115 research outputs found

    Filter Bank Multicarrier Modulation for Spectrally Agile Waveform Design

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    In recent years the demand for spectrum has been steadily growing. With the limited amount of spectrum available, Spectrum Pooling has gained immense popularity. As a result of various studies, it has been established that most of the licensed spectrum remains underutilized. Spectrum Pooling or spectrum sharing concentrates on making the most of these whitespaces in the licensed spectrum. These unused parts of the spectrum are usually available in chunks. A secondary user looking to utilize these chunks needs a device capable of transmitting over distributed frequencies, while not interfering with the primary user. Such a process is known as Dynamic Spectrum Access (DSA) and a device capable of it is known as Cognitive Radio. In such a scenario, multicarrier communication that transmits data across the channel in several frequency subcarriers at a lower data rate has gained prominence. Its appeal lies in the fact that it combats frequency selective fading. Two methods for implementing multicarrier modulation are non-contiguous orthogonal frequency division multiplexing (NCOFDM)and filter bank multicarrier modulation (FBMC). This thesis aims to implement a novel FBMC transmitter using software defined radio (SDR) with modulated filters based on a lowpass prototype. FBMCs employ two sets of bandpass filters called analysis and synthesis filters, one at the transmitter and the other at the receiver, in order to filter the collection of subcarriers being transmitted simultaneously in parallel frequencies. The novel aspect of this research is that a wireless transmitter based on non-contiguous FBMC is being used to design spectrally agile waveforms for dynamic spectrum access as opposed to the more popular NC-OFDM. Better spectral containment and bandwidth efficiency, combined with lack of cyclic prefix processing, makes it a viable alternative for NC-OFDM. The main aim of this thesis is to prove that FBMC can be practically implemented for wireless communications. The practicality of the method is tested by transmitting the FBMC signals real time by using the Simulink environment and USRP2 hardware modules

    A proposal for the Co6 chapter of the NAG Algol 68 library

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    Theoretical Analysis and Performance Comparison of multi-carrier Waveforms for 5G Wireless Applications

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    5G wireless technology is a new wireless communication system that must meet different complementary needs: high data rate for mobile services, low energy consumption and long-range for connected objects, low latency to ensure real-time communication for critical applications and high spectral efficiency to improve the overall system capacity. The waveforms and associated signals processing, present a real challenge in the implementation for each generation of wireless communication networks. This paper presents the diverse waveforms candidate for 5G systems, including: CE-OFDM (Constant Envelope OFDM), Filter-Bank Multi Carrier (FBMC), Universal Filtered Multi-Carrier (UFMC) and Filtered OFDM (F-OFDM). In this work, simulations are carried out in order to compare the performance of the OFDM, CE-OFDM, F-OFDM, UFMC and FBMC in terms of Power spectral density (PSD) and of Bit Error Rate (BER). It has been demonstrated that (CE-OFDM), constitutes a more efficient solution in terms of energy consumption than OFDM signal. Moreover, the (F-OFDM), (UFMC) and (FBMC) could constitute a more efficient solution in terms of power spectral density, spectral efficiency and bit error rates. In fact, CE-OFDM reduces the Peak to Average Power Ratio (PAPR) associated with OFDM system, FBMC is a method of improving out-of-band (OOB) characteristic by filtering each subcarrier and resisting the inter-carrier interference (ICI). While, UFMC offers a high spectral efficiency compared to OFDM

    Digital filter structures from classical analogue networks

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    Imperial Users onl

    MATLAB

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    A well-known statement says that the PID controller is the "bread and butter" of the control engineer. This is indeed true, from a scientific standpoint. However, nowadays, in the era of computer science, when the paper and pencil have been replaced by the keyboard and the display of computers, one may equally say that MATLAB is the "bread" in the above statement. MATLAB has became a de facto tool for the modern system engineer. This book is written for both engineering students, as well as for practicing engineers. The wide range of applications in which MATLAB is the working framework, shows that it is a powerful, comprehensive and easy-to-use environment for performing technical computations. The book includes various excellent applications in which MATLAB is employed: from pure algebraic computations to data acquisition in real-life experiments, from control strategies to image processing algorithms, from graphical user interface design for educational purposes to Simulink embedded systems

