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In this paper, we investigate various channel estimators that exploit channel sparsity in the time and/or Doppler domain for a multicarrier underwater acoustic system. We use a path-based channel model, where the channel is described by a limited number of paths, each characterized by a delay, Doppler scale, and attenuation factor, and derive the exact… (More)
—Compressive sensing is a topic that has recently gained much attention in the applied mathematics and signal processing communities. It has been applied in various areas, such as imaging, radar, speech recognition, and data acquisition. In communications, compressive sensing is largely accepted for sparse channel estimation and its variants. In this paper… (More)
Passive radar is a concept where illuminators of opportunity are used in a multistatic radar setup. New digital signals, like digital audio/video broadcast (DAB/DVB), are excellent candidates for this scheme, as they are widely available, can be easily decoded to acquire the noise-free signal, and employ orthogonal frequency division multiplex (OFDM).… (More)
In decentralized detection, local sensor observations have to be communicated to a fusion center through the wireless medium, inherently a multiple-access channel (MAC). As communication is bandwidth- and energy-constrained, it has been suggested to use the properties of the MAC to combine the sensor observations directly on the channel. Although this leads… (More)
—Recently it has been shown that sparse channel estimation , implemented with orthogonal matching pursuit (OMP) and basis pursuit (BP) algorithms, has impressive performance gains over alternatives that do not take advantage of the channel sparsity, for underwater acoustic (UWA) communications. We in this paper compare the performance and complexity of… (More)
— Precise positioning is one attractive application of ultra wideband (UWB) systems. Its enormous bandwidth has generated high expectation on the spatial resolution that it could achieve. However, synchronization in the presence of dense multipath is challenging, since the first arrival is not necessarily the strongest one due to channel fading. It is… (More)
We select the optimum design parameters for real-time optical OFDM transceivers running at 25 Gb/s and analyze power consumption and ASIC footprint for a variety of configurations based on synthesis for a 65nm standard-cell library. Experiments quantify the effects of modulation format and the number of IFFT/FFT points used in transceivers.
We study the effects of clipping and quantization noise due to limited resolution of D/A and A/D converters on the performance of an optical OFDM system. To this end we derive a closed-form formula that links optimum clipping with the bit resolution of signal converters.
—In this paper, we propose a novel method for detection, synchronization and Doppler scale estimation for underwater acoustic communication using orthogonal frequency division multiplex (OFDM) waveforms. This new method involves transmitting two identical OFDM symbols together with a cyclic prefix, while the receiver uses a bank of parallel… (More)
Multicarrier modulation in the form of orthogonal-frequency-division-multiplexing (OFDM) has been intensively pursued for underwater acoustic (UWA) communications recently due to its ability to handle long dispersive channels. Fast variation of UWA channels destroys the orthogonality of the sub-carriers and leads to inter-carrier interference (ICI), which… (More)