Flexible Multicarrier PHY Design for Cognitive Radio in White Space

Abstract

Opportunistic use of White Spaces (WS) has opened up a whole new paradigm in research on cognitive radio (CR). One of the issues addressed by the QoSMOS project is the design of a flexible and efficient physical layer (PHY) for CR systems. To this aim, different modulation techniques are being investigated and are presented in this paper. They fulfill the low out of band leakage and spectral efficiency requirements of a CR operating in fragmented WS. The design of reconfigurable and flexible radio-frequency (RF) front-end is also introduced, since its performance is tightly linked to these parameters and to the implementation feasibility and constraints. Emphasis is put on benchmarking the performance of the proposed schemes over classical approaches.

Advances in opportunistic radio technologies for TVWS

“…[50] and Saltzberg [51] in the mid-1960s suggests combining filtering and multicarrier modulation techniques. This solution is becoming a strong contender to replace OFDM for CR applications [52], whenever drastic adjacent incumbent protection is required, as in the case of TVWS communication. This alternative solution is known as filter bank multicarrier communication techniques or FBMC.…”

Investigation of Techniques for Reducing Mobile Communication Systems Harmful Out-Of-Band Emission

“…Therefore, in applications where OFDM performs well, e.g., point-to-point transmission is an environment with low to medium mobility, OFDM may be preferred. FBMC, on the other hand, is expected to find applications in multiple access and cognitive radio networks (Datta et al 2011;Medjahdi, Terre, et al 2011;Schellmann et al 2014).…”

“…FBMC informacijos perdavimo būdas reikalauja didesnio duomenų apdorojimo sudėtingumo, lyginant su OFDM sistemomis (Renfors et al 2013;Premnath et al 2013). OFDM sistemos turi didelių pranašumų taškas-taškas tipo radijo ryšio sistemose, o FBMC lengviau įdiegiamas taškas-daug taškų bei kognityviojo pobūdžio sistemose (Datta et al 2011;Medjahdi, Terre, et al 2011;Schellmann et al 2014).…”

Coexistence of filter banks and CP-OFDM: What are the real gains?

“…A first way of studying the impact of the waveform used by the secondary user on the amount of interference injected onto the incumbent is to consider the width of the guard band that is necessary to protect the incumbent system. This is the approach followed for example in [5], [6], [11], [13], [15]. Here we study this problem in the following layout: we consider that the secondary and the incumbent users both use 20 subcarriers, and we measure the number of guard subcarriers that is necessary between them to reach the amount of protection expected by the incumbent.…”

“…This spectrum mask is usually specified by the standard followed by the incumbent users. CP-OFDM, suffering from poor spectral containment, can hardly fit efficiently in these spectrum masks and is therefore not efficiently applicable to secondary users [2], [3], [5], [6]. This observation has motivated the research community to look for new waveforms whose OOBE are decreased compared to CP-OFDM, so that the secondary transmissions could fit into the specified spectrum masks.…”