Rapid development of software defined radio : FMCW radar on Zynq SDR

FMCW Radar is a relatively simple radar technology. Here, an FMCW chirp is transmitted, bounces off a surface and reflects back to the receive antenna. The received signal is out of phase with the transmitted signal, due to the additional propagation time. The time difference between the Transmit (Tx) and Receive (Rx) chirps is directly proportional to the distance travelled (distance-speed-time), and by calculating what the time difference is, the propagation distance can be estimated. A standard use case for FMCW radar is Adaptive Cruise Control. The Coffee Can Radar project was originally developed by academics at MIT [1]. As part of a radar course, it aims to have students build FMCW radars from $100 worth of analogue components that are capable of estimating range. These radars do not work in real time, as the received signals need to be processed offline in MATLAB. Using this as a starting point, work was carried out to develop a similar system that could operate in real time using only SDR equipment. A Zynq ZC706 development board was chosen for this task, along with an FMCOMMs 3 radio front end

Dynamic spectrum access : secondary user coexistence in the FM band

The explosion of wireless everything in recent years has placed a strain on the radio spectrum, and has led to the so-called ‘spectrum crunch’, where the spectrum is described as being nearly at capacity [1]. It is widely accepted that in reality this is not the case, as great numbers of ‘allocated’ bands are underutilized or not in use at all. In other words, the radio spectrum is not used as efficiently as it could be. Commonly, bands (containing many channels) are classified by spectrum regulators for a particular type of use, such as those for FM Radio, Digital TV and cellular services. If there are not enough Primary Users (PUs) to use all of the channels in these bands, they lie empty. Using new spectrum access techniques, these channels can be targeted for 5G and IoT applications. This work focuses on targeting the FM Radio band (88-108 MHz). Signals broadcast at these frequencies have excellent propagation characteristics, and are able to diffract around objects such as hills and human-made structures, and penetrate through buildings well. Recent studies [2] have shown that a significant portion of the 100 individual 200 kHz-wide FM Radio channels are unused at any given location

Rapid prototyping and validation of FS-FBMC dynamic spectrum radio with simulink and ZynqSDR

This paper presents the research carried out in developing and targeting a novel real-time Dynamic Spectrum Access (DSA) Frequency Spread Filter Bank Multicarrier (FS-FBMC) transmitter prototype to programmable ‘ZynqSDR’ Software Defined Radio (SDR) hardware, and introduces a series of experiments used to validate the design’s ‘cognitive’ DSA capabilities. This transmitter is a proof of concept, that uses DSA techniques to enable Secondary Users (SUs) to access the band traditionally used for FM Radio broadcasting (88-108 MHz), and establish data communication channels in vacant parts of the FM Radio Primary User (PU) spectrum using a multicarrier modulation scheme with a Non Contiguous (NC) channel mask. Once implemented on the hardware, the transmitter is subjected to various FM Radio environments sampled from around Central Scotland, and it is demonstrated that it can dynamically adapt its NC transmitter mask in real time to protect the FM Radio signals it detects. A video is presented of this dynamic on-hardware spectral reconfiguration, and the reader is encouraged to view the video to appreciate the responsiveness of the design. An investigation into potential FBMC guardband sizes is carried out, with initial findings indicating a guardband of 200 kHz (either side of an FM Radio station) is required in order to prevent interference with the PUs. This paper also demonstrates the capabilities of the MATLAB®/ Simulink ZynqSDR workflow, and provides a case study and reference design that we feel other researchers working in this field can benefit from

Model based design for 4G and 5G wireless communications software defined radio using MATLAB

Model based design workflow for wireless communications using MATLAB in combination with supported Xilinx Zynq based SDR hardware implementation platforms, from developing floating point simulations for the PHY layer of a LTE receiver, to implementing fixed point simulations, and verifying performance using real off-the-air RF data

A low-cost desktop software defined radio design environment using MATLAB, simulink, and the RTL-SDR

In the last 5 years, the availability of powerful DSP and Communications design software, and the emergence of relatively affordable devices that receive and digitize RF signals, has brought Software Defined Radio (SDR) to the desktops of many communications engineers. However, the more recent availability of very low cost SDR devices such as the RTL-SDR, costing less than $20, brings SDR to the home desktop of undergraduate and graduate students, as well as both professional engineers and the maker communities. Since the release of the various open source drivers for the RTL-SDR, many in the digital communications community have used this device to scan the RF spectrum and digitise I/Q signals that are being transmitted in the range 25MHz to 1.75GHz. This wide bandwidth enables the sampling of frequency bands containing signals such as FM radio, ISM signals, GSM, 3G and LTE mobile radio, GPS and so on. In this paper we will describe the opportunity and operation of the RTL-SDR, and the development of a hands-on, open-course for SDR. These educational materials can be integrated into core curriculum undergraduate and graduate courses, and will greatly enhance the teaching of DSP and communications theory, principles and applications. The lab and teaching materials have recently been used in Senior (4th year Undergraduate) courses and are available as open course materials for all to access, use and evolve

