An energy efficient sub-threshold baseband processor architecture for pulsed ultra-wideband communications

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 79-83).Ultra-wideband (UWB) communications is currently being explored as a medium for high-data-rate last-meter wireless links. Accordingly, there has been much interest in integrating UWB radios onto battery-operated devices, creating a strong demand for energy efficient UWB systems. The objective of this work is to describe how operating the digital baseband processor in the sub-threshold region and increasing the degree of parallelism can translate into energy savings across the entire UWB receiver. While sub-threshold operation is traditionally used for low energy, low performance applications such as wrist-watches, this work examines how sub-threshold operation can be applied to low energy, high performance applications. Simulation results for a 100-Mbps UWB baseband processor using the digital logic cell library of a 90-nm process are presented.by Vivienne Sze.S.M

A high speed image transmission system for ultra-wideband wireless links

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (p. 97-98).Ultra-wideband (UWB) communication is an emerging technology that offers short range, high data rate wireless transmission, with low power consumption and low consumer cost. Operating in the 3.1 GHz - 10.6 GHz frequency band with bandwidth above 500 MHz, it is an overlay technology that can co-exist with other narrowband services in the same frequency range, thus alleviating the problem of over-crowded spectrum. In particular, pulse-based UWB technologies allows for building of ultra-low power, medium- to long-range transceivers, at the expense of data transmission rate. This thesis presents a pulse-based, non-coherent UWB wireless image transmission platform. The system features a one-way wireless link. On the transmitter side, a host PC processes the images into transmittable packets in MATLAB, and sends them to the UWB radio through an interfacing FPGA module. On the receiver side, the UWB receiver radio receivers the packets, decodes the bits, and passes them back to the receiver host PC through another interfacing FPGA module. The receiver host PC collects the decoded bits and reconstructs the original image in MATLAB. The unidirectional wireless channel is complemented by a feedback path, provided through internet connection between the two host PCs. To improve usability, graphical user interfaces are setup on both host PCs. The overall system transmits 120 x 160 uncompressed bitmap images. It achieves a maximum payload data rate of 8 Mb/s.(cont.) It is able to transmit data reliably, with above 95% packet reception rate and below 2 x 10-5 bit error rate, for distances up to 16 meters. At 16 meters, the system has a maximum transmission data rate of 2.67 Mbps.by Helen He Liang.M.Eng

Digital ADCs and ultra-wideband RF circuits for energy constrained wireless applications by Denis Clarke Daly.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 173-183).Ongoing advances in semiconductor technology have enabled a multitude of portable, low power devices like cellular phones and wireless sensors. Most recently, as transistor device geometries reach the nanometer scale, transistor characteristics have changed so dramatically that many traditional circuits and architectures are no longer optimal and/or feasible. As a solution, much research has focused on developing 'highly digital' circuits and architectures that are tolerant of the increased leakage, variation and degraded voltage headrooms associated with advanced CMOS processes. This thesis presents several highly digital, mixed-signal circuits and architectures designed for energy constrained wireless applications. First, as a case study, a highly digital, voltage scalable flash ADC is presented. The flash ADC, implemented in 0.18 [mu]m CMOS, leverages redundancy and calibration to achieve robust operation at supply voltages from 0.2 V to 0.9 V. Next, the thesis expands in scope to describe a pulsed, noncoherent ultra-wideband transceiver chipset, implemented in 90 nm CMOS and operating in the 3-to-5 GHz band. The all-digital transmitter employs capacitive combining and pulse shaping in the power amplifier to meet the FCC spectral mask without any off-chip filters. The noncoherent receiver system-on-chip achieves both energy efficiency and high performance by employing simple amplifier and ADC structures combined with extensive digital calibration. Finally, the transceiver chipset is integrated in a complete system for wireless insect flight control.(cont.) Through the use of a flexible PCB and 3D die stacking, the total weight of the electronics is kept to 1 g, within the carrying capacity of an adult Manduca sexta moth. Preliminary wireless flight control of a moth in a wind tunnel is demonstrated.Ph.D

DSP algorithm and system design for UWB communication systems

Master'sMASTER OF ENGINEERIN

Dual-band FSK receiver and building block design for UWB impulse radio

Master'sMASTER OF ENGINEERIN

A 3.1-4.8GHz IR-UWB All-Digital Pulse Generator in 0.13-um CMOS Technology for WBAN Systems

Analog, Digital & RF Circuit DesignImpulse Radio Ultra-WideBand (IR-UWB) systems have drawn growing attention for wireless sensor networks such as Wireless Personal Area Network (WPAN) and Wireless Body Area Network (WBAN) systems ever since the Federal Communications Commission (FCC) released the spectrum between 3.1 and 10.6GHz for unlicensed use in 2002. The restriction on transmitted power spectral density in this band is equal to the noise emission limit of household digital electronics. This band is also shared with several existing service, therefore in-band interference is expected and presents a challenge to UWB system design. UWB devices as secondary spectrum users must also detect and avoid (DAA) other licensed users from the cognitive radio???s point of view. For the DAA requirement, it is more effective to deploy signal with variable center frequency and a minimum 10dB bandwidth of 500MHz than a signal covering the entire UWB spectrum range with fixed center frequency. A key requirement of the applications using IR-UWB signal is ultra-low power consumption for longer battery life. Also, cost reduction is highly desirable. Recently, digital IR-UWB pulse generation is studied more than analog approach due to its lower power consumption. An all-digital pulse generator in a standard 0.13-um CMOS technology for communication systems using Impulse Radio Ultra-WideBand (IR-UWB) signal is presented. A delay line-based architecture utilizing only static logic gates and leading lower power consumption for pulse generation is proposed in this thesis. By using of all-digital architecture, energy is consumed by CV2 switching losses and sub-threshold leakage currents, without RF oscillator or analog bias currents. The center frequency and the fixed bandwidth of 500MHz of the output signal can be digitally controlled to cover three channels in low band of UWB spectrum. Delay based Binary Shift Keying (DB-BPSK) and Pulse Position Modulation (PPM) schemes are exploited at the same time to modulate the transmitted signals with further improvement in spectrum characteristics. The total energy consumption is 48pJ/pulse at 1.2V supply voltage, which is well suitable for WBAN systems.ope

IC design, UWB synchronization circuit

Master'sMASTER OF ENGINEERIN

Realization Limits of Impulse-Radio UWB Indoor Localization Systems

In this work, the realization limits of an impulse-based Ultra-Wideband (UWB) localization system for indoor applications have been thoroughly investigated and verified by measurements. The analysis spans from the position calculation algorithms, through hardware realization and modeling, up to the localization experiments conducted in realistic scenarios. The main focus was put on identification and characterization of limiting factors as well as developing methods to overcome them

Implementation of an ultra-wideband transceiver for sensor applications

Ultra-wideband (UWB) radio is the transmission of data using an extremely wide bandwidth and very low power spectral density. In this thesis, the mereits and challenges of UWB architectures versus conventional narrowband architectures will be compared. Pulsed UWB systems can be implemented with very simple architectures. These advantages make UWB well suited for short range, battery powered applications where a high bit rate is still needed. A prototype transceiver for a radio frequency identification (RFID) tag has been developed and its implementation and performance will be discussed. The prototype is used to demonstrate the feasibility of a pulsed UWB architecture and illustrate the advantages of UWB targeted to this application. The design will be covered from architectural choices, component selection, PCB design through lab experiments and optimization