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Photoplethysmographic signals are synthesized using a Fourier representation with a fundamental and 2 harmonic components, and an accurate method for parameter estimation using this synthesis model is discussed. The estimated parameters enable to determine physiologically meaningful features related to arterial stiffness, heart rate variability, blood pressure variations, etc. The method allows signal...
A model for Photoplethysmographic signal description through a Fourier representation with a fundamental and 2 harmonic components is discussed. Accurate method for parameter estimation using the model is also presented. The estimated parameters enable to determine physiologically meaningful features that can be related to heart rate variability, blood pressure variations, etc. Proposed method allows...
Computationally efficient methods for accurate, bias free DOA estimation from a source signal impinging on a sparse array are presented. In particular, the presence of I/Q mismatch and D.C. offsets are discussed. Since the methods meet Cramer-Rao bounds and able to cope array imperfections such as nonuniform gains, element failure, they are useful in short sparse array implementations with simplified...
Photoplethysmographic signals contain physiologically meaningful features that can be related to heart rate variability, blood pressure variations, etc. This paper presents a description for the photoplethysmographic signal through the use of Empirical mode decomposition. This description allows the signal feature extraction to be simplified via traditional signal processing methods such as spectral...
Efficient iterative frequency estimation method using the Discrete Fourier Transform (DFT) for estimating a sequence of frequencies is presented. The estimated frequencies are used for symbol detection in a raised cosine Continuous Phase Modulation (CPM) receiver. Performance of the method has been analyzed and evaluated through simulations. It is shown that the proposed method is advantageous as...
This paper presents a robust design of the transmit beampattern for uniform linear antenna arrays. Existing designs are usually completed at the stage of achieving an optimal transmit covariance matrix from identifying a weighting matrix with the assumption of ideally orthogonal waveforms. However, we propose a compensation technique to achieve the optimal covariance matrix without the requirement...
Frequency Modulated (FM) signals are encountered in many natural and human-made applications in earth, oceanic and atmospheric environments. In this paper, the limitations and optimality of existing FM signal characterization methods, in particular at low signal to noise ratios are investigated. For proper characterization, the selection of a time-frequency representation through spectrally smoothed...
A Discrete Fourier transform (DFT) based method for estimating a sequence of frequencies is presented. The method is computationally efficient and also meets the Cramer-Rao bound. The method is then used for symbol detection in a Continuous Phase Modulation receiver. The performance of detection has been analyzed and simulation results are provided for comparison against other existing algorithms...
We present a comparison on direction-of-arrival (DOA) parameter identifiability between multiple-input multiple-output (MIMO) and phased-array radar, which could be considered as additional work to the literature of comparison between these two systems. Conventional and advanced transmission strategies are considered, i.e., transmission without and with beampattern synthesis, respectively. At the...
The design of the transmit beampattern of a radar system aims to focus the energy of the transmitted signals to the desired spatial section(s) in order to enhance the direction of arrival (DOA) estimation at the receiver. In this paper, we consider this problem for both multiple-input-multiple-output (MIMO) and phased-array radar from the perspective of finite impulse response (FIR) filter design...
In this paper, we propose a novel adaptive soft input soft output (SISO) demodulator that addresses the problem of joint data detection and channel estimation for serially concatenated continuous phase modulation (SCCPM) operating in a time-varying frequency-flat fading channel. Due to its ability of incorporating prior symbol probabilities and its soft output decisions, the proposed SISO demodulator...
Traditionally used time-frequency distributions such as the STFT and the WVD are not suitable for FM signal characterization at low SNRs. A new method is proposed using the cross quadratic spectrum (XQS) which provides accurate temporal characterization for both signal's instantaneous frequency and the instantaneous-frequency-rate.
This paper proposes a novel singular-value decomposition based algorithm that can be used in source localization and time synchronization using the time of arrival and/or the time difference of arrival measurements. The algorithm performance has been investigated in an autonomous underwater vehicle operating environment. Through extensive simulations the superiority of the algorithm has been demonstrated...
This paper addresses the problem of joint data detection and channel estimation on continuous phase modulation (CPM) operating under a frequency-flat time-varying Rayleigh fading channel. The proposed framework comprises of two parts working in a joint manner: a symbol by symbol MAP CPM receiver and a channel tracking scheme. We first illustrate the robustness of MSK over modulation schemes without...
Multiple-input-multiple-output (MIMO) radar transmit beamforming mainly relies on designing transmitted signals with an appropriate covariance matrix. The signals can be designed using a two-step method which first optimizes the covariance matrix and then searches for the signals accordingly. A more efficient way is to synthesize transmitted signals by designing a weight matrix given a set of orthogonal...
Novel instantaneous frequency estimation based symbol detection is proposed for implementing Continuous Phase Modulation receivers. The method is simple as only two symbol periods are used. An efficient instantaneous frequency estimation algorithm that could be used in the implementation is also proposed. The performance of the method has been analyzed and simulation results are provided for comparison...
In this paper, we propose a novel block construction using tail sequence to enable the use of space time block codes (STBC) on continuous phase modulation (CPM). Due to the requirement of phase continuity and the associated inherent memory of CPM, the combination of STBC with CPM is not as straightforward as linear modulation schemes. In the proposed method, to ensure the phase continuity, a tail...
A novel filter design method has been proposed for implementing linear Continuous Phase Modulation receivers. The design is based on the observation of all possible waveform tracks at the receiver. A piece-wise approximation is subsequently used to obtain a triangular filter which can be efficiently implemented in hardware. The resulting filters have shown excellent bit error rate performances in...
In this paper, a novel receiver for joint data detection and channel tracking on continuous phase modulation (CPM) operating under a frequency-flat time-varying Rayleigh fading channel is proposed. Due to the inherent memory of CPM, channel tracking on CPM is not as straightforward as on PSK and FSK, and therefore we first derive a phase estimation based CPM scheme to facilitate the phase tracking...
This paper proposes and investigates a discrete Fourier transform based receiver for continuous phase modulation. The architecture is robust and thus can be used even if the channel exhibits Doppler spreading. e.g. due to fading and relative motion as in an wideband underwater communication channel. The proposed receiver performance is compared with other widely used receivers such as the Viterbi...
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