Browsing by Author "Shepard, Clayton"

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    Argos: Practical Base Stations for Large-scale Beamforming
    (2012-09-05) Shepard, Clayton; Zhong, Lin; Knightly, Edward W.; Sabharwal, Ashutosh
    MU-MIMO theory predicts manyfold capacity gains by leveraging many antennas (e.g. M >> 10) on wireless base stations to serve many users simultaneously through multi-user beamforming (MUBF). However, realizing such a large-scale design is nontrivial, and has yet to be achieved in the real world. We present the design, realization, and evaluation of Argos, the first reported large-scale base station that is capable of serving many (e.g., 10s of) terminals simultaneously through MUBF. Designed with extreme flexibility and scalability in mind, Argos exploits hierarchical and modular design principles, properly partitions baseband processing, and holistically considers real-time requirements of MUBF. To achieve unprecedented scalability, we devise a novel, completely distributed, beamforming technique, as well as an internal calibration procedure to enable implicit beamforming across large arrays. We implement a prototype with 64 antennas, and demonstrate that it can achieve up to 6.7 fold capacity gains while using a mere 1/64th the transmission power.
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    Heterogeneous network access on devices with one or more network interfaces
    (2014-11-04) Nicoara, Angela; Rahmati, Ahmad; Shepard, Clayton; Zhong, Lin; Singh, Jatinder Pal; Deutsche Telekom AG; Rice University; United States Patent and Trademark Office
    A method for managing TCP flows in a mobile device adapted to connect to two or more wireless network types includes enabling connection to a number of networks of different types at the mobile device and executing a plurality of Internet-enabled applications on the mobile device. Each such application forms an existing TCP connection over a first one of the wireless networks. The routing table is modified such that any additional TCP connection will be created on a second one of the wireless networks. The device determines that a termination condition has occurred and in response to determining that the termination condition has occurred, renders an interface on the mobile device to the first one of the wireless networks inoperative.
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    Seeing Using Sound
    (Rice University, 2005-12-15) Shepard, Clayton; Hall, Richard; Flatow, Jared
    Elec 301 Project - Fall 2005. Seeing using Sound transforms images in to sound to aid blind people.