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We investigate the problem of beamformer design for communications systems coexisting with legacy radar systems with mechanically rotating antennas. Based on measurement campaign findings that support the assumption of fast decoherence for the radar-to-base station interference within a radar rotation, as well as the assumption of very strong correlation of interference channel realizations corresponding to the same radar rotation phase, we introduce beamforming solutions exploring these channel characteristics, without imposing the need for current channel state information. Different beamformer designs are proposed, characterized by different levels of computational complexity, that are applicable both in the case of synchronous systems, where the communication system is aware of the radar rotation phase, as well as in the case of asynchronous systems.

Description of network services for each Facility-site. Includes configuration of Infrastructure, RAN, Core and MANO components and of the interconnections among them. Used as a reference for the orchestration and testing activities. Description of the cross Facility-site services and interconnection requirements and configurations.

The escalating interest on the topic of coexistence between radar systems and broadband communication devices is a direct consequence of the significant portion of the international radio spectrum currently allocated to radar systems. However, studies show that their spectrum occupancy is low in the spatial, temporal, and frequency domains. The most promising radar bands for shared use are the L, S, and C bands located in the 960-1400 MHz, 2.7-3.6 GHz, and 5.0-5.85 GHz frequency ranges, respectively. These frequencies are sufficiently low to avoid high power consumption and the usage of highly directional antennas, and sufficiently high to offer considerable bandwidth to commercial services. Furthermore, they are close to the cellular and ISM bands used for 2G/3G/4G and wireless local area networks (WLAN), respectively, facilitating the production of low-cost devices capable of using all these frequencies.

This work leverages recent advances in machine learning for radio environment monitoring with context awareness, and uses the obtained information for creating radio slices that can optimally coexist with ongoing traffic in a given spectrum band. We instantiate radio slices as virtualised radios built on a software-defined radio platform. Then, we describe a proof-of-concept experiment that validates and demonstrates our proposed solution.

This paper describes the design, experimental assessmant and Software Defined Radio (SDR) implementation of a Secondary User (SU) link for the IEEE DySPAN Challenge 2017. The objective is to successfully discern the behavior of and coexist with a Primary User (PU), whose channel access patterns vary over time. For that end, we utilize sensing, deep learning and dynamic optimization.

Opportunistic access has been considered by regulators for a number of different spectrum bands. In this paper, we discuss and qualitatively evaluate techniques used in the discovery of spectrum opportunities, also called white spaces, in the radar, TV, and cellular bands. These techniques include spectrum sensing, cooperative spectrum sensing, geolocation databases, and the use of beacons. We make the case that each of the three bands considered calls for a different set of spectrum access techniques. While TV bands are well matched to the adoption of geolocation databases, a database-assisted spectrum sensing mechanism may represent the most efficient solution to exploit the spectrum holes in radar bands. We drew this conclusion based on a multitude of factors, such as the radar antennas' constant motion, and the absence of a hidden node problems in these bands. The unpredictability of cellular systems, on the other hand, calls for a more coordinated spectrum access approach, namely beacon signaling, that could be implemented using the already established cellular infrastructure and spare bits of its logical channels.

The need for extra spectrum to support future 5G networks and the fact that a large amount of spectrum below 6 GHz is allocated for different radar systems have motivated regulatory bodies and wireless researchers to investigate the feasibility of Dynamic Spectrum Access (DSA) in radar bands. Moreover, the next generation of infrastructures and devices will need to be more flexible to support a much wider range of application services, operate over much wider bandwidths, and exploit multiple radio access technologies. Radio Environment Maps (REMs) can be utilized to enhance the awareness of network entities of their operational radio environment. In the context of potential spectrum sharing in radar bands, REMs can be used to determine spectrum usage and propagation patterns of different incumbent radar systems operating in a given area. This information in turn can be utilized to establish different radar systems protection requirements in a particular band, and can also help to mitigate any interference between incumbent radar systems and Secondary Users (SUs). In this paper, based on spectrum measurement campaigns in Finland and Ireland, we explore the functional architecture of REMs for potential spectrum sharing in radar bands. We argue that the unique operating principle and signal characteristics of this type of incumbent needs to be considered in implementation of the sensor network, REM communication protocol, and REM architecture. We also discuss the potential of REM to facilitate the use of more advanced interference cancellation or avoidance technologies such as temporal sharing that can significantly reduce exclusion zones.

The goal of this paper is to construct a dynamic Secondary User (SU) link that can successfully coexist with a Primary User (PU).

