Desarrollo de una forma de onda GFDM con radio definida por software

In this paper the performance of a Generalized Frequency Division Multiplexing waveform is evaluated when compared to an Orthogonal Frequency Division Multiplexing signal. For the development of the previous waveforms, the GNU radio software and the Software Defined Radio (SDR) equipment USRP N210 are used. Through a spectrum analyzer the power of both waveforms are measured and the Out-of-Band Radiation is analyzed. Then, the results obtained are compared and the advantages and disadvantages of the implementation of GFDM as a waveform within the fifth generation systems are exposed.En este documento se evalúa el desempeño de una forma de onda GFDM (Generalized Frequency Division Multiplexing) que es comparada con una señal OFDM (Orthogonal Frequency Division Multiplexing). Para el desarrollo de las anteriores formas de onda se utilizan el software GNU radio y los equipos de Radio Definida por Software (SDR) USRP N210. Mediante un analizador de espectros se mide la potencia de ambas formas de onda y se analiza la Radiación Fuera de Banda (OOB). Luego, se comparan los resultados obtenidos y se exponen las ventajas e inconvenientes de la implementación de GFDM como forma de onda dentro de los sistemas de quinta generación

A hardware implementation for efficient spectrum access in cognitive radio networks

Opportunistic spectrum access is a propitious technique to overcome the under-utilization of spectrum bands. In this work, we design an experimental test-bed for evaluating an un-slotted spectrum access scheme under real indoor environment conditions. To this end, we use the USRP software defined radio platform along with the GNURadio software that incorporates the PHY and MAC functions and modules. Our contribution is multi-fold. First, we design a MAC protocol to integrate the packet based transmission of the coexisting PU/SU network, while compensating for spectrum sensing imperfection as well as collision detection faults. Second, we evaluate the USRP-induced latency (delay) and show that it has random behavior.We work around it to obtain a fixed packet transmission time which is crucial for the channel access scheme realization and evaluation. Third, we perform helping experiments to quantify the spectrum sensing imperfection in terms of false alarm and detection probabilities. We also quantify the imperfection in collision detection. Finally, we evaluate the performance of the whole channel access scheme and compare its results to the classical sense-transmit scheme. We show that 28.5% increase in SU throughput can be achieved for the same PU packet collision rate.Scopu