Secondary user access for IoT applications in the FM radio band using FS-FBMC

In this paper a Dynamic Spectrum Access (DSA) Physical layer (PHY) technique is proposed that allows Secondary User (SU) access to the traditional FM Radio spectrum (88-108 MHz) for alternative data communication applications. FM radio waves have excellent propagation characteristics for long distance transmission, and have high levels of penetration through buildings. Using tools such as a structured geolocation database of licensed Primary User (PU) FM Radio transmitters, unlicensed SUs can access portions of the 20 MHz-wide band and transmit signals that place spectral ‘holes’ with suitable guard bands around all known PUs. Based on the PU protection ratios published by Ofcom and the FCC, the operation of a FBMC (Filter Bank Multi-Carrier) transmitter is demonstrated for an urban environment, and through ‘field test’ simulation it is shown that the Out Of Band (OOB) leakage of the proposed PHY (energy in the ‘holes’ that can interfere with the PU) is 47 dB lower than that of using an equivalent OFDM PHY. The results show that the proposed PHY is a suitable candidate for DSA-SU communication (e.g. in smart city IoT applications), whilst ensuring the integrity of incumbent PU signals

Software Defined Radio using MATLAB & Simulink and the RTL-SDR

The availability of the RTL-SDR for less than $20 brings SDR to the home and work desktops of EE students, professional engineers and the maker community. The RTL-SDR device can be used to acquire and sample RF (radio frequency) signals transmitted in the frequency range 25MHz to 1.75GHz, and using some official software add-ons, these samples can be brought into the MATLAB and Simulink environment for users to develop receivers using first principles DSP algorithms. Signals that the RTL-SDR hardware can receive include: FM radio, UHF band signals, ISM signals, GSM, 3G and LTE mobile radio, GPS and satellite signals, and any that the reader can (legally) transmit of course! In this free book we introduce readers to SDR methods by viewing and analysing downconverted RF signals in the time and frequency domains, and then provide extensive DSP enabled SDR design exercises which the reader can learn from. The hands-on examples begin with simple AM and FM receivers, and move on to the more challenging aspects of PHY layer DSP, where receive filter chains, real-time channelisers, and advanced concepts such as carrier synchronisers, digital PLL designs and QPSK timing and phase synchronisers are implemented. Towards the end of the book, we demonstrate how the RTL-SDR can be used with SDR transmitters to develop a more complete communications system, capable of transmitting text strings and images across the desktop

Partial Discharge Localization Based on Received Signal Strength

Partial Discharge (PD) occurs when insulation containing defects or voids is subject to high voltages. If left untreated PD can degrade insulation until, eventually, catastrophic insulation failure occurs. The detection of PD current pulses, however, can allow incipient insulation faults to be identified, located and repaired prior to plant failure. Wireless technology has paved the path for PD detection and monitoring. Software Defined Radio (SDR) is a promising technology. Signals from two PD sources are received at six outdoors locations using an SDR USRP N200 which is connected to a laptop. PD sources, thereafter, are localized based on received signal strengths

District schools and the erosion of parental rights under the Poor Law:a case study from London 1889-1899

This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this recordThis article investigates the empirical backing for the claim that poor law officials needed legal authority to refuse poor parents' right to the custody of their children in order to stabilise children's welfare institutions during the nineteenth century. Although workhouses were capable of accommodating children, Victorian lawmakers feared children would model themselves on adult paupers to become permanent burdens on the state. To tackle this problem, a system of children's welfare institutions called 'district schools' was introduced to train children to become industrious adult labourers. Children were usually classified as orphans or deserted so they could be sent to district schools without fear of family intervention. However, children with ambiguous parental circumstances were labelled as 'other' and considered a problematic class because they were perceived to be at risk of having on-going contact with their birth families. Lawmakers feared parents of 'other' children would undermine reformation efforts by asserting their custody rights, and passed the first laws in English history to allow the state to restrict parental rights on this basis. This article explores the claim of unwanted parental involvement, and in doing so, seeks to contextualise the origins of public law interference in the family sphere within a narrative of imposed citizenship rather than protection