Software Defined Radio Architecture Research Articles

Proposed SAR range focusing algorithm based on simulation analysis and SDR implementation

Synthetic aperture radar (SAR) imaging systems use pulse focusing techniques for achieving fine range resolution and large range detection. Stretch processing and correlation pulse focusing techniques are the most popular algorithms used in the radar signal processing stage. The architecture of the stretch processing technique makes it commonly used in frequency modulated continuous wave (FMCW) radar systems due to its simple architecture, low sampling rate, and inexpensive hardware. This paper discusses how the stretch range focusing approach can be used instead of the matched filter technique in the processing stage of the SAR Range-Doppler algorithm (RDA) to generate images of finer resolution and higher quality. In addition, validating the proposed algorithm and evaluating its performance according to some evaluation indices such as peak sidelobe ratio (PSLR), integrated sidelobe ratio (ISLR), and the impulse response width (IRW). Also, this paper presents a comprehensive analysis and hardware implementation of the two SAR algorithms, based on software-defined radio (SDR) architecture where it is characterized by less complexity, low cost, and high flexibility due to the usage of both software data processing and software waveform generation. Two Universal Software Radio Peripheral (USRP-2932) and NI-LabVIEW® software development environment are the platforms used for the hardware validation process. The transmitted waveform is a linear frequency modulated (LFM) signal generated by the first USRP (transmitter) which will hit a target located at a certain distance. The second USRP is used as a receiver for target’s echo processing and detection. This processing stage contains two architectures, which are the matched filter pulse compression architecture and the stretch range focusing approach. Finally, the validation process of the hardware results is performed based on the pre-mentioned evaluation indices.

Wireless Communication Between Multi-FPGAs

PHY Layer implementation of the IEEE 802.11 a/g/n Wi-Fi standard using Software-Defined Radio (SDR) architecture. It addresses the challenge of implementing Wi-Fi on SDR platforms, which has been difficult due to the strict timing requirements of Wi-Fi protocols such as the Short Inter-Frame Space (SIFS) and the need for low-latency communication between the radio front-end and the processing unit. This architecture enables the implementation of the PHY (Physical layer) and low-level MAC (Media Access Control) functionalities in the FPGA, ensuring low latency and precise timing control. Key Words:

Software-Defined Networking Meets Software-Defined Radio in Mobile ad hoc Networks: State of the Art and Future Directions

The aims of this survey article are to elaborate on cross-layer optimization, Software-Defined Networking (SDN) and Software-Defined Radio (SDR) as separate domains of wireless network design for which a unified view has not been adequately considered to date and present lessons learned, with a view towards the challenges associated with SDN-SDR interaction that would facilitate benefits in cross-layer optimization of mobile ad hoc networks (MANETs). We focus on MANETs because ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${i}$ </tex-math></inline-formula> ) they are still at the forefront of technology, and in some scenarios they are the only meaningful option for establishing communication; ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ii</i> ) they expose the full potential and benefits of coexistence and interaction of SDN and SDR, in terms of optimizing key performance indicators. While SDN and SDR are mature technologies, their interaction and joint consideration have been largely overlooked. Current SDN approaches do not span the physical (PHY) and medium-access control (MAC) layers, but they rather concentrate on network-level routing and traffic flow optimization. As a result, PHY- and MAC-layer related parameters which notoriously affect key network performance metrics remain static or at best are adapted based on some heuristic or local approaches. On the other hand, the reach of SDR architectures is restricted to the PHY and MAC layers. We discuss the state of the art of cross-layer optimization, SDN and SDR, and current challenges associated with coexistence and interaction of SDN and SDR. Such an interaction would extend the span of SDN to PHY and MAC layers and lead to realizations of centralized approaches across all layers so as to control and optimize parameters, towards global network objectives. It would also create a bridge between centralized network control that is inherent in SDN and the distributed nature of MANETs, with the add-on features of flexible and fast PHY and MAC layer adaptation offered by SDR, for solid, autonomous and ultimately better network control implementations that span all layers, towards realizing and implementing the holy grail of real cross-layer optimization.

