Browsing by Author "Magistretti, Eugenio"

Now showing 1 - 3 of 3
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    Coordination and Interference in 802.11 Networks: Inference, Analysis and Mitigation
    (2013-09-16) Magistretti, Eugenio; Knightly, Edward W.; Gurewitz, Omer; Johnson, David B.; Sabharwal, Ashutosh
    In the last decade, 802.11 wireless devices data-rates have increased by three orders of magnitude, while communications experiencing low throughput are still largely present. Such throughput loss is a fundamental problem of wireless networking that is difficult to diagnose and amend. My research addresses two key causes of throughput loss: MAC layer protocol overhead and destructive link interference. First, I design WiFi-Nano reducing the channel access overhead by an order of magnitude leveraging an innovative speculative technique to transmit preambles. This new concept is based on simultaneous preamble transmission and detection via a self-interference cancellation design, and paves the way to the realization of the collision detection paradigm in wireless networks. Next, I propose 802.11ec (Encoded Control), the first 802.11-based protocol that eliminates the overhead of control packets. Instead, 802.11ec coordinates node transmissions via a set of predefined pseudo-noise codewords, resulting in the dramatic increase of throughput and communication robustness. Finally, I design MIDAS, a model-driven network management tool that alleviates low throughput wireless links identifying key corrective actions. MIDAS' key contribution is to reveal the fundamental role of node transmission coordination in characterizing destructive interference. I implement WiFi-Nano, 802.11ec, and MIDAS using a combination of WARP FPGA-based radio boards, custom emulation platforms, and network simulators. The results obtained show that WiFi-Nano increases the network throughput by up to 100%, 802.11ec improves network access fairness by up to 90%, and MIDAS identifies corrective actions with a prediction error as low as 20%.
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    Method and system for reducing sounding overhead in wireless communication
    (2018-08-14) Bejarano, Oscar; Quadri, Sadia; Knightly, Edward W.; Gurewitz, Omer; Magistretti, Eugenio; Rice University; United States Patent and Trademark Office
    A method for transmitting packets. The method includes making a first determination, using a first relevant sample set for a first client device, that the first client device does not need to be sounded and making a second determination, using a second relevant sample set for the second client device, that a second client device needs to be sounded. The method further includes, based on the first and second determination, performing a sounding operation for the second client device to obtain channel state information for the second client device and after performing the sounding operation for the second client device: wirelessly transmitting at least one packet to the first client device using historical channel state information for the first client device, and wirelessly transmitting at least one packet to the second client device using the channel state information.
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    Method and system for wirelessly transmitting data
    (2015-02-17) Magistretti, Eugenio; Gurewitz, Omer; Knightly, Edward W.; Rice University; United States Patent and Trademark Office
    A method for transmitting data from a sender to a receiver over a channel. The method includes identifying the receiver, obtaining an initiation correlated symbol sequence (CSS) associated with the receiver, transmitting the initiation CSS, where the sender and the receiver are configured to communicate over the channel, where the channel is a frequency band in a radio-frequency spectrum. The method further includes receiving a first reservation CSS from the receiver signaling that the receiver has reserved the channel in order to receive the data from the sender. In response to receiving the first reservation CSS, transmitting the data to the receiver, and receiving an acknowledgment CSS from the receiver signaling that the receiver has received the data from the sender.