The term ‘bridging the digital divide’ has been common currency in the telecommunications arena for a number of years, concerning both the complete lack of broadband internet access for ‘unserved’ populations and the limited narrowband access to IP services for ‘underserved’ populations. It can apply to the more rural parts of developed counties, but still, primarily, it concerns the developing regions of the world.
Martin Jarrold, Chief of International Programme Development at the Global VSAT Forum (GVF), says that in the build-up to the ITU World Radiocommunications Conference in Geneva in November 2015, research confirmed that VSAT earth stations/ground segments – particularly satellite services delivered over VSATs operating in the C-band part of the spectrum – are essential for continued socio-economic development across developing nations. They are also needed for development facilitated by accelerated internet access for enterprise, for governments and for communities. This is only achievable with satellite.
Satellites orbit the Earth, and receive and transmit signals from space. This allows a VSAT network operator to quickly deploy services to any point on the Earth’s surface where IP services are required, including vessels on the sea and offshore oil fields. The only requirement is connectivity to an electrical source.
Jack Buechler, VP Business Development, Talia, explains: “Electrical power is required to power the VSAT, but now there are many methods of generating enough power using sources such as solar cells to charge batteries, which in turn are used to power the VSAT equipment. Once the VSAT is deployed, users have access to many different types of services, including internet services.”
With a constantly growing appetite for data, VSAT solutions must deliver higher throughput, and this is starting to happen with the implementation of high throughput satellite (HTS).
It’s difficult to give specific speed rates, since up and down link rates can vary enormously with VSAT connectivity. The governing factors deriving these speeds of service are frequency selection, antenna size and quality and service provision. Invariably, though, HTS constellations are coming closer to levels which are comparable with terrestrial networks.
“Some of the current satellites provide seamless global broadband at downlink speeds of up to 50Mbps and uplink speeds of 10Mbps using small VSAT terminals. The advent of HTS networks has led to demand on the VSAT component manufacturers to create products which can operate at these higher frequencies and support faster data rates. The exciting part is that this access to faster data rates opens up numerous new and great ways to use satellite communications in many market areas.
“Now that all three Global Xpress satellites are fully commissioned, broadband access will be available via VSAT anywhere in the world, with the exception of the polar regions. This delivers a service that no other satellite constellation today can provide, meaning that a ship or aircraft could circumnavigate the globe and almost never be without broadband access. There are also a number of more regional satellites that have a similar ability to provide high-speed services,” says Ulf Sandberg, Managing Director of Paradigm.
From the point of view of the user, internet speeds over VSAT will vary according to the particular proprietary service offering they are using and according to the service level agreement (SLA) and committed information rate (CIR) in their service contract. Hence, across a competitive marketplace these speeds will vary, as will the associated costs of various levels of service.
Jarrold says it is more straightforward to address the issue of satellite throughput levels, which are improving substantially. Indeed, projections on the characteristics of the next generation of HTS – sometimes identified as ultra-HTS – shows throughput levels projected to soon exceed 300Gbps. This will feature continuing reductions in throughput costs per bit and costs per transponder, higher EIRP and more payload accommodation, higher payload densities and lower mass per transponder, together with more aggressive frequency reuse schemes to enhance capacity and the adoption of DVB-S2x to increase throughput, power, frequency and coverage flexibility.
So what is the role of VSAT in broadcast? Martin Evans, IP Sales Manager at SIS Live, says: “It is predominantly for providing connectivity for ISDN communications talkback or for uploading edited video or streaming a multicast programme to additional territories not covered in main broadcast transmissions. It is also used in cases where the customer wants to take advantage of lower-cost TDMA technologies.”
Buechler says VSAT in broadcast provides IP connectivity, and hence IPTV is just one of many IP applications that VSAT will support. Typically, a video source such as the output of a camera is connected through a video encoder to convert the video into an IP stream. This IP stream can then be connected directly into the VSAT for onward transmission. Reception of IPTV signals is the converse. An IP stream is received by the VSAT. The VSAT then passes the IPTV stream to a decoder, a set-top box or PC for example, for display.
VSAT in broadcast mostly uses highly transportable flyaway terminals which can be quickly and easily deployed and operated by one person. These are then primarily used to communicate sports and news contributions back to studios for editing and broadcasting to the users, either by satellite, terrestrially or via the internet.
Sandberg says: “Paradigm’s Hornet100, YellowJacket65 and Swarm45 are all transportable terminals which provide a range of streaming video speeds and operational flexibility whilst being easy to set up in the field. The rapid deploy flat panel Swarm45, for instance, will have you pointed and on the air in a few minutes, whilst the Hornet100 provides the maximum possible data throughput for a 98cm portable terminal.”
However, broadcast through VSAT can be marred by interference. New ground equipment being manufactured allows different techniques to be incorporated to mitigate interference and increase efficiency.
Sandberg further adds that terrestrial use of the Ka-band frequency is still very low compared to use of C-band and Ku-band, which will minimise interference on the Ka-band spectrum. Consequently, at a terrestrial level, operators can mitigate the chance of interference by solely using Ka-band for VSAT.
“Challenges caused by weather when operating on the Ka-band spectrum can also be mitigated with advances in adaptive modulation and coding techniques. These can change the modulation and FEC of an RF carrier on the fly and thus react to changing weather conditions. Should rain fade affect the condition of the link, the system will automatically change the parameters to avoid loss of signal. This has greatly improved the Ka-band signal reliability in the face of deteriorating weather conditions.
“The industry is also starting to collectively use carrier ID to combat interference from unauthorised users, unintentional or not. This is a system whereby all broadcast transmission terminals will be identified by their carrier ID, allowing any interfering terminals to be quickly located,” explains Sandberg.
Once identified and located, interference from rogue carriers can be quickly and easily fixed.
“Frequency reuse results in greater satellite throughput and therefore lower operational and in-orbit costs per Mbps. These terminals are generally lower power and operate into defined network hubs; this leads to less risk of interference,” adds Evans.
Other challenges to VSAT operators come from fibre providers. With increasing bandwidth in constant demand for end users, telecom providers keep extending their fibre networks.
Buechler explains that 20 years ago, Africa was a fibre desert. Today, fibre is widely deployed across the continent, with VSAT now not required. He thinks, however, that VSAT services can be complementary to fibre.
The second challenge comes from mobile phone usage. The success story of the mobile phone industry and specifically the mobile data sector of the industry has hit the VSAT market. Increasing bandwidth through the use of LTE, 4G, 3G and even 2G has required increasingly more bandwidth. The financial gains of this success have been invested in fibre to rural areas, at the cost of VSAT deployment.
“We see VSAT as being very complementary to fibre. Talia provides services to fibre providers where they have no coverage. Talia provides VSAT as a backup to fibre in case of fibre failure. Talia is still able to deploy VSAT services much faster than it takes to dig a fibre trench, install and commission such a service. Typically Talia will install a VSAT within 24 hours. VSAT equipment and the bandwidth associated with it has been falling in price over the past 20 years. This still makes it a viable alternative to some other technologies. There is of course an ever growing demand for VSAT where no direct connectivity is possible, including planes, trains and vehicles,” concludes Beuchler.