Joint symbol and chip synchronization for a burst-mode-communication superregenerative MSK receiver

In this paper we describe a superregenerative (SR) MSK receiver able to operate in a burst-mode framework where synchronization is required for each packet. The receiver is based on an SR oscillator which provides samples of the incoming instantaneous phase trajectories. We develop a simple yet effective technique to achieve joint chip and symbol synchronization within the time limits of a suitable preamble. We develop some general results and focus on the case of the IEEE 802.15.4 MSK physical layer. We provide details on a VHDL implementation on an FPGA where the most complex digital processing block is an accumulator. Simulation and experimental results are provided to validate the described technique.Peer ReviewedPostprint (published version

RF TRANSCEIVER DESIGN FOR WIRELESS SENSOR NETWORKS

Ph.DDOCTOR OF PHILOSOPH

A Fully Integrated CMOS Receiver.

The rapidly growing wireless communication market is creating an increasing demand for low-cost highly-integrated radio frequency (RF) communication systems. This dissertation focuses on techniques to enable fully-integrated, wireless receivers incorporating all passive components, including the antenna, and also incorporating baseband synchronization on-chip. Not only is the receiver small in size and requires very low power, but it also delivers synchronized demodulated data. This research targets applications such as implantable neuroprosthetic devices and environmental wireless sensors, which need short range, low data-rate wireless communications but a long lifetime. To achieve these goals, the super-regenerative architecture is used, since power consumption with this architecture is low due to the simplified receiver architecture. This dissertation presents a 5GHz single chip receiver incorporating a compact on-chip 5 GHz slot antenna (50 times smaller than traditional dipole antennas) and a digital received data synchronization. A compact capacitively-loaded 5 GHz standing-wave resonator is used to improve the energy efficiency. An all-digital PLL timing scheme synchronizes the received data clock. A new type of low-power envelope detector is incorporated to increase the data rate and efficiency. The receiver achieves a data rate up to 1.2 Mb/s, dissipates 6.6 mW from a 1.5 V supply. The novel on-chip capacitively-loaded, transmission-line-standing-wave resonator is employed instead of a conventional low-Q on-chip inductor. The simulated quality factor of the resonator is very high (35), and is verified by phase-noise measurements of a prototype 5GHz Voltage Control Oscillator (VCO) incorporating this resonator. The prototype VCO, implemented in 0.13 µm CMOS, dissipates 3 mW from a 1.2 V supply, and achieves a measured phase noise of -117 dBc/Hz at a 1 MHz offset. In the on-chip antenna an efficient shielding technique is used to shield the antenna from the low-resistivity substrate underneath. Two standalone on-chip slot antenna prototypes were designed and fabricated in 0.13 µm CMOS. The 9 GHz prototype occupies a die area of only 0.3 mm2, has an active gain of -4.4 dBi and an efficiency of 9%. The second prototype occupies a die area of 0.47 mm2, and achieves a passive gain of approximately -17.0 dBi at 5 GHz.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/60739/1/shid_1.pd

Energy Aware RF Transceiver for Wireless Body Area Networks (WBAN)

Ph.DDOCTOR OF PHILOSOPH

Analysis and simulation methods for free-running, injection-locked and super-regenerative oscillators

RESUMEN: En los últimos años, muchos esfuerzos han sido dedicados al desarrollo de técnicas complementarias para el análisis de circuitos autónomos de microondas. Estas técnicas están pensadas para su uso en combinación con balance armónico, ampliamente usado para el análisis a frecuencias de microondas. De hecho, balance armónico sufre de restricciones cuando se utiliza para el análisis de circuitos autónomos, en su mayoría debidos a su falta de sensibilidad a las propiedades de estabilidad de la solución que se genera o se extingue mediante bifurcaciones. En esta tesis doctoral se presentan nuevos métodos de simulación y análisis para la caracterización y modelado de osciladores libres, sincronizados y superregenerativos. Todos los resultados obtenidos mediante los nuevos métodos de simulación y análisis han sido comparados satisfactoriamente con otras técnicas de simulación y con medidas.ABSTRACT: In the last years, numerous efforts have been devoted to the development of complementary analysis tools for autonomous microwave circuits. They are intended to be applied in combination with the harmonic-balance (HB) method, widely used at microwave frequencies. In fact, HB suffers from a number of shortcomings when dealing with autonomous circuits, mostly due the fact that it is insensitive to the stability properties of the solution, generated and extinguished through bifurcation phenomena. Here, new simulation and analysis methodologies for the characterization and modeling of free-running, injection-locked and super-regenerative oscillators have been proposed to overcome these problems when using commercial software. Results from the different new analysis methodologies have been successfully compared with independent simulations and with measurements

