Browsing by Subject "Receiver structure"

Now showing 1 - 3 of 3

Open Access
Blind phase noise estimation in OFDM systems by sequential Monte Carlo method
(Springer, 2006) Panayırcı, Erdal; Çırpan, H. A.; Moeneclaey, M.; Noels, N.
In this paper, based on a sequential Monte Carlo method, a computationally efficient algorithm is presented for estimating the residual phase noise, blindly, generated at the output the phase tracking loop employed in OFDM systems. The basic idea is to treat the transmitted symbols as "missing data" and draw samples sequentially of them based on the observed signal samples up to time t. This way, the Bayesian estimates of the phase noise is obtained through these samples, sequentially drawn, together with their importance weights. The proposed receiver structure is seen to be ideally suited for high-speed parallel implementation using VLSI technology.
Open Access
Multiple-resampling receiver design for OFDM over Doppler-distorted underwater acoustic channels
(2013) Tu, K.; Duman, T. M.; Stojanovic, M.; Proakis J. G.
In this paper, we focus on orthogonal frequency-division multiplexing (OFDM) receiver designs for underwater acoustic (UWA) channels with user-and/or path-specific Doppler scaling distortions. The scenario is motivated by the cooperative communications framework, where distributed transmitter/receiver pairs may experience significantly different Doppler distortions, as well as by the single-user scenarios, where distinct Doppler scaling factors may exist among different propagation paths. The conventional approach of front-end resampling that corrects for common Doppler scaling may not be appropriate in such scenarios, rendering a post-fast-Fourier-transform (FFT) signal that is contaminated by user-and/or path-specific intercarrier interference. To counteract this problem, we propose a family of front-end receiver structures that utilize multiple-resampling (MR) branches, each matched to the Doppler scaling factor of a particular user and/or path. Following resampling, FFT modules transform the Doppler-compensated signals into the frequency domain for further processing through linear or nonlinear detection schemes. As part of the overall receiver structure, a gradient-descent approach is also proposed to refine the channel estimates obtained by standard sparse channel estimators. The effectiveness and robustness of the proposed receivers are demonstrated via simulations, as well as emulations based on real data collected during the 2010 Mobile Acoustic Communications Experiment (MACE10, Martha's Vineyard, MA) and the 2008 Kauai Acomms MURI (KAM08, Kauai, HI) experiment.
Open Access
A new signaling scheme for Underwater Acoustic communications
(IEEE, 2013) Elmoslimany, A.; Zhou, M.; Duman, Tolga M.; Papandreou-Suppappola, A.
Underwater Acoustic (UWA) communications has attracted a lot of interest in recent years motivated by a wide range of applications. Different signaling solutions have been developed to date including non-coherent communications, phase coherent systems, multi-input multi-output (MIMO) solutions and multi-carrier based approaches. In this paper, we develop a novel UWA communications paradigm using biomimetic signals. In our scheme, digital information is mapped to the parameters of a class of biomimetic signal set and at the receiver an estimator to obtain the parameter values is utilized. To facilitate this, we develop analytical signal models with nonlinear instantaneous frequencies matching mammalian sound signatures in the time-frequency plane. We provide suitable receiver structures, and present decoding results using data recorded during the Kauai Acomms MURI 2011 (KAM11) UWA communications experiment. © 2013 MTS.