Power-efficient Circuit Architectures for Receivers Leveraging Nanoscale CMOS

Cellular and mobile communication markets, together with CMOS technology scaling, have made complex systems-on-chip integrated circuits (ICs) ubiquitous. Moving towards the internet of things that aims to extend this further requires ultra-low power and efficient radio communication that continues to take advantage of nanoscale CMOS processes. At the heart of this lie orthogonal challenges in both system and circuit architectures of current day technology. By enabling transceivers at center frequencies ranging in several tens of GHz, modern CMOS processes support bandwidths of up to several GHz. However, conventional narrowband architectures cannot directly translate or trade-off these speeds to lower power consumption. Pulse-radio UWB (PR-UWB), a fundamentally different system of communication enables this trade-off by bit-level duty-cycling i.e., power-gating and has emerged as an alternative to conventional narrowband systems to achieve better energy efficiency. However, system-level challenges in the implementation of transceiver synchronization and duty-cycling have remained an open challenge to realize the ultra-low power numbers that PR-UWB promises. Orthogonally, as CMOS scaling continues, approaching 28nm and 14nm in production digital processes, the key transistor characteristics have rapidly changed. Changes in supply voltage, intrinsic gain and switching speeds have rendered conventional analog circuit design techniques obsolete, since they do not scale well with the digital backend engines that dictate scaling. Consequently, circuit architectures that employ time-domain processing and leverage the faster switching speeds have become attractive. However, they are fundamentally limited by their inability to support linear domain-to-domain conversion and hence, have remained un-suited to high-performance applications. Addressing these requirements in different dimensions, two pulse-radio UWB receiver and a continuous-time filter silicon prototypes are presented in this work. The receiver prototypes focus on system level innovation while the filter serves as a demonstration vehicle for novel circuit architectures developed in this work. The PR-UWB receiver prototypes are implemented in a 65nm LP CMOS technology and are fully integrated solutions. The first receiver prototype is a compact UWB receiver front end operating at 4.85GHz that is aggressively duty-cycled. It occupies an active area of only 0.4 mm², thanks to the use of few inductors and RF G_m-C filters and incorporates an automatic-threshold-recovery-based demodulator for digitization. The prototype achieves a sensitivity of -88dBm at a data rate of 1Mbps (for a BER of 10^-3), while achieving the lowest energy consumption gradient (dP/df_data=450pJ/bit) amongst other receivers operating in the lower UWB band, for the same sensitivity. However, this prototype is limited by idle-time power consumption (e.g., bias) and lacks synchronization capability. A fully self-duty-cycled and synchronized UWB pulse-radio receiver SoC targeted at low-data-rate communication is presented as the second prototype. The proposed architecture builds on the automatic-threshold-recovery-based demodulator to achieve synchronization using an all-digital clock and data recovery loop. The SoC synchronizes with the incoming pulse stream from the transmitter and duty-cycles itself. The SoC prototype achieves a -79.5dBm, 1Mbps-normalized sensitivity for a >5X improvement over the state of the art in power consumption (375pJ/bit), thanks to aggressive signal path and bias circuit duty-cycling. The SoC is fully integrated to achieve RF-in to bit-out operation and can interface with off-chip, low speed digital components. Finally, switched-mode signal processing, a signal processing paradigm that enables the design of highly linear, power-efficient feedback amplifiers is presented. A 0.6V continuous-time filter prototype that demonstrates the advantages of this technique is presented in a 65nm GP CMOS process. The filter draws 26.2mW from the supply while operating at a full-scale that is 73% of the V_dd, a bandwidth of 70MHz and a peak signal-to-noise-and-distortion ratio (SNDR) of 55.8dB. This represents a 2-fold improvement in full-scale and a 10-fold improvement in the bandwidth over state-of-the-art filter implementations, while demonstrating excellent linearity and signal-to-noise ratio. To sum up, innovations spanning both system and circuit architectures that leverage the speeds of nanoscale CMOS processes to enable power-efficient solutions to next-generation wireless receivers are presented in this work

