Spinning-in of new enabling technologies to space systems
Spinning the cognitive radio concept into space communications will lead not only to drastic improvements but also enable new approaches and a new generation of emerging missions based on multiple satellites, such as formation flying, on-orbit servicing or LEO communication networks. These missions have critical requirements in terms of communication, since the platforms need to interact permanently to coordinate actions. For the Satcom market, the focus of SCREEN, cognitive radio can enable different approaches for managing the growing satellite communication demands and provide flexibility to explore new types of hybrid networks. Of particular interest are the LEO communication networks. These can be seen as temporary Satcom networks, since their goal is to provide communication capability in specific locations. With the recent emergence of inexpensive small satellite platforms, such as CubeSats, LEO missions are starting to be attractive, despite their limitations in longevity. Either for emergency-relief scenarios or for local connectivity, small CubeSat networks with cognitive radios on-board could easily deploy communications capability and manage their spectral usage efficiently, to allow higher throughput and to reduce their own power consumption requirements.
Improving communications performance
The ability to dynamically and autonomously decide which part of the spectrum to use provides a level of flexibility, robustness and security in communications that is extremely valuable in any application. For the defence market, such capability provides protection to environmental signal degradation or deliberate jamming. Ultimately, this leads to lower power consumption, which is a significant performance improvement in any scenario. Apart from improving the quality of the communications, a cognitive radio can also make use of its learning capability to identify patterns on spectrum behaviour or user demand, which greatly improves the speed of the cognitive cycle, reducing latency whenever changing to a different part of the spectrum.
The same benefits also apply in space and especially in the Satcom segment, where the services provided need to ensure quality, so that the operator can be competitive in the market. Instead of reserving a fixed band within the regulatory constraints, a Satcom operator would benefit from having the flexibility to allocate frequency slots dynamically, according to the instantaneous traffic patterns. Ultimately, by optimizing the spectrum management and allocation, a Satcom operator can accommodate more users at the same time, without sacrificing the network performance.
The costs involved with using cognitive radio must be assessed against the benefits of optimising the spectrum usage. The added capacity coming from the optimisation is expected to generate additional revenues coming from a larger number of users. Cognitive radio can also solve critical interference issues that undermine the true capability of the satellite communications. In the long term, the benefits of cognitive radio will compensate the investment made in developing and maturing the technology. In terms of space missions, cognitive radios can also help to reduce costs, taking into account their flexibility. Since the transceivers are based on Software-Defined Radio technology, they can be modified before or after launch and during the mission operations. This brings great advantages in terms of mission reliability and lifetime and is also adaptable to technology upgrades and changes in the regulations.
Incorporation of new partners into space
Since most of the technical and regulatory challenges in Space have parallels with those on the Ground, if the space market opens its doors to terrestrial technology, the partners that have the background and the expertise will follow naturally. It has recently been found that opening the space market to the spin-in of terrestrial technologies can bring fresh ideas to address new problems and challenges that in fact are not very different from those faced on Earth. This speeds up the incorporation of new technologies and makes space a more attractive market to invest.
Cognitive radio is a terrestrial state-of-the-art technology that has been researched to solve the problem of having a more efficient usage of the communications spectrum to cope with the ever-growing demand for reliable and robust wireless communications. The same challenge exists in space and the spectrum saturation will soon be a major concern to be addressed. Since the underlying concept has an application in space and since SDR, the key enabling technology, has already been successfully used in orbit, cognitive radio can be implemented for space applications and provide the same solutions as on Ground to solve similar problems.
Developments affecting a range of sectors
SCREEN is expected to have an impact on the future of ISLs and TT&C subsystems, especially for the novel trends in multi-satellite collaborative missions. However, given the flexibility of SDR platforms, there are other areas that could benefit from this technology developments and concept maturity, inside and outside the space market. The Ground segments, for instance, would also need to incorporate the technology to be able to track and communicate with the satellites using cognitive radios. One attractive Ground segment corresponds to mobile communications, which has massively evolved and grown in the last decade. Mobile phones could definitely benefit from cognitive radio technology to deal with the signal coverage gaps in remote areas or the overcrowded areas in urban environments.
Improving innovation capacity
The potential of cognitive radio in space has been addressed in projects such as ACROSS, CoRaSat, GAMANET, CORASMA and CO2SAT. SCREEN creates a bridge between the already implemented SDR systems for space applications and future cognitive satellite networks, improving the capacity for innovation in space communications with the implementation of future systems that are more efficient, flexible, adaptable, allowing automatic and adaptive deployments, and increasing the capacity in the S-band. The cognitive network idea is already being studied but, in general, thinking of cognitive radio as an enabler, many other concepts will surely appear once this capability is in place, building a foundation to foster and increase the overall innovation capacity in space.