The purpose of this thesis work is to examine the possibility of building a software-defined radio (SDR) for the VHF-band. The goal is to accomplish this with as few components as possible, thus cutting down the size and the production cost. An SDR solution means that the sampling of the signal is done as close to the antenna as possible. The wide bandwidth needed in such a product is achieved by using SP Devices algorithm for time-interleaved ADCs. Two hardware prototypes and two versions of the software were designed and implemented using this technology. They were also analyzed within this thesis work. The results proved to be good, and the possibilities to produce a commercial software-defined radio receiver for the VHF-band are good. / Syftet med det här examensarbetet är att utreda möjligheten att bygga en mjukvarustyrd radiomottagare (SDR) för VHF-bandet. Målet är att göra detta genom att använda så få komponenter som möjligt, och därigenom minska storleken och produktionskostnaden. En SDR lösning ger att samplingen kommer att ske så nära antennen som möjligt. Den stora bandbredd som behövs för en sådan produkt uppnås genom att använda SP Devices algoritm för att ''tidsinterleava'' höghastighets ADC:er. Två hårdvaruprototyper och två versioner av mjukvaran har designats och implementerats. Analyserna har visat bra resultat, och möjligheterna att bygga en komersiell mjukvarudefinierade radiomottagare för VHF-bandet ses som goda.

The paper focuses on the design and implementation of the base-band basic receiving functions, for a binary CP-FSK demodulator pilot study, as independent modules of a complete Reconfigurable Data-Link (RDL). A model-based approach and Software Defined Radio (SDR) paradigm are used for the design. The implementation will be executed on Field-Programmable Gate Array (FPGA) based hardware.

