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Satellite cellular backhaul is at the forefront of modern connectivity solutions

By , Senior Vice President of Sales, Enterprise and Emerging Markets at Speedcast
Africa , 08 Feb 2021
James Trevelyan, Senior Vice President of Sales, Enterprise and Emerging Markets at Speedcast.
James Trevelyan, Senior Vice President of Sales, Enterprise and Emerging Markets at Speedcast.

Of all the things this last year has taught us, the importance of the internet particularly stands out due to the global COVID-19 pandemic. While everybody isolated to protect themselves and others, the internet allowed mission critical communications to continue and for the rest of us to carry on with a somewhat ‘normal’ life; our homes became our offices and businesses went online.

This makes it more shocking that by 2020, just 59% of the World’s population were using the internet, according to Statista. This need for increased coverage to remote regions of the planet, is one of the main drivers for cellular backhaul connectivity. Once an unattractive option to Mobile Network Operators (MNOs), cellular backhaul through satellites is making a comeback, as they endeavour to meet an ever-increasing demand for connectivity.

A satellite revolution

Around a decade ago, the cost of using satellites for cellular backhaul made it a last resort for the majority of MNOs. The only time it was really utilised, was to serve extremely remote locations to avoid the penalty for not meeting service requirements.

Why was the cost so high? Satellites in high, geosynchronous orbit offered limited capacity, operating mostly in C-band – the lowest of the satellite frequency bands – to ensure service levels in rain-soaked regions. 7 metre antennas along with a plethora of civil works and high-powered transmit-and-receive gear racked up the cost beyond reasonable limits.

But fast-forward 10 years, and the picture is entirely different. While the satellite industry has leaped forward, the cost of providing backhaul connectivity has fallen dramatically. Now, prices are roughly US$3 per Gigabyte according to research firm NSR, with more recent projects seeing them as low as US$2 per Gigabyte. This development has led to a considerable increase in the adoption of satellite backhaul. It is forecast by 2029, that backhaul will generate satellite revenues worth over US$30-billion, without considering the added cost effectiveness of 5G activity.

Driving the evolution

This evolution did not happen overnight; a decade of advancements has got us to where we are today. In 2004, Telesat launched Anik F2: containing the first “high-throughput satellite” (HTS) payload in the business. HTS created an enormous increase in effective capacity per satellite, by changing the way the satellite operated. Instead of large, broad beams that covered entire nations, HTS shared the same frequencies across hundreds of narrow beams which operated at the higher Ka- or Ku-band frequencies, packing more capacity into the same bandwidth.

Satellite operators began launching HTS payloads, but it was not until 2010 that all HTS-spacecraft were launched. This move by companies like Eutelsat, Viasat, Hughes/EchoStar and new entrants Viasat and Avanti, marked the first real commercialisation of HTS. When Viasat-1 entered service in 2011, it had a capacity of 140 Gigabytes per second - more than all other commercial communications satellites over North America combined.

Thanks to the success of these HTS spacecraft, Viasat and Hughes/Echostar soon ordered second generation spacecraft to meet the increasing market demand. These new craft had an even higher capacity and steerable beams, providing an even better business case. These advancements meant that enterprise data was quickly becoming the industry’s fastest growing sector. Intelsat was the first to launch satellites for non-commercial purposes, supporting government, industry, and terrestrial telecom with its 3 satellite, HTS global constellation.

Jump forward to 2017, third-generation spacecraft with very high-throughput satellites (VHTS) were on the scene, thanks to Viasat. Scheduled for launch in 2021, these three satellites are predicted to put an additional three terabits of network capacity into orbit around the world. Additional VHTS satellites from Hughes and Eutelsat will each add another 500 Gigabytes per second of capacity when launch later this year.

With this all taken into consideration, satellite backhaul is fast becoming an increasingly attractive prospect for MNOs. In fact, out of all the industry sectors, the price decline has been most significant for enterprise data. Between 2018 and 2019, NSR found a global average price decline of 18% which increased to 35-65% over a 2-year period.

