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

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

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

Control and visualisation of a software defined radio system on the Xilinx RFSoC platform using the PYNQ framework

The availability of commercial Radio Frequency System on Chip (RFSoC) devices brings new possibilities for implementing Software Defined Radio (SDR) systems. Such systems are of increasing interest given the pace of innovation in wireless technology, and the pressure on RF spectrum resources, leading to a growing need to access the spectrum in more dynamic and innovative ways. In this paper, we present an SDR demonstration system based on the Xilinx RFSoC platform, which leverages the Python- based 'PYNQ' (Python Productivity for Zynq) software framework. In doing so, we highlight features that can be extremely useful for prototyping radio system design. Notably, our developed system features Python-based control of hardware processing blocks and Radio Frequency (RF) data converters, as well as direct visualisation of communications signals captured within the chip. The system architecture is reviewed, hardware and software components are discussed, functionality is demonstrated, and aspects of the system's performance are evaluated. Finally, it is noted that this combined RFSoC + PYNQ approach is readily extensible for other SDR systems; we highlight our online shared resources, and invite other engineers to investigate and build upon our work

Design and implementation of real-time cognitive dynamic spectrum radio, targeting the FM radio band with PHYDYAS FS-FBMC

Demand for wireless connectivity is exponentially increasing. Allocated bands in the Radio Frequency (RF) spectrum are commonly presented as being nearly at capacity but in reality, they are often under-utilised. New shared spectrum regulations, combined with Dynamic Spectrum Access (DSA) technologies and Software Defined Radio (SRD) allow third parties to access vacant spectrum that has been traditionally licensed to broadcasters and mobile network operators. Regulators and research institutions worldwide are actively exploring the sharing of finite spectral resources, driving a wireless revolution that will bring lower cost and ubiquitous connectivity.;This thesis presents and validates a disruptive new spectrum sharing technique that facilitates access to the significant amount of vacant spectrum in the band traditionally used for analogue FM Radio broadcasting (88-108 MHz), providing a potential communications solution for load balancing and demand side management in smart grid networks. In this work, a novel, real-time DSA-enabled radio transmitter is designed, implemented, and targeted to programmable 'ZynqSDR' hardware, and investigations are carried out to determine whether it is capable of coexisting with incumbent FM Radio stations. The transmitter uses the Frequency Spread Filter Bank Multicarrier (FS-FBMC) modulation scheme - which has low levels of Out-Of-Band (OOB) leakage - and a non-contiguous subchannel mask, which can automatically reconfigure itself in real time to change the spectral characteristics of the output signal. It was developed using low level Digital Signal Processing (DSP) components from within MATLAB and Simulink.;The FBMC Secondary User (SU) radio was shown to cause minimal interference to FM Radio stations when 'transmitting' at low broadcast powers (e.g. 20 dBm) and using a 200 kHz guardband, indicating that an SU such as the one proposed in this thesis would be capable of legally coexisting with (and transmit alongside) incumbent FM Radio signals; provided radio spectrum regulations were modified to permit legal operation.Demand for wireless connectivity is exponentially increasing. Allocated bands in the Radio Frequency (RF) spectrum are commonly presented as being nearly at capacity but in reality, they are often under-utilised. New shared spectrum regulations, combined with Dynamic Spectrum Access (DSA) technologies and Software Defined Radio (SRD) allow third parties to access vacant spectrum that has been traditionally licensed to broadcasters and mobile network operators. Regulators and research institutions worldwide are actively exploring the sharing of finite spectral resources, driving a wireless revolution that will bring lower cost and ubiquitous connectivity.;This thesis presents and validates a disruptive new spectrum sharing technique that facilitates access to the significant amount of vacant spectrum in the band traditionally used for analogue FM Radio broadcasting (88-108 MHz), providing a potential communications solution for load balancing and demand side management in smart grid networks. In this work, a novel, real-time DSA-enabled radio transmitter is designed, implemented, and targeted to programmable 'ZynqSDR' hardware, and investigations are carried out to determine whether it is capable of coexisting with incumbent FM Radio stations. The transmitter uses the Frequency Spread Filter Bank Multicarrier (FS-FBMC) modulation scheme - which has low levels of Out-Of-Band (OOB) leakage - and a non-contiguous subchannel mask, which can automatically reconfigure itself in real time to change the spectral characteristics of the output signal. It was developed using low level Digital Signal Processing (DSP) components from within MATLAB and Simulink.;The FBMC Secondary User (SU) radio was shown to cause minimal interference to FM Radio stations when 'transmitting' at low broadcast powers (e.g. 20 dBm) and using a 200 kHz guardband, indicating that an SU such as the one proposed in this thesis would be capable of legally coexisting with (and transmit alongside) incumbent FM Radio signals; provided radio spectrum regulations were modified to permit legal operation

Design and Implementation of Real-Time Cognitive Dynamic Spectrum Radio, Targeting the FM Radio Band with PHYDYAS FS-FBMC

Demand for wireless connectivity is exponentially increasing. Allocated bands in the Radio Frequency (RF) spectrum are commonly presented as being nearly at capacity, but in reality, they are often under-utilised. New shared spectrum regulations, combined with Dynamic Spectrum Access (DSA) technologies and Software Defined Radio (SDR) allow third parties to access vacant spectrum that has been traditionally licensed to broadcasters and mobile network operators. Regulators and research institutions worldwide are actively exploring the sharing of finite spectral resources, driving a wireless revolution that will bring lower cost and ubiquitous connectivity. This thesis presents and validates a disruptive new spectrum sharing technique that facilitates access to the significant amount of vacant spectrum in the band traditionally used for analogue FM Radio broadcasting (88-108 MHz), providing a potential communications solution for load balancing and demand side management in smart grid networks. In this work, a novel, real-time DSA-enabled radio transmitter is designed, implemented, and targeted to programmable ‘ZynqSDR’ hardware, and investigations are carried out to determine whether it is capable of coexisting with incumbent FM Radio stations. The transmitter uses the Frequency Spread Filter Bank Multicarrier (FS-FBMC) modulation scheme—which has low levels of Out-Of-Band (OOB) leakage—and a non-contiguous subchannel mask, which can automatically reconfigure itself in real time to change the spectral characteristics of the output signal. It was developed using low level Digital Signal Processing (DSP) components from within MATLAB and Simulink. The FBMC Secondary User (SU) radio was shown to cause minimal interference to FM Radio stations when ‘transmitting’ at low broadcast powers (e.g. 20 dBm) and using a 200 kHz guardband, indicating that an SU such as the one proposed in this thesis would be capable of legally coexisting with (and transmit alongside) incumbent FM Radio signals; provided radio spectrum regulations were modified to permit legal operation