Experiences in the co-design of software and hardware elements in a SDR platform

The Center for Telecommunications Value-Chain Research (CTVR) has developed an integrated software radio platform that combines a reconfigurable hardware radio platform, called NUIM SDR transceiver, and a modular software radio framework, called Implementing Radio in Software (IRIS). This paper outlines the design challenges in achieving the integration between these two systems, and also presents experimental results. The test consists of transmitting an image file using DQPSK modulation with IRIS and the Universal Software Radio Peripheral (USRP) RF front-end at 2.41GHz, and receiving it with IRIS and the NUIM SDR transceiver. The integrated software radio platform presented in this paper enables new research opportunities testing real-world environments and developing cognitive radios for dynamic spectrum access techniques

Multiband OFDM for Cognitive Radio – A Way for Cyclostationary Detection and Interference Cancellation

With the tremendous growth in wireless technology there has been a shortage in the spectrum utilized for certain applications while some spectrum remains idle. To overcome this problem and for the efficient utilization of the spectrum cognitive radio is the suitable solution.Multiband OFDM can be easily modeled as cognitive radio, a technology that is employed for utilizing the available spectrum in the most efficient way. Since sensing of the free spectrum for detecting the arrival of the primary users is the foremost job of cognitive, here cyclostationary based spectrum sensing is carried out. Its performance is investigated using universal software defined radio peripheral (USRP) kit which is the hardware test bed for the cognitive radio system. Results are shown using Labview software. Further to mitigate the interference between the primary and cognitive users a modified intrusion elimination (AIC) algorithm had been proposed which in turn ensures the coexistence of both the users in the same wireless environment

A General Framework for Analyzing, Characterizing, and Implementing Spectrally Modulated, Spectrally Encoded Signals

Fourth generation (4G) communications will support many capabilities while providing universal, high speed access. One potential enabler for these capabilities is software defined radio (SDR). When controlled by cognitive radio (CR) principles, the required waveform diversity is achieved via a synergistic union called CR-based SDR. Research is rapidly progressing in SDR hardware and software venues, but current CR-based SDR research lacks the theoretical foundation and analytic framework to permit efficient implementation. This limitation is addressed here by introducing a general framework for analyzing, characterizing, and implementing spectrally modulated, spectrally encoded (SMSE) signals within CR-based SDR architectures. Given orthogonal frequency division multiplexing (OFDM) is a 4G candidate signal, OFDM-based signals are collectively classified as SMSE since modulation and encoding are spectrally applied. The proposed framework provides analytic commonality and unification of SMSE signals. Applicability is first shown for candidate 4G signals, and resultant analytic expressions agree with published results. Implementability is then demonstrated in multiple coexistence scenarios via modeling and simulation to reinforce practical utility

Spectrum sensing through software defined radio

Dissertação apresentada para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaA change in paradigm when it comes to controlling radio transmissions is in course. Tasks usually executed in an exclusive class of hardware systems are increasingly controlled by software systems. A deep change to the software domain is foreseeable, creating a true Software Defined Radio. At the same time this change occurs, the radioelectric spectrum is almost completely licensed. However, the spectrum is rarely used to its full extent over time, enabling its opportunistic use while the licensed devices do not communicate. This is a part of the notion of Cognitive Radio, a new kind of radio capable of using the spectrum in an opportunistic way. These two new paradigms in radio access can be combined to produce a exible and reliable radio, overcoming the issues with radioelectric spectrum scarcity. This dissertation starts an exploration in this area by combining these two paradigms through the use of an Energy Detector implemented in a Universal Software Radio Peripheral device and using the GNURadio suite. The performance of such a system is tested by calculating the Probabilities of Detection and False Alarm in real scenarios and comparing them to the expected theoretical values. A method for defining thresholds for narrowband signals is also tested based on works in Information Theory concepts, i.e.,the Akaike Information Criteria and the Minimum Description Length. The results are tested for a real transmission using two USRP platforms communicating with each other,one acting as the licensed user and the other acting as the secondary, opportunistic user. Finally, we highlight the technological work developed in this dissertation, which may support future research works through the use of the developed scripts, allowing a faster method to test algorithms with different parameterization

On the Deployment of Cognitive Relay as Underlay Systems

The objective of this paper is to extend the idea of Cognitive Relay (CR). CR, as a secondary user, follows an underlay paradigm to endorse secondary usage of the spectrum to the indoor devices. To seek a spatial opportunity, i.e., deciding its transmission over the primary user channels, CR models its deployment scenario and the movements of the primary receivers and indoor devices. Modeling is beneficial for theoretical analysis, however it is also important to ensure the performance of CR in a real scenario. We consider briefly, the challenges involved while deploying a hardware prototype of such a system.Comment: 6 pages, 7 figures, 4 tables, accepted in Proceedings of CrownCom 2014, Oulu (Finland), June 2-4, 201