A radio control board passes a plurality of digital samples between a memory of a computing device and a radio frequency (RF) transceiver coupled to a system bus of the computing device. Processing of the digital samples is carried out by one or more cores of a multi-core processor to implement a software-defined radio.

Software-defined radio using multi-core processor

Embodiments include processes, systems, and devices that allow a white space base station to request available frequency ranges for white space transmission in a local area. A white space finder service models a primary user device's transmission signal propagation area using terrain data associated with the local area of the primary user device. The white space finder service also determines, based on the location of the white space base station and the modeled propagation area, one or more locally available, non-interfering frequency ranges and provides them to the white space base station. The white space base station compares the provided frequency ranges to policies and selects one or more of the available frequencies that accommodate the policies. The white space base station also maps the transmission frequency ranges to virtual frequency ranges for transmission by a software-defined radio employing spectrum virtualization.

Spectrum allocation for base station

Based on the typical topology and physical properties of a 10-kV power network, this paper first proposes a linear time-variant filter with additive noise to be the general channel model which takes into account the main problems that interfere with communications. Then it discusses the corresponding measurement methods. Next, for the first time in the related research area, the electrical loop wire was applied for the measurement of amplitude and phase responses of the transfer function H(f), which provides a better way to solve the problem of obtaining the phase response if the power line is relatively long. Also, the multitones method for the narrow-band fading measurement is put forward. Finally, it is concluded that moving the calibration reference plane of the network analyzer to a proper position improves the measurements efficiency and accuracy and these methods can be referred to in the 10-kV power-line channel study

Channel Model and Measurement Methods for 10-kV Medium-Voltage Power Lines

A radio control board exchanges data with a radio frequency (RF) front end using a messaging protocol over an interface that includes separate data and control channels. Training data can also be passed over the interface for tuning the clock phase.

Radio control board for software-defined radio platform

An extensive use of look-up table (LUT) and single instruction multiple data (SIMD) in different algorithms in a software-defined radio (SDR) system is described. In particular, the LUT is used during spreading modulation, mapping and spreading, scrambling, de-scrambling, soft demapping, and the like. The SIMD is executed by a multi-core processor during implementation of a “min” operation to find an optimal path in a Trellis diagram for a Viterbi decoder.

High performance digital signal processing in software radios

The second generation of DVB specs, DVB-S2, was developed for satisfying the today's needs for reliable and effective broadband satellite communication services even under 'hostile' conditions. This is achieved by exploiting the new advances in the fields of coding and modulation. Software defined radio (SDR) proves to be an enabling technology for future multimode and reconfigurable satellite receivers. This work presents the design and implementation of a new digital down- converter (DDC) architecture that can be integrated into the next generation software radio DVB-S2 receivers. The presented DDC module is based on two cascaded stages of frequency conversion, operating on samples fed by an A/D converter of moderate sampling frequency. The DDC contains also a sample rate conversion subunit which performs decimation on the resulting in-phase and quadrature (I/Q) samples for proper interfacing with demodulator logic at lower rates. The presented DDC has been implemented and tested using field programmable gate arrays (FPGA), while its performance has been evaluated under additive white Gaussian noise and for various DVB-S2 modulation schemes.

An IF Digital Down-Converter for Software Radio DVB-S2 Receivers

This paper presents a flexible and versatile DVB-S2 test-bed that combines a set of automated signal generation and analysis instruments along with a powerful software radio processing unit for executing performance analysis experiments of DVB-S2 receiver circuits using realistic scenarios. The test-bed provides a rich set of forward satellite channel impairments and also supports real DVB-S2 signals. All test-bed subunits are interconnected over a LAN and are controlled through a central processing unit, allowing fully automated data acquisition and processing of measurements collected from the various receiver circuits.

A software-radio test-bed for measuring the performance of DVB-S2 receiver circuits

This paper presents the design and implementation of a baseband demodulator for DVB-S2 satellite receivers. In order to meet the requirements of different complex and multi- domain signal processing stages of the DVB-S2 baseband signal- flow, the presented architecture is based on efficient fixed-point implementation of the various demodulation algorithms and on the use of a dynamic time-sharing scheduler for the various DSP software tasks. The prototyping of the demodulator and its verification in the design of a complete digital DVB-S2 satellite receiver using a versatile testbed is also presented.

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Architecture and DSP Implementation of a DVB-S2 Baseband Demodulator

Air defense systems protect land and maritime resources from air attack Depending on the regional characteristics and type of conflicting forces, air defense threats vary considerably In regional conflicts, where forces with similar capabilities are involved and no air-superiority can be achieved, the role of air defense systems becomes critical In combat terrains containing mountains (in mainland or in small islands), the man-operated or computer-controlled (using passive sensors) anti-aircraft artillery can be highly effective The simulator presented in this work aims to exploit the capabilities provided by current commercial-off-the-shelf (COTS) communication and multimedia technologies for providing a training environment that improves the personnel capability for effective use of man-controlled anti-aircraft weapons

Anti-aircraft artillery simulator

This paper presents a flexible and adaptable instrument for generating DVB-S2 signals for multi-level testing and performance analysis of satellite receivers. The instrument is based on a high level system model that describes and implements the processing chain of the DVB-S2 transmission system and GEO satellite channel impairments insertion mechanisms, while it utilizes high-speed and high resolution DACs for output signals generation. With the contribution of such a setup, numerous validation and verification tests, under real conditions, can be performed on prototype implementations and realization development stages of emerging DVB-S2 satellite receivers.

/pdf/a-dvb-s2-signal-generator-with-forward-satellite-channel-30xz6qruvl.pdf

P. Savvopoulos

Papers

An IF Digital Down-Converter for Software Radio DVB-S2 Receivers

A software-radio test-bed for measuring the performance of DVB-S2 receiver circuits

Architecture and DSP Implementation of a DVB-S2 Baseband Demodulator

Anti-aircraft artillery simulator

A DVB-S2 Signal Generator with Forward Satellite Channel Impairments