R-3 Repository :: Browsing by Author "Frantz, Patrick"

Browsing by Author "Frantz, Patrick"

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802.11b Operating in a Mobile Channel: Performance and Challenges
(2003-09-20) Steger, Christopher; Radosavljevic, Predrag; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
In the past, the worlds of wireless voice and data transmission have been largely disjoint. Voice traffic has been carried over circuit-switched cellular links, and data has been largely restricted to packet-switched wireless LANs. Now, as consumers demand higher bandwidth connections without sacrificing mobility and traffic transitions from primarily voice to data, service providers must produce what is essentially a ubiquitous wireless LAN. To this end, we have studied the effects of a mobile channel on current generation 802.11 A, B, and G wireless LAN cards to see how readily they can be applied to more challenging environments. Not surprisingly, current WLAN technology suffers from significantly degraded performance when subjected to the rigors of a mobile channel. We created emulated bi-directional peer-to-peer links in which we were able to manipulate individual channel parameters. By isolating individual propagation effects and testing several different implementations of the standards, we have discovered which channel parameters have the most significant impact on performance. For instance, the large delay spreads typical of an outdoor channel seem to produce the most deleterious effect on throughput in 802.11b. We use our observations to evaluate the viability of direct-sequence spread-spectrum systems (similar to 802.11b) versus that of OFDM systems (like 802.11a and 802.11g). Then we offer suggestions for how future systems should be adapted in order to manage these effects, and we project the ultimate limitations and possibilities for subsequent 802.11-like systems.
Benefits of DSP Extra-curricular Activities: A Look at the Texas Instruments DSP and Analog Challenge
(2002-05-20) Robinson, Torrence; Peleg, Nimrod; Rhodes, Jacob; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
This paper describes the benefits associated with student and faculty participation in DSP design-related activities that fall outside of the usual university course requirements. It will also describe industry's role in sponsoring these extra-curricular activities. The paper details the lessons learned and skill sets honed of both the students and faculty who participated in the 2000 Texas Instruments Digital Signal Processor (DSP) and Analog Challengeâ ¢. The TI Challenge was a worldwide skills-based competition for university students, where they were challenged to create and submit an original design that employed a TI digital signal processor and included any applicable original software program. Student teams were free to apply their ingenuity to create entirely new applications or improve upon already existing applications, as they competed for prize awards up to US$100,000. In addition to the opportunity for a monetary award, students gained invaluable hands-on experiences by working with state-of-the-art equipment. They were exposed to the reality of uncompromising time schedules and to the challenges of effectively matching project responsibilities to team member capabilities. Faculty and staff benefited because they were then able to offer students the advantage of a comprehensive experience that allowed them to put into practice the theory learned in the classroom, and industry benefited by expanding the pool of applicants experienced with the entire design process. In short, the TI Challenge provided a framework for exposing students to a real world design experience with the additional opportunity for award, recognition, and publication.
Design of the Transit Access Point Hardware Platform
(2005-09-01) Murphy, Patrick; Frantz, Patrick; Aazhang, Behnaam; Center for Multimedia Communications (http://cmc.rice.edu/)
Our objective is to design, analyze, prototype and experimentally study the theoretical underpinnings for a wireless internet that simultaneously achieves deployability, scalability, high performance and a cost-effective economic model. A core building block will be what we call wireless Transit Access Points. A transit access point, or TAP, is a wireless base station with two major features. First, like any standard base station, it provides wireless data services to mobile users. Second, and more importantly, a TAP is capable of high speed wireless links to other TAPs. These connections utilize multiple antennas at each end to dramatically increase the spectral efficiency and throughput of the link. Such TAP-to-TAP links are designed to supplement, or even replace, the wired network infrastructure usually required when deploying wireless data systems. This paper presents the custom hardware platform designed for the TAPs project.
Development of Digital Signal Processor controlled Quantum Cascade Laser based Trace Gas Sensor Technology
(2006-08-01) So, Stephen; Wysocki, Gerard; Frantz, Patrick; Tittel, Frank K.; Center for Multimedia Communications (http://cmc.rice.edu/); Digital Signal Processing (http://dsp.rice.edu/)
This work reports the design and integration of a custom digital signal processor (DSP) system into a pulsed quantum cascade laser (QCL) based trace gas sensor to improve its portability, robustness and operating performance. Specifically, this work describes the implementation of a custom prototype DSP data acquisition/system controller based on the Texas Instruments TMS320F2812 for embedded control and processing. In addition, the sensor incorporates oversampling by taking advantage of the high speed conversion capabilities of the analog-to-digital converter (ADC) which is embedded in the DSP. A carbon monoxide (CO) sensor employing a thermoelectrically (TE) cooled, pulsed 4.6 Âµm distributed feedback (DFB) QCL as a mid-infrared radiation source is used to evaluate the performance characteristics of such a DSP controlled spectroscopic gas sensor.
