Wideband and connectivity are important, but the future of satellite communication also involves resilience. In an era of increasing cyber warfare and electronic attacks, reliance on satellites makes them a mark. That's why the development of a dynamically controlled satellite hub is noteworthy. This innovative technology has the potential to transform transponded satellite systems from vulnerable targets into adaptable, self-defending networks, ensuring critical communications stay online.
Dr. Khanh Pham, a supervisory principal aerospace engineer at the Air Force Research Laboratory (AFRL), has an extensive background in satellite communications. He was recently awarded a patent for the dynamically controlled satellite hub, a technology geared toward improving the efficiency and resiliency of satellite communications.
“The purpose of this patent is to increase autonomy or automation for the ground hub and ensure that the flexible coordination of joint transmission and the uplink resource allocation for those terminals are efficiently planned and also fair,” said Dr. Pham, who’s been awarded additional patents involving satellite communications. “You want to connect all those terminals, whether they are important or not, and ensure they have a fair chance for connectivity to operate, meeting their application performance requirements. So, that's an important objective for the satellite system controller and the ground hub.”
Dr. Pham's innovation tackles a major challenge in satellite communications: how to efficiently manage limited resources (by selecting the uplink carrier powers for transponded links, maintaining the total downlink power at the hub receiver and adjusting the signal quality requirements for the chosen link waveforms), especially when facing interference or attacks. His smart satellite system controller acts like a traffic manager for connected terminals all within the constraints of a bent-pipe satellite transponder – where the connection goes up to the satellite and comes back down – with the shared communication resources and uniform channel gains.
By automatically adjusting the power of signals via return-link communication resource activations sent up to the satellite transponder, based on real-time monitoring of changing link conditions, the ground hub, equipped with his innovative satellite system controller ensures that critical communications get through, even in tough radio environments. This is particularly important because current satellite systems often struggle with uplink interference and shared powers, which can lead to dropped signals and communication failures.
“Our newly patented satellite system controller technique stands as a significant leap forward in enterprise management and control performance, effectively preventing and mitigating potential losses while ensuring that warfighters maintain their operational capabilities,” Dr. Pham said.
With applications spanning military and commercial, this technology transforms satellite communication capabilities, allowing users to outpace rivals across different scopes.
“Any connectivity has to reach the area underdeveloped by 5G or terrestrial communication, and satellite communication is a good way to reach those areas,” Dr. Pham said. “However, they oftentimes operate the same way, using a bent-pipe, meaning the terminal connectivity must go up to space and then go down. So, the operation is the same. This setup mirrors a provider backbone bridging network, seamlessly connecting user networks to both the user terminals and the ground hub’s reach-back networks.
“The satellite transponder is only relaying, amplifying and forwarding. If these transponders are being jammed, then nothing will be possible for communication. So, it happens for commercial satellite communication, as well.”
A significant asset for Dr. Pham’s dynamically controlled satellite hub is its ability to accelerate connections around satellite communications.
“Man-in-the-loop interactions with satellite or network operations center for satellite access request and satellite access authorization have to be coordinated in advance,” he said. “These two processes, in addition of traffic demand reports, fairness policies, etc., take a long time in coordinating. Statistics have shown that it takes weeks or months in advance.”
That will change with this technology, reducing responses from weeks or months to minutes.
“If you put in a new process, you have an intelligent satellite system controller that will automatically look across all requests from all terminals using a feedback control framework and multi-layer pre-qualifications for link supportability, and you’ll be able to do reliable dynamic resource allocation for those requests using the minimum cost variance control theory. To this end, autonomous adjustments of the strength of the signals transmitted from terminals work by minimizing the variance of a closed-loop performance measure, while keeping its average within an acceptable range. This measure involves continuously monitoring the actual strength of total downlink signals in relation to the noise, considering the effects of transponder power robbing, and ensuring that the strength of downlink signals relative to the noise at the hub receiver does not exceed the maximum allowable limit,” Dr. Pham said.
“That will reduce a lot of the man-in-the-loop hours and be able to let the machine do what they do best in terms of computational aspects, which machines can do better than humans. So, the humans are still on the loop and control the behavior of the satellite hub, as well, but at a higher level so they can deal with something related to the priority of the mission the warfighter needs.”
As an expert in the field, Dr. Pham sees even more optimism from this innovation.
“This line of work can be further developed,” he said.
United States Patent Office Patent: #12, 133, 210
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