Design of low power CMOS UWB transceiver ICs

Master'sMASTER OF ENGINEERIN

Ultra-Wideband Transceiver Design And Optimization

University of Minnesota Ph.D. dissertation. July 2015. Major: Electrical Engineering. Advisor: Ramesh Harjani. 1 computer file (PDF); xiii, 128 pages.The technology landscape has quickly changed over the last few years. Developments in personal area networks, IC technology, DSP processing and bio-medical devices have enabled the integration of short range communication into low cost personal health care solutions. Newer technologies and solutions are being developed to cater to the personal operating space(POS) and body area networks(BAN). Health care is driving towards using multiple sensor and therapeutic nodes inside the POS. Technology has enabled remote patient care where the patient has low cost on-body wearables that allow the patient/physician to access vital signs without the patient physically visiting the clinic. Big semiconductor giants want to move into the wearable health monitor space. Along with the developments in fitness based health wearables, there has been a lot of interest towards developing BAN devices catering to the 'mission-critical' wearables and implants. Hearing aids, EKG monitors, neurostimulators are some examples. This work explores the use of the 802.15 ulta wideband (UWB) standard for designing a radio to operate in the a wireless sensor network in the BAN. The specific application targeted is a hearing aid. However, the design in this work is capable of working in a low power low range application with the ability to have multiple data rates ranging from a few kHz to 10's of MHz. The first radio designed by Marconi using spark-gap transmitters was an impulse radio (IR). The IR UWB technology boasts of low power, low cost, high data rates, multiple channels, simultaneous networking, the ability to carry information through obstacles that more limited bandwidths cannot, and also potentially lower complexity hardware design. The inherent timing accuracy associated with the technology gives UWB transmissions immunity to multipath fading and are hence make them more suitable for a cluttered indoor environment. The key difference with the traditional narrowband transceiver is that instead of using continuous wave (CW) transmission, impulses in time are used. The timing accuracy associated with these impulses require synchronization in time, rather than synchronization in frequency for carrier-based CW systems. A complete fully integrated system is presented in thesis. This work presents a low-power noncoherent IR UWB transceiver operating at 5GHz in 0.13um CMOS. A fully-digital transmitter generates a shaped output pulse of 1GHz 3-dB bandwidth. DLLs provide a PVT-tolerant time-step resolution of 1ns over the entire symbol period and regulate the pulse generator center frequency. The transmitter outputs -31dBm (0.88pJ/pulse at 1Mpulse/s) with a dynamic (energy) efficiency of 16pJ/pulse. The transmit out pulse is FCC part 15 compliant over process voltage and temperature (PVT) variations. The transmitter is semi-compliant with IEEE 802.15.6 and IEEE 802.15.4 standards and will become completely compliant with minor modifications. The receiver presented in this work is a non-coherent energy detect IR UWB receiver. The receiver has an on-chip transformer preceding the LNA, which is followed by a super-regenerative amplifier (SRA), envelope detector, sample-and-holds, and a bank of comparators. The design is SRA based energy-detection receiver. Measured results show a receiver efficiency of 0.32nJ/bit at 20.8Mb/s and operation with inputs as low as -70dBm. The SRA based energy-detection receiver utilizes early/late detection for a two-step baseband synchronization algorithm. An integrated solution to the issue of synchronization is also proposed. The system proposed is capable of synchronization and tracking control. The system in this work utilizes early/late detection for a two-step baseband synchronization algorithm. The algorithm is implemented in Matlab and the time to synchronization is observed to be between 250us to a few couple of ms. Measurements have also been made using the receiver and manually implementing the algorithm. This work addresses all aspects time synchronization in an IR transceiver. The initial mismatch is addressed by two methods. Beyond the initial synchronization, the system presented in this system is also capable of tracking. This would mean that once the transceiver has been synchronized, the timing generation would continue to track the phase and the frequency changes depending upon crystal drift over time or movement between the receiver and the transmitter. A test was also performed on the complete transceiver system with two radios talking to each other over a highly attenuated wired channel