Το ραδιόφωνο είναι από τις πλέον διαδεδομένες μορφές εκπομπής δεδομένων, χρησιμοποιείται δε ακόμα και σήμερα, σε μια εποχή που οι ψηφιακές τηλεπικοινωνίες επεκτείνονται ταχύτατα. Αρχικά επέτρεπε την μετάδοση μόνο ενός καναλιού ήχου, όμως επεκτάθηκε σε στερεοφωνική (δικάναλη) εκπομπή, προσετέθησαν μέθοδοι μετάδοσης ψηφιακών πληροφοριών (RDS/RBDS, DirectBand) για την πληροφόρηση χρηστών αλλά και για μεγαλύτερη ευελιξία των δεκτών. Παράδειγμα του τελευταίου είναι η λειτουργία "AF" (εναλλακτικές συχνότητες, alternative frequencies) η οποία δίνει την δυνατότητα σε ένα δέκτη να μεταπηδήσει σε άλλη συχνότητα στην οποία εκπέμπει ο ίδιος σταθμός αλλά με ισχυρότερο ή καθαρότερο σήμα. Δεδομένου του εύρους των λειτουργιών που χρησιμοποιούνται στις ραδιοφωνικές εκπομπές, είναι πολύ καλή επιλογή για την ανάπτυξη προγραμμάτων που τις εκμεταλλεύονται, από απλές μέχρι περίπλοκες τόσο στο αναλογικό όσο και στο ψηφιακό τμήμα. Για το αναλογικό τμήμα, στο ένα άκρο έχουμε έναν απλό μονοφωνικό δέκτη ενώ στο άλλο άκρο έναν στερεοφωνικό δέκτη ο οποίος μετρώντας την καθαρότητα του λαμβανόμενου σήματος επιλέγει το ποσοστό χρήσης στερεοφωνίας ώστε να επιτύχει συμβιβασμό μεταξύ διαχωρισμού καναλιών (στερεοφωνικής εικόνας) και χαμηλού θορύβου. Στα πλαίσια της παρούσας διπλωματικής, αναπτύχθηκε πρόγραμμα σε γλώσσα C το οποίο εκτελεί λειτουργία δέκτη ραδιοφωνικού σήματος διαμορφωμένου αναλογικά κατά συχνότητα (FM radio). Στον προγραμματισμό χρησιμοποιήθηκαν τεχνικές Software Defined Radio (SDR). Επιπλέον, το πρόγραμμα εκτελεί λήψη ψηφιακού σήματος ραδιοφωνικών πληροφοριών (Radio Broadcast Data System, RBDS/RDS). Στόχος της διπλωματικής είναι η επίδειξη της εφαρμογής τεχνικών SDR στα πλαίσια της υλοποίησης τηλεπικοινωνιακών συστημάτων. Με την αύξηση της ανάγκης της βιομηχανίας αλλά και των χρηστών για ταχύτερη μετάδοση δεδομένων, επήλθε και αύξηση της περιπλοκότητας των μεθόδων διαμόρφωσης στα τηλεπικοινωνιακά συστήματα. Η περιπλοκότητα αυτή απαιτεί χρήση αλγορίθμων που είναι αδύνατη με συστήματα με διακριτά στοιχεία. Μία λύση στο πρόβλημα αυτό είναι η αξιοποίηση σύγχρονων μικροεπεξεργαστών, των οποίων η ισχύς, ειδικά αυτή των εξειδικευμένων σε DSP, έχει γνωρίσει αλματώδη εξέλιξη. Προκειμένου να καταστεί δυνατή η αξιοποίηση του κατάλληλου υλικού για τα τηλεπικοινωνιακά συστήματα, χρειάζεται κατάλληλη μέθοδος προγραμματισμού. Η ιδέα αυτή έχει ήδη χρησιμοποιηθεί σε εμπορικά συστήματα. Ένα παράδειγμα είναι modem κοινής τηλεφωνικής γραμμής (PSTN/POTS) για οικιακούς υπολογιστές που το μεγαλύτερο μέρος της αποδιαμόρφωσης και διαμόρφωσης το εκτελούσε η κεντρική μονάδα επεξεργασίας του υπολογιστή. Συνεπώς, υπάρχουν παραδείγματα εφαρμογής αυτής της τεχνικής με ήδη υπαρκτό υλικό, δεν απαιτείται εξειδικευμένο hardware. Η εξέλιξη της ιδέας και η ευκολότερη πρόσβαση σε υλικό κατάλληλο, οδήγησε στην ανάπτυξη του Software Defined Radio. Software Defined Radio είναι ένα σύστημα ασύρματης τηλέπικοινωνίας (αν και είναι απολύτως εφικτή και η εφαρμογή σε ενσύρματα συστήματα) όπου αλγόριθμοι και μέρη του συστήματος που τυπικά υλοποιούνταν με ηλεκτρονικά στοιχεία (πυκνωτές, αντιστάτες, κ.α.) πραγματοποιούνται με προγράμματα που εκτελούνται σε σύστημα με επεξεργαστή, μικροελεγκτή ή άλλο προγραμματιζόμενο σύστημα. Η ονομασία Software Defined Radio αναφέρεται, επίσης, στο πρόγραμμα που εκτελεί το ανωτέρω σύστημα. Σε αυτά τα προγράμματα, χρησιμοποιούνται κατά κύριο λόγο τεχνικές επεξεργασίας ψηφιακού σήματος (DSP). Ως παράδειγμα προς μελέτη της τεχνικής θα χρησιμοποιήσουμε ένα από τα πλέον γνωστά πρωτόκολλα, το οποίο δεν είναι τετριμμένο και χρησιμοποιείται ευρύτατα και στη σύγχρονη εποχή, το ραδιόφωνο FM. Το πρωτόκολλο FM είναι αρκετά απλό ώστε η ανάλυσή του να είναι προσβάσιμη χωρίς να απαιτεί εξειδικευμένες γνώσεις τηλεπικοινωνιακών συστημάτων, αλλά όχι τετριμμένο, ώστε να αναδεικνύει την χρησιμότητα της τεχνικής SDR. Ένας δεύτερος λόγος για αυτή την επιλογή είναι η ταυτόχρονη εκπομπή ψηφιακής πληροφορίας από τους σταθμούς. Η λήψη αυτών των πληροφοριών με τη χρήση SDR υπογραμμίζει την ευελιξία της τεχνικής, η οποία επιτρέπει τον ταυτόχρονο χειρισμό τόσο των αναλογικών πληροφοριών (ήχου, στη συγκεκριμένη περίπτωση) όσο και των ψηφιακών πληροφοριών (RBDS/RDS) από το ίδιο πρόγραμμα. Στο Κεφάλαιο 1 περιγράφεται η αρχή λειτουργίας της αναλογικής διαμόρφωσης κατά συχνότητα καθώς και η εφαρμογή της στη ραδιοφωνία. Ορίζονται οι σχετικές παράμετροι και καθορίζονται οι τιμές που λαμβάνουν στην κοινή ραδιοφωνία FM. Τέλος, περιγράφεται η μετάδοση ψηφιακών πληροφοριών με το πρωτόκολλο RDS. Στο Κεφάλαιο 2 περιγράφεται η δομή και λειτουργία ενός δέκτη FM με διακριτά στοιχεία. Αναλύεται η αρχή λειτουργίας του δέκτη, ονομάζονται μερικά από τα στοιχεία που χρησιμοποιούνται συνήθως και διαγράφονται βασικές ομοιότητες με τους δέκτες SDR. Στο Κεφάλαιο 3 περιγράφεται η αρχή λειτουργίας του SDR. Δίνονται παραδείγματα υλικού κατάλληλου για SDR και οι δυνατότητες που απαιτούνται. Δίνονται παραδείγματα λογισμικού κατάλληλου για SDR και παραδείγματα εφαρμογών του. Στο Κεφάλαιο 4 αναλύεται το υλικό που χρησιμοποιήθηκε και το πρόγραμμα που αναπτύχθηκε για την αποδιαμόρφωση σήματος FM και αποκωδικοποίηση σήματος RDS. Επίσης περιγράφεται το υλικό που χρησιμοποιήθηκε καθώς και τα κριτήρια επιλογής τους. Ορίζονται οι είσοδοι και έξοδοι του προγράμματος και περιγράφεται η δομή του. Αναλύεται η λειτουργία των επιμέρους στοιχείων του προγράμματος που αναπτύχθηκε και μελετάται η συμπεριφορά τους. Τέλος, αναλύεται η αποδιαμόρφωση και αποκωδικοποίηση του ψηφιακού σήματος (RDS) από το πρόγραμμα. Στα παραρτήματα δίδονται οι συντελεστές των ψηφιακών φίλτρων που χρησιμοποιήθηκαν στην ανάπτυξη του δέκτη, ο πλήρης κώδικας του δέκτη και οδηγίες για την δημιουργία φασματογραφημάτων με το MATLAB. / FM radio is one of the most widespread forms of data transmission, used even today, in an era where digital telecommunications are quickly spreading. Initially, it allowed transmission of only one audio channel, but it was extended to stereo (two channel) transmission, digital information methods of transmission were added (RDS/RBDS, DirectBand) for user information and for greater receiver versatility. One example of the latter is the AF ("alternative frequencies") functionality which allows a receiver to switch over to another frequency, carrying the same radio program but with better reception. Given the great width of functions that are used in radio transmissions, it is a very good choice for developing software that take advantage of them, from simple to complex, both in the analog and digital domain. For the analog domain, on one end, there may be a simple monophonic receiver and on the other end a stereo receiver which, according to the clarity of the received signal, can adjust the level of stereo separation to achieve a preferable compromise between stereo image and low noise audio. For the purposes of this project, a software program was written, in C, which functions as a frequency modulated, analog radio signal receiver (FM radio). Software Defined Radio techniques were used while developing this program. Additionally, the program performs RDS ("radio data system") signal reception. The objective of this project is to demonstrate the use of Software Defined Radio techniques in the development of telecommunication systems. The industry's, and the users', need for faster data transmission, brought an increase in modulation method complexity in telecommunication systems. This complexity requires use of algorithms that is impossible with systems with discrete components. One solution to this problem is via utilization of modern microprocessors, especially those specializing in DSP, the performance of which has increased dramatically. In order to be able to use the appropriate hardware in a telecommunication system using SDR, an appropriate method of programming them is necessary. This idea has been already used in commercial systems. One example are modems for the common copper telephone line (PSTN /POTS) for home computers, where most of the modulation and demodulation was performed by the computers central processor. Therefore, there are examples of applications of this method using common hardware. The evolution of this idea and the easier access to necessary hardware led to the development of Software Defined Radio. Software Defined Radio is a wireless telecommunication system (although a wired system is equally feasible) where algorithms and components that would, typically, be implemented with electronic elements (capacitors, resistors, etc) are realized with a software program running on a system with a microprocessor, microcontroller or other programmable device. The name Software Defined Radio is also used to refer to the program itself. In such a program, DSP techniques are commonly used. As an example for studying this method we are using one of the most widely known protocols, one that is not trivial and is widely used even in modern times, the FM radio. The FM protocol is simple enough so that its analysis is approachable without specialized knowledge of telecommunication systems, but not trivial, so that it demonstrates the usefulness of the SDR method. Another reason for this choice is the simultaneous transmission of digital information from an FM broadcast station. Reception of this signal, by the program, underlines the versatility of SDR, which allows simultaneous handling of both analog (audio, in this case) and digital (RDS) information. The first chapter presents the principle of operation of analog frequency modulation and its application in radio broadcasting. The respective parameters are defined and specific values for common FM radio broadcasting are given. Finally, digital data transmission via the RDS protocol is described. The second chapter presents the structure and functionality of an FM receiver implemented with discrete elements. Its principle of operation is analyzed, some of the more common elements used are named and similarities with SDR receivers are drawn. The third chapter presents the principle of operation of an SDR system. Examples of useful hardware and relevant requirements are given. Finally, examples of suitable software and respective applications are given. The fourth chapter presents an analysis of the hardware that was used and the software program that was developed for the demodulation of the FM signal and decoding of the RDS signal, along with the criteria for choosing them. The program structure is described and its input and output data signal formats are defined. The functionality of each component of the software program is analyzed and its behavior is studied. Finally, the demodulation and decoding process for the RDS signal by the program is analyzed. In the appendixes, the coefficients of the digital filters are listed, along with the full source code for the software program that was developed and, finally, a guide for creating spectral graphs with MATLAB, similar to those in section 4.3.2.

