Browsing by Author "Welsh, Erik"

Now showing 1 - 7 of 7
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    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.
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    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.
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    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.
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    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.
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    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.
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    Using Bluetooth for Short-Term Ad-Hoc Connections Between Moving Vehicles: A Feasibility Study
    (2002-05-01) Murphy, Patrick; Welsh, Erik; Frantz, Patrick; Center for Multimedia Communications (http://cmc.rice.edu/)
    Bluetoothâ ¢ is a promising wireless technology designed for short-range ad-hoc connections, and it has many potentially useful applications. One such use is the transfer of data between two fast-moving vehicles such as automobiles. In this paper we explore the suitability of Bluetooth to make connections in highly mobile environments. In particular, we have developed a hardware testbed to make an empirical analysis of the time it takes to establish Bluetooth connections and the impact this will have on any potential data transfer. We also propose changes in the Bluetooth standard that may offer faster connection setup times.
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    VALID: Custom ASIC Verification and FPGA Education Platform
    (2003-06-01) Murphy, Patrick; Welsh, Erik; Frantz, Patrick; Hardy, Ricky; Mohsenin, Tinoosh; Cavallaro, Joseph R.; Center for Multimedia Communications (http://cmc.rice.edu/)
    This paper describes VALID, a platform for testing student designed ASICs and for teaching the basics of FPGA design. VALID is designed to maximize ease of use from a student?s perspective while maintaining enough flexibility for its use as an FPGA development and instruction platform. This system was designed entirely by students, has been successfully manufactured and is currently being used in a number of courses at Rice.