Now showing items 179-198 of 268

  • Parallel Nonbinary LDPC Decoding on GPU 

    Wang, Guohui; Shen, Hao; Yin, Bei; Wu, Michael; Sun, Yang; Cavallaro, Joseph R. (IEEE, 2012-12-01)
    Nonbinary Low-Density Parity-Check (LDPC) codes are a class of error-correcting codes constructed over the Galois field GF(q) for q > 2. As extensions of binary LDPC codes, nonbinary LDPC codes can provide better ...
  • Parallel Searching-Based Sphere Detector for MIMO Downlink OFDM Systems 

    Radosavljevic, Predrag; Kim, Kyeong Jin; Shen, Hao; Cavallaro, Joseph R. (IEEE, 2012-06-01)
    In this paper, implementation of a detector with parallel partial candidate-search algorithm is described. Two fully independent partial candidate search processes are simultaneously employed for two groups of transmit ...
  • Parallel VLSI Architectures for Real-Time Control of Redundant Robots 

    Walker, Ian D.; Cavallaro, Joseph R. (ANS, 1991-02-01)
    We present new architectures for the efficient computation of redundant manipulator inverse kinematics. A key component of our architecture is the calculation in VLSI hardware of the Singular Value Decomposition of the ...
  • Parallel VLSI Architectures for Real-Time Kinematics of Redundant Robots 

    Walker, Ian D.; Cavallaro, Joseph R. (IEEE Computer Society Press, 1993-05-01)
    We describe new architectures for the efficient computation of redundant manipulator kinematics (direct and inverse). By calculating the core of the problem in hardware, we can make full use of the redundancy by implementing ...
  • Parallel VLSI Architectures for Real-Time Kinematics of Redundant Robots 

    Walker, Ian D.; Cavallaro, Joseph R. (Kluwer Academic Publishers, 1994-01-01)
    We describe new architectures for the efficient computation of redundant manipulator kinematics (direct and inverse). By calculating the core of the problem in hardware, we can make full use of the redundancy by implementing ...
  • Partial Detection for Multiple Antenna Cooperation 

    Amiri, Kiarash; Cavallaro, Joseph R. (IEEE, 2009-03-01)
    Multi-antenna relays can significantly increase the speed and reliability of wireless systems. However, because of the complexity of MIMO detection, there is considerable overhead in implementing a MIMO relay if the ...
  • Partially Coherent Constellations for Multiple-Antenna Systems 

    Borran, Mohammad Jaber; Sabharwal, Ashutosh; Aazhang, Behnaam; Varshney, Prabodh (2003-11-20)
    We consider the problem of digital communication in a Rayleigh flat fading environment using a multiple antenna system. We assume that the transmitter doesnâ t know the channel coefficients, and that the receiver has only ...
  • Partially Coherent Multiple Antenna Systems: Design Criterion and Construction Methods for Constellations and Coded Modulation 

    Borran, Mohammad Jaber; Sabharwal, Ashutosh; Aazhang, Behnaam (2004-01-15)
    We consider multiple-antenna communication systems in Rayleigh fading channel, where the transmitter does not know the channel coefficients and the receiver has only an estimate of them. We further assume that the transmitter ...
  • PathChirp: Efficient Available Bandwidth Estimation for Network Paths 

    Ribeiro, Vinay Joseph; Riedi, Rudolf H.; Baraniuk, Richard G.; Navratil, Jiri; Cottrell, Les (2003-04-01)
    This paper presents <i>PathChirp</i>, a new active probing tool for estimating the available bandwidth on a communication network path. Based on the concept of "self-induced congestion," PathChirp features an exponential ...
  • Performance - Complexity Comparison of Receivers for a LTE MIMO–OFDM System 

    Ketonen, Johanna; Juntti, Markku; Cavallaro, Joseph R. (IEEE, 2010-06-01)
    Implementation of receivers for spatial multiplexing multiple-input multiple-output (MIMO) orthogonal-frequency-division-multiplexing (OFDM) systems is considered. The linear minimum mean-square error (LMMSE) and the K-best ...
  • Performance Evaluation of Two LMMSE Detectors in a MIMO-OFDM Hardware Testbed 

    Myllylä, Markus; Juntti, Markku; Limingoja, Matti; Byman, Aaron; Cavallaro, Joseph R. (IEEE, 2006-11-01)
    The performance of two field programmable gate array (FPGA) implementations of a linear minimum mean square error (LMMSE) based detector is evaluated in real-time radio channels. Two square root free algorithms based on ...
  • Physical Layer Algorithm and Hardware Verification of MIMO Relays Using Cooperative Partial Detection 

    Amiri, Kiarash; Wu, Michael; Duarte, Melissa; Cavallaro, Joseph R. (IEEE, 2010-03-01)
    Cooperative communication with multi-antenna relays can significantly increase the reliability and speed. However, cooperative MIMO detection would impose considerable complexity overhead onto the relay if a full ...
  • Power efficient broadcast scheduling with delay deadlines 

    Rajan, Dinesh; Sabharwal, Ashutosh; Aazhang, Behnaam (2004-10-01)
    In this paper, we present a framework for the design of minimal power schedulers that satisfy average packet delay bounds for multiple users in a Gaussian wireless broadcast channel. We completely characterize the achievable ...
  • Preamble-based Symbol Timing Estimation for Wireless OFDM Systems 

    Gadhiok, Manik; Cavallaro, Joseph R. (IEEE, 2007)
    We propose a timing estimation scheme that reduces computational complexity while achieving performance comparable to the autocorrelation method commonly employed at the wireless receiver. The proposed method is based ...
  • Preamble-based Symbol Timing Estimation for Wireless OFDM Systems 

    Gadhiok, Manik; Cavallaro, Joseph R. (IEEE, 2007-11-01)
    We propose a timing estimation scheme that reduces computational complexity while achieving performance comparable to the autocorrelation method commonly employed at the wireless receiver. The proposed method is based on ...
  • Probabilistically Bounded Soft Sphere Detection for MIMO-OFDM Receivers: Algorithm and System Architecture 

    Radosavljevic, Predrag; Guo, Yuanbin; Cavallaro, Joseph R. (IEEE, 2009-10-01)
    Iterative soft detection and channel decoding for MIMO OFDM downlink receivers is studied in this work. Proposed inner soft sphere detection employs a variable upper bound for number of candidates per transmit antenna and ...
  • A programmable baseband processor design for software defined radios 

    Rajagopal, Sridhar; Rixner, Scott; Cavallaro, Joseph R. (IEEE, 2002-08-20)
    Future wireless systems need extremely fast and flexible architectures to support varying standards, algorithms and protocols with data rates in the range of 10-100 Mbps. Software Defined Radios (SDRs) based on DSP-FPGAs ...
  • Protective Operating System Shell Environment for Robots 

    Cavallaro, Joseph R.; Walker, Ian D. (SPIE, 1995-10-01)
    This paper describes the synthesis of a protective operating system shell environment for robots. The approach is designed to protect the robot from the effects of errors in the lower level manipulator system and the higher ...
  • A Prototype Platform for a Multitier Network Interface Card (mNIC) 

    Frantz, Patrick (2002-09-20)
    The Center for Multimedia Communication at Rice University has developed a hardware testbed for multitier wireless environments. These types of environments incorporate many diverse wireless standards, such as 802.11 and ...