Consider: The Cost Factor

VSAT communication is often viewed as complicated and costly. Originally, terminals were heavy with large components and the set-up process was lengthy. With innovative advances in technology for accurate satellite pointing, intuitive web interfaces, and completely integrated VSAT, the cost factor is being mitigated and VSAT is being perceived as the ideal alternative technology and even one of the main communication tools.

A significant advantage of opting for VSAT technology is that it can be provided anywhere on the globe regardless of the time period

involved for a project or mission, density of population, or even the investment involved. As the performance and throughput of VSATs have increased, the cost of the terminal and service delivery has decreased.

VSATs Continue To Evolve

Deployment of new Ka-band satellite systems means that VSAT service providers can offer customers increased bandwidth and higher service levels for the same price as before.

IEC Telecom offers additional VSAT services that further supplement the experience, with solutions to suit a variety of applications. IEC Telecom is committed to extending benefits of digitalisation to all customers with an innovative solution that, for example, helps shipowners overcome challenges due to technical specifications and costs.

OneGate Marine Compact by IEC Telecom offers a VSAT-like experience over a Mobile Satellite Services (MSS) terminal for small and medium-sized vessels. With the COVID-19 pandemic escalating the demand for digitalisation in the shipping industry and the introduction of the International Maritime Organisation’s (IMO) cyber security resolution in January 2021, IEC Telecom has constantly been working closely with fleet managers to develop an individual cyber security policy for each vessel.

IEC Telecom is at the forefront of satellite service innovation, providing solutions to humanitarian organizations such as Global Xpress that is deployable in just a few seconds using an auto-pointing, mobile terminal. Such solutions are an ideal fit for NGOs which need maximum mobility and have multi-regional requirements to overcome the limitations of terrestrial infrastructure and legacy VSAT services.

Additional VSAT Services

IEC Telecom’s VSAT enhanced add-on services ensure operational continuity when the VSAT link is down, keeping key business applications working even over L-band. VSAT add-on services, like crew and guest vouchers reward hard working teams, while local dashboards, filtration, usage controls ensure safety and proper usage.

No where are the benefits of VSAT seen better than during unexpected events such as the worldwide Covid-19 pandemic. With ports closed to vessels, airlines grounding planes, and seafarers stranded onboard, a clear difference has been observed between those vessels with VSAT capability onboard and those without. There has been an increase in demand for crew communication provisions and companies have had to prioritise communication links to maintain operations. With connectivity systems down, research has revealed that 13% of companies immediately start losing money and 46% suffer a financial hit after just four hours! IEC Teleco m’s VSAT services enable companies to offer their staff and crew with enhanced connections to cope with escalating digital traffic.

Enhance Your VSAT Experience

In harsh weather conditions availability of VSAT link is not given. Efficiency of vessel operations increasingly depend on availability of digital access to ashore infrastructure. This covers reporting, training, trouble shooting, remote maintenance and more. In these conditions, it is important to ensure that both corporate and welfare applications remain fully operational over back-up line (L-band) when VSAT is down.

Communications can be bolstered with OptiConnect, a suite of applications that provides hands-free video conferencing, live technical assistance and advanced surveillance capabilities. The OptiSoft application suite provides email management, data transfers and cybersecurity to marine vessels for more streamlined operations with superior cost-efficiency.

Recent additions to IEC Telecom’s roster of VSAT applications also include OneAssist, which supports voice, video-streaming, file exchange and includes a hands-free headset.

OneAssist enables local and or staff technicians to perform maintenance, system updates and set-up on remote terminal units with virtual assistance from experts, saving teams both time and added expense in the process.

VSAT Solutions Designed To Meet the Toughest Networking Challenges

IEC Telecom understands that one size does not fit all.

Network needs vary, so IEC Telecom creates affordable plans tailored to each client’s specific requirements by aligning the right VSAT device with the right service and enhancements.

IEC Telecom’s targeted VSAT solutions come as a single cost-effective package, meeting business needs and bottom lines alike.

With IEC Telecom’s VSAT satellite services and applications, your team always has the connectivity and tools they require to get the job done.

Contacts for media inquiries: marketing@iec-telecom.com | +971 (0)4 447 5180