Development of Japanese-language DSP Education Content in the Connexions Project
(2005-10-01) Frantz, Patrick; Yamada, Yoji; Center for Multimedia Communications (http://cmc.rice.edu/); Digital Signal Processing (http://dsp.rice.edu/)
Due to factors such as a small and fragmented market and rapid hardware development, the conventional textbook is inadequate for DSP lab education. Freely available open-content materials that enable and promote local customization and further development by a community of educators offer a fresh approach to lab text aurthoring that can surmount these barriers. In this paper, we will explain the Connexions system that can be used to generate content for several types of DSP lab courses. In addition, we show how Connexions is well-suited to internationalization and introduce Japanese language DSP content that has been developed in the Connexions system and is free for use at any Japanese university.
DSP Education At Rice University
(2003-09-01) Frantz, Patrick; Choi, Hyeokho; Baraniuk, Richard G.; Center for Multimedia Communications (http://cmc.rice.edu/); Digital Signal Processing (http://dsp.rice.edu/)
Rice University has a decades-long tradition of both digital signal processing (DSP) research and education, beginning in 1968. Since that time, Rice University has become a world leader and continued to be a pioneer in the DSP field. This paper will focus on the following three areas of activity at Rice. First, a brief history of DSP education and research at Rice will be presented, along with the current state of DSP research and education (Section 2). Second, a DSP Lab course will be presented, which utilizes Riceâ s Texas Instruments Elite DSP Laboratory and the C6x series of DSPs to educate students in the practical art of DSP (Section 3). This course is a 1-semester long series of labs, with a larger DSP project to be completed at the end of the course. Third, a brief overview of the Connexions project will be given, a tool originally developed to advance DSP education at Rice and other institutions (Sections 4 - 8). Connexions is a collaborative, community-driven approach to authoring, teaching, and learning that seeks to provide a cohesive body of high-quality educational content to anyone in the world, for free.
A DSP-Based Platform for Wireless Video Compression
(2002-11-01) Murphy, Patrick; Bharadwaj, Vinay; Welsh, Erik; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
With the exponential growth of wireless voice markets, demand for wireless video services is soon to follow. However, bandwidth limited wireless channels coupled with mobility issues pose a great challenge in the hardware, software and algorithm design of communication systems. Raw video transmission is a high bandwidth application due to its spatial and temporal redundancies. Hence effective video communication over wireless channels calls for intelligent video coding and protection schemes. Also, the real-time nature of video necessitates high performance hardware and efficient software. This paper describes a modular and standards-independent DSP-based testbed (Paladin) designed for real-time video communication over low-bandwidth channels. In particular, we demonstrate the real-time transmission of MPEG-4 video and JPEG2000 still images over the Bluetooth wireless standard. Such a demonstration has many potential applications. We have designed the testbed to explore the possibilities, demands, and challenges of real-time wireless video transmission. We have implemented the MPEG-4 and JPEG2000 source coding on two DSP platforms: a Texas Instruments (TI) TMS320C6211, and a TI TMS3206416.
A Fast Algorithm and Testbed Evaluation for Sound Source Localization Using Sensor Networks
(2005-09-01) Johnston, Brian; Yin, Xiaoming; Valenzuela, Adrian; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/); Digital Signal Processing (http://dsp.rice.edu/)
The theoretical idea of a network composed of small, low-cost sensor nodes able to localize the source of acoustic events has the potential to make a multitude of exciting applications possible. However, this potential can only be realized if computationally tractable algorithms are employed. In this paper, we propose a novel algorithm that offers not only low computational complexity, but also high accuracy, making it an excellent choice for implementation on low-power systems. Moreover, we have developed a flexible sensor network testbed and utilized it to determine the performance of our algorithm relative to existing methods. Finally, we present the results of our experimentation using real data collected with our sensor nodes, demonstrating the effectiveness of our localization scheme, and showing that our hardware platform is well-suited to the needs of sensor network applications.
