Browsing by Author "Sadeghi, Mohammad"

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    Master ThesisPublicationMetadata only
    Adaptive OFDM-based acoustic underwater transmission: system design and experimental verification
    (2017-08) Sadeghi, Mohammad; Uysal, Murat; Durak, Kadir; Uysal, Murat; Baykaş, T.; Department of Electrical and Electronics Engineering; Sadeghi, Mohammad
    In this study, we design and implement an adaptive Underwater Acoustic (UWA) orthogonal frequency division multiplexing (OFDM) system employing adaptive modulation and transmit power. Recently, UWA communications gain more attractions as there has been a growing interest in exploring the communications possibilities for underwater applications such as oil field monitoring, oceanographic data collection, maritime archaeology and disaster prevention. However, the harsh characteristic of underwater environments imposes various difficulties for communication in this medium. Thus, proposing a reliable UWA communication system which has a high data rate can improve these applications performance significantly. Since UWA communications suffer from low data rates, we propose an adaptive OFDM communication system to support higher data rates over UWA channel. OFDM is an attractive technique for underwater channels due to the fact that inter-symbol-interference resulted from frequency selective channels can be removed completely. Additionally, adaptive communications achieve significant improvements in transmission data rate. For the sake of implementation, we take advantages of LabVIEW software to generate OFDM blocks. The generated data is transmitted to the receiver side with the aid of Software defined radios (USRPs) and acoustic front-ends. The received data at the acoustic hydrophones are transferred to the USRPs and then processed in LabVIEW for information detection. We conduct our experiments at the pool to investigate the performance of the proposed system over a real UWA channel.
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    Conference ObjectPublicationOpen Access
    Adaptive OFDM-based acoustic underwater transmission: system design and experimental verification
    (IEEE, 2017) Sadeghi, Mohammad; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; UYSAL, Murat; Sadeghi, Mohammad; Elamassie, Mohammed
    In this paper, we present the design and implementation of a software defined orthogonal frequency division multiplexing (OFDM)-based underwater acoustic (UWA) communication system with link adaptation. Our system implementation is based on the customized versions of National Instruments Universal Software Radio Peripheral (USRP). The modified USRPs are interfaced with hydrophone front-ends for acoustic transmission. We investigate the performance of various adaptive algorithms where both modulation order/type and power on each subcarrier are selected based on channel conditions in order to maximize throughput. The experimental in-pool test results verify the superiority of adaptive transmission.