12 December 2024
John Yates, Managing Director, Atheras
Keeping networks up – whatever the weather
Africa is full of variations of climate and geography. From the Sahara Desert to the Atlas Mountains and the Nile Valley, although 61% of the population is focused mostly in urban areas, the rest are based in rural regions where fibre is either not available or patchy in coverage.
At a time when the digital society is commonplace and the ability to access important online services such as finance, health and governance is a fundamental need, reliable broadband connectivity is essential.
Although there have been significant improvements in fibre reach across the region, in January 2024, 85.9 million north Africans still did not use the internet. This underscores the importance of satcoms in unlocking digital opportunities and providing critical communications when and where they are required. Rural areas are reliant upon satcoms to access the high bandwidth applications necessary for daily life. High Throughput Satellites (HTS) have become indispensable across Africa due to their use of high frequencies which can deliver more than twenty times the data capacity of traditional satellites at a fraction of the cost per bit – an important consideration for the continent where many people reside below the poverty line.
HTS provide an excellent solution to help the African nations overcome their connectivity issues at an affordable price, but the high frequency bands used by HTS networks are highly sensitive to atmospheric attenuation, which can cause outages and take down essential access to broadband connectivity.
Deserts to floods
Several regions of Africa have experienced their highest rainfall this year, some the wettest since records in the region began, 40 years ago. Sudan, Eritrea and Ethiopia have been severely affected and in Greater Darfur, northeast of Sudan, damage and destruction has affected homes, bridges and dams causing the displacement of over 170,000 people. It is often (wrongly) assumed that Africa is a dry continent, but it is a region of very mixed weather where the rainy season runs from July to November.
For satcom users, the complex weather systems and heavy rainfall can be a particular problem. Links are easily disrupted yet there is no other means of connectivity in such remote regions. And with the weather becoming increasingly unpredictable, satellite operators must have means to mitigate the effect of adverse weather conditions. For service efficiency, it’s critical that networks are designed and adapted to manage the impact of weather events.
Emergence of LEO
It’s not just GEO satellite operators that need to consider the effects of the weather. LEO is also gaining a significant foothold in the African region due to the huge cost savings that it can offer to users. LEO represents a huge growth area for the African satellite sector due to its lower operational cost. Couple this with the fact that the introduction of satellite-to-cellphone connectivity is fast approaching and that 76% of people across Africa have access to a mobile phone. The popularity of LEO is set to soar even higher and it’s clear that the effects of the weather need to be managed across all orbits.
Managing the effects of weather
Rain fade is nothing new and satellite operators have a range of tools and techniques at their disposal to mitigate its effects. However, while legacy techniques such as fade margin, Uplink Power Control (UPC) and Adaptive Coding and Modulation (ACM) work well in traditional C and Ku-band satellite networks they’re less effective when used in Ka and Q/V-bands, which are becoming increasingly widespread.
Diversity gateways can be implemented so that the operator can hot-switch from one to the other when impacted by the weather. However, HTS satellites require dozens or even hundreds of gateways and this becomes enormously expensive. By employing Smart Gateway Diversity, though, a few diversity gateways shared between many active gateways can have exactly the same effect yet reduce ground segment costs by around 40%.
AI-techniques combined with scaleable power of cloud-computing can be used to improve weather management, by leveraging it to optimise network design and also using AI-techniques to predict which gateways would likely be affected by weather before the event occurs.
AI techniques are used to assimilate huge volumes of historical and real-time data, for enhanced accuracy and specificity of predictions. AI identifies complex patterns that traditional models might miss. As well as providing precise, short- and near-term predictions for specific locations, AI also strengthens early warning systems for extreme weather events, enabling better disaster preparedness and management.
Utilising AI for network planning and management allows operators to design robust networks to minimise impacts caused by regional weather patterns and implement contingency plans well in advance, which can prevent service disruptions and ensure continuity of connectivity, whatever the weather. Not only does this enhance operational resilience, but it also optimises resource allocation, bringing cost benefits. With the ability to accurately forecast weather events, operators can manage traffic proactively, maximising network availability.
The need for high throughput services is only going to increase as satellite operators providing service in Africa seek to continue the quest to close digital divides and meet the demand for broadband-based services that is sweeping the continent. By employing technologies such as HTS and Smart Gateway Diversity and utilising AI-based tools for network design and weather management, they have the tools to keep costs down yet deliver a highly reliable service to their customers.
