Software Defined Radio Paradigm Research Articles

Development of an Affordable FPGA Board for Advancing Software-Defined Radio Research in Auchi Polytechnic

This paper detailed the design and development of an affordable software-defined radio (SDR) system tailored for academic environments at Auchi Polytechnic. The system integrated a moderately fast analog-to-digital converter (ADC), an audio digital-to-analog converter (DAC), and an off-the-shelf field-programmable gate array (FPGA) for digital signal processing. The primary objective was to enhance the teaching of fundamental engineering concepts related to communications. To demonstrate its capabilities, the system included hardware blocks for demodulating amplitude modulation (AM) and frequency modulation (FM) signals. This approach provided a cost-effective solution for advancing SDR research and education. The SDR paradigm, which replaces traditional hardware configurations with flexible software-based solutions, has revolutionized communication receivers. Incorporating SDR into undergraduate curricula has become increasingly valuable, offering students hands-on experience with cutting-edge technologies and skills relevant in both academic and industrial settings. While commercial SDR solutions such as the RTL-SDR dongle offer an accessible introduction to SDR concepts, they often fall short in providing a deep understanding of the underlying principles and design intricacies. To address this educational gap, the developed SDR platform aimed to offer practical experience and delve into the fundamental principles of SDR design, leveraging advancements in digital technologies like FPGAs and ADCs to create a cost-effective, educational SDR system.

Performance Comparison of Energy Detection Based non – Cooperative Spectrum Sensing Techniques in Cognitive Radio

Cognitive radio is a ground-breaking software-defined radio paradigm that offers Dynamic spectrum access, allowing secondary users to use the frequency band allotted to the principal user when it is not in use and vacate when the prime application returns. The ability to sense the spectrum is critical to cognitive radio's efficiency. Energy detection sensing is the simplest and most often used spectrum sensing approach, owing to its ease of implementation in cognitive radio applications. The three-energy detection-based algorithms adopted for different scenarios have been compared in this study. The algorithms include the double-threshold energy detection, adaptive single threshold energy detection, and the adaptive double threshold spectrum sensing algorithm. Since the noise prediction in the practical situation is difficult, the necessity is to find the best algorithm in this condition. The other equally important parameters for efficiently sensing the spectrum are spectrum efficiency and less interference to the primary user. Simulation findings show that the adaptive double threshold approach outperforms the other two algorithms in all respect. The detection probability of the method is typically found to be substantially greater as compared to other two techniques. In addition, the likelihood of a false alarm is significantly reduced. Furthermore, when the signal-to-noise ratio value is low, often below -5dB, the performance of this approach is poor. MATLAB is used to run all of the simulations.

Design of a Configurable Monitoring Station for Scintillations by Means of a GNSS Software Radio Receiver

This letter addresses the design and implementation of a monitoring station for Global Navigation Satellite Systems signals based on the software-defined radio paradigm. The monitoring platform exploits a digital data grabber based on the use of Universal Software Radio Peripheral devices and a satellite navigation fully software receiver; with respect to a traditional commercial receiver, this implementation solution grants a higher level of flexibility for the processing strategy, enabling the possibility of a deeper analysis of the signals in case of meaningful events, such as ionospheric scintillations or radio frequency interference, through the storage of raw samples. Such an implementation approach yields valuable advantages in critical and remote areas, such as polar regions, where resources are limited and installation, maintenance, and replacement of hardware may be critical.

Multi-Band Software-Defined Coherent Radar Based on a Single Photonic Transceiver

In this paper, a photonics-based architecture of a multi-band coherent radar system is proposed and validated. The precision and flexibility of photonic technologies are exploited for generating and detecting simultaneously multiple radar signals in an extremely wide frequency range. Moreover, the fully digital approach enables the software-defined radio paradigm, allowing the flexible use of several advanced radar techniques such as waveform diversity or frequency hopping. The proposed architecture is therefore promising for future radar systems that need to adapt to different scenarios for improved situation awareness. The proposed system exploits a single laser unit for the multiband transmitter and receiver sections, reducing the architectural complexity with potential benefits on system dimensions, cost, and reliability. This paper details the principle of operation of the proposed multi-band coherent radar system, and describes the implementation of a proof-of-concept dual-band transceiver operating in the X- and S-bands simultaneously and independently. The results from the characterization of the transceiver are presented. The system validation through the coherent detection of moving targets confirms the suitability of the proposed solution, laying the basis for a new paradigm of radar systems.

In-Field Experiments of the First Photonics-Based Software-Defined Coherent Radar

The complete scheme of the first photonics-based fully digital coherent radar system demonstrator is presented. The proposed architecture relies on a novel flexible photonic transceiver, based on the software-defined radio paradigm, capable of generating and receiving signals with arbitrary waveform and carrier frequency. The system core is a single mode-locked laser, whose inherent phase and amplitude stability allows generating high-quality carriers over an extremely broad frequency range, as well as directly digitizing high-frequency signals with unprecedented precision. The implementation of the field trial demonstrator is presented in detail, focusing on both the photonic transceiver and the antenna's front-end, as well as on the employed digital signal processing. The excellent performance is proved by the results of the in-field experiments carried out with noncooperative targets in real scenarios. The outcomes from the aerial and naval target detections are here presented and discussed.

Adding accurate timestamping capability to wireless networks for smart grids

Smart grids rely on bi-directional communications between energy production sites and utilization sites. Usually, different approaches are used for implementing the required Wide, Field, and Home Area Networks (WAN, FAN and HAN, respectively). These networks are realized using very different (hybrid) technologies, for instance wired for WAN and wireless for FAN and HAN. However, an accurate common sense of time must be guaranteed among all smart grid participants, as it happens in any other distributed systems. Satisfying this need is challenging for wireless networks, while mature time distribution technologies are available for wired networks. The major issue for wireless devices is to provide accurate timestamping of network events, the key element of any time synchronization protocol. The objective of this paper is to propose low-cost and low-complexity timestamping techniques that also maintain full compatibility with already existing (unlicensed) communication standard for wireless nodes used in smart grids. In addition, a suitable platform exploiting the Software Defined Radio paradigm for comparative evaluation of these techniques is also discussed. Simulation and experimental results confirm the feasibility of the proposed approach, with the standard deviation of the timestamping error scalable down to 5ns.