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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - SCREEN (Space Cognitive Radio for Electromagnetic Environment maNagement)

Teaser

Summary

The SCREEN project proposes to bring the concept of cognitive radio to Space and exploit the benefits that this technology has already shown in the terrestrial domain. The project will look into analysing, developing, implementing and testing cognitive radio algorithms for the different stages of the transceiver operation cycle: spectrum sensing, dynamic spectrum management (DSM) and decision making, radio reconfiguration and cognition/learning. The ground breaking element in SCREEN is however the implementation and testing. Even though some of the underlying technologies for the individual stages are not novel, the incorporation of all stages in a radio transceiver has never been done to the full extent of a cognitive, and not adaptive, system. It is also important to mention that one of the main concerns of SCREEN is to address all regulatory issues from the initial framework analysis and requirement definition, to the post-project exploitation and standardisation activities.

In short, the overall SCREEN objectives are to:
â€¢ Derive cognitive radio requirements based on the Satcom and ISL market needs and specifications and taking into account regulatory constraints.
â€¢ Analyse, select, develop and simulate cognitive radio algorithms for spectrum sensing, dynamic spectrum management and learning.
â€¢ Adapt an existing SDR platform based on the radio reconfiguration requirements and use it to implement the cognitive algorithms.
â€¢ Test, validate and evaluate the prototype in laboratory environment (TRL4/5).
â€¢ Derive an optimised CR S-band transceiver architecture, based on the performance results obtained and constraints identified during the tests.
â€¢ Address all regulatory issues and develop exploitation strategies to build an adequate framework to allow future implementations of cognitive radio in space.

Work performed

The project has concluded with all objectives fulfilled, all milestones successfully achieved and all deliverables submitted. The core of the technical work focused on studies on the different cognitive radio technologies, which have allowed a thorough review of the current state-of-the-art on the different fields and the selection and adaptation of the best for this particular application, and on the implementation and test of these techniques using a real off-the-shelf Software-Defined Radio transceiver. This approach of the SCREEN project has allowed to end the project with a TRL4/5 for a cognitive radio for space applications. The tests have shown adaptability and robustness of this approach and allowed to validate the use of SDR as the underlying technology for cognitive radio and to derive a CR architecture for future implementation.

The project results have been widely disseminated, focused on target communities due to its yet low level of maturity, but also reaching broader audiences and the general public. Conference papers, workshop presentations and press releases have been issued throughout the project and the public website and social media tools put in place have also reached a large number of followers. In the end, the project has allowed to develop a CR simulator, which has now the potential for immediate exploitation, and also a baseline architecture that, in the medium term, could originate a new product in the space market.

Final results

Since cognitive radio is a novel technology, the innovations beyond the current state of the art proposed and achieved by SCREEN can be roughly divided in two categories: those coming from the incorporation of cognitive radio technology in space applications and those brought by the project itself into the current research in the topic. The first is easy to understand, based on the considerations already presented in the previous sections. Cognitive radio revolutionises the way the communications spectrum is managed nowadays, going from static frequency allocations to adaptive and dynamic bandwidth usage, depending on the availability and performance requirements. Currently, there is no flexibility to adapt radio parameters in order to adapt them to the current needs. Frequencies are allocated beforehand and through a time consuming and complex process. Communications are then confined to that restricted part of the spectrum. The second category for innovation comes from evolving the maturity of the cognitive radio technology, when compared to on-going research in that area. These innovations are easier to identify, as they refer to practical achievements. At this level, SCREEN managed to raise the cognitive radio technology maturity levels from TRL3 to TRL4/5, which is a major breakthrough for a successful incorporation of the concept. SCREEN dealt essentially with implementation and representative testing of the CR algorithms and concept, unlike previous projects which focused on feasibility studies and algorithm simulation. SCREEN has faced the challenges of implementation and testing, such as real estate limitations, typical performance degradation or real-world constraints. This constitutes a major step towards concept validation and it also allowed defining a baseline transceiver architecture that is compatible with and optimised for cognitive radio algorithms.

The concept of cognitive radio was initially explored for terrestrial applications. The ability to decide at each moment and autonomously which part of the spectrum to use gives a level of flexibility, robustness and security in communications that is extremely attractive for defence applications. On the other hand, the ability to optimise the spectrum usage, which is a valuable resource in any application, is attractive by itself. 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. Particularly, it will enable major improvements in the two fields mentioned in the topic: technologies for flexible Satcom payloads and advanced ISL and downlink communications. 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. An example is the hybrid networks studied in the project MONET, introducing Satcom capability in mobile wireless networks to provide remote connectivity. The biggest impact in the Satcom segment is however in performance. However, in terms of future space missions, the flexibility of cognitive radio, supported by the underlying SDR technology, holds promising advantages to a wide range of mission types, especially those involving multiple satellite platforms. Missions such as formation flying, on-orbit servicing or LEO communication networks have critical requirements in terms of communication, since the platforms need to interact permanently to coordinate actions. Having the capability of sensing the environment and detect which frequencies are available and more reliable to communicate would ensure robustness for critical operations. The fact that the process is entirely autonomous is also fully compatible with the nature of this new generation of missions.