29 November 2024
Joakim Espeland, CEO, Quadsat
Addressing avoidable RF interference
Radio frequency interference (RFI) mitigation is a crucial part of the day-to-day management of satellite operations. Most operators have good processes in place to deal with interference when it happens, and the tools and techniques for doing this have naturally become more sophisticated over time. Yet still, the majority of interference cases that operators have to deal with are caused by human error and equipment failure, so could be avoided in the first place.
The industry is facing many unknowns as a result of recent innovations and a more complex and growing operating environment that may result in new causes of interference. Given this, it’s crucial that the industry implements proactive measures and best practices that prevent those ‘known’ causes of avoidable interference.
Understanding RF interference
Interference is a longstanding problem with big implications. When an interference incident occurs, it doesn’t only affect the satellite network generating the interference. A single anomaly can have a ripple effect and impact the operation of other satellites and networks. And when interference occurs, it can cause service disruptions, preventing the transmission of critical data and communications. When this happens, satellite operators can face financial implications and can lose customers.
Interference can be caused by several different things including natural phenomena and intentional jamming. However, the most common cause is generally considered to be poor and incorrect installations as well as equipment error. If equipment is installed incorrectly, mispointing can occur along with issues relating to frequency, power and polarization, all of which can cause signal degradation and RF interference.
That said, instances of interference today have greatly reduced from the number of occurrences that were experienced in the past. Better tools are available for identifying sources of interference and operators have grown accustomed to working together to resolve interference problems. Mitigation techniques have also matured over time to the point where the primary industry focus is on prevention as opposed to only acting in response to an incident.
The unknowns
However, the way that space is being used is changing and there are several factors that have the potential to increase the risk of interference.
Operators are leveraging LEO, MEO and GEO orbits as well as integrating orbits in multi-orbit networks. Huge numbers of satellites are being deployed in mega constellations and this is causing the RF spectrum to be more congested. Additionally, LEO constellations are dynamic, and ground systems are complex: with more moving parts, there is greater opportunity for errors and interference.
“When an interference incident occurs, it doesn’t only affect the satellite network generating the interference. A single anomaly can have a ripple effect and impact the operation of other satellites and networks.”
Currently, there is also a lack of standardisation around operating performance for new style non-parabolic antennas. And within LEO, there is the potential that multi constellations may use the same bandwidth which could lead to intermittent interference which would likely be difficult to detect and resolve.
There is also the operational impact of 5G to consider. To be effective, a 5G network requires a high number of 5G cells, and there is a potential risk that these may cause spectrum overload, again resulting in interference.
It’s not yet clear exactly what impact each of these factors will have in terms of increasing the risk of interference, which is why it’s all the more important that all preventable and ‘known’ causes of interference are mitigated.
Preventing avoidable interference: the knowns
While the industry has become much better at understanding and preventing interference, there are still cases of engineers installing terminals incorrectly, as well as equipment failing. So, what can the industry do to ensure that all of these avoidable cases of interferences are avoided? This comes largely down to ensuring that best practices are adopted, which includes properly training personnel and carrying out regular and ongoing testing and maintenance of RF equipment.
It’s accepted now that field engineers and network operations personnel need to be qualified to install and maintain RF equipment, so that they can ensure that antennas are pointed correctly, polarization is correctly set, the signal is transmitted at the correct power, modem signals are correct, and cabling and connectors are all fitted correctly. But what about those instances when engineers are trained and certified but still make a mistake? We’re only human after all, and sometimes mistakes do happen. This is one reason why testing is so important. If an error does occur, provided regular and ongoing testing is carried out, any issues will hopefully be detected before they cause a major problem.
What about interference that comes from equipment failing or degrading over time? Equipment failure can be largely avoided if all equipment is subject to a regular testing program. Any anomalies will then be picked up before they become an issue. This way, maintenance can be carried out or replaced as required with minimal disruption to service and no interference generated by degradation or failure. Continuous and rigorous testing is really the only way to ensure that equipment is working as it should be at all times.
Room for improvement
There’s an awful lot going on in the satellite industry at the moment, much of which may increase the risk of interference as new technology and ways of operating are rolled out. It’s critical that we get even better at what we’re already doing to prevent known causes of interference from happening, so that the industry can focus it’s time and energy on ensuring that new causes of interference are managed and mitigated as much as possible.
