George Sklivanitis

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This article describes the design of a custom software-defined modem with adaptive physical layer for underwater acoustic (UWA) communications. The modem consists of a commercial software-defined radio (SDR) interfaced with a wideband acoustic transducer through amplifying circuitry. With this custom-built platform, we focus on the unique physical layer(More)
—Existing commercial wireless systems are mostly hardware-based, and rely on closed and inflexible designs and architectures. Moreover, despite recent significant algorithmic developments in cross-layer network adaptation and resource allocation , existing network architectures are unable to incorporate most of these advancements. While software-defined(More)
M odern digital communications, informatics, and electronics increasingly blend together in our daily lives. Cell phones, for example, have evolved into powerful, handheld computers with smart human-computer interfaces, broadband wireless connectiv-ity, and a multitude of sensors (cameras, capacitive touch-screens, accelerometers, GPS receivers, and so on).(More)
—We create new software signal processing blocks and provide transmitter and receiver designs in GNU Radio and MATLAB to experimentally demonstrate the theoretical concepts of all-spectrum cognitive channelization in a software-defined-radio (SDR)-based testbed. Three low-cost, SDR nodes (USRPN-210) are deployed in an indoor, multipath-fading, lab(More)
We present the setup of a complete software-defined radio (SDR) testbed for non-coherent zero-feedback distributed beamforming. Three custom-built, embedded RF transceivers along with a commodity, low-cost SDR commercial receiver are deployed in an indoors lab environment. In sharp contrast with prior art on collaborative beamforming, the proposed scheme(More)
—We propose a receiver configuration and we develop a software-defined-radio testbed for real-time cognitive underwater multiple-access communications. The proposed receiver is fully reconfigurable and executes (i) all-spectrum cognitive channelization and (ii) combined synchronization, channel estimation , and demodulation. Online (real-time) experimental(More)
We implement and real-time demonstrate for the first time ROCH; a distributed cognitive algorithm that maximizes secondary network throughput, while at the same time avoids interference to primary users through joint Routing and cOde-waveform CHannelization. ROCH performance is evaluated on a $7$-node software-defined radio testbed using the open-source(More)