Radio-Communications Architectures

Wireless communications, i.e. radio-communications, are widely used for our different daily needs. Examples are numerous and standard names like BLUETOOTH, WiFI, WiMAX, UMTS, GSM and, more recently, LTE are well-known [Baudoin et al. 2007]. General applications in the RFID or UWB contexts are the subject of many papers. This chapter presents radio-frequency (RF) communication systems architecture for mobile, wireless local area networks (WLAN) and connectivity terminals. An important aspect of today's applications is the data rate increase, especially in connectivity standards like WiFI and WiMAX, because the user demands high Quality of Service (QoS). To increase the data rate we tend to use wideband or multi-standard architecture. The concept of software radio includes a self-reconfigurable radio link and is described here on its RF aspects. The term multi-radio is preferred. This chapter focuses on the transmitter, yet some considerations about the receiver are given. An important aspect of the architecture is that a transceiver is built with respect to the radio-communications signals. We classify them in section 2 by differentiating Continuous Wave (CW) and Impulse Radio (IR) systems. Section 3 is the technical background one has to consider for actual applications. Section 4 summarizes state-of-the-art high data rate architectures and the latest research in multi-radio systems. In section 5, IR architectures for Ultra Wide Band (UWB) systems complete this overview; we will also underline the coexistence and compatibility challenges between CW and IR systems

Wireless power and data transmission to high-performance implantable medical devices

Novel techniques for high-performance wireless power transmission and data interfacing with implantable medical devices (IMDs) were proposed. Several system- and circuit-level techniques were developed towards the design of a novel wireless data and power transmission link for a multi-channel inductively-powered wireless implantable neural-recording and stimulation system. Such wireless data and power transmission techniques have promising prospects for use in IMDs such as biosensors and neural recording/stimulation devices, neural interfacing experiments in enriched environments, radio-frequency identification (RFID), smartcards, near-field communication (NFC), wireless sensors, and charging mobile devices and electric vehicles. The contributions in wireless power transfer are the development of an RFID-based closed-loop power transmission system, a high-performance 3-coil link with optimal design procedure, circuit-based theoretical foundation for magnetic-resonance-based power transmission using multiple coils, a figure-of-merit for designing high-performance inductive links, a low-power and adaptive power management and data transceiver ASIC to be used as a general-purpose power module for wireless electrophysiology experiments, and a Q-modulated inductive link for automatic load matching. In wireless data transfer, the contributions are the development of a new modulation technique called pulse-delay modulation for low-power and wideband near-field data communication and a pulse-width-modulation impulse-radio ultra-wideband transceiver for low-power and wideband far-field data transmission.Ph.D

A scalable 2.9mW 1Mb/s eTextiles body area network transceiver with remotely powered sensors and bi-directional data communication

Advances in sensor design have made ambulatory health monitoring possible and have created the need for low-power communication systems to replace bulkier traditional links. Micropower sensors should also be powered by a non-local energy source for system miniaturization and long life. Recently proposed communication systems using wireless body area networks [1,2] and body-coupled communication [3] suffer from high path loss around the human body for efficient remote power delivery. In contrast, eTextiles are becoming an increasingly popular technology for efficiently powering and communicating with such sensors [4-6] due to wide coverage around the human body combined with low path loss and comfort of use.MIT Masdar Program (Cooperative Agreement 196F/002/707/102f/70/9374