Recent advancement in the design of mixers for software‐defined radios

The implementation of software-defined radio necessitates a versatile radio frequency (RF) front-end that can support multiple standards in different frequency bands. This article presents the state-of-the-art multiband and wideband mixers in the context of different receiver architectures suitable for software-defined radio (SDR). Wideband and multiband mixer designs reported in the literature are categorized on the basis of their circuit architecture. This study tabulates the results of mixer designs with an emphasis on noise figure (NF), conversion gain (CG), linearity, and image rejection ratio. The best parameters reported in the comparison are 68–84 dB of CG, 3.2 dB of NF, 2.5 mW of power consumption, 12.5 dBm of third-order input intercept point, and 0.015 mm2 of area at different frequencies. The study also discusses the design challenges and techniques to overcome those issues. The article concludes with the summary and prospective developments for SDR architectures.

SDR-Based High-Definition Video Transmission for Biomedical Engineering

Background: Software-Defined Radio (SDR) frameworks from cellular telephone base stations, e.g., Multiservice Distributed Access System (MDAS) and small cells, employ extensively integrated RF agile transceivers. The Internet of Medical Things (IoMT) is the collection of medical devices and applications that connect to healthcare IT systems through online computer networks. Medical devices equipped with Wi-Fi allow M2M communication, which is the backbone of IoMT and associated devices linked to cloud platforms containing stored data to be analyzed. Examples of IoMT include remote patient monitoring of people with chronic or long-term conditions, tracking patient medication orders and the location of patients admitted to hospitals, and patients' wearables to send info to caregivers. Infusion pumps connected to dashboards and hospital beds rigged with sensors measuring patients' vital signs are medical devices that can be converted to or deployed as IoMT technology.&#x0D; Methods: This work proposes an SDR architecture to allow wireless High-Definition (HD) video broadcast for biomedical applications. This text examines a Wideband Wireless Video (WWV) signal chain implementation using the transceivers, the data transmitted volume, the matching occupied RF bandwidth, the communication distance, the transmitter’s power, and the implementation of the PHY layer as Orthogonal Frequency Division Multiplexing (OFDM) with test results to evade RF interference.&#x0D; Results: As the IoMT grows, the amount of possible IoMT uses increases. Many mobile devices employ Near Field Communication (NFC) Radio Frequency Identification (RFID) tags allowing them to share data with IT systems. RFID tags in medical equipment and supplies allow hospital staff can remain aware of the quantities they have in stock. The practice of using IoMT devices to observe patients in their homes remotely is also known as telemedicine. This kind of treatment spares patients from traveling to healthcare facilities whenever they have a medical question or change in their condition.&#x0D; Conclusion: An SDR-based HD biomedical video transmission is proposed, with its benefits and disadvantages for biomedical WWV are discussed. The security of IoMT sensitive data is a developing concern for healthcare providers.

Efficient co-design partitioning of WLANs on SoC-based SDRs

Software-defined radio (SDR) is a programmable transceiver with the capability of operating various wireless communication protocols without the need to change or update the hardware. Progress in the SDR field has led to the escalation of protocol development and a wide spectrum of applications, with a greater emphasis on programmability, flexibility, portability, and energy efficiency in cellular, WiFi, and M2M communication. SDR designers intend to simplify the realization of communication protocols while enabling researchers to experiment with prototypes on deployed networks. In this paper, we discuss the HW/SW co-design approach for SDR platforms in the context of wireless communication protocols. We offer a partitioning method of heterogeneous SDR architectures and then discuss the use of Xilinx SDSoC tool for accurate and effective system profiling. To demonstrate our method, we use IEEE 802.11a wireless standard to implement on the Xilinx Zynq-7000 System-on-Chip (SoC). We are able to achieve a significant speedup of 8.7 $$\times$$, compared to a software-only implementation. We also achieved a factor of 1.07 $$\times$$ improvement in terms of power consumption, compared to a hardware-only implementation. Optimization techniques are also adopted for further speedups, and their effectiveness enable us to achieve a speedup of 1.08 $$\times$$, compared to a hardware-only implementation.

Implementation of High Order QAM Modulation on SDR

Nowadays, SDR (software-defined radio) has increasingly occupied a place in scientific research and teaching with its powerful signal processing capability and custom ability. XSRP is a development platform which uses an SDR architecture. In this paper, we develop a wireless real-time audio transmission system with high order modulation (64QAM) based on XSRP platform. We use LabVIEW and MATLAB to write the program’s overall framework and functions. We also analyse the performance of different modulation modes by comparing the constellations and waveforms of the transmitter and receiver under the real situation. The results show that high order QAM modulation achieves a good balance between efficiency and quality.

