6 research outputs found
Improved convergence performance of adaptive algorithms through logarithmic cost
We present a novel family of adaptive filtering algorithms based on a relative logarithmic cost. The new family intrinsically combines the higher and lower order measures of the error into a single continuous update based on the error amount. We introduce the least mean logarithmic square (LMLS) algorithm that achieves comparable convergence performance with the least mean fourth (LMF) algorithm and overcomes the stability issues of the LMF algorithm. In addition, we introduce the least logarithmic absolute difference (LLAD) algorithm. The LLAD and least mean square (LMS) algorithms demonstrate similar convergence performance in impulse-free noise environments while the LLAD algorithm is robust against impulsive interference and outperforms the sign algorithm (SA). © 2014 IEEE
Enabling Ultra Reliable Wireless Communications for Factory Automation with Distributed MIMO
Factory automation is one of the most challenging use cases for 5G-and-beyond
mobile networks due to strict latency, availability and reliability
constraints. In this work, an indoor factory scenario is considered, and
distributed multiple-input multiple-output (MIMO) schemes are investigated in
order to enable reliable communication to the actuators (ACs) active in the
factory. Different levels of coordination among the access points serving the
ACs and several beamforming schemes are considered and analyzed. To enforce
system reliability, a max-min power allocation (MPA) algorithm is proposed,
aimed at improving the signal to interference plus noise ratio (SINR) of the
ACs with the worst channel conditions. Extensive system simulations are
performed in a realistic scenario, which includes a new path-loss model based
on recent measurements in factory scenarios, and, also, the presence of
non-Gaussian impulsive noise. Numerical results show that distributed MIMO
schemes with zero-forcing (ZF) beamforming and MPA have the potential of
providing SINR gains in the order of tens of dB with respect to a centralized
MIMO deployment, as well as that the impulsive noise can strongly degrade the
system performance and thus requires specific detection and mitigation
techniques.Comment: Accepted at the IEEE Vehicular Technology Conference (VTC-Fall),
Honolulu (HI), Sep. 201
A Novel Family of Adaptive Filtering Algorithms Based on The Logarithmic Cost
We introduce a novel family of adaptive filtering algorithms based on a
relative logarithmic cost. The new family intrinsically combines the higher and
lower order measures of the error into a single continuous update based on the
error amount. We introduce important members of this family of algorithms such
as the least mean logarithmic square (LMLS) and least logarithmic absolute
difference (LLAD) algorithms that improve the convergence performance of the
conventional algorithms. However, our approach and analysis are generic such
that they cover other well-known cost functions as described in the paper. The
LMLS algorithm achieves comparable convergence performance with the least mean
fourth (LMF) algorithm and extends the stability bound on the step size. The
LLAD and least mean square (LMS) algorithms demonstrate similar convergence
performance in impulse-free noise environments while the LLAD algorithm is
robust against impulsive interferences and outperforms the sign algorithm (SA).
We analyze the transient, steady state and tracking performance of the
introduced algorithms and demonstrate the match of the theoretical analyzes and
simulation results. We show the extended stability bound of the LMLS algorithm
and analyze the robustness of the LLAD algorithm against impulsive
interferences. Finally, we demonstrate the performance of our algorithms in
different scenarios through numerical examples.Comment: Submitted to IEEE Transactions on Signal Processin
Robust adaptive algorithms for underwater acoustic channel estimation and their performance analysis
We introduce a novel family of adaptive robust channel estimators for highly challenging underwater acoustic (UWA) channels. Since the underwater environment is highly non-stationary and subjected to impulsive noise, we use adaptive filtering techniques based on minimization of a logarithmic cost function, which results in a better trade-off between the convergence rate and the steady state performance of the algorithm. To improve the convergence performance of the conventional first and second order linear estimation methods while mitigating the stability issues related to impulsive noise, we intrinsically combine different norms of the error in the cost function using a logarithmic term. Hence, we achieve a comparable convergence rate to the faster algorithms, while significantly enhancing the stability against impulsive noise in such an adverse communication medium. Furthermore, we provide a thorough analysis for the tracking and steady-state performances of our proposed methods in the presence of impulsive noise. In our analysis, we not only consider the impulsive noise, but also take into account the frequency and phase offsets commonly experienced in real life experiments. We demonstrate the performance of our algorithms through highly realistic experiments performed on accurately simulated underwater acoustic channels. © 2017 Elsevier Inc