Design and Implementation of Multiplatform Indoor and Outdoor Tracking System

RFID berupaya mengatasi kekurangan GPS dalam persekitaran yang tertutup. Manakala, WSN mampu untuk memanjangkan jarak komunikasi antara dua nod sensor dan GSM boleh menyokong komunikasi WSN semasa gangguan rangkaian. Oleh itu, satu sistem baru platform pelbagai pengesanan dalaman dan luaran (ER2G) yang beroperasi pada frekuensi 2.4 GHz berdasarkan piawaian ZigBee IEEE 802.15.4 diperkenalkan bagi mengatasi kekurangan setiap teknologi. Sistem ER2G dengan fungsi M2M menggunakan mod API untuk menghantar dan menerima data masa sebenar secara wayarles dan menyediakan pensuisan antara lokasi dalamanluaran dan platfom WSN-GSM. Semua ujikaji dijalankan dalam persekitaran sebenar sebagai POC dalam mencapai komunikasi M2M. Prestasi sistem ER2G dinilai dan dibandingkan dengan sistem RFID berdiri sendiri dan ERG, dan ianya didapati lebih cekap daripada dua sistem berkenaan. Sistem ER2G menyediakan perambatan isyarat LOS yang lebih baik daripada sistem RFID berdiri sendiri dengan 2.66 % dalaman dan 26.49 % luaran. Kadar pensuisan adalah 0.95 % dan 16.47 % lebih tinggi daripada sistem ERG dalam persekitaran dalaman dan luaran. Algoritma yang dicadangkan berdasarkan arahan permintaan AT menggunakan mod API berupaya menghantar dan menerima data dengan 10.11 % lebih cepat daripada mod AT. Purata masa pengumpulan tag bagi sistem ER2G untuk TTF dan RTF protokol adalah 14.29 % dan 7.14 % lebih tinggi daripada sistem RFID yang berdiri sendiri. Daya pemprosesan sistem RFID berdiri sendiri adalah 18.06 % lebih rendah daripada sistem ER2G untuk TTF, manakala 7.09 % lebih tinggi daripada sistem ER2G untuk RTF dalam persekitaran pelbagai hop dengan nisbah penghantaran 100 %. ________________________________________________________________________________________________________________________ RFID has the potential to address the inadequacy of GPS inside closed environment. While, WSN is capable to extend the communication range between two sensor nodes and GSM supports WSN during network disruptions. Therefore, a new multi-platform indoor and outdoor tracking (ER2G) system that operates at 2.4 GHz based on ZigBee IEEE 802.15.4 standards is presented to overcome the disadvantages present in each technology. The ER2G system with M2M functionalities utilizes API mode to transmit and receive real time data wirelessly and provides switching between indoor-outdoor location and WSN-GSM platform. All tests are conducted in real environments as POC in achieving M2M communication. The performance of ER2G system is evaluated and compared with standalone RFID and ERG system, and it is found to be more efficient than both systems. The results indicate that the ER2G system provides better LOS signal propagation than the standalone RFID by 2.66 % indoor and 26.49 % outdoor. In addition, the switching rate between indoor and outdoor is faster than the ERG system by 0.95 % indoor and 16.47 % outdoor. The proposed algorithm based on AT command request using API mode is able to transmit and receive data by 10.11 % faster than the AT mode. The average tag collection times of ER2G system for TTF and RTF protocols are 14.29 % and 7.14 % respectively, which are higher than the standalone RFID. Furthermore, the average throughput of the standalone RFID is 18.06 % lower than ER2G system for TTF and 7.09 % higher than ER2G system for RTF in multi-hops environment with 100 % delivery ratio

Design and Implementation of Multiplatform Indoor and Outdoor Tracking System

RFID berupaya mengatasi kekurangan GPS dalam persekitaran yang tertutup. Manakala, WSN mampu untuk memanjangkan jarak komunikasi antara dua nod sensor dan GSM boleh menyokong komunikasi WSN semasa gangguan rangkaian. Oleh itu, satu sistem baru platform pelbagai pengesanan dalaman dan luaran (ER2G) yang beroperasi pada frekuensi 2.4 GHz berdasarkan piawaian ZigBee IEEE 802.15.4 diperkenalkan bagi mengatasi kekurangan setiap teknologi. Sistem ER2G dengan fungsi M2M menggunakan mod API untuk menghantar dan menerima data masa sebenar secara wayarles dan menyediakan pensuisan antara lokasi dalamanluaran dan platfom WSN-GSM. Semua ujikaji dijalankan dalam persekitaran sebenar sebagai POC dalam mencapai komunikasi M2M. Prestasi sistem ER2G dinilai dan dibandingkan dengan sistem RFID berdiri sendiri dan ERG, dan ianya didapati lebih cekap daripada dua sistem berkenaan. Sistem ER2G menyediakan perambatan isyarat LOS yang lebih baik daripada sistem RFID berdiri sendiri dengan 2.66 % dalaman dan 26.49 % luaran. Kadar pensuisan adalah 0.95 % dan 16.47 % lebih tinggi daripada sistem ERG dalam persekitaran dalaman dan luaran. Algoritma yang dicadangkan berdasarkan arahan permintaan AT menggunakan mod API berupaya menghantar dan menerima data dengan 10.11 % lebih cepat daripada mod AT. Purata masa pengumpulan tag bagi sistem ER2G untuk TTF dan RTF protokol adalah 14.29 % dan 7.14 % lebih tinggi daripada sistem RFID yang berdiri sendiri. Daya pemprosesan sistem RFID berdiri sendiri adalah 18.06 % lebih rendah daripada sistem ER2G untuk TTF, manakala 7.09 % lebih tinggi daripada sistem ER2G untuk RTF dalam persekitaran pelbagai hop dengan nisbah penghantaran 100 %. ________________________________________________________________________________________________________________________ RFID has the potential to address the inadequacy of GPS inside closed environment. While, WSN is capable to extend the communication range between two sensor nodes and GSM supports WSN during network disruptions. Therefore, a new multi-platform indoor and outdoor tracking (ER2G) system that operates at 2.4 GHz based on ZigBee IEEE 802.15.4 standards is presented to overcome the disadvantages present in each technology. The ER2G system with M2M functionalities utilizes API mode to transmit and receive real time data wirelessly and provides switching between indoor-outdoor location and WSN-GSM platform. All tests are conducted in real environments as POC in achieving M2M communication. The performance of ER2G system is evaluated and compared with standalone RFID and ERG system, and it is found to be more efficient than both systems. The results indicate that the ER2G system provides better LOS signal propagation than the standalone RFID by 2.66 % indoor and 26.49 % outdoor. In addition, the switching rate between indoor and outdoor is faster than the ERG system by 0.95 % indoor and 16.47 % outdoor. The proposed algorithm based on AT command request using API mode is able to transmit and receive data by 10.11 % faster than the AT mode. The average tag collection times of ER2G system for TTF and RTF protocols are 14.29 % and 7.14 % respectively, which are higher than the standalone RFID. Furthermore, the average throughput of the standalone RFID is 18.06 % lower than ER2G system for TTF and 7.09 % higher than ER2G system for RTF in multi-hops environment with 100 % delivery ratio

