IEEE Transactions on Signal Processing 
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This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.High-Throughput and Flexible Belief Propagation List Decoder for Polar Codes
Due to its high parallelism, belief propagation (BP) decoding is amenable to high-throughput applications and thus represents a promising solution for the ultra-high peak data rate required by future communication systems. To bridge the performance gap compared to the widely used successive cancellation list (SCL) decoding algorithm, BP list (BPL) decoding for polar codes extends candidate codeword exploration via multiple permuted factor graphs (PFGs) to improve the error-correcting performance of BP decoding. However, it is a significant challenge to design a unified and flexible BPL hardware architecture that supports v...
Source: IEEE Transactions on Signal Processing - February 1, 2024 Category: Biomedical Engineering Source Type: research
Two New Algorithms for Maximum Likelihood Estimation of Sparse Covariance Matrices With Applications to Graphical Modeling
In this paper, we propose two new algorithms for maximum-likelihood estimation (MLE) of high dimensional sparse covariance matrices. Unlike most of the state-of-the-art methods, which either use regularization techniques or penalize the likelihood to impose sparsity, we solve the MLE problem based on an estimated covariance graph. More specifically, we propose a two-stage procedure: in the first stage, we determine the sparsity pattern of the target covariance matrix (in other words the marginal independence in the covariance graph under a Gaussian graphical model) using the multiple hypothesis testing method of false disc...
Source: IEEE Transactions on Signal Processing - February 1, 2024 Category: Biomedical Engineering Source Type: research
Activity Detection for Massive Connectivity in Cell-Free Networks With Unknown Large-Scale Fading, Channel Statistics, Noise Variance, and Activity Probability: A Bayesian Approach
Activity detection is an important task in the next generation grant-free multiple access. While there are a number of existing algorithms designed for this purpose, they mostly require precise information about the network, such as large-scale fading coefficients, small-scale fading channel statistics, noise variance at the access points, and user activity probability. Acquiring these information would take a significant overhead and their estimated values might not be accurate. This problem is even more severe in cell-free networks as there are many of these parameters to be acquired. Therefore, this paper sets out to in...
Source: IEEE Transactions on Signal Processing - February 1, 2024 Category: Biomedical Engineering Source Type: research
Corrections to “Semiparametric CRB and Slepian-Bangs Formulas for Complex Elliptically Symmetric Distributions”
Errors in [1] are corrected below. 1. In Eq. (17), $\mathrm{vecs}(\boldsymbol{\Sigma}_{0})$ should be $\mathrm{vec}(\boldsymbol{\Sigma}_{0})$. Specifically, the correct version of Eq. (17) is: \begin{align*} \mathbf{s}_{\boldsymbol{\phi}_{0}}\triangleq\nabla_{\boldsymbol{\phi}}\ln p_{Z}(\mathbf{z};\boldsymbol{\phi}_{0},h_{0})=[\mathbf{s}^{T}_{\boldsymbol{\mu}_{0}},\mathbf{s}^{T}_{\boldsymbol{\mu}^{*}_ {0}},\mathbf{s}^{T}_{\mathrm{vec}(\boldsymbol{\Sigma}_{0})}]^{T}.\tag{17} \end{align*} 2. In the first line after Eq. (18), $\mathbf{s}^{T}_{\mathrm{vecs}(\boldsymbol{\Sigma}_{0})}$ should be $\mathbf{s}^{T}_{\mathrm{vec}(\bo...
Source: IEEE Transactions on Signal Processing - January 31, 2024 Category: Biomedical Engineering Source Type: research
Federated Inference With Reliable Uncertainty Quantification Over Wireless Channels via Conformal Prediction
In this paper, we consider a wireless federated inference scenario in which devices and a server share a pre-trained machine learning model. The devices communicate statistical information about their local data to the server over a common wireless channel, aiming to enhance the quality of the inference decision at the server. Recent work has introduced federated conformal prediction (CP), which leverages devices-to-server communication to improve the reliability of the server's decision. With federated CP, devices communicate to the server information about the loss accrued by the shared pre-trained model on the local dat...
Source: IEEE Transactions on Signal Processing - January 29, 2024 Category: Biomedical Engineering Source Type: research
Nested Tensor-Based Integrated Sensing and Communication in RIS-Assisted THz MIMO Systems
In this paper, we propose a nested tensor-based algorithm for integrated sensing and communication (ISAC) in reconfigurable intelligent surface (RIS)-assisted downlink terahertz (THz) multiple-input multiple-output (MIMO) systems. By exploiting the multi-group Khatri-Rao space-time (KRST) coding scheme at the base station (BS) and the structure of RIS phase shifts, we formulate the received signal at the vehicle terminal (VT) as a nested tensor that is composed of multiple outer parallel factor (PARAFAC) tensors and an inner PARATUCK tensor. With the outer PARAFAC tensors, a low-complexity least squares Khatri-Rao factoriz...
Source: IEEE Transactions on Signal Processing - January 29, 2024 Category: Biomedical Engineering Source Type: research
Accelerated and Deep Expectation Maximization for One-Bit MIMO-OFDM Detection
In this study we analyze the convergence rate of EM for a class of approximate maximum-likelihood OMOD formulations, or, in a broader sense, a class of problems involving regression from quantized data. We show how the SNR and channel conditions can have an impact on the convergence rate. We do so by making a connection between the EM and the proximal gradient methods in the context of OMOD. This connection also gives us insight to build new accelerated and/or inexact EM schemes. The accelerated scheme has faster convergence in theory, and the inexact scheme provides us with the flexibility to implement EM more efficiently...