An FPGA Based Rapid Prototyping Platform for MIMO Systems
(2003-11-20) Murphy, Patrick; Lou, Feifei; Sabharwal, Ashutosh; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
There exists a seemingly limitless demand for wireless communications systems capable of higher datarates with lower power consumption. While the demand for improvement in these systems seems limitless, the spectrum allocated for providing such services is undeniably restricted. There is a great deal of research directed at solving the problem of providing more wireless communications capabilities without any increase in allocated spectrum. One significant result of this research has been the development of algorithms targeted at transmitters and receivers equipped with multiple antennas, often described as multiple-input multiple-output (MIMO) systems. We describe in this paper a FPGA-based platform designed to explore MIMO algorithms and architectures in real hardware. This system utilizes Xilinx?s System Generator for DSP, a Simulink blockset designed to allow both PC-based simulation and FPGA implementation of DSP designs. MIMO algorithms implemented in System Generator are targeted to FPGA systems connected to 2.4 GHz spread spectrum radios. These radios are interconnected via a pair of Spirent RF channel emulators and can realize a variety of transmitter and receiver configurations. The use of FPGAs as baseband processors allows a great deal of flexibility in implementing designs while maintaining the capability to measure the resource utilization and power consumption of real hardware. Such measurements play a crucial role in evaluating the suitability of algorithms for deployment in real-world systems.
An FPGA Implementation Of Alamouti's Transmit Diversity Technique
(2003-10-01) Murphy, Patrick; Frantz, Patrick; Dick, Chris; Center for Multimedia Communications (http://cmc.rice.edu/)
This paper presents the FPGA implementation of a multiple antenna wireless communications system based on Alamouti's transmit diversity scheme. Alamouti's transmit diversty scheme is a space-time block code with support for two transmit antennas and an arbitrary number of receive antennas. Our implementaiton demonstrates this space-time code in a system with two transmit and just one antenna at the receiver. In addition to implementing the encoding and decoding algorithms described in Alamouti's paper, we have designed and implemented additional subsystems necessary to establish an end-to- end link over real wireless channels. These systems, described in detail below, address the challenges of timing synchronization, carrier offset recovery and channel estimation. When combined with an implementaiton of Alamouti's code, these designs form a complete multiple antenna wireless communications sytem.
An FPGA-based Daughtercard for TIs C6000 family of DSKs
(2005-06-01) Gadhiok, Manik; Hardy, Ricky; Murphy, Patrick; Frantz, Patrick; Choi, Hyeokho; Cavallaro, Joseph R.; Digital Signal Processing (http://dsp.rice.edu/)
In this paper we present an FPGA-based daughtercard designed for TIs C6000 family of DSP Starter Kits (DSKs). The hardware, initially designed for a course project, provides a platform for studying heterogeneous systems and hardware software co-design. Students will leverage the DSK-FPGA system for rapid prototyping of signal processing algorithms and to study task-partitioning and system integration. These techniques are becoming increasingly important for system designers as we move to system-on-chip (SOC) devices. The daughtercard hardware is fully functional, and a software package is being developed to provide a seamless communication interface between the DSK and FPGA.
A FPGAÂBased Experimental PHY for 802.11b WLAN
(2003-10-20) Lou, Feifei; Murphy, Patrick; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
The swift proliferation of wireless data communication systems, and the ever-increasing demand for faster data rates requires that engineers be able to quickly design, implement and test new wireless algorithms for data communications. While simulation is useful, it is often beneficial to verify these algorithms in real hardware. This process of implementation can provide useful feedback to the algorithm designer (e.g. the hardware resources used by an algorithm). This paper provides a description of a rapid prototyping system used to design, implement, and validate an 802.11b PHY as a starting point for developing new wireless data algorithms.
GNOMES: A Testbed for Low-Power Heterogeneous Wireless Sensor Networks
(2003-05-20) Welsh, Erik; Fish, Walt; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
Continuing trends in sensor, semiconductor and communication systems technology (smaller, faster, cheaper) make feasible very dense networks of fixed and mobile wireless devices for use in many different sensing and decision-making systems. In this paper we present the design and development of GNOMES, a low-cost hardware and software testbed. This testbed was designed to explore the properties of heterogeneous wireless sensor networks, to test theory in sensor networks architecture, and be deployed in practical application environments. We also present an overview of architectures for extending the lifetime of individual nodes in the network, along with the design tradeoffs that this presents.