Temporal sharing has been suggested in the literature as a promising approach to tackle the inefficiencies that result from the use of Geolocation Database (GL-DB) access technology, by enabling the Secondary Users (SUs) to operate inside radar systems' exclusion zones, whenever the radar antennas are pointing away. While several studies have been made to quantify the number of spectrum opportunities potentially obtained through the use of such mechanism, none of them focuses on how it would be implemented on a real-time radio system. We address this absence of experimental work by implementing a temporal sharing mechanism in Software Defined Radio (SDR) using Iris framework and Ettus USRP N210 hardware as RF front-ends. To better illustrate its performance and flexibility to adjust to a time-varying radio environment we built a Graphical User Interface (GUI) that enables the configuration of the SDRs' operating parameters on-the-fly and the visualization of metrics, such as interference to the radar system and throughput of the SU.

Regulatory bodies worldwide are currently considering opening up radar bands to more dynamic spectrum access techniques. There is, however, a lack of experimental testbed models to support experimental investigation of spectrum sharing with radar systems. This paper describes an experimental framework capable of emulating a wide range of radar systems and recreating their effects on devices sharing its spectrum. We implemented our models using the Iris software-defined radio system and USRP N210 radio front-end hardware. We demonstrate our system's support for various forms of intra-pulse modulations, beam shapes, and elevation angles.

Coexistence between radar systems and low-power broadband devices has recently become a focus of research by regulators, industry and academic bodies, with the possibility of sharing the 3.5 GHz band indicated by the Federal Communications Commission (FCC) in 2012. Radar bands are seen as attractive candidates for Dynamic Spectrum Access (DSA) due to the large portion of spectrum they occupy and their spectral occupancy being fairly low. However, the current reliance on Geolocation Database (GL-DB) spectrum access techniques for protecting radar systems from interference leads to large exclusion zones and inevitably will block a great percentage of the world population from benefiting from this spectrum. In this paper, we analyse the adequacy of cognitive beamforming as a technique employed by small cells to reduce caused interference on radar systems and, consequently, decrease their exclusion zones' sizes. We start by discussing the impact the radar systems' antenna rotation has on the dynamics of the interference channel and what challenges it brings to the design of a cognitive beamforming technique with guaranteed performance. We then propose a GL-DB-aided beamforming scheme, where a centralized GL-DB defines an exclusion zone size matching the cognitive beamforming capabilities of the small cell evolved Node Basestation (eNB) querying for spectrum access. We show that when an eNB dedicates 4 antennas to cancelling its interference to a radar, exclusion zones can be reduced by approximately 40 km. We also studied the degrading effect cognitive beamforming may have on the small cells' throughput and propose, as a solution, an adaptive scheme that selects the best beamforming strategy to use based on the distance between the radar and the small cell.

In this paper we present an approach towards empowering online telecommunications engineering education by enabling hands-on remote experimentation over Trinity College Dublin's wireless testbed. Moreover, in order to offer a flexible testbed, capable of fulfilling the different and particular requirements of experimenters, we have created a framework that allows the virtualization of our testbed resources to create experimentation units to be used by remote experimenters/learners. Furthermore, we present the FORGEBox framework that offers an environment and resources to create online material capable to access the virtualized and physical testbed resources for incorporating experimentation into HTML-based online educational material.

The considerable amount of spectrum reserved for but underutilized by radar systems has motivated several regulatory bodies to make Dynamic Spectrum Access (DSA) in radar bands a reality. Taking into account the incumbents' very long ranges, one of the main issues of DSA in these bands is the aggregate interference, derived from multiple secondary users (SUs) operating in the same channel. In this paper, we assess the impact of this phenomenon when spectrum sharing is performed in a totally opportunistic manner, for instance, when Dynamic Frequency Selection (DFS) developed by the IEEE 802.11h standard is employed, and when there is a cooperation mechanism between radar systems and SUs. We considered the operating characteristics of a real C band meteorological radar system with acceptable levels of interference standardized by the International Telecommunication Union (ITU).

In this paper, we describe the original problem statement and the two winning solutions to the IEEE DySPAN Challenge, organized in Baltimore in 2017. The idea of the challenge was to invite teams to propose as diverse as possible solutions to a well defined problem, and evaluate the performance of the proposed solutions in a realistic environment. The challenge is defined to enable benchmarking and comparison of multiple teams, possibly working on different parts of the system, in a real environment. The winning solutions represented a complete and working system, working robustly and adapting to both anticipated scenario changes, as well as random effects caused by the conference setting. The code for running the challenge along with the winning solutions is publicly available, so that interested teams can start from the code when designing or benchmarking solutions, as well as when setting up own challenges and competitions. As a result, the challenge can serve as a milestone toward the creation of a benchmarking series. This paper contains all the necessary details about the software repositories so that it becomes possible to rerun the challenge and start building novel solutions based on the winners in IEEE DySPAN 2017.