In November 2021, Darwin and ESA collaborated on a connectivity test at Harwell Science and Innovation Campus. We spoke to Darwin’s Rodrigo Barreto and ESA’s Antonio Franchi to get some insight into this test.
The background to the test
Both Darwin and ESA have facilities at Harwell where we explore our shared interest in combining satellite and terrestrial communications: the Darwin SatCom Lab, and ESA’s 5G/6G Hub.
Antonio Franchi, ESA’s Head of 5G/6G and IoT Strategic Programme, suggested that it might be interesting to explore ways that the Darwin and ESA facilities could interact. ESA and Darwin had already collaborated successfully on other projects, such as the Air Quality Platform and Darwin Autonomous Shuttle, so we were very happy to agree to a cross-organisational experiment.
Rodrigo Barreto, Darwin’s Lead Architect, visited ESA’s 5G/6G Hub to familiarise himself with it. After the tour, he and Antonio discussed potential tests that Darwin and ESA could perform together.
Antonio sketched out what they were envisioning. ESA and Darwin would attempt to communicate over the internet, via video call, while switching between terrestrial 5G and satellite networks on both sides. Would they be able to maintain the connection across different network configurations?
The test itself
ESA and Darwin decided to use Microsoft Teams for the experiment. During a continuous video call between ESA’s 5G/6G Hub and Darwin’s SatCom Lab, both ESA and Darwin would switch back and forth between different network topologies.
If the connection could be maintained, that would be considered a good outcome; it would show that both ESA and Darwin had the capacity to switch between terrestrial and satellite networks without a loss of connectivity, and, more importantly, that widely used applications like Microsoft Teams work well across multiple 5G terrestrial and satellite connections.
Rodrigo and Antonio, at the Darwin SatCom Lab and ESA 5G/6G Hub respectively, connected over a Teams call. Over the course of the call, they switched repeatedly between terrestrial and satellite networks on both sides.
On the Darwin side, we took advantage of Darwin’s ubiquitous communications technology, which switched automatically between terrestrial and satellite networks when one became unavailable. Rodrigo would periodically disconnect one of the networks, and the technology would switch at once to whatever other network was available. With the use of O2’s mobile network and Hispasat’s satellites, we were able to remain connected to the video call.
At the 5G/6G Hub, ESA were able to switch manually between network configurations at the press of a button. ESA used Avanti and Eutelsat’s satellite networks, whereas Darwin used Hispasat. At points, the visual and audio information for the call was being sent through two different satellite networks before arriving at its destination.
This was a bizarre way to communicate, of course; it’s rare that you’ll repeatedly switch back and forth between multiple 5G and satellite networks on a single video call! However, we were able to maintain a continuous connection across many different combinations of network configurations (see below how Antonio’s sketch has evolved as a result), which was an impressive achievement.
The network switching did have a consequence in the form of slightly delayed communication. When the call had to pass through two satellite networks, Rodrigo and Antonio experienced latencies of up to 1.5 seconds: a result of the sheer distance the information needed to travel, as it was sent into space and returned to earth twice, covering approximately 140,000 km in those 1.5 seconds. Although Rodrigo and Antonio could sense a slight delay in the conversation, the voice and video quality remained good.
What does this mean, and what other tests could be performed in the future?
Some credit for the continuity of connection has to go to Teams itself; the program is designed to accommodate changes in latency, and was able to maintain the video call throughout multiple network changes. However, much of the credit must go to both Darwin and ESA’s capacity to shift quickly between different networks as necessary; Teams wouldn’t have been able to compensate if Darwin or ESA had lost their connection to the internet entirely.
This ability to switch networks without losing a connection has many potential applications, from staying connected while travelling to enabling drone deliveries in remote areas. You can learn more about the advantages of supplementing terrestrial networks with satellites in our post ‘Why combine terrestrial and satellite communications?’
Both Darwin and ESA were pleased with the outcome of the test, and we’re already looking forward to other tests we could perform together. In the future, we’d be interested in experimenting with remotely controlling vehicles over different network configurations.
ESA also has an article about these over-the-air tests, if you’d like to read more: ‘ESA tests space-enabled 5G connectivity’.
Darwin Innovation Group is a UK-based company that provides services related to autonomous vehicles and communications. If you’re interested in working with us, take a look at our careers page. If you’d like to know how we can help your organisation make use of autonomous vehicles, contact us. You can also follow us on LinkedIn or Twitter.