LordCore: Energy-Efficient OpenCL-Programmable Software-Defined Radio Coprocessor

This paper proposes a single instruction multiple data (SIMD) processor, which is programmed with high-level OpenCL language. The low-power processor is customized for executing multiple-input-multiple-output (MIMO) detection algorithms at a high performance while consuming very little power making it suitable for software-defined radio (SDR) applications. The novel combination of SIMD operations on a transport programmed multicore datapath allows saving power on both the execution front end and the back end, leading to very good energy efficiency with a compiler programmable design. We demonstrate the feasibility of the architecture with the layered orthogonal lattice detector and minimum mean-square-error MIMO algorithms, which can be used as a software-defined radio implementation of the 3GPP local thermal equilibrium r11 standard. Compared to other state-of-the-art SDR architectures, the proposed design adds features that improve programmer productivity with an insignificant power and area impact.

The concept of a fully electronic beamforming antenna array for modern radar systems

AbstractIn this article the concept of a fully electronic beamforming antenna array for radar systems based on a SDR architecture is proposed and experimentally evaluated in an anechoic chamber. The system uses 2 software defined radio (SDR) transceivers with 4 independently controlled transmitters, allowing an individual digital control of both amplitude and phase of the signal fed to each element of an antenna array. It is also proposed a beamforming method that greatly reduces the sidelobes of the radiation pattern and it was compared to traditional beam steered radiation patterns. Moreover, the proposed architecture has the advantage of being modular, and therefore easily scalable, for larger and more powerful solutions based on the presented antenna array system.

Frequency Domain based Digital Down Conversion Architecture for Software Defined Radio and Cognitive Radio

This paper presents a sampling rate digital down converter that is totally based on frequency domain processing. The proposed DDC is targeted for Software Defined Radio and Cognitive Radio architectures. The proposed architecture is based on replacement of the complex multiplication with direct rotation of the spectrum. Different aspects of frequency domain filtering are also discussed. The Xilinx Virtex-6 family FPGA, XC6VLX240T is used for the implementation and synthesis of the proposed FFT-IFFT based architecture. The overlapping in time domain at the output of the IFFT block is avoided using overlap and add method. In terms area, highly optimized implementation is observed in the proposed architecture when compared to the conventional DDC. The synthesis results have shown that the developed core works at a maximum clock rate of 250 MHz and at the same time occupies only 10% of the slices of FPGA.

Radio Hardware Virtualization for Software-Defined Wireless Networks

Software-Defined Network (SDN) is a promising architecture for next generation Internet. SDN can achieve Network Function Virtualization much more efficiently than conventional architectures by splitting the data and control planes. Though SDN emerged first in wired network, its wireless counterpart Software-Defined Wireless Network (SDWN) also attracted an increasing amount of interest in the recent years. Wireless networks have some distinct characteristics compared to the wired networks due to the wireless channel dynamics. Therefore, network controllers present some extra degrees of freedom, such as taking measurements against interference and noise, or adapting channels according to the radio spectrum occupation. These specific characteristics bring about more challenges to wireless SDNs. Currently, SDWN implementations are mainly using customized firmware, such as OpenWRT, running on an embedded application processor in commercial WiFi chips, and restricted to layers above lower Media Access Control. This limitation comes from the fact that radio hardware usually require specific drivers, which have a proprietary implementation by various chipset vendors. Hence, it is difficult, if not impossible, to achieve virtualization on the radio hardware. However, this status has been changing as Software-Defined Radio (SDR) systems open up the entire radio communication stack to radio hobbyists and researchers. The bridge between SDR and SDN will make it possible to bring the softwarization and virtualization of wireless networks down to the physical layer, which will unlock the full potential of SDWN. This paper investigates the necessity and feasibility of extending the virtualization of wireless networks towards the radio hardware. A SDR architecture is presented for radio hardware virtualization in order to facilitate SDWN design and experimentation. We do believe that by adopting the virtualization-oriented hardware accelerator design presented here, an all-layer end-to-end high performance SDWN can be achieved.

NomadicBTS: Evolving cellular communication networks with software-defined radio architecture and open-source technologies

Utilization of software-defined radio (SDR) and open-source technologies in the next evolution of cellular communication networks may significantly reduce the capital expenditure (CAPEX) and operat...

