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 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 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)
—In this paper we design, implement, and experimentally evaluate a wireless software-defined radio platform for cognitive channelization in the presence of narrowband or wideband primary stations. Cognitive channelization is achieved by jointly optimizing the transmission power and the waveform channel of the secondary users. The process of joint resource(More)
We present the first complete software-based framework for real-time experimental evaluation of secondary multi-hop cognitive underlay networks with decentralized control. We build a $7$-node software-defined radio testbed and implement a distributed algorithm that maximizes the secondary network throughput, while at the same time avoids interference to(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)