Back down to Earth

With all this innovation happening in space, of course there were advancements on the ground too, which also contributed to the viability of satellite backhaul we know today. Initially, HTS satellites operating at the high Ka-band frequencies faced a battle with rain fade, which happens when the size of water droplets means they start to absorb radio wavelengths. As a result, we did not expect Ka-band services to become viable for areas with moderate rainfall. Thankfully, advancements in ground systems allowed the first Ku-band and then Ka-band services to withstand even heavy rain fade to solve the issue.

The success of higher frequencies then made it possible to replace those costly 7 metre antennas with a fraction-of-the-size 1.2 metre alternatives, reducing the cost of installation. Technological advancements simultaneously brought down the size and power consumption of satcom equipment, so much so that base stations in some locations are powered by no more than batteries and solar panels.

Business case opportunities

Business cases that were previously unviable for satellite backhaul, are suddenly well within the realm of possibility - thanks to these new economics. In turn, the potential markets where MNOs can expand are increasing and they are seeing greater opportunities as a result.

Network extension

By replacing long fibre runs or microwave shots with cost-effective satellite links, MNOs can navigate areas of difficult topography that would have previously posed a significant difficulty. Scattered and rural population pockets can now be reached in a way that is economically viable. Not only is this financially beneficial, but it provides those living in coverage gaps with vital connectivity that is no longer a luxury, but a necessity for modern life.

Capturing roaming revenues

Although smaller MNOs running 2.5 or 3G networks do have licences for 4G spectrum and want to roll out 4G to capture roaming revenues, it is costly. However now they can deploy 4G infrastructure using satellite connectivity parallel to their existing infrastructure to generate revenue with minimal expenditure.

Serving peak demand

When there is low demand for connectivity in a rural area, microwave is the traditional method of backhaul. But when the connectivity demand in a rural area spikes, for example if more people visit an area during a holiday season, building enough microwave capacity is not cost effective. A small capacity satellite solution is a great alternative for meeting this demand, and thanks to new economics, it can do so at an attractive price.

Edge content caching

Undeniably, the consumption of video content online is increasing. Not only is the popularity of video streaming services at an all-time high, social media platforms are putting a larger focus on video content. At a staggering 80% of all mobile traffic, video streaming is putting a strain on the core network and on sites at the remote edge. To combat this, MNOs are experimenting with downloading popular content to edge servers during off-peak hours. Because of its location at the heart of broadcast distribution, satellite is the ideal solution for this video caching technique.

What the future holds

It comes as no surprise that the future is all about 5G. The first deployments will focus on delivering the ‘5G promise’ of low latency, high-capacity delivery to densely populated areas. But as MNOs begin to expand into more rural areas, the new economics of satellite backhaul will play an important role.

In contrast to previous generations, 5G has been developed with satellite capabilities in mind; the industry inserted its recommendations into the standards development process and worked to make these standards “satellite-friendly.” Base station and modem equipment has been designed to simplify the interface, allowing for the incorporation of satellite, effectively minimising the cost and complexity of satellite backhaul and fronthaul.

One of 5G’s headline acts will be its impressive low latency, which cannot be currently achieved by satellites in high, geostationary orbits. A generation of satellites for low Earth orbit (LEO) are currently being designed, making satellite a major contributor for 5G deployment. They will support very high capacity at 20 MS of latency, far closer to the 5G standard of 1 to 10 MS depending on what band it operates in.

While 4G has long been a part of everyday life, there are over 4 billion worldwide subscribers still using earlier generations - mostly in lower income and lower density markets. HTS will continue to play a major role in expanding the subscription for 4G/LTE, long before LEO service becomes a commercial reality.

For MNOs wanting to unlock the full potential of satellite cellular backhaul, they must have access to solutions which overcome the many complex challenges faced when providing satellite connectivity. Operators wanting to achieve the best performance possible must make sure their network is streamlined and future-proofed against the continuing growth in the demand for connectivity. Solutions that seamlessly bring together satellite connectivity into standards-based mobile networks will allow for real-time management to guarantee that all demand is met even under changing conditions.

Providing a cyber-secure service and overcoming the many complications when it comes to configurations of satellite, microwave and mobile connectivity, solutions such as these will provide MNOs with an ultra-competitive edge.

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