Broadband plays a vital role in personal and business life, yet large swathes of the world remain unconnected to fast internet services.

This connectivity gap means that many of us are unable to access critical services in areas that include healthcare, education, financial services, and government. The risk is real that businesses with unreliable or slow network connections will fall even further behind their better-connected competitors. Mobile network operators have traditionally filled this connectivity gap in many rural areas, particularly in developing countries. However, only 75% of the worldwide rural population has access to 4G networks, with 88% falling within the range of 3G. This leaves 12% still connected to 2G networks, which were launched more than 30 years ago, and are incapable of supporting modern digital services. Even in highly-connected Europe, 6% of the rural population has only 2G network access. 

Mobile networks on 4G and 5G can offer fast speeds, low latency, and many devices at different price points. The main challenge lies in the cost of the fibre rollout needed to backhaul traffic from cell towers to the core network. 

While rollout costs such as power, and tower, and civil works are around a third higher in rural locations compared to urban, backhaul costs are more than double. In rural areas, rolling out each km of fibre for backhaul is estimated to cost between $3,000-$5,000. Microwave is an alternative, but it is often unavailable due to line-of-sight requirements over large distances.

Significantly reducing the cost of backhaul is a game-changer for mobile operators who want to launch services into places that are harder to reach, and build up demand while incrementally expanding their terrestrial network footprint. That said, fibre networks will never be an option for some. The Philippine archipelago consists of more than 7,000 islands, of which around 2,000 are inhabited. Indonesia lists more than 17,000 islands, of with approximately 6,000 are inhabited. Laying subsea fibre between them all, including across many deep-sea channels, is unrealistic. Where subsea fibre networks do link to island communities, they may be prone to damage caused by accidents or natural events that can cut cable and leave them unconnected.

Satellite backhaul capabilities

The so-called digital divide between those with access to fast broadband and those without is persistent and likely to widen. To help plug this terrestrial gap, mobile operators have turned to satellite backhaul; though not all satellite services can support the push to mobile broadband services. Once past the 350ms latency threshold, many useful applications time out. Standard 4G services such as voice-over-LTE (VoLTE) require a latency no higher than 150ms. The latency of a typical one-way connection from user to ISP via geo-stationary satellite networks can range between 500–700 ms.

Low earth orbit satellites 1,000km from earth - compared to 35,000km for GEO satellites - significantly increase bandwidth and reduce latency in space to around 50-70ms. This enables them to operate effectively as base stations are upgraded to 4G and beyond. LEO can act as a primary backhaul network or in combination with fixed line or GEO satellites to ensure maximum resilience. In addition, LEO antennas require less power and a smaller antenna size for a reliable link, and are substantially easier and less expensive to deploy.

LEO can also offer a truly global service. As GEO satellites are located around the equator, their coverage of the earth's surface is constrained. LEO on the other hand can cover everywhere, including polar regions, and provide backup to fibre and microwave radio links in territories worst affected by natural disasters, such as Japan.

Standardisation and 6G 

For core LEO satellite services to meet the backhaul requirements of mobile operators they need to be fully compliant with 3rd Generation Partnership Project (3GPP) standards. And for LEO to play an even more important role in the roll-out of 6G services, it will need to integrate fully into the network infrastructure and allow users to roam between mobile and satellite networks seamlessly as the situation requires, without disrupting any services or additional fixed infrastructure. We look forward to enhanced comms on the move, along flight paths that are often out of reach of mobile networks, or on train journeys that pass through notspots. Wherever LEO's ubiquitous broadband connectivity can go, a whole new range of IoT-based use cases come online.