Aplicaciones avanzadas del principio superregenerativo a comunicaciones por radiofrecuencia

There exists today an increasing demand for wireless devices which require low cost and minimum power consumption radiofrequency front-ends. Precisely, these are two remarkable characteristics of the superregenerative receiver (SR). In this thesis, we present some novel applications of the SR receiver which make use of both simple methods and simple implementations that fit perfectly with its main features. The superregenerative reception principle was presented for the first time in 1922, and it was initially used with analog amplitude modulations, such as voice communications. The same principle was spread to digital amplitude modulations in applications where data transmission was required. Moreover, it has also been used in frequency modulation reception through an FM-to-AM conversion mechanism, but due to the inherent characteristics of the receiver, it is only suitable with wide band modulations.In the latest few years, some SR receiver proposals for phase modulation detection have emerged. It has been demonstrated that, with this type of modulation, the resulting architecture might be even simpler than the traditional ones devoted to detect amplitude modulations. This thesis advances in this line and its main goal is to discover new possibilities of the SR receiver in angular modulation detection, which have been little exploited so far. With this aim, a variety of prototypes were designed and implemented for PSK modulations on the one hand and, on the other hand, for narrow band FSK modulations. More specificifically, the thesis describes a SR QPSK transceiver and a SR M-PSK transceiver. These transceivers make use of a digital phase detection technique that is very simple. In order to confirm the viability of the proposed idea, some implementations in the HF band operating at a symbol rate of 10 kHz were developed. Regarding frequency modulations, we present a SR receiver detection method suitable for the narrowband case. This method is based on the observation of the instantaneous phase once per symbol, so that we are able to detect the received frequency through the value of the detected phase. For this case two implementations are presented: a SR receiver for Sunde's FSK modulation, and a SR receiver for MSK modulation. By using the designed SR receiver for the MSK modulations as a starting point, a SR MSK transceiver compatible with the IEEE 802.15.4 standard is implemented. This standard defines the physical layer and the medium access control (MAC) layer used for low speed wireless personal area network, a field in which the SR receiver fits perfectly. Finally, we describe a synchronization method for SR MSK receivers at the symbol, chip and frame levels. This method is presented in a general way and it is able to sinchronize through any preamble satisfying some specific requirements. In particular, we describe an implementation that aims to synchronize IEEE 802.15.4 standard frames. Simplicity has been prioritized in all the presented designs and implementations in order to potentiate the characteristic low cost and low power consumption features of the SR receiver. Likewise, we prove that this kind of receiver is especially efficient in the detection of phase and narrowband frequency modulations.Actualmente existe una demanda creciente de dispositivos inalámbricos que requieren el uso de front-ends de radiofrecuencia de bajo coste y consumo de potencia reducido, requisitos en los que el receptor superregenerativo (SR) destaca de forma especial. En esta tesis, se presentan distintas aplicaciones novedosas del receptor SR con métodos e implementaciones simples en consonancia con sus principales prestaciones. El principio de recepción superregenerativo fue presentado en el año 1922, siendo utilizado en sus inicios para modulaciones analógicas de amplitud como, por ejemplo, comunicaciones de voz. El mismo principio fue extendido posteriormente a modulaciones de amplitud digitales en aplicaciones que requerían la transmisión de datos. Por otro lado, también se ha utilizado en la recepción de modulaciones de frecuencia, mediante un mecanismo de conversión de modulación de frecuencia a modulación de amplitud. Sin embargo, debido a las características intrínsecas del receptor, este solo resulta adecuado para modulaciones de banda ancha. En los últimos años, han surgido algunas propuestas de receptor SR para modulaciones de fase. Se ha demostrado que, con este tipo de modulaciones, la arquitectura resultante puede ser incluso más simple que las tradicionales para la detección de modulaciones de amplitud. Esta tesis avanza precisamente en esta línea y tiene como objetivo descubrir nuevas posibilidades de utilización del receptor SR en la detección de modulaciones angulares, poco explotadas hasta el momento en combinación con este tipo de receptor. Con este objetivo, se diseñan e implementan diversos prototipos para modulaciones de fase PSK, por un lado, y para modulaciones de frecuencia FSK de banda estrecha, por otro. Más concretamente, se describe un transceptor SR QPSK y un transceptor SR M-PSK. Estos transceptores se basan en una técnica de detección de fase digital de gran simplicidad. Se han realizado implementaciones en la banda de HF operando a una frecuencia de símbolo de 10 kHz, con el fin de demostrar la viabilidad del concepto propuesto. Con respecto a las modulaciones de frecuencia, se presenta un método de detección con receptor SR para el caso de banda estrecha. Este método se basa en observar la fase instantánea una vez por símbolo, consiguiendo detectar la frecuencia recibida a través del valor de la fase detectada. En este caso, se presentan dos implementaciones: un receptor SR para la modulación FSK de Sunde y un receptor SR para la modulación MSK. Utilizando el receptor SR para la modulación MSK diseñado como punto de partida, se implementa un transceptor SR MSK compatible con el estándar 802.15.4. Este estándar define la capa física y la capa de control de acceso al medio (MAC) para redes inalámbricas de área personal de baja velocidad, ámbito en el cual el receptor SR encaja a la perfección. Finalmente, se describe un método de sincronización para receptores SR MSK a nivel de símbolo, de chip y de trama. Este método se presenta de forma genérica, pudiéndose sincronizar con cualquier preámbulo que cumpla unas características determinadas. En particular, se describe una implementación que tiene como objetivo sincronizar tramas del estándar IEEE 802.15.4