    Digital Filters

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    The new technology advances provide that a great number of system signals can be easily measured with a low cost. The main problem is that usually only a fraction of the signal is useful for different purposes, for example maintenance, DVD-recorders, computers, electric/electronic circuits, econometric, optimization, etc. Digital filters are the most versatile, practical and effective methods for extracting the information necessary from the signal. They can be dynamic, so they can be automatically or manually adjusted to the external and internal conditions. Presented in this book are the most advanced digital filters including different case studies and the most relevant literature

    Design and implementation of a microstrip filter biosensor for healthcare applications

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    PhD ThesisThe aim of this research was to develop high-frequency biosensors by a combination of traditional microstrip filters and microfluidics. Lowpass and bandpass microstrip filters were designed for operational frequencies less than 3 GHz. Analytical modelling was used to initially determine microstrip filter geometry and then 3D electromagnetic simulation software utilised to examine their performance. Once the design was optimised, devices were fabricated using traditional PCB manufacturing approaches and clean room evaporation techniques. The fabricated filters were compared with the simulation results. The characteristic filter features at 0.66 GHz, 0.80 GHz, and 1.60 GHz demonstrated good agreement to within 90% of the simulated models. Microfluidic reservoirs were then attached to the microstrip filters prior to biological testing. The targeted biomolecules for detection were prostate specific antigen (PSA). A vector network analyser was used to measure the S-parameters of the filters at each stage of functionalisation and immobilisation. Biosensor performance was assessed by measurement of the resonant amplitude and frequency shifts at the characteristic operational frequencies as a function of concentration of the immobilised PSA. The efficacy test of the produced biosensors demonstrated label-free detection down to a minimum analyte concentration of 6.125 ng/ml, this corresponding to an amplitude change of 9 dB and a frequency shift of 10 MHz in the characteristic feature of the S11 signal. This work has demonstrated the applicability of both lowpass and bandpass microstrip filters, with an operational frequency range less than 3 GHz and with suitably integrated microfluidics, to perform as biosensors. This is the first experimental assessment report of this type of radio frequency-based biosensor showing the real-time detection of PSA biomarkers

    RHINO software-defined radio processing blocks

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    This MSc project focuses on the design and implementation of a library of parameterizable, modular and reusable Digital IP blocks designed around use in Software-Defined Radio (SDR) applications and compatibility with the RHINO platform. The RHINO platform has commonalities with the better known ROACH platform, but it is a significantly cut-down and lowercost alternative which has similarities in the interfacing and FPGA/Processor interconnects of ROACH. The purpose of the library and design framework presented in this work aims to alleviate some of the commercial, high cost and static structure concerns about IP cores provided by FPGA manufactures and third-party IP vendors. It will also work around the lack of parameters and bus compatibility issues often encountered when using the freely available open resources. The RHINO hardware platform will be used for running practical applications and testing of the blocks. The HDL library that is being constructed is targeted towards both novice and experienced low-level HDL developers who can download and use it for free, and it will provide them experience of using IP Cores that support open bus interfaces in order to exploit SoC design without commercial, parameter and bus compatibility limitations. The provided modules will be of particularly benefit to the novice developers in providing ready-made examples of processing blocks, as well as parameterization settings for the interfacing blocks and associated RF receiver side configuration settings; all together these examples will help new developers establish effective ways to build their own SDR prototypes using RHINO

    Towards a table top quantum computer

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    Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 1999.Includes bibliographical references (leaves 135-139).In the early 1990s, quantum computing proved to be an enticing theoretical possibility but a extremely difficult experimental challenge. Two advances have made experimental quantum computing demonstrable: Quantum error correction; and bulk, thermal quantum computing using nuclear magnetic resonance (NMR). Simple algorithms have been implemented on large, commercial NMR spectrometers that are expensive and cumbersome. The goal of this project is to construct a table-top quantum computer that can match and eventually exceed the performance of commercial machines. This computer should be an inexpensive, easy-to-use machine that can be considered more a computer than its "supercomputer" counterparts. For this thesis, the goal is to develop a low-cost, table-top quantum computer capable of implementing simple quantum algorithms demonstrated thus far in the community, but is also amenable to the many scaling issues of practical quantum computing. Understanding these scaling issues requires developing a theoretical understanding of the signal enhancement techniques and fundamental noise sources of this powerful but delicate system. Complementary to quantum computing, this high performance but low cost NMR machine will be useful for a number of medical, low cost sensing and tagging applications due the unique properties of NMR: the ability to sense and manipulate the information content of materials on macroscopic and microscopic scales.Yael G. Maguire.S.M
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