Airborne Cognitive Networking: Design, Development, and Deployment

We design, develop, and experimentally validate a complete integrated software/hardware platform for airborne cognitive networking in both indoor and outdoor environments. We first present the concept of all-spectrum cognitive networking and describe a distributed algorithm for maximizing network spectral efficiency by jointly optimizing channel access code-waveforms and routes in a multi-hop network. We then discuss system design parameters and implementation details for setting up a software-defined radio (SDR) testbed that enables reconfigurability at the physical (PHY), medium-access control (MAC), and network (NET) layers of the network protocol stack, either by a user or by means of autonomous decisions. Our algorithmic developments toward spectrally-efficient cognitive networking are software optimized on heterogeneous multi-core general-purpose processor-based SDR architectures by leveraging the design of a novel software-radio framework that offers self-optimization and real-time adaptation capabilities at the PHY, MAC, and NET layers of the network protocol stack. We verify our system design approach in a large-scale testbed deployment of ten terrestrial and one airborne SDR platforms at the Stockbridge Controllable Contested Environment at the Air Force Research Laboratory, Rome, NY, USA. Proof-of-concept experimental results from both indoor and outdoor testbed deployments show that the proposed system can be used to build all-spectrum cognitive networks that withstand intentional interference at PHY and NET layers and can cognitively coexist with non-cross-layer optimized networks.

Increasing SDR Receiver Dynamic Range by ADC Diversity

Nowadays, most radio implementations are based on software-defined radio (SDR) technologies. The capabilities of digital signal processing enable new applications like low power wide area networks (LPWAN), which are expected to play a decisive role in the upcoming Internet of Things. Centralized gateways, usually realized in an SDR architecture, are used to connect many thousands of objects to the internet. Due to the high variance of the received signal level, a high dynamic range is required for the SDR receiver front-end. In current receiver architectures, the dynamic range is mainly limited by the analog-to-digital converter (ADC). Several techniques have been proposed to extend the dynamic range by stacking multiple ADCs and driving them with different gain factors. Correlation of quantization noise was identified as key parameter to determine the dynamic range enhancement. This paper compares the proposed techniques and extends existing analysis tools for the use of arbitrary gain factors. Additionally, the influence of further noise sources like thermal noise and jitter are taken into account. The theoretical considerations are supported by simulations and measurements using a real LPWAN SDR implementation.

Improvements in CPU &amp; FPGA Performance for Small Satellite SDR Applications

The ongoing evolution in constellation/formation of CubeSats, along with a steadily increasing number of satellites deployed in lower earth orbit, demands a generic reconfigurable multimode communication platform. As the number of satellites increase, the existing protocols combined with the trend to build one control station per CubeSat become a bottleneck for existing communication methods to support data volumes from these spacecraft at any given time. This paper explores the software-defined radio (SDR) architecture for the purposes of supporting multiple signals from multiple satellites, deploying mobile and/or distributed ground station nodes to increase the access time of the spacecraft and enabling a future SDR for distributed satellite systems. Performance results of differing software transceiver blocks and the decoding success rates are analyzed for varied symbol rates over different cores to inform on bottlenecks for field programmable gate array acceleration. Furthermore, an embedded system architecture is proposed based on these results favoring the ground station which supports the transition from single satellite communication to multisatellite communications.

A 2.4/5.2/5.8 GHz Triple-Band Common-Gate Cascode CMOS Low-Noise Amplifier

This paper presents a 2.4/5.2/5.8 GHz, triple-band, common-gate, cascode CMOS low-noise amplifier using only a band-selection switch that alters the equivalent LC tank and thus the resonant frequencies of the tank. The aspect ratio of the cascode MOS device is designed to optimize the gain–bandwidth product of the proposed low-noise amplifier so that wideband performance can be achieved. The proposed triple-band low-noise amplifier is suitable for use in the frequency-partitioning scheme that utilizes a wideband frontend with three medium-sized bands, to implement wideband RF frontend architecture for software-defined radio. Theoretical analyses of the input impedance, noise factor, and three resonant frequencies of the switched LC tank that show good agreement with the experimental results are also presented. The measured 3-dB bandwidths of the three bands of 2.4, 5.2, and 5.8 GHz are 720, 1080, and 910 MHz, respectively, which demonstrate the feasibility of the proposed design methodology. The proposed low-noise amplifier provides forward gains (\(\left| S_{21} \right| \)) of 10.6, 17.4, and 15.6 dB, with minimum noise figures of 4.96, 5.16, and 5.57 dB, for the three operation bands. A test chip with a die area of \(0.64\,\hbox {mm}^{2}\) was fabricated using a 0.18-\(\upmu \hbox {m}\) RF-CMOS process. The proposed triple-band low-noise amplifier consumes only 3.6 mW, excluding the buffer, from a supply voltage of 1.8 V.