Research indicates that multiprocessor-based architectures will provide a flexible alternative to hard-wired application-specific integrated circuits (ASICs) suitable to implement the multitude of wireless standards required by mobile devices, while meeting their strict area and power requirements. This shift in design philosophy has led to the software-defined radio (SDR) paradigm, where a significant portion of a wireless standard's physical layer is implemented in software, allowing multiple standards to share a common architecture. Turbo codes offer excellent error-correcting performance, however, turbo decoders are one of the most computationally complex baseband tasks of a wireless receiver. Next generation wireless standards such as Worldwide Interoperability for Microwave Access (WiMAX), support enhanced double-binary turbo codes, which offer even better performance than the original binary turbo codes, at the expense of additional complexity. Hence, the design of efficient double-binary turbo decoder software is required to support wireless standards in a SDR environment. This thesis describes the optimization, parallelization, and simulated performance of a software double-binary turbo decoder implementation supporting the WiMAX standard suitable for SDR. An adapted turbo decoder is implemented in the C language, and numerous software optimizations are applied to reduce its overall computationally complexity. Evaluation of the software optimizations demonstrated a combined improvement of at least 270% for serial execution, while maintaining good bit-error rate (BER) performance. Using a customized multiprocessor simulator, special instruction support is implemented to speed up commonly performed turbo decoder operations, and is shown to improve decoder performance by 29% to 40%. The development of a flexible parallel decoding algorithm is detailed, with multiprocessor simulations demonstrating a speedup of 10.8 using twelve processors, while maintaining good parallel efficiency (above 89%). A linear-log-MAP decoder implementation using four iterations was shown to have 90% greater throughput than a max-log-MAP decoder implementation using eight iterations, with comparable BER performance. Simulation also shows that multiprocessor cache effects do not have a significant impact on parallel execution times. An initial investigation into the use of vector processing to further enhance performance of the parallel decoder software reveals promising results. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-09-25 16:22:47.288