Source: IEEE Transactions on Signal Processing - January 29, 2024 Category: Biomedical Engineering Source Type: research
Signal Detection for Ultra-Massive MIMO: An Information Geometry Approach
In this paper, we propose an information geometry approach (IGA) for signal detection (SD) in ultra-massive multiple-input multiple-output (MIMO) systems. We formulate the signal detection as obtaining the marginals of the a posteriori probability distribution of the transmitted symbol vector. Then, a maximization of the a posteriori marginals (MPM) for signal detection can be performed. With the information geometry theory, we calculate the approximations of the a posteriori marginals. It is formulated as an iterative m-projection process between submanifolds with different constraints. We then apply the central-limit-the...
Source: IEEE Transactions on Signal Processing - January 29, 2024 Category: Biomedical Engineering Source Type: research
On the False Alarm Probability of the Normalized Matched Filter for Off-Grid Targets: A Geometrical Approach and Its Validity Conditions
Off-grid targets are known to induce a mismatch that dramatically impacts the detection probability of the popular Normalized Matched Filter. To overcome this problem, the unknown target parameter is usually estimated through a Maximum Likelihood strategy, resulting in a GLRT (Generalized Likelihood Ratio Test) detection scheme. While the test statistic for the null hypothesis is well known in the on-grid case, the off-grid scenario is more involved, and to the best of our knowledge, no such theoretical result is available. This paper fills this gap by proposing such an expression under circular compound Gaussian noise wit...
Source: IEEE Transactions on Signal Processing - January 25, 2024 Category: Biomedical Engineering Source Type: research
UNO: Unlimited Sampling Meets One-Bit Quantization
Recent results in one-bit sampling provide a framework for a relatively low-cost, low-power sampling, at a high rate by employing time-varying sampling threshold sequences. Another recent development in sampling theory is unlimited sampling, which is a high-resolution technique that relies on modulo ADCs to yield an unlimited dynamic range. In this paper, we leverage the appealing attributes of the two aforementioned techniques to propose a novel unlimited one-bit (UNO) sampling approach. In this framework, the information on the distance between the input signal value and the threshold is stored and utilized to accurately...
Source: IEEE Transactions on Signal Processing - January 25, 2024 Category: Biomedical Engineering Source Type: research
Mixed-ADC Based PMCW MIMO Radar Angle-Doppler Imaging
Phase-modulated continuous-wave (PMCW) multiple-input multiple-output (MIMO) radar systems are known to possess excellent mutual interference mitigation capabilities, but require costly and power-hungry high sampling rate and high-precision analog-to-digital converters (ADC's). To reduce cost and power consumption, we consider a mixed-ADC architecture, in which most receive antenna outputs are sampled by one-bit ADC's, and only one or a few outputs by high-precision ADC's. We first derive the Cramér-Rao bound (CRB) for the mixed-ADC based PMCW MIMO radar to characterize the best achievable performance of an unbiased targe...
Source: IEEE Transactions on Signal Processing - January 25, 2024 Category: Biomedical Engineering Source Type: research
Massive Synchrony in Distributed Antenna Systems
Distributed antennas must be phase-calibrated (phase-synchronized) for certain operations, such as reciprocity-based joint coherent downlink beamforming, to work. We use rigorous signal processing tools to analyze the accuracy of calibration protocols that are based on over-the-air measurements between antennas, with a focus on scalability aspects for large systems. We show that (i) for some who-measures-on-whom topologies, the errors in the calibration process are unbounded when the network grows; and (ii) despite that conclusion, it is optimal – irrespective of the topology – to solve a single calibration problem for...
Source: IEEE Transactions on Signal Processing - January 25, 2024 Category: Biomedical Engineering Source Type: research
Information Flow Rate for Cross-Correlated Stochastic Processes
Causal inference seeks to identify cause-and-effect interactions in coupled systems. A recently proposed method by Liang detects causal relations by quantifying the direction and magnitude of information flow between time series. The theoretical formulation of information flow for stochastic dynamical systems provides a general expression and a data-driven statistic for the rate of entropy transfer between different system units. To advance understanding of information flow rate in terms of intuitive concepts and physically meaningful parameters, we investigate statistical properties of the data-driven information flow rat...
Source: IEEE Transactions on Signal Processing - January 25, 2024 Category: Biomedical Engineering Source Type: research
Fast Computation of Zero-Forcing Precoding for Massive MIMO-OFDM Systems
As a simple and popular transmission scheme, zero-forcing (ZF) precoding can effectively reap the great benefits of a multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) wireless system. But as the wireless technology evolves to massive MIMO-OFDM, even the ZF precoding may incur too cumbersome computational complexity. In this paper, we first derive the ZF precoder in the time domain. By exploiting the block-Toeplitzness of the time-domain channel matrix, we propose a novel approximate solution to the original time-domain ZF precoding problem for fast computation. We then provide an approx...
Source: IEEE Transactions on Signal Processing - January 22, 2024 Category: Biomedical Engineering Source Type: research
Joint Detection and Delay-Doppler Estimation Algorithms for MIMO Radars
In this paper, we consider the joint detection and localization (in the delay-Doppler domain) of targets by using Multiple-Input Multiple-Output radars. Specifically, inspired by the fact that most of existing contributions do not encompass target energy spillover between adjacent matched filter samples, we firstly analyze all the energy configurations associated with the target position within the delay-Doppler cell under test. Then, at the design stage, we formulate the detection problem by considering all data samples that might contain target components. The resulting problem is solved by applying the generalized likel...
Source: IEEE Transactions on Signal Processing - January 22, 2024 Category: Biomedical Engineering Source Type: research
