1 code implementation • 18 Oct 2022 • Jane H. Lee, Saeid Haghighatshoar, Amin Karbasi
their weights, and (2) we propose a novel training algorithm, called \emph{forward propagation} (FP), that computes exact gradients for SNN.
1 code implementation • 20 May 2022 • Felix Christian Bauer, Gregor Lenz, Saeid Haghighatshoar, Sadique Sheik
In this paper, (i) we modify SLAYER and design an algorithm called EXODUS, that accounts for the neuron reset mechanism and applies the Implicit Function Theorem (IFT) to calculate the correct gradients (equivalent to those computed by BPTT), (ii) we eliminate the need for ad-hoc scaling of gradients, thus, reducing the training complexity tremendously, (iii) we demonstrate, via computer simulations, that EXODUS is numerically stable and achieves a comparable or better performance than SLAYER especially in various tasks with SNNs that rely on temporal features.
no code implementations • 30 Oct 2019 • Yi Song, Mahdi Barzegar Khalilsarai, Saeid Haghighatshoar, Giuseppe Caire
The modern literature on massive MIMO has recognized that the knowledge of covariance matrix of user channel vectors is very useful for various applications such as hybrid digital analog beamforming, pilot decontamination, etc.
no code implementations • 31 Oct 2018 • Saeid Haghighatshoar, Giuseppe Caire
Although there is a vast literature on the analysis of MMV, it is not yet fully known how the number of signal samples and their statistical correlations affects the performance of the joint estimation in MMV.
no code implementations • 11 Jan 2018 • Saeid Haghighatshoar, Mahdi Barzegar Khalilsarai, Giuseppe Caire
In this paper, we show that although this effect is generally negligible for a small number of antennas $M$, it results in a considerable distortion of the covariance matrix and especially its dominant signal subspace in the massive MIMO regime where $M \to \infty$, and can generally incur a serious degradation of the performance especially in frequency division duplexing (FDD) massive MIMO systems where the uplink (UL) and the downlink (DL) communication occur over different frequency bands.
no code implementations • 9 May 2017 • Mahdi Barzegar Khalilsarai, Saeid Haghighatshoar, Giuseppe Caire, Gerhard Wunder
To design such a blind predictor, we use the random spectral representation of a stationary Gaussian process.
no code implementations • 30 Jan 2017 • Saeid Haghighatshoar, Giuseppe Caire
In this paper, we study the recovery of a signal from a set of noisy linear projections (measurements), when such projections are unlabeled, that is, the correspondence between the measurements and the set of projection vectors (i. e., the rows of the measurement matrix) is not known a priori.
no code implementations • 24 Sep 2015 • Saeid Haghighatshoar, Giuseppe Caire
Massive MIMO is a variant of multiuser MIMO where the number of base-station antennas $M$ is very large (typically 100), and generally much larger than the number of spatially multiplexed data streams (typically 10).
no code implementations • 11 Jan 2014 • Saeid Haghighatshoar
It is observed that by spatially coupling the measurement matrices, the rate-distortion curve of MAMP algorithm undergoes a phase transition, where the measurement rate region corresponding to a low distortion (approximately zero distortion) regime is fully characterized by the joint and conditional Renyi information dimension (RID) of the multi-terminal source.
no code implementations • 7 Oct 2013 • Robin Scheibler, Saeid Haghighatshoar, Martin Vetterli
A new iterative low complexity algorithm has been presented for computing the Walsh-Hadamard transform (WHT) of an $N$ dimensional signal with a $K$-sparse WHT, where $N$ is a power of two and $K = O(N^\alpha)$, scales sub-linearly in $N$ for some $0 < \alpha < 1$.