The ability to accurately sense the surrounding wireless spectrum, without having any prior information about the type of signals present, is an important aspect for dynamic spectrum access and cognitive radio. Energy detection is one viable method, however its performance is limited at low SNR and must adhere to Nyquist sampling theorem. Compressive sensing has emerged as a potential method to recover wideband signals using sub-Nyquist sampling rates, under the presumption that the signals are sparse in a certain domain. In this study, the performance and some of the practical limitations of energy detection and compressive sensing are compared via simulation, and also implementation using the Universal Software Radio Peripheral (USRP) software defined radio (SDR) platform. The usefulness and simplicity of the USRP and GNU Radio software toolkit for simulation and experimentation, as well as some other application areas of compressive sensing and SDR, is also discussed.

A bidirectional two-hop relay network with decode-and-forward strategy is implemented using GNU Radio (software) and several USRPs (hardware) on Ubuntu (operating system). The relay communication system is comprised of three nodes; Base Station A, Base Station B, and Relay Station (the intermediate node). During the first time slot, Base Station A and Base Station B will each transmit data, e.g., a JPEG file, to Relay Station using DBPSK modulation and FDMA. For the final time slot, Relay Station will perform a bitwise XOR of the data, and transmit the XORed data to Base Station A and Base Station B, where the received data is decoded by performing another XOR operation with the original data.

Using communication signals for radar applications has been a major area of research in radar engineering. In the recent years, due to the widely available wireless signals, a new area of research called commensal radars has emerged. Commensal radars use available wireless Radio Frequency (RF) signals to detect and track targets of interest. This is achieved by placing two antennas, one towards the transmitting base station and the other towards the surveillance area. The signal received by these two antennas are correlated to determine the location and velocity of the target. When a signal passes through a channel, it reflects off the obstacles within its path. These reflections usually degrade quality of the signal and cause interference to the telecommunication systems. To mitigate the effects of the channel on a signal these systems transmit a known bit sequence within each frame. Our goal, with this thesis, is to design and implement a working prototype of a novel architecture for the commensal radar system, which uses these known bit sequences to extract the channel information and determine events of interest. The major novelties of the system are as follows. Firstly, this system will be built upon existing communication systems using Software Defined Radio (SDR) technology. Secondly, this design eliminates the need for a reference antenna, which reduces the cost of the system and creates an opportunity to make the system portable. We name this system Communication-Sensing (CommSense). Since, our plan is to use Global System for Mobile Communication (GSM) as the parent system for the prototype development, we decide to update the name to GSM based Communication-Sensing (GSM-CommSense) system. This thesis begins with theoretical analysis of the feasibility of the GSM-CommSense system. First of all, we perform a link budget analysis to determine the power requirements for the system. Then we calculate the ambiguity function and Cram´er-Rao Lower Bound (CRLB) for a two-path received signal model. With encouraging theoretical results, we design a prototype of the system that can capture real GSM base station broadcast signals. After the design of the GSMCommSense system, we capture channel data from multiple locations with varying environmental conditions. The aim for this set of experiment is to be able to distinguish between different environmental conditions. Then, we performed statistical analysis on the data by means of Probability Density Function (PDF) fitting, a goodness-of-fit test called chi-square test and a clustering algorithm called Principal Components Analysis (PCA). We have presented the results from each analysis and discussed them in detail. Upon, receiving positive results in each step we have decided to move towards using learning algorithms to categorise the data captured by the system. We have compared two widely accepted supervised learning algorithms, called Support Vector Machines (SVM) and Multi-Layer Perceptron (MLP). The results showed that with the current hardware capabilities of the system and the amount of data available per GSM frame, the performance of SVM is better than MLP. Thus, we have used SVM to classify two events of detection and classification across a wall. We have presented our findings and discussed the results in detail. We conclude our current work and provide scope for future work in development and analysis of the GSM-CommSense system.

No description available.

This thesis deals with car remote keyless systems, analysis of these systems and most common attacks on these systems. It also deals with design and realisation of secure car remote keyless system, which should be resistant to said attacks, and with design and realisation of attack against existing car remote keyless system.

A common method of connecting to the internet is a wireless network. These networks can be monitored to discover the area of their coverage, but commercial receivers don't always provide the most accurate results. A software-defined radio was programmed to sniff wireless signals and tested against a commercial receiver and the results were compared. The results suggest that the software-defined radio performs at least as well as the commercial receiver in distance measurements and significantly better in samples taken per minute. It was determined that the software-defined radio is a viable replacement for a commercial receiver in 3D heat mapping.