Modulation and Multiple Access Techniques for Ultra-Wideband Communication Systems

Two new energy detection (ED) Ultra-Wideband (UWB) systems are proposed in this dissertation. The first one is an ED UWB system based on pulse width modulation (PWM). The bit error rate (BER) performance of this ED PWM system is slightly worse than ED pulse position modulation (PPM) system in additive white Gaussian noise (AWGN) channels. However, the BER performance of this ED PWM system surpasses that of a PPM system in multipath channels since a PWM system does not suffer cross-modulation interference (CMI) as a PPM system. In the presence of synchronization errors, the BER performance of a PWM system also surpasses that of a PPM system. The second proposed ED UWB system is based on using two pulses, which are the different-order derivatives of the Gaussian pulse, to transmitted bit 0 or 1. These pulses are appropriately chosen to separate their spectra in frequency domain.The receiver is composed of two energy detection branches and each branch has a filter which captures the signal energy of either bit 0 or 1. The outputs of two branches are subtracted from each other to generate the decision statistic and the value of this statistic is compared to a threshold to determine the transmitted bits. This system is named as acf{GFSK} system in this dissertation and it exhibits the same BER performance as a PPM system in AWGN channels. In multipath channels, a GFSK system surpasses a PPM system because it does not suffer CMI. And the BER performance of a GFSK system is better than a PPM system in the presence of synchronization errors. When a GFSK system is compared to a PWM system, it will always achieve approximately 2 dB improvement in AWGN channels, multipath channels, and in the presence synchronization errors. However, a PWM system uses lower-order derivatives of the Gaussian pulse to transmit signal, and this leads to a simple pulse generator. In this dissertation, an optimal threshold is applied to improve PPM system performance. The research results show that the application of an optimal threshold can e

Modulation and Multiple Access Techniques for Ultra-Wideband Communication Systems

Two new energy detection (ED) Ultra-Wideband (UWB) systems are proposed in this dissertation. The first one is an ED UWB system based on pulse width modulation (PWM). The bit error rate (BER) performance of this ED PWM system is slightly worse than ED pulse position modulation (PPM) system in additive white Gaussian noise (AWGN) channels. However, the BER performance of this ED PWM system surpasses that of a PPM system in multipath channels since a PWM system does not suffer cross-modulation interference (CMI) as a PPM system. In the presence of synchronization errors, the BER performance of a PWM system also surpasses that of a PPM system. The second proposed ED UWB system is based on using two pulses, which are the different-order derivatives of the Gaussian pulse, to transmitted bit 0 or 1. These pulses are appropriately chosen to separate their spectra in frequency domain.The receiver is composed of two energy detection branches and each branch has a filter which captures the signal energy of either bit 0 or 1. The outputs of two branches are subtracted from each other to generate the decision statistic and the value of this statistic is compared to a threshold to determine the transmitted bits. This system is named as acf{GFSK} system in this dissertation and it exhibits the same BER performance as a PPM system in AWGN channels. In multipath channels, a GFSK system surpasses a PPM system because it does not suffer CMI. And the BER performance of a GFSK system is better than a PPM system in the presence of synchronization errors. When a GFSK system is compared to a PWM system, it will always achieve approximately 2 dB improvement in AWGN channels, multipath channels, and in the presence synchronization errors. However, a PWM system uses lower-order derivatives of the Gaussian pulse to transmit signal, and this leads to a simple pulse generator. In this dissertation, an optimal threshold is applied to improve PPM system performance. The research results show that the application of an optimal threshold can e