A Hardware Testbed for the Implementation and Evaluation of MIMO Algorithms
(2003-10-20) Murphy, Patrick; Lou, Feifei; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
As the demand for higher performance wireless communications continues to grow, novel algorithms have been developed which provide increased performance and efficiency. One such class of algorithms involves the use of multiple antennas on either end of a wireless link. Many of these multiple input, multiple output (MIMO) algorithms offer impressive performance gains over their single antenna counterparts. The practicality of implementing such algorithms in a real system, however, is a topic in need of further exploration. We present in this paper a testbed designed specifically to test such algorithms. This testbed provides hardware for baseband processing, up and downconversion to RF and emulation of multiple wireless channels. It was designed to provide sufficient exibility to implement a wide range of algorithms while preserving the ability to evaluate an algorithm's resource and power requirements. The testbed hardware and configuration options are presented, along with a basic demonstration of its functionality.
Improving Connection Times for Bluetooth Devices in Mobile Environments
(2002-03-20) Welsh, Erik; Murphy, Patrick; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
Communications devices in a highly mobile environment need to minimize connection setup times in order to maximize useful data transfer. In this paper we investigate - empirically and through simulations - the device discovery process of Bluetoothâ ¢, a technology that has potential in short-range, high-mobility applications. In order to improve Bluetooth's performance in a mobile environment, it is desirable to lessen the amount of time it takes to set up connections between two devices. We suggest three possible changes to the Bluetooth specification: eliminating or decreasing the random backoff delay in INQUIRY SCAN, using a single frequency train instead of two in INQUIRY, and a combination of the two. These simple changes can dramatically decrease connection setup times without having deleterious effects on overall system performance.
INNOVATE2005
(Rice University, 2005-09-25) Frantz, Patrick; Gulick, Debbie; Matherly, Cheryl; Lin, Stephanie
Multi-institutional educational materials for the INNOVATE 2005 conference in Singapore and Japan.
Microcontroller and Embedded Systems Laboratory
(Rice University, 2007-07-07) Frantz, Patrick; Ganier, C.J.; Welsh, Erik; valenzuela, adrian
Basic introduction to microcontroller-based embedded systems development. Includes structured laboratory exercises in the following areas: assembly programming, C language programming, peripheral interfacing, interrupt management, structured programming, task scheduling, simple digital signal processing (DSP), and other related topics. This course assumes no prerequisites and is primarily intended for first and second year engineering students.
A Mobile Testbed for GPS-Based ITS/IVC and Ad Hoc Routing Experimentation
(2002-10-01) Welsh, Erik; Murphy, Patrick; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
Past investigations into the formation of ad hoc networks and ad hoc routing have focused on computer simulations of mobile traffic. However, the proliferation of mobile electronic devices (mobile phones, PDAs, and laptop computers) combined with the commoditization of GPS chipsets has made realizable the construction of a large-scale testbed for both GPS and non-GPS aware ad hoc network applications. In this paper we present the Rice University Shuttle Bus Project (RUSH) as such a testbed in its first stages of development, in which we have outfitted the shuttle bus system at Rice University with custom wireless and GPS hardware.
Multilingual Open-Content Signal Processing Laboratories in Connexions
(2004-11-01) Frantz, Patrick; Baraniuk, Richard G.; Choi, Hyeokho; Jones, Douglas L.; Center for Multimedia Communications (http://cmc.rice.edu/); Digital Signal Processing (http://dsp.rice.edu/)
Due to inherent factors like a small and fragmented market and rapid hardware obsolescence, the conventional textbook is inadequate for DSP laboratory education. Freely available open-content materials that enable and promote both local customization and further development by a community of educators offer a fresh approach to lab text development that can surmount these barriers. In this paper, we overview a joint effort under the aegis of the Connexions Project to develop a large pool of DSP lab modules sufficient to serve as a complete, stand-alone text for several types of DSP lab courses. In addition, we introduce a pilot project whose aim is to demonstrate the suitability of using Connexions for languages other than English, such as the Japanese, Chinese and Thai languages.
Performance of IEEE 802.11b Wireless LAN in an Emulated Mobile Channel
(2003-04-20) Steger, Christopher; Radosavljevic, Predrag; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
The performance of 802.11b wireless LANs is well understood for indoor environments. However, their behavior in outdoor and mobile environments has remained largely unexplored. We have performed experiments to bridge this knowledge gap by empirically measuring the performance of an 802.11b system in a broad spectrum of emulated environments. The goal of our work is to contribute to the evolution of currently existing wireless standards by measuring the effects of different channel phenomena on 802.11b. Our results show that current implementations of the 802.11b standard may not be well suited to use in a mobile environment, but that they could conceivably be modified to have better performance in such situations.

Browsing by Author "Frantz, Patrick"

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