Micropower Impulse Radio For Remote Controlled Insect Flight

Insects have remarkable strength and stamina compared to their body mass and fly and manuver effortlessly in ways that are impossible for present day robotic flyers. Therefore, efforts to control and direct flying insects for our own purposes have a huge potential payoff. One such effort, discussed in this dissertation, concerns the control of a Manduca Sexta moth by sending commands by radio to neural probes implanted in the thorax. The electronics hardware represents a major challenge in itself because the moth can carry only 700 milligrams, most of which is occupied by a small watch-battery. Ultimately, the moth must carry not only a radio receiver to pick up commands sent by the controller, but also a transmitter to return gathered information and fulfill its mission. Commercial "low-power", burst-mode radios have proven inadeqate because the battery cannot satisfy their peak power consumption. Instead, this dissertation focuses on the development of an alternative "impulse radio", which consumes power only during the ~100 picosecond interval required to generate a microwave pulse. The specific transmitter architecture presented here uses a nonlinear transmission line to directly convert digital signals provided by a microcontroller into microwave pulses broadcast by an antenna. This dissertation discusses (1) the background and theory of impulse-radios and (2) nonlinear transmission lines, (3) circuit board prototypes and (4) a CMOS implementation of the trans- mitter, (5) a study of the wireless link between the moth and its controller, as well as (6) efforts to implement the radio using light-weight, inexpensive plastic and polymer materials, before (7) reflecting on the potential of the new transmitter and possible directions for future work

Ultra-Wideband Transceiver with Error Correction for Cortical Interfaces in NanometerCMOS Process

This dissertation reports a high-speed wideband wireless transmission solution for the tight power constraints of cortical interface application. The proposed system deploysImpulse Radio Ultra-wideband (IR-UWB) technique to achieve very high-rate communication. However, impulse radio signals suffer from significant attenuation within the body,and power limitations force the use of very low-power receiver circuits which introduce additional noise and jitter. Moreover, the coils’ self-resonance has to be suppressed to minimize the pulse distortion and inter-symbol interference, adding significant attenuation. To compensate these losses, an Error correction code (ECC) layer is added for functioning reliably to the system. The performance evaluation is made by modeling a pair of physically fabricated coils, and the results show that the ECC is essential to obtain the system’s reliability. Furthermore, the gm/ID methodology, which is based on the complete exploration ofall inversion regions that the transistors are biased, is studied and explored for optimizingthe system at the circuit-level. Specific focuses are on the RF blocks: the low noise am-plifier (LNA) and the injection-locked voltage controlled oscillator (IL-VCO). Through the analytical deduction of the circuit’s features as the function of the gm/ID for each transistor, it is possible to select the optimum operating region for the circuit to achieve the target specification. Other circuit blocks, including the phase shifter, frequency divider,mixer, etc. are also described and analyzed. The prototype is fabricated in a 65-nm CMOS(Complementary Metal-Oxide-Semiconductor) process