Broadband Spectrum Survey Measurements for Cognitive Radio Applications

It is well known that the existing spectrum licensing system results in a gross under-utilization of the frequency spectrum. Spectrum background measurements – spectrum surveys – provide useful data for spectrum regulation, planning or finding frequency niches for spectrum sharing. Dynamic spectrum sharing as a main goal of cognitive radio (CR) is the modern option on how to optimize usage of the frequency spectrum. A spectrum survey measurement system is introduced with results obtained from a variety of markedly different scenarios allowing us, unlike other studies, to focus on wideband and fast spectrum scans. The sensitivity of the receiver is no worse than -113 dBm in the whole band. The utilization of the frequency spectrum is analyzed to prove its under-utilization and to show spectrum sharing opportunities. This was shown to be true in the frequency band higher than 2.5 GHz. A comparison with other spectrum survey campaigns is provided

Resource management for QoS support in cognitive radio networks

Cognitive radio technology is a key enabler to reuse a finite, scarce, and expensive resource: the radio spectrum. Guaranteeing required levels of QoS to cognitive users and ensuring necessary protection to incumbent users are the two main challenges in opportunistic spectrum access. This article identifies the main requirements and challenges for QoS support in cognitive radio networks. A framework for a twofold cognitive manager is presented; one part managing spectrum availability on longer timescales and the other handling resource management on shorter timescales. This article gives particular focus to the functionalities of the latter cognitive manager related to resource management. Finally, we present a few key scenarios and describe how QoS can be managed with the proposed approach without disturbing the communications of incumbent users

Flexible architecture for spectrum and resource management in the whitespace

Abstract Spectrum resources unused in the spatio-temporal domain, so-called whitespace, can be utilised by opportunistic devices during the absence of their incumbent users. The possibility to opportunistically use whitespace implies the knowledge of diverse constraints: knowledge about whitespace utilisation, which can be obtained by spectrum sensing or from a data repository and constraints internal to the opportunistic system, such as quality of service (QoS) levels and mobility targets. The use of whitespace requires therefore a multi-faced management of the above constraints. In this paper, an architecture for use of whitespaces under QoS and mobility constraints is proposed. The proposed architecture flexibly adapts to different operating scenarios also described in this paper. Examples show how different realisations of the same architecture are derived. The interactions of constituent blocks are illustrated also with the help of charts, showing the management of context information and its use