Awireless passive radar system for real-time through-wall movement detection

In this paper, a reconfigurable real-time passive wireless detection system is described. The system is based on software-defined radio (SDR) architecture. The signal processing method and processing flow that enable through-wall target detection are introduced. The high-speed noise and interference mitigation methods implemented in the system for through-wall target detection are also described. A series of experimental results are presented for both large and small human body movements in through-wall scenarios. It is shown that the high-resolution Doppler event history implemented in the system enables the system to recognize and distinguish a range of body movements. The results demonstrate that this real-time SDR-based wireless detection system is a low-cost solution for human movement and recognition, with a range of applications.

FPGA-Based Realisation of SDR with OFDM Tranceiver

Software-defined radio architecture is the key point of next generation communication systems in which some of the functional units are designed as software on a reconfigurable processor. This paper proposes the physical layer architecture of SDR with modified orthogonal frequency division multiplexing (OFDM). One of the main drawbacks of OFDM is that its high peak-to-average reduction (PAPR) ratio. The PAPR can be reduced using filtering and adaptive peak windowing method with Kaiser window. The adaptive window method finds the positions of maximum peak values using a peak detector in the signal and applies the window function with variable parameter. The radix 2 scalable N point FFT algorithm is used in the system. The mapping of the information signal is done with BPSK, PSK, and 16 QAM modulation. According to the signal-to- noise ratio (SNR) value, the type of modulation can be selected. Decoding of the OFDM signal in the receiver is done with Viterbi decoding algorithm. The communication system simulation is done in MATLAB and the baseband operations are implemented on Xilinx FPGA. Defence Science Journal, Vol. 65, No. 3, May 2015, pp.233-239, DOI: http://dx.doi.org/10.14429/dsj.65.6011

Coarse Grained ADRES Based MIMO-OFDM Transceiver with New Radix- $${2}^{5}$$ 2 5 Pipeline FFT/IFFT Processor

Software defined radio (SDR) is an adaptive radio that sense and adjust the operating parameters based on the environment. MIMO-OFDM technique based SDR transceiver is an advanced technique over the conventional radio system in terms of complex adaptation strategies. To improve the performance of the OFDM architecture, a new algorithm was developed for FFT/IFFT unit called the radix-$${2}^{5}$$25 modified booth encoding algorithm. This paper describes the system-on-chip (SoC) implementation of MIMO-OFDM transceiver architecture for SDR. This architecture design is based on the concept of reusing the same software and hardware modules to handle different algorithms with the help of dynamic reconfigurable system. It provides a greater flexibility in the operation of reconfigurable system; also it can able to add new abilities into it, without adding additional hardware. The SoC functional verification of this transceiver circuit was carried out in the Xilinx Virtex 5 FPGA, on top of the ADRES reconfigurable SoC architecture. The result shows that the proposed method provides a greater performance by two times than the previous works. It had provided a high throughput (2.4 Gsample/s) with low latency (2.941 ns) and less area utilization (27k logic gates).

A Real-Time Implementation of the Mobile WiMAX ARQ and Physical Layer

This paper presents an innovative software-defined radio architecture for the real-time implementation of WiMAX transceivers. The architecture consists of commercially available field-programmable gate array and digital signal processor modules. We show how the architecture can be used for the real-time implementation of a full-featured standard-compliant time-division duplex WiMAX physical layer together with the ARQ functionality of the MAC layer. Both the mobile and the base station contain a transmitter and a receiver to enable real-time concurrent downlink and uplink communications. The design supports the different configurations defined by the standard and the WiMAX Forum. This work also provides the verification and validation of the proposed real-time implementation based on repeatable and reproducible performance evaluation considering the reference scenarios defined by the WiMAX Forum, including both static and mobile scenarios. Typical figures of merit such as physical-layer bit and frame error rates and MAC-layer throughput are obtained with the help of a custom-made real-time channel emulator implementing the channel